POWER MANAGEMENT IN SINGLE CIRCUIT HVAC SYSTEMS AND IN MULTIPLE CIRCUIT HVAC SYSTEMS
A thermostat includes a plurality of HVAC (heating, ventilation, and air conditioning) wire connectors for receiving a plurality of HVAC control wires corresponding to an HVAC system. The thermostat also includes a thermostat processing and control circuit operative to at least partially control the operation of the HVAC system and a powering circuit coupled to the HVAC wire connectors and configured to provide an electrical load power to the thermostat processing and control circuit. The thermostat includes circuitry and methods for maximizing efficiency of energy harvested from the HVAC system connected to the thermostat, and depending on which system is connected to the thermostat, different power schemes can be implemented in order to obtain power from the HVAC system.
This patent application is a continuation-in-part of each of the following commonly-assigned applications: U.S. patent application Ser. No. 13/467,025 (Attorney Docket No. NES0177-US), filed May 8, 2012; PCT Application No. PCT/US12/00007 (Attorney Docket No. NES0190-PCT), filed Jan. 3, 2012; U.S. patent application Ser. No. 13/267,877 (Attorney Docket No. NES0100-US), filed Oct. 6, 2011; U.S. patent application Ser. No. 13/034,674 (Attorney Docket No. NES0006-US), filed Feb. 24, 2011; and U.S. patent application Ser. No. 13/034,678 (Attorney Docket No. NES0007-US), filed Feb. 24, 2011. Each of U.S. patent application Ser. Nos. 13/267,877, 13/034,674, and 13/034,678, supra, claims the benefit of each of U.S. Provisional Patent Application No. 61/415,771 (Attorney Docket No. NES037-PROV), filed Nov. 19, 2010, and 61/429,093 (Attorney Docket No. NES037A-PROV), filed Dec. 31, 2010. Each of U.S. patent application Ser. No. 13/467,025 and PCT Application No. PCT/US12/00007, supra, claims the benefit of U.S. Provisional Patent Application No. 61/627,996 (Attorney Docket No. NES0101-PROV), filed Oct. 21, 2011.
Each of the above-referenced patent applications is incorporated herein by reference in its entirety for all purposes.
TECHNICAL FIELDThis patent specification relates to systems and methods for the monitoring and control of energy-consuming systems or other resource-consuming systems. More particularly, this patent specification relates to control units that govern the operation of energy-consuming systems, household devices, or other resource-consuming systems, including systems and methods for providing electrical power for thermostats that govern the operation of heating, ventilation, and air conditioning (HVAC) systems.
BACKGROUNDSubstantial effort has been put forth on the development of new and more sustainable energy supplies, as well as efforts to increase energy efficiency of existing energy consumption systems. An example of an energy consumption system is the heating and cooling system of an enclosure such as a home or building. According to a report from the United States Department of Energy, heating and cooling can account for 56% of the energy use in a typical home, making it a significant energy expense. Heating and cooling systems can realize greater efficiency by improving physical aspects of the system (e.g., higher efficiency furnace) and enclosure (e.g., more or better insulation). Substantial increases in energy efficiency can also be achieved through enhanced thermostat control of the heating and cooling system.
Thermostats of all types have been used to control heating and cooling systems. For example, older generation thermostats were strictly mechanical devices that used a bimetallic strip to sense temperature, and controlled an HVAC system based on the sensed temperature. The mechanical thermostats required neither electronics nor power to operate, because the strip itself would activate or deactivate circuitry within the HVAC system. This changed, however, when thermostats evolved to include electronics. Electronic thermostats, though requiring a power source in order to operate, offered more advanced HVAC control as compared to their mechanical counterparts. For example, an electronic thermostat can be programmed to have multiple temperature set points in a given day. As another example, advanced microprocessor controlled “intelligent” thermostats may have further enhanced HVAC system control capabilities. These thermostats may also be capable of connecting to computer networks, including both local area networks (or other “private” networks) and wide area networks such as the Internet (or other “public” networks), in order to obtain current and forecasted outside weather data, cooperate in so-called demand-response programs (e.g., automatic conformance with power alerts that may be issued by utility companies during periods of extreme weather), enable users to have remote access and/or control thereof through their network-connected device (e.g., smartphone, tablet computer, PC-based web browser), and other advanced functionalities that may require network connectivity.
Increases in functionality for electronic thermostats are often accompanied by increased demands for power. Accordingly, what are needed are electronic thermostats that can maximize its own power consumption efficiency depending on the HVAC system it is controlling.
SUMMARYThis patent specification relates to systems and methods for the monitoring and control of energy-consuming systems or other resource-consuming systems. More particularly, this patent specification relates to control units that govern the operation of energy-consuming systems, household devices, or other resource-consuming systems, including systems and methods for providing electrical power for thermostats that govern the operation of heating, ventilation, and air conditioning (HVAC) systems. Even more particularly, this patent specification relates to circuitry and methods for maximizing efficiency of energy harvested from the HVAC system connected to the thermostat. HVAC systems exist in all types of different configurations, and depending on which system is connected to the thermostat, different power schemes can be implemented in order to obtain power from the HVAC system.
Each HVAC system can fall into one of three general HVAC wiring schemes. These schemes include a single circuit system having no common wire, a multiple circuit system having no common wire, and a common wire system. A single circuit system with no common wire includes wiring configurations in which only one call relay wire (e.g., W, Y, G, O/B, or AUX) and its associated return relay power wire (e.g., Rh or Rc) are connected to the thermostat, and no “C” power wire (e.g., common wire) is connected to the thermostat. The “single” designation implies that only one call can be made by the thermostat for this particular HVAC wiring scheme. A multiple circuit system with no common wire includes wiring configurations in which at least two different call relay wires (e.g., W, Y, G, O/B, or AUX) are connected to the thermostat, but no “C” power wire is connected to the thermostat. The “multiple” designation implies that at least two different calls can be made by the thermostat. A common wire system includes a wiring configuration in which a “C” common power wire and any combination of call relay wires and relay power wires are connected to the thermostat.
Depending on which HVAC wiring scheme is connected to the thermostat, a power scheme specifically curtailed to that wiring scheme can be implemented. The power schemes can use different methods for drawing power from the HVAC system. These methods include active power stealing, inactive power stealing, and drawing dedicated “C” power. As used herein, “active power stealing” refers to the power stealing that is performed during periods in which there is an active call in place based on the lead from which power is being stolen. As used herein, “inactive power stealing” refers to the power stealing that is performed during periods in which there is no active call in place based on the lead from which power is being stolen. Drawing dedicated “C” power does not constitute “power stealing” per se because there is no power being “stolen” from a wire that leads to an HVAC call relay coil (or to the electronic equivalent of an HVAC call relay coil for some newer HVAC systems). For the case in which the “C” wire is present, there is no need to worry about accidentally tripping (for inactive power stealing) or untripping (for active power stealing) an HVAC call relay, and therefore relatively large amounts of power can be assumed to be available to be drawn from the HVAC system.
Inactive power stealing is generally more power efficient for extracting power from the HVAC system than active power stealing. Accordingly, various embodiments discussed herein provide circuits and techniques for utilizing this power efficiency advantage when no C wire is connected to the thermostat. In one embodiment, a thermostat can include a plurality of HVAC wire connectors operative to receive a plurality of HVAC wires corresponding to an HVAC system, control circuitry operative to at least partially control the operation of the HVAC system, and power wire selection circuitry connected to the HVAC wire connectors and to the control circuitry. The power wire selection circuitry can be operative to select which wire connector is electrically coupled to a power node. The thermostat can also include powering circuitry operative to receive power from the power wire selection circuitry via the power node and receive control signals from the control circuitry. The control circuitry can be further operative to determine an HVAC wiring scheme based on which wire connectors have received HVAC wires, cause the powering circuitry to operate according to a selected one of a plurality of power schemes based on the determined HVAC wiring scheme, and instruct the power wire selection circuitry to selectively couple a predetermined one of the wire connectors to the power node based on the determined HVAC wiring scheme and the selected power scheme.
In another embodiment, a method for controlling an HVAC system can be implemented in a thermostat. The method can determine which one of a plurality of different HVAC wiring schemes is connected to the thermostat, the plurality of different HVAC wiring schemes including a single circuit system having no common wire, a multiple circuit system having no common wire, and a common wire system. The method can further implement a power scheme based on the determined HVAC wiring scheme. If the determined HVAC wiring scheme is the single circuit system, the implemented power scheme uses active and inactive power stealing on the single circuit system. If the determined HVAC wiring scheme is the multiple circuit system, the implemented power scheme only uses inactive power stealing on a non-enabled circuit within the multiple circuit system. If the determined HVAC wiring scheme is the common wire system, the implemented power scheme uses neither active power stealing nor inactive power stealing.
In another embodiment, a thermostat can include a plurality of wiring connectors operative to connect to a plurality of HVAC wires and insertion sensing circuitry operative to provide insertion sensing signals indicative of which wiring connectors have an HVAC wire connected thereto. The thermostat can also include power wire selection circuitry, which can include an output node, a control node, and at least two input nodes. Each input node can be electrically coupled to a different one of at least two wiring connectors, and the power wire selection circuitry can be operative to selectively couple any input node to the output node based on a signal received at the control node. A microcontroller can be included with the thermostat and can be operative to receive the insertion sensing signals and process HVAC call signals, the HVAC call signals including at least two different types of calls. The microcontroller can be further operative to determine an HVAC wiring scheme based on the received insertion sensing signals, implement a power scheme based on the determined HVAC wiring scheme, and provide a selection signal to the control node based on the determined HVAC wiring scheme, the HVAC call signal, and the implemented power scheme.
In yet another embodiment, a thermostat for use in connection with a HVAC system is provided. The HVAC system can be a single circuit system, a multiple circuit system, or a common wire system. The thermostat can include insertion sensing circuitry operative to provide insertion sensing signals indicative of which HVAC system is connected to the thermostat and control circuitry. The control circuitry can be operative to receive the insertion sensing signals and engage in single circuit power stealing, multi-circuit power stealing, or common wire power utilization for obtaining power from the HVAC system based on the received insertion sensing signals.
A further understanding of the nature and advantages of the embodiments discussed herein may be realized by reference to the remaining portions of the specification and the drawings.
In the following detailed description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of the various embodiments of the present invention. Those of ordinary skill in the art will realize that these various embodiments of the present invention are illustrative only and are not intended to be limiting in any way. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure.
In addition, for clarity purposes, not all of the routine features of the embodiments described herein are shown or described. One of ordinary skill in the art would readily appreciate that in the development of any such actual embodiment, numerous embodiment-specific decisions may be required to achieve specific design objectives. These design objectives will vary from one embodiment to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming but would nevertheless be a routine engineering undertaking for those of ordinary skill in the art having the benefit of this disclosure.
It is to be appreciated that while one or more embodiments are described further herein in the context of typical HVAC systems used in a residential home, such as single-family residential home, the scope of the present teachings is not so limited. More generally, thermostats according to one or more of the preferred embodiments are applicable for a wide variety of enclosures having one or more HVAC systems including, without limitation, duplexes, townhomes, multi-unit apartment buildings, hotels, retail stores, office buildings and industrial buildings. Further, it is to be appreciated that while the terms user, customer, installer, homeowner, occupant, guest, tenant, landlord, repair person, and the like may be used to refer to the person or persons who are interacting with the thermostat or other device or user interface in the context of one or more scenarios described herein, these references are by no means to be considered as limiting the scope of the present teachings with respect to the person or persons who are performing such actions.
Provided according to one or more embodiments are systems, methods, computer program products, and related business methods for controlling one or more HVAC systems based on one or more versatile sensing and control units (VSCU units), each VSCU unit being configured and adapted to provide sophisticated, customized, energy-saving HVAC control functionality while at the same time being visually appealing, non-intimidating, elegant to behold, and delightfully easy to use. The term “thermostat” is used hereinbelow to represent a particular type of VSCU unit (Versatile Sensing and Control) that is particularly applicable for HVAC control in an enclosure. Although “thermostat” and “VSCU unit” may be seen as generally interchangeable for the contexts of HVAC control of an enclosure, it is within the scope of the present teachings for each of the embodiments hereinabove and hereinbelow to be applied to VSCU units having control functionality over measurable characteristics other than temperature (e.g., pressure, flow rate, height, position, velocity, acceleration, capacity, power, loudness, brightness) for any of a variety of different control systems involving the governance of one or more measurable characteristics of one or more physical systems, and/or the governance of other energy or resource consuming systems such as water usage systems, air usage systems, systems involving the usage of other natural resources, and systems involving the usage of various other forms of energy.
Some embodiments of thermostat 110 in
As used herein, a “learning” thermostat refers to a thermostat, or one of plural communicating thermostats in a multi-thermostat network, having an ability to automatically establish and/or modify at least one future setpoint in a heating and/or cooling schedule based on at least one automatically sensed event and/or at least one past or current user input.
As used herein, a “primary” thermostat refers to a thermostat that is electrically connected to actuate all or part of an HVAC system, such as by virtue of electrical connection to HVAC control wires (e.g. W, G, Y, etc.) leading to the HVAC system.
As used herein, an “auxiliary” thermostat refers to a thermostat that is not electrically connected to actuate an HVAC system, but that otherwise contains at least one sensor and influences or facilitates primary thermostat control of an HVAC system by virtue of data communications with the primary thermostat.
In one particularly useful scenario, the thermostat 110 is a primary learning thermostat and is wall-mounted and connected to all of the HVAC control wires, while the remote thermostat 112 is an auxiliary learning thermostat positioned on a nightstand or dresser, the auxiliary learning thermostat being similar in appearance and user-interface features as the primary learning thermostat, the auxiliary learning thermostat further having similar sensing capabilities (e.g., temperature, humidity, motion, ambient light, proximity) as the primary learning thermostat, but the auxiliary learning thermostat not being connected to any of the HVAC wires. Although it is not connected to any HVAC wires, the auxiliary learning thermostat wirelessly communicates with and cooperates with the primary learning thermostat for improved control of the HVAC system, such as by providing additional temperature data at its respective location in the enclosure, providing additional occupancy information, providing an additional user interface for the user, and so forth.
It is to be appreciated that while certain embodiments are particularly advantageous where the thermostat 110 is a primary learning thermostat and the remote thermostat 112 is an auxiliary learning thermostat, the scope of the present teachings is not so limited. Thus, for example, while certain initial provisioning methods that automatically pair associate a network-connected thermostat with an online user account are particularly advantageous where the thermostat is a primary learning thermostat, the methods are more generally applicable to scenarios involving primary non-learning thermostats, auxiliary learning thermostats, auxiliary non-learning thermostats, or other types of network-connected thermostats and/or network-connected sensors. By way of further example, while certain graphical user interfaces for remote control of a thermostat may be particularly advantageous where the thermostat is a primary learning thermostat, the methods are more generally applicable to scenarios involving primary non-learning thermostats, auxiliary learning thermostats, auxiliary non-learning thermostats, or other types of network-connected thermostats and/or network-connected sensors. By way of even further example, while certain methods for cooperative, battery-conserving information polling of a thermostat by a remote cloud-based management server may be particularly advantageous where the thermostat is a primary learning thermostat, the methods are more generally applicable to scenarios involving primary non-learning thermostats, auxiliary learning thermostats, auxiliary non-learning thermostats, or other types of network-connected thermostats and/or network-connected sensors.
Enclosure 100 further includes a private network accessible both wirelessly and through wired connections and may also be referred to as a Local Area Network or LAN. Network devices on the private network include a computer 124, thermostat 110 and remote thermostat 112 in accordance with some embodiments of the present invention. In one embodiment, the private network is implemented using an integrated router 122 that provides routing, wireless access point functionality, firewall and multiple wired connection ports for connecting to various wired network devices, such as computer 124. Each device is assigned a private network address from the integrated router 122 either dynamically through a service like Dynamic Host Configuration Protocol (DHCP) or statically through actions of a network administrator. These private network addresses may be used to allow the devices to communicate with each directly over the LAN. Other embodiments may instead use multiple discrete switches, routers and other devices (not shown) to perform more other networking functions in addition to functions as provided by integrated router 122.
Integrated router 122 further provides network devices access to a public network, such as the Internet, provided enclosure 100 has a connection to the public network generally through a cable-modem, DSL modem and an Internet service provider or provider of other public network service. Public networks like the Internet are sometimes referred to as a Wide-Area Network or WAN. In the case of the Internet, a public address is assigned to a specific device allowing the device to be addressed directly by other devices on the Internet. Because these public addresses on the Internet are in limited supply, devices and computers on the private network often use a router device, like integrated router 122, to share a single public address through entries in Network Address Translation (NAT) table. The router makes an entry in the NAT table for each communication channel opened between a device on the private network and a device, server, or service on the Internet. A packet sent from a device on the private network initially has a “source” address containing the private network address of the sending device and a “destination” address corresponding to the public network address of the server or service on the Internet. As packets pass from within the private network through the router, the router replaces the “source” address with the public network address of the router and a “source port” that references the entry in the NAT table. The server on the Internet receiving the packet uses the “source” address and “source port” to send packets back to the router on the private network which in turn forwards the packets to the proper device on the private network doing a corresponding lookup on an entry in the NAT table.
Entries in the NAT table allow both the computer device 124 and the thermostat 110 to establish individual communication channels with a thermostat management system (not shown) located on a public network such as the Internet. In accordance with some embodiments, a thermostat management account on the thermostat management system enables a computer device 124 in enclosure 100 to remotely access thermostat 110. The thermostat management system passes information from the computer device 124 over the Internet and back to thermostat 110 provided the thermostat management account is associated with or paired with thermostat 110. Accordingly, data collected by thermostat 110 also passes from the private network associated with enclosure 100 through integrated router 122 and to the thermostat management system over the public network. Other computer devices not in enclosure 100 such as Smartphones, laptops and tablet computers (not shown in
In some embodiments, thermostat 110 may wirelessly communicate with remote thermostat 112 over the private network or through an ad hoc network formed directly with remote thermostat 112. During communication with remote thermostat 112, thermostat 110 may gather information remotely from the user and from the environment detectable by the remote thermostat 112. For example, remote thermostat 112 may wirelessly communicate with the thermostat 110 providing user input from the remote location of remote thermostat 112 or may be used to display information to a user, or both. Like thermostat 110, embodiments of remote thermostat 112 may also include sensors to gather data related to occupancy, temperature, light and other environmental conditions. In an alternate embodiment, remote thermostat 112 may also be located outside of the enclosure 100.
In heating, heating coils or elements 242 within air handler 240 provide a source of heat using electricity or gas via line 236. Cool air is drawn from the enclosure via return air duct 246 through filter 270, using fan 238 and is heated through heating coils or elements 242. The heated air flows back into the enclosure at one or more locations via supply air duct system 252 and supply air registers such as register 250. In cooling, an outside compressor 230 passes a gas such as Freon through a set of heat exchanger coils 244 to cool the gas. The gas then goes through line 232 to the cooling coils 234 in the air handler 240 where it expands, cools and cools the air being circulated via fan 238. A humidifier 254 may optionally be included in various embodiments that returns moisture to the air before it passes through duct system 252. Although not shown in
Referring to
For some embodiments, the backplate processor 316 is a very low-power device that, while having some computational capabilities, is substantially less powerful than the head unit processor 314. The backplate processor 316 is coupled to, and responsible for polling on a regular basis, most or all of the sensors 322 including the temperature and humidity sensors, motion sensors, ambient light sensors, and proximity sensors. For sensors 322 that may not be located on the backplate hardware itself but rather are located in the head unit, ribbon cables or other electrical connections between the head unit and backplate are provided for this purpose. Notably, there may be other sensors (not shown) for which the head unit processor 314 is responsible, with one example being a ring rotation sensor that senses the user rotation of an outer ring of the thermostat. Each of the head unit processor 314 and backplate processor 316 is capable of entering into a “sleep” state, and then “waking up” to perform various tasks.
The backplate processor 316, which in some embodiments will have a low-power sleep state that corresponds simply to a lower clock speed, generally enters into and out of its sleep mode substantially more often than does the more powerful head unit processor 314. The backplate processor 316 is capable of waking up the head unit processor 314 from its sleep state. For one preferred embodiment directed to optimal battery conservation, the head unit processor 314 is allowed to sleep when its operations are not being called for, while the backplate processor 316 performs polling of the sensors 322 on an ongoing basis, maintaining the sensor results in memory 317. The backplate processor 316 will wake up the head unit processor 314 in the event that (i) the sensor data indicates that an HVAC operation may be called for, such as if the current temperature goes below a currently active heating setpoint, or (ii) the memory 317 gets full and the sensor data needs to be transferred up to the head unit processor 314 for storage in the memory 315. The sensor data can then be pushed up to the cloud server (thermostat management server) during a subsequent active communication session between the cloud server and the head unit processor 314.
In the case of Wi-Fi module 312, one embodiment may be implemented using Murata Wireless Solutions LBWA19XSLZ module, which is based on the Texas Instruments WL1270 chipset supporting the 802.11 b/g/n WLAN standard. Embodiments of the present invention configure and program Wi-Fi module 312 to allow thermostat 308 to enter into a low power or “sleep” mode to conserve energy until one or several events occurs. For example, in some embodiments the Wi-Fi module 312 may leave this low power mode when a user physically operates thermostat 308, which in turn may also cause activation of both head-unit processor 314 and backplate processor 316 for controlling functions in head-unit and backplate portions of thermostat 110.
It is also possible for Wi-Fi module 312 to wake from a low power mode at regular intervals in response to a beacon from wireless access point 372. To conserve energy, Wi-Fi module 312 may briefly leave the low power mode to acknowledge the beacon as dictated by the appropriate wireless standard and then return to a low power mode without activating the processors or other components of thermostat 308 in
In yet another embodiment, Wi-Fi module 312 may selectively filter an incoming data packet to determine if the header is merely an acknowledgement packet (i.e., a keep-alive packet) or contains a payload that needs further processing. If the packet contains only a header and no payload, the Wi-Fi module 312 may be configured to either ignore the packet or send a return acknowledgement to the thermostat management system or other source of the packet received.
In further embodiments, Wi-Fi module 312 may be used to establish multiple communication channels between thermostat 112 and a cloud-based management server as will be described and illustrated later in this disclosure. As previously described, thermostat 112 uses multiple communication channels to receive different types of data classified with different levels of priority. In one embodiment, Wi-Fi module 312 may be programmed to use one or more filters and a wake-on-LAN feature to then selectively ignore or discard data arriving over one or more of these communication channels. For example, low-priority data arriving over a port on Wi-Fi module 312 may be discarded by disabling the corresponding wake-on-LAN feature associated with the port. This allows the communication channel to continue to operate yet conserves battery power by discarding or ignoring the low-priority packets.
Operation of the microprocessors 314, 316, Wi-Fi module 312, and other electronics may be powered by a rechargeable battery (not shown) located within the thermostat 110. In some embodiments, the battery is recharged directly using 24 VAC power off a “C” wire drawn from the HVAC system or an AC-DC transformer coupled directly into the thermostat 110. Alternatively, one or more different types of energy harvesting may also be used to recharge the internal battery if these direct methods are not available as described, for example, in U.S. Ser. No. 13/034,678, supra, and U.S. Ser. No. 13/267,871, supra. Embodiments of the present invention communicate and operate the thermostat 110 in a manner that promotes efficient use of the battery while also keeping the thermostat operating at a high level of performance and responsiveness controlling the HVAC system. Some embodiments may use the battery-level charge and the priority or relative importance of a communication to determine when a thermostat management system located on a public network such as the Internet may communicate with the thermostat 110. Further details on the communication methods and system used in accordance with these embodiments are described in detail later herein.
Turning now to power harvesting methods and systems,
The HVAC functions are controlled by the HVAC control general purpose input/outputs (GPIOs) 322 within microcontroller (MCU) 320. MCU 320 is a general purpose microcontroller such as the MSP430 16-bit ultra-low power MCU available from Texas Instruments. MCU 320 communicates with the head unit via Head Unit Interface 340. The head unit together with the backplate make up the thermostat. The head unit has user interface capability such that it can display information to a user via an LCD display and receive input from a user via buttons and/or touch screen input devices. According to some embodiments, the head unit has network capabilities for communication to other devices either locally or over the internet. Through such network capability, for example, the thermostat can send information and receive commands and setting from a computer located elsewhere inside or outside of the enclosure. The MCU detects whether the head unit is attached to the backplate via head unit detect 338.
Clock 342 provides a low frequency clock signal to MCU 320, for example 32.768 kHz. According to some embodiments there are two crystal oscillators, one for high frequency such as 16 MHz and one for the lower frequency. Power for MCU 320 is supplied at power input 344 at 3.0 V. Circuitry 336 provides wiring detection, battery measurement, and buck input measurement. A temperature sensor 330 is provided, and according to some embodiments and a humidity sensor 332 are provided. According to some embodiments, one or more other sensors 334 are provided such as: pressure, proximity (e.g. using infrared), ambient light, and pyroelectric infrared (PIR).
Power circuitry 350 is provided to supply power. According to some embodiments, when the thermostat is first turned on with insufficient battery power, a bootstrap power system is provided. A high voltage low dropout voltage regulator (LDO) 380 provides 3.0 volts of power for the bootstrap of the MCU 320. The bootstrap function can be disabled under MCU control but according to some embodiments the bootstrap function is left enabled to provide a “safety net” if the head unit supply vanishes for any reason. For example, if the head-unit includes the re-chargeable battery 384 and is removed unexpectedly, the power would be lost and the bootstrap function would operate. The input to this Bootstrap LDO 380 is provided by connectors and circuitry 368 that automatically selects power from common 362 (highest priority), cool 366 (lower priority); or heat (lowest priority) 364.
In normal operation, a 3.0 volt primary LDO 382 powers the backplate circuitry and itself is powered by VCC Main. According to some embodiments, high voltage buck 360 is provided as a second supply in the backplate. The input to this supply is the circuitry 368. According to some embodiments, the high voltage buck 380 can supply a maximum of 100 mA at 4.5v. According to some embodiments, the VCC main and the Primary LDO 382 can be powered by a rechargeable battery (shown in
Rectified input 624 is input to the high voltage buck circuit 610, according to some embodiments. In buck circuit 610, which corresponds to high voltage buck 360 in
In order to control the HVAC functions, the HVAC function wire is shorted to the return or power wire. For example, in the case of heating, the W wire is shorted to the Rh (or R or Rc depending on the configuration). In the case of cooling the Y wire is shorted to the Rc (or R or Rh depending on the configuration). By shorting these two wires, the 24 VAC transformer is placed in series with a relay that controls the HVAC function. However, for power harvesting, a problem is that when these wires are shorted, there is no voltage across them, and when open, there is no current flow. Since power equals voltage multiplied by current, if either quantity is zero the power that can be extracted is zero. According to some embodiments, the power harvesting circuitry allows power to be taken from the two wires in both the states of HVAC—the HVAC “on” and the HVAC “off”.
In the HVAC “off” state, some energy can be harvested from these two wires by taking less energy than would cause the of the relay to turn on, which would cause the HVAC function to erroneously turn on. Based on testing, it has been found that HVAC functions generally do not turn on when (0.040 A*4.5V)=0.180 watts is extracted at the output. So after the input diodes, capacitors, and switching regulator, this allows us to take 40 mA at 4.5 volts from these wires without turning on the HVAC system.
In the HVAC “on” state, the two wires must be connected together to allow current to flow, which turns on the HVAC relay. This, however, shorts out the input supply, so our system does not get any power when the HVAC “on” switch is closed. To get around this problem, the voltage is monitored on the capacitors 612, 614 and 616 at the input switching power supply node 620. When the voltage on these capacitors “Cin” drops close to the point at which the switching power supply would “Drop out” and lose output regulation, for example at about +8 Volts, the HVAC “on” switch is turned off and Cin is charged. During the time that Cin is charging, current is still flowing in the HVAC relay, so the HVAC relay stays on. When the Cin capacitor voltages increases some amount, for example about +16 Volts, the HVAC “on” switch is closed again, Cin begins to discharge while it feeds the switching regulator, and current continues to flow in the HVAC relay. Note that Cin is not allowed to discharge back to the HVAC “on” switch due to input diodes 632. When the voltage on Cin drops to about +8 Volts the HVAC “on” switch is turned off and the process repeats. This continues until the system tells the HVAC “on” switch to go off because HVAC is no longer needed. According to some embodiments, the ability of the HVAC “on” switch to turn on and off relatively quickly is provided by circuitry 450 as shown in and described with respect to
According to some embodiments, one or more alternative power harvesting techniques are used. For example, rather than having the HVAC “on” switch turn on when the voltage on Cin reaches a certain point, it the system might turn off the “HVAC “on” switch for a predetermined period of time instead. According to some embodiments, power harvesting is enhanced by synchronizing the power harvesting with the AC current waveform.
According to some embodiments, charger 673 is a USB power manager and li-ion battery charger such as the LTC4085-3 from Linear Technology. Backplate voltage 671 is input to charger 673. The circuitry 672 is used to select the charging current. In particular the value of resistor 674 (24.9 k) in parallel with resistor 634 (16.9 k) in combination with the inputs Double Current 638 and High Power 628 are used to select the charging current. If High Power 628 and Double Current 638 are both set to 0, then the charging current is 8.0 mA; if the High Power 628 is set to 0 and Double Current 638 is set to 1, then the charging current is 19.9 mA; if the High Power 628 is set to 1 and Double Current 638 is set to 0, then the charging current is 40.1 mA; and if the High Power 628 and Double Current 638 are both set to 1, then the charging current is 99.3 mA. Resistor 636 is used to set the default charge current. In the case shown, a 220 k resistor set the default charge current to 227 mA. According to some embodiments, a charge temperature range of 0-44 degrees C. is set via the Thermistor Monitoring Circuits.
According to some embodiments, the thermostat is capable of being powered by a USB power supply. This could be supplied by a user, for example, by attaching the thermostat via a USB cable to a computer or another USB power supply. In cases where USB power supply is available, it is selected as the preferred power source for the thermostat and can be used to recharge the rechargeable battery. According to some embodiments, a charge current of about 227 mA is used when a USB supply source is available; a charge current of about 100 mA is used when an HVAC common wire is present; and a charge current of between about 20-40 mA is used when power is harvested from an HVAC heating and/or cooling circuit.
For the initial installation process, the customer (or their handyman, or an HVAC professional, etc.) first installs the HVAC-coupling wall dock 702, including all of the necessary mechanical connections to the wall and HVAC wiring connections to the HVAC wiring 298. Once the HVAC-coupling wall dock 702 is installed, which represents the “hard work” of the installation process, the next task is relatively easy, which is simply to slide the VSCU unit 700 thereover to mate the electrical connectors 704/705. Preferably, the components are configured such that the HVAC-connecting wall dock 702 is entirely hidden underneath and inside the VSCU unit 700, such that only the visually appealing VSCU unit 700 is visible.
For one embodiment, the HVAC-connecting wall dock 702 is a relatively “bare bones” device having the sole essential function of facilitating electrical connectivity between the HVAC wiring 298 and the VSCU unit 700. For another embodiment, the HVAC-coupling wall dock 702 is equipped to perform and/or facilitate, in either a duplicative sense and/or a primary sense without limitation, one or more of the functionalities attributed to the VSCU unit 700 in the instant disclosure, using a set of electrical, mechanical, and/or electromechanical components 706. One particularly useful functionality is for the components 706 to include power-extraction circuitry for judiciously extracting usable power from the HVAC wiring 298, at least one of which will be carrying a 24-volt AC signals in accordance with common HVAC wiring practice. The power-extraction circuitry converts the 24-volt AC signal into DC power (such as at 5 VDC, 3.3 VDC, etc.) that is usable by the processing circuitry and display components of the main unit 701.
The division and/or duplication of functionality between the VSCU unit 700 and the HVAC-coupling wall dock 702 can be provided in many different ways without departing from the scope of the present teachings. For another embodiment, the components 706 of the HVAC-coupling wall dock 702 can include one or more sensing devices, such as an acoustic sensor, for complementing the sensors provided on the sensor ring 104 of the VSCU unit 700. For another embodiment, the components 706 can include wireless communication circuitry compatible with one or more wireless communication protocols, such as the Wi-Fi and/or ZigBee protocols. For another embodiment, the components 706 can include external AC or DC power connectors. For another embodiment, the components 706 can include wired data communications jacks, such as an RJ45 Ethernet jack, an RJ11 telephone jack, or a USB connector.
The docking capability of the VSCU unit 700 according to the embodiment of
Provided in accordance with one or more embodiments related to the docking capability shown in
As used herein, the term “primary VSCU unit” refers to one that is electrically connected to actuate an HVAC system in whole or in part, which would necessarily include the first VSCU unit purchased for any home, while the term “auxiliary VSCU unit” refers to one or more additional VSCU units not electrically connected to actuate an HVAC system in whole or in part. An auxiliary VSCU unit, when docked, will automatically detect the primary VSCU unit and will automatically be detected by the primary VSCU unit, such as by Wi-Fi or ZigBee wireless communication. Although the primary VSCU unit will remain the sole provider of electrical actuation signals to the HVAC system, the two VSCU units will otherwise cooperate in unison for improved control heating and cooling control functionality, such improvement being enabled by virtue of the added multi-sensing functionality provided by the auxiliary VSCU unit, as well as by virtue of the additional processing power provided to accommodate more powerful and precise control algorithms. Because the auxiliary VSCU unit can accept user control inputs just like the primary VSCU unit, user convenience is also enhanced. Thus, for example, where the tabletop docking station and the auxiliary VSCU unit are placed on a nightstand next to the user's bed, the user is not required to get up and walk to the location of the primary VSCU unit if they wish to manipulate the temperature set point, view their energy usage, or otherwise interact with the system.
A variety of different VSCU-compatible docking stations are within the scope of the present teachings. For example, in another embodiment there is provided an auxiliary wall dock (not shown) that allows an auxiliary VSCU unit to be mounted on a wall. The auxiliary wall dock is similar in functionality to the tabletop docking station in that it does not provide HVAC wiring connections, but does serve as a physical mounting point and provides electrical power derived from a standard wall outlet.
For one embodiment, all VSCU units sold by the manufacturer are identical in their core functionality, each being able to serve as either a primary VSCU unit or auxiliary VSCU unit as the case requires, although the different VSCU units may have different colors, ornamental designs, memory capacities, and so forth. For this embodiment, the user is advantageously able, if they desire, to interchange the positions of their VSCU units by simple removal of each one from its existing docking station and placement into a different docking station. Among other advantages, there is an environmentally, technically, and commercially appealing ability for the customer to upgrade to the newest, latest VSCU designs and technologies without the need to throw away the existing VSCU unit. For example, a customer with a single VSCU unit (which is necessarily serving as a primary VSCU unit) may be getting tired of its color or its TFT display, and may be attracted to a newly released VSCU unit with a different color and a sleek new OLED display. For this case, in addition to buying the newly released VSCU, the customer can buy a tabletop docking station to put on their nightstand. The customer can then insert their new VSCU unit into the existing HVAC-coupling wall dock, and then take their old VSCU unit and insert it into the tabletop docking station. Advantageously, in addition to avoiding the wastefulness of discarding the old VSCU unit, there is now a new auxiliary VSCU unit at the bedside that not only provides increased comfort and convenience, but that also promotes increased energy efficiency by virtue of the additional multi-sensor information and processing power provided.
For other embodiments, different VSCU units sold by the manufacturer can have different functionalities in terms of their ability to serve as primary versus auxiliary VSCU units. This may be advantageous from a pricing perspective, since the hardware cost of an auxiliary-only VSCU unit may be substantially less than that of a dual-capability primary/auxiliary VSCU unit. In other embodiments there is provided distinct docking station capability for primary versus auxiliary VSCU units, with primary VSCU units using one kind of docking connection system and auxiliary VSCU units using a different kind of docking connection system. In still other embodiments there is provided the docking station capability of
In still other embodiments, all VSCU units are provided as non-docking types, but are interchangeable in their abilities as primary and auxiliary VSCU units. In still other embodiments, all VSCU units are provided as non-docking types and are non-interchangeable in their primary versus auxiliary abilities, that is, there is a first set of VSCU units that can only serve as primary VSCU units and a second set of VSCU units that can only serve as auxiliary VSCU units. For embodiments in which primary VSCU units are provided as non-docking types, their physical architecture may still be separable into two components for the purpose of streamlining the installation process, with one component being similar to the HVAC-coupling wall dock 702 of
The HVAC-coupling wall dock 702′ is configured and designed in conjunction with the VSCU unit 700, including both hardware aspects and programming aspects, to provide a DIY installation process that is simple, non-intimidating, and perhaps even fun for many DIY installers, and that further provides an appreciable degree of foolproofing capability for protecting the HVAC system from damage and for ensuring that the correct signals are going to the correct equipment. For one embodiment, the HVAC-coupling wall dock 702′ is equipped with a small mechanical detection switch (not shown) for each distinct input port, such that the insertion of a wire (and, of course, the non-insertion of a wire) is automatically detected and a corresponding indication signal is provided to the VSCU 100 upon initial docking. In this way, the VSCU 100 has knowledge for each individual input port whether a wire has, or has not been, inserted into that port. Preferably, the VSCU unit 700 is also provided with electrical sensors (e.g., voltmeter, ammeter, and ohmmeter) corresponding to each of the input wiring ports 851. The VSCU 100 is thereby enabled, by suitable programming, to perform some fundamental “sanity checks” at initial installation. By way of example, if there is no input wire at either the Rc or Rh terminal, or if there is no AC voltage sensed at either of these terminals, further initialization activity can be immediately halted, and the user notified on the circular display monitor 102, because there is either no power at all or the user has inserted the Rc and/or Rh wires into the wrong terminal. By way of further example, if there is alive voltage on the order of 24 VAC detected at any of the W, Y, and G terminals, then it can be concluded that the user has placed the Rc and/or Rh wire in the wrong place, and appropriate installation halting and user notification can be made.
One particularly advantageous feature from a safety and equipment preservation perspective provided according to one embodiment relates to automated opening versus automated shunting of the Rc and Rh terminals by the VSCU unit 700. In many common home installations, instead of there being separate wires provided for Rc (24 VAC heating call switch power) and Rh (24 VAC cooling call switch power), there is only a single 24 VAC call switch power lead provided. This single 24 VAC lead, which might be labeled R, V, Rh, or Rc depending on the unique history and geographical location of the home, provides the call switch power for both heating and cooling. For such cases, it is electrically necessary for any thermostat to have its Rc and Rh input ports shunted together so that the power from that single lead can be respectively accessed by the heating and cooling call switches. However, in many other common home installations, there are separate 24 VAC wires provided for Rc and Rh running from separate transformers and, when so provided, it is important not to shunt them together to avoid equipment damage. These situations are resolved historically by (i) the professional installer examining the HVAC system and ensuring that a shunting lead (or equivalent DIP switch setting) is properly installed or not installed as appropriate, and/or (ii) the historical presence on most thermostats of a discrete user-toggled mechanical or electromechanical switch (e.g., HEAT-OFF-COOL) to ensure that heating and cooling are never simultaneously activated. Notably, it is desired to omit any discrete mechanical HEAT-OFF-COOL in most embodiments and to eliminate the need for a professional installer for the instant DIY product version environment. Advantageously, according to an embodiment, the VSCU 100 is advantageously equipped and programmed to (i) automatically test the inserted wiring to classify the user's HVAC system into one of the above two types (i.e., single call power lead versus dual call power leads), (ii) to automatically ensure that the Rc and Rh input ports remain electrically segregated if the if the user's HVAC system is determined to be of the dual call power lead type, and (iii) to automatically shunt the Rc and Rh input ports together if the user's HVAC system is determined to be of the single call power lead type. The automatic testing can comprise, without limitation, electrical sensing such as that provided by voltmeter, ammeters, ohmmeters, and reactance-sensing circuitry, as well as functional detection as described further below.
Also provided at installation time according to an embodiment, which is particularly useful and advantageous in the DIY scenario, is automated functional testing of the HVAC system by the VSCU unit 700 based on the wiring insertions made by the installer as detected by the small mechanical detection switches at each distinct input port. Thus, for example, where an insertion into the W (heating call) input port is mechanically sensed at initial startup, the VSCU unit 700 actuates the furnace (by coupling W to Rh) and then automatically monitors the temperature over a predetermined period, such as ten minutes. If the temperature is found to be rising over that predetermined period, then it is determined that the W (heating call) lead has been properly connected to the W (heating call) input port. However, if the temperature is found to be falling over that predetermined period, then it is determined that Y (cooling call) lead has likely been erroneously connected to the W (heating call) input port. For one embodiment, when such error is detected, the system is shut down and the user is notified and advised of the error on the circular display monitor 102. For another embodiment, when such error is detected, the VSCU unit 700 automatically reassigns the W (heating call) input port as a Y (cooling call) input port to automatically correct the error. Similarly, according to an embodiment, where the Y (cooling call) lead is mechanically sensed at initial startup, the VSCU unit 700 actuates the air conditioner (by coupling Y to Rc) and then automatically monitors the temperature, validating the Y connection if the temperature is sensed to be falling and invalidating the Y connection (and, optionally, automatically correcting the error by reassigning the Y input port as a W input port) if the temperature is sensed to be rising. In view of the present disclosure, the determination and incorporation of other automated functional tests into the above-described method for other HVAC functionality would be achievable by the skilled artisan and are within the scope of the present teachings. By way of example, for one embodiment there can be a statistical study done on the electrical noise patterns associated with the different control wires and a unique or partially unique “noise fingerprint” associated with the different wires, and then the VSCU unit 700 can automatically sense the noise on each of the existing control wires to assist in the automated testing and verification process.
Also provided at installation time according to an embodiment, which is likewise particularly advantageous in the DIY scenario, is automated determination of the homeowner's pre-existing heat pump wiring convention when an insertion onto the O/B (heat pump) input port is mechanically sensed at initial startup. Depending on a combination of several factors such as the history of the home, the geographical region of the home, and the particular manufacturer and installation year of the home's heat pump, there may be a different heat pump signal convention used with respect to the direction of operation (heating or cooling) of the heat pump. According to an embodiment, the VSCU unit 700 automatically and systematically applies, for each of a plurality of preselected candidate heat pump actuation signal conventions, a cooling actuation command and a heating actuation command, each actuation command being followed by a predetermined time period over which the temperature change is sensed. If the cooling command according to the presently selected candidate convention is followed by a sensed period of falling temperature, and the heating command according to the presently selected candidate convention is followed by a sensed period of rising temperature, then the presently selected candidate convention is determined to be the actual heat pump signal convention for that home. If, on the other hand, the cooling command was not followed by a sensed period of cooling and/or the heating command was not followed by a sensed period of heating, then the presently selected candidate convention is discarded and the VSCU unit 700 repeats the process for the next candidate heat pump actuation signal convention. For one example, a first candidate heat pump actuation signal convention is (a) for cooling, leave O/B open and connect Y to Rc, and (b) for heating, connect O/B to Rh, while a second candidate heat pump actuation signal convention is (a) for cooling, connect O/B to Rc, and (b) for heating, leave O/B open and connect W to Rh. In view of the present disclosure, the determination and incorporation of other candidate heat pump actuation signal conventions into the above-described method would be achievable by the skilled artisan and are within the scope of the present teachings.
Although being formed from a single lens-like piece of material such as polycarbonate, the cover 914 has two different regions or portions including an outer portion 914o and a central portion 914i. According to some embodiments, the cover 914 is painted or smoked around the outer portion 914o, but leaves the central portion 914i visibly clear so as to facilitate viewing of an electronic display 916 disposed thereunderneath. According to some embodiments, the curved cover 914 acts as a lens that tends to magnify the information being displayed in electronic display 916 to users. According to some embodiments the central electronic display 916 is a dot-matrix layout (individually addressable) such that arbitrary shapes can be generated, rather than being a segmented layout. According to some embodiments, a combination of dot-matrix layout and segmented layout is employed. According to some embodiments, central display 916 is a backlit color liquid crystal display (LCD). An example of information displayed on the electronic display 916 is illustrated in
Motion sensing as well as other techniques can be use used in the detection and/or predict of occupancy, as is described further in the commonly assigned U.S. Ser. No. 12/881,430, supra. According to some embodiments, occupancy information is used in generating an effective and efficient scheduled program. Preferably, an active proximity sensor 970A is provided to detect an approaching user by infrared light reflection, and an ambient light sensor 970B is provided to sense visible light. The proximity sensor 970A can be used to detect proximity in the range of about one meter so that the thermostat 900 can initiate “waking up” when the user is approaching the thermostat and prior to the user touching the thermostat. Such use of proximity sensing is useful for enhancing the user experience by being “ready” for interaction as soon as, or very soon after the user is ready to interact with the thermostat. Further, the wake-up-on-proximity functionality also allows for energy savings within the thermostat by “sleeping” when no user interaction is taking place our about to take place. The ambient light sensor 970B can be used for a variety of intelligence-gathering purposes, such as for facilitating confirmation of occupancy when sharp rising or falling edges are detected (because it is likely that there are occupants who are turning the lights on and off), and such as for detecting long term (e.g., 24-hour) patterns of ambient light intensity for confirming and/or automatically establishing the time of day.
According to some embodiments, for the combined purposes of inspiring user confidence and further promoting visual and functional elegance, the thermostat 900 is controlled by only two types of user input, the first being a rotation of the outer ring 912 as shown in
According to some embodiments, the thermostat 900 includes a processing system 960, display driver 964 and a wireless communications system 966. The processing system 960 is adapted to cause the display driver 964 and display area 916 to display information to the user, and to receiver user input via the rotatable ring 912. The processing system 960, according to some embodiments, is capable of carrying out the governance of the operation of thermostat 900 including the user interface features described herein. The processing system 960 is further programmed and configured to carry out other operations as described further hereinbelow and/or in other ones of the commonly assigned incorporated applications. For example, processing system 960 is further programmed and configured to maintain and update a thermodynamic model for the enclosure in which the HVAC system is installed, such as described in U.S. Ser. No. 12/881,463, supra. According to some embodiments, the wireless communications system 966 is used to communicate with devices such as personal computers and/or other thermostats or HVAC system components, which can be peer-to-peer communications, communications through one or more servers located on a private network, or and/or communications through a cloud-based service.
To more accurately determine the ambient temperature, the temperature taken from the lower thermal sensor 330b is taken into consideration in view of the temperatures measured by the upper thermal sensor 330a and when determining the effective ambient temperature. This configuration can advantageously be used to compensate for the effects of internal heat produced in the thermostat by the microprocessor(s) and/or other electronic components therein, thereby obviating or minimizing temperature measurement errors that might otherwise be suffered. In some implementations, the accuracy of the ambient temperature measurement may be further enhanced by thermally coupling upper thermal sensor 330a of temperature sensor 330 to grille member 1190 as the upper thermal sensor 330a better reflects the ambient temperature than lower thermal sensor 334b. Details on using a pair of thermal sensors to determine an effective ambient temperature is disclosed in U.S. Pat. No. 4,741,476, which is incorporated by reference herein.
In accordance with the teachings of the commonly assigned U.S. Ser. No. 13/269,501, supra, the commonly assigned U.S. Ser. No. 13/275,307, supra, and others of the commonly assigned incorporated applications, the thermostat 900 represents an advanced, multi-sensing, microprocessor-controlled intelligent or “learning” thermostat that provides a rich combination of processing capabilities, intuitive and visually pleasing user interfaces, network connectivity, and energy-saving capabilities (including the presently described auto-away/auto-arrival algorithms) while at the same time not requiring a so-called “C-wire” from the HVAC system or line power from a household wall plug, even though such advanced functionalities can require a greater instantaneous power draw than a “power-stealing” option (i.e., extracting smaller amounts of electrical power from one or more HVAC call relays) can safely provide. By way of example, the head unit microprocessor 1502 can draw on the order of 250 mW when awake and processing, the LCD module 1160 can draw on the order of 250 mW when active. Moreover, the Wi-Fi module 1510 can draw 250 mW when active, and needs to be active on a consistent basis such as at a consistent 2% duty cycle in common scenarios. However, in order to avoid falsely tripping the HVAC relays for a large number of commercially used HVAC systems, power-stealing circuitry is often limited to power providing capacities on the order of 100 mW-200 mW, which would not be enough to supply the needed power for many common scenarios.
The thermostat 900 resolves such issues at least by virtue of the use of the rechargeable battery 1144 (or equivalently capable onboard power storage medium) that will recharge during time intervals in which the hardware power usage is less than what power stealing can safely provide, and that will discharge to provide the needed extra electrical power during time intervals in which the hardware power usage is greater than what power stealing can safely provide. In order to operate in a battery-conscious manner that promotes reduced power usage and extended service life of the rechargeable battery, the thermostat 900 is provided with both (i) a relatively powerful and relatively power-intensive first processor (such as a Texas Instruments AM3703 microprocessor) that is capable of quickly performing more complex functions such as driving a visually pleasing user interface display and performing various mathematical learning computations, and (ii) a relatively less powerful and less power-intensive second processor (such as a Texas Instruments MSP430 microcontroller) for performing less intensive tasks, including driving and controlling the occupancy sensors. To conserve valuable power, the first processor is maintained in a “sleep” state for extended periods of time and is “woken up” only for occasions in which its capabilities are needed, whereas the second processor is kept on more or less continuously (although preferably slowing down or disabling certain internal clocks for brief periodic intervals to conserve power) to perform its relatively low-power tasks. The first and second processors are mutually configured such that the second processor can “wake” the first processor on the occurrence of certain events, which can be termed “wake-on” facilities. These wake-on facilities can be turned on and turned off as part of different functional and/or power-saving goals to be achieved. For example, a “wake-on-PROX” facility can be provided by which the second processor, when detecting a user's hand approaching the thermostat dial by virtue of an active proximity sensor (PROX, such as provided by a Silicon Labs SI1142 Proximity/Ambient Light Sensor with I2C Interface), will “wake up” the first processor so that it can provide a visual display to the approaching user and be ready to respond more rapidly when their hand touches the dial. As another example, a “wake-on-PIR” facility can be provided by which the second processor will wake up the first processor when detecting motion somewhere in the general vicinity of the thermostat by virtue of a passive infrared motion sensor (PIR, such as provided by a PerkinElmer DigiPyro PYD 1198 dual element pyrodetector). Notably, wake-on-PIR is not synonymous with auto-arrival, as there would need to be N consecutive buckets of sensed PIR activity to invoke auto-arrival, whereas only a single sufficient motion event can trigger a wake-on-PIR wake-up.
The Rh wire, which leads to one side of the HVAC power transformer (or simply “HVAC transformer”) that is associated with a heating call relay, can go by different names in the art, which can include heating call switch power wire, heat call power return wire, heat return wire, return wire for heating, or return for heating. The Rc wire, which leads to one side of the HVAC transformer that is associated with a cooling call relay, can likewise go by different names including cooling call switch power wire, cooling call power return wire, cooling return wire, return wire for cooling, or return for cooling. In the case of single-HVAC-transformer systems having both heating and cooling functions, it is one and the same HVAC power transformer that is associated with both the heating call relay and cooling call relay, and in such cases there is just a single wire, usually labeled “R”, leading back to one side of that HVAC transformer, which likewise can go by different names in the art including call switch power wire, call relay power wire, call power return wire, power return wire, or simply return wire.
As illustrated generally in
Thermostat 2000 further comprises powering circuitry 2010 that comprises components contained on both the backplate 2004 and head unit 2002. Generally speaking, it is the purpose of powering circuitry 2010 to extract electrical operating power from the HVAC wires and convert that power into a usable form for the many electrically-driven components of the thermostat 2000. Thermostat 2000 further comprises insertion sensing components 2012 configured to provide automated mechanical and electrical sensing regarding the HVAC wires that are inserted into the thermostat 2000. Thermostat 2000 further comprises a relatively high-power head unit microprocessor 2032, such as an AM3703 Sitara ARM microprocessor available from Texas Instruments, that provides the main general governance of the operation of the thermostat 2000. Thermostat 2000 further comprises head unit/backplate environmental sensors 2034/2038 (e.g., temperature sensors, humidity sensors, active IR motion sensors, passive IR motion sensors, ambient visible light sensors, accelerometers, ambient sound sensors, ultrasonic/infrasonic sound sensors, etc.), as well as other components 2036 (e.g., electronic display devices and circuitry, user interface devices and circuitry, wired communications circuitry, wireless communications circuitry such as Wi-Fi and/or ZigBee chips) that are operatively coupled to the head unit microprocessor 2032 and/or backplate microprocessor 2008 and collectively configured to provide the functionalities described in the instant disclosure and/or the commonly assigned incorporated applications.
The insertion sensing components 2012 include a plurality of HVAC wiring connectors 2014, each containing an internal springable mechanical assembly that, responsive to the mechanical insertion of a physical wire thereinto, will mechanically cause an opening or closing of one or more dedicated electrical switches associated therewith. Exemplary configurations for each of the HVAC wiring connectors 2014 can be found in the commonly assigned U.S. Ser. No. 13/034,666, supra. With respect to the HVAC wiring connectors 2014 that are dedicated to the C, W, Y, Rc, and Rh terminals, those dedicated electrical switches are, in turn, networked together in a manner that yields the results that are illustrated in
Likewise, for clarity of presentation in
As illustrated in
Basic operation of each of the FET switches 2006 is achieved by virtue of a respective control signal (OFF or ON) provided by the backplate microcontroller 2008 that causes the corresponding FET switch 2006 to “connect” or “short” its respective HVAC lead inputs for an ON control signal, and that causes the corresponding FET switch 2006 to “disconnect” or “leave open” or “open up” its respective HVAC lead inputs for an OFF control signal. For example, the W-Rh FET switch keeps the W and Rh leads disconnected from each other unless there is an active heating call, in which case the W-Rh FET switch shorts the W and Rh leads together. As a further example, the Y-Rc FET switch keeps the Y and Rc leads disconnected from each other unless there is an active cooling call, in which case the Y-Rc FET switch shorts the Y and Rc leads together. (There is one exception to this basic operation for the particular case of “active power stealing” that is discussed in more detail infra, in which case the FET switch corresponding to the HVAC lead from which power is being stolen is opened up for very brief intervals during an active call involving that lead. Thus, if power-stealing is being performed using the Y lead, then during an active cooling call the Y-Rc FET switch is opened up for very brief intervals from time to time, these brief intervals being short enough such that the Y HVAC relay does not un-trip.)
Advantageously, by virtue of the above-described operation of block 2018, it is automatically the case that for single-transformer systems having only an “R” wire (rather than separate Rc and Rh wires as would be present for two-transformer systems), that “R” wire can be inserted into either of the Rc or Rh terminals, and the Rh-Rc nodes will be automatically shorted to form a single “R” node, as needed for proper operation. In contrast, for dual-transformer systems, the insertion of two separate wires into the respective Rc and Rh terminals will cause the Rh-Rc nodes to remain disconnected to maintain two separate Rc and Rh nodes, as needed for proper operation. The G-Rc FET switch keeps the G and Rc leads disconnected from each other unless there is an active fan call, in which case the G-Rc FET switch shorts the G and Rc leads together (and, advantageously, the proper connection will be achieved regardless of whether the there is a single HVAC transformer or dual HVAC transformers because the Rc and Rh terminals will be automatically shorted or isolated accordingly). The AUX-Rh FET switch keeps the AUX and Rh leads disconnected from each other unless there is an active AUX call, in which case the AUX-Rh FET switch shorts the AUX and Rh leads together (and, advantageously, the proper connection will be achieved regardless of whether the there is a single HVAC transformer or dual HVAC transformers because the Rc and Rh terminals will be automatically shorted or isolated accordingly). For heat pump calls, the O/B-Rc FET switch and Y-Rc FET switch are jointly operated according to the required installation-dependent convention for forward or reverse operation (for cooling or heating, respectively), which convention can advantageously be determined automatically (or semi-automatically using feedback from the user) by the thermostat 2000 as described further in the commonly assigned PCT/US12/30084, supra.
Referring now to the powering circuitry 2010 in
By virtue of the configuration illustrated in
Operation of the powering circuitry 2010 for the case in which the “C” wire is present is now described. Although the powering circuitry 2010 may be referenced as a “power-stealing” circuit in the general sense of the term, the mode of operation for the case in which the “C” wire is present does not constitute “power stealing” per se, because there is no power being “stolen” from a wire that leads to an HVAC call relay coil (or to the electronic equivalent of an HVAC call relay coil for some newer HVAC systems). For the case in which the “C” wire is present, there is no need to worry about accidentally tripping (for inactive power stealing) or untripping (for active power stealing) an HVAC call relay, and therefore relatively large amounts of power can be assumed to be available from the input at nodes 2019/2017. When the 24 VAC input voltage between nodes 2019 and 2017 is rectified by the full-wave bridge rectifier 2020, a DC voltage at node 2023 is present across the bridge output capacitor 2022, and this DC voltage is converted by the buck regulator 2024 to a relatively steady voltage, such as 4.45 volts, at node 2025, which provides an input current IBP to the power-and-battery (PAB) regulation circuit 2028.
The microcontroller 2008 controls the operation of the powering circuitry 2010 at least by virtue of control leads leading between the microcontroller 2008 and the PAB regulation circuit 2028, which for one embodiment can include an LTC4085-3 chip available from Linear Technologies Corporation. The LTC4085-3 is a USB power manager and Li-Ion/Polymer battery charger originally designed for portable battery-powered applications. The PAB regulation circuit 2028 provides the ability for the microcontroller 2008 to specify a maximum value IBP(max) for the input current IBP. The PAB regulation circuit 2028 is configured to keep the input current at or below IBP(max), while also providing a steady output voltage Vcc, such as 4.0 volts, while also providing an output current Icc that is sufficient to satisfy the thermostat electrical power load, while also tending to the charging of the rechargeable battery 2030 as needed when excess power is available, and while also tending to the proper discharging of the rechargeable battery 2030 as needed when additional power (beyond what can be provided at the maximum input current IBP(max)) is needed to satisfy the thermostat electrical power load. If it is assumed for the sake of clarity of explanation that the voltages at the respective input, output, and battery nodes of the PAB regulation circuit 2028 are roughly equal, the functional operation of the PAB regulation circuit 2028 can be summarized by relationship IBP=Icc+IBAT, where it is the function of the PAB regulation circuit 2028 to ensure that IBP remains below IBP(max) at all times, while providing the necessary load current Icc at the required output voltage Vcc even for cases in which Icc is greater than IBP(max). The PAB regulation circuit 2028 is configured to achieve this goal by regulating the value of IBAT to charge the rechargeable battery 2030 (IBAT>0) when such charge is needed and when Icc is less than IBP(max), and by regulating the value of IBAT to discharge the rechargeable battery 2030 (IBAT<0) when Icc is greater than IBP(max).
For one embodiment, for the case in which the “C” wire is present, the value of IBP(max) for the PAB regulation circuit 2028 is set to a relatively high current value, such as 100 mA, by the microcontroller 2008. Assuming a voltage of about 4.45 volts at node 2025, this corresponds to a maximum output power from the buck regulator 2024 of about 445 mW. Advantageously, by virtue of the rechargeable battery-assisted operation described above, the powering circuitry 2010 can provide instantaneous thermostat electrical power load levels higher than 445 mW on an as-needed basis by discharging the rechargeable battery, and then can recharge the rechargeable battery once the instantaneous thermostat electrical power load goes back down. Generally speaking, depending especially on the instantaneous power usage of the large visually pleasing electronic display (when activated by the user coming close or manipulating the user interface), the high-powered microprocessor 2032 (when not in sleep mode), and the Wi-Fi chip (when transmitting), the instantaneous thermostat electrical power load can indeed rise above 445 mW by up to several hundred additional milliwatts. For preferred embodiments in which the rechargeable battery 2030 has a capacity in the several hundreds of milliamp-hours (mAh) at or near the nominal Vcc voltage levels (e.g., 560 mAh at 3.7 volts), supplying this amount of power is generally not problematic, even for extended time periods (even perhaps up to an hour or more), provided only that there are sufficient periods of lower-power usage below 445 mW in which the rechargeable battery 2030 can be recharged. The thermostat 2000 is configured such that this is easily the case, and indeed is designed such that the average power consumption is below a much lower threshold power than this, as discussed further below in the context of “active power stealing.”
Operation of the powering circuitry 2010 for the case in which the “C” wire is not present is now described. For such case, in accordance with the above-described operation of insertion sensing components/switches 2012/2016, it will be the Y-lead that is connected to the node 2019 if a “Y” wire has been inserted, and it will otherwise be the W-lead that is connected to the node 2019 if no “Y” wire has been inserted. Stated differently, it will be the Y-lead from which “power is stolen” if a “Y” wire has been inserted, and it will otherwise be the W-lead from which “power is stolen” if no “Y” wire has been inserted. As used herein, “inactive power stealing” refers to the power stealing that is performed during periods in which there is no active call in place based on the lead from which power is being stolen. Thus, for cases where it is the “Y” lead from which power is stolen, “inactive power stealing” refers to the power stealing that is performed when there is no active cooling call in place. As used herein, “active power stealing” refers to the power stealing that is performed during periods in which there is an active call in place based on the lead from which power is being stolen. Thus, for cases where it is the “Y” lead from which power is stolen, “active power stealing” refers to the power stealing that is performed when there is an active cooling call in place.
Operation of the powering circuitry 2010 for “inactive power stealing” is now described. In the description that follows it will be assumed that the “Y” wire has been inserted and therefore that power is to be stolen from the Y-lead, with it being understood that similar counterpart operation based on the “W” lead applies if no “Y” wire has been inserted and power is to be stolen from the W-lead. During inactive power stealing, power is stolen from between the “Y” wire that appears at node 2019 and the Rc lead that appears at node 2017. As discussed previously, the Rc lead will be automatically shorted to the Rh lead (to form a single “R” lead) for a single-HVAC transformer system, while the Rc lead will be automatically segregated from the Rh lead for a dual-HVAC transformer system. In either case, there will be a 24 VAC HVAC transformer voltage present across nodes 2019/2017 when no cooling call is in place (i.e., when the Y-Rc FET switch is open). For one embodiment, the maximum current IBP(max) is set to a relatively modest value, such as 20 mA, for the case of inactive power stealing. Assuming a voltage of about 4.45 volts at node 2025, this corresponds to a maximum output power from the buck regulator 2024 of about 90 mW. The power level of 90 mW has been found to be a generally “safe” power stealing level for inactive power stealing, where the term “safe” is used to indicate that, at such power level, all or virtually all HVAC cooling call relays that are installed in most residential and commercial HVAC systems will not accidentally trip into an “on” state due to the current following through the cooling call relay coil. During this time period, the PAB regulator 2028 operates to discharge the battery 2030 during any periods of operation in which the instantaneous thermostat electrical power load rises above 90 mW, and to recharge the battery (if needed) when the instantaneous thermostat electrical power load drops below 90 mW. Provided that the rechargeable battery 2030 is selected to have sufficient capacity (such as 560 mAh at 3.7 volts as discussed above), supplying power at above 90 mW (even several hundred milliwatts more) is generally not problematic even for extended time periods (even perhaps up to an hour or more), provided only that there are sufficient periods of lower-power usage below 90 mW in which the rechargeable battery 2030 can be recharged. The thermostat 2000 is configured such that the average power consumption is well below 90 mW, and indeed for some embodiments is even below 10 mW on a long term time average.
According to one embodiment, the powering circuitry 2010 is further monitored and controlled during inactive power stealing by the microcontroller 2008 by virtue of monitoring the voltage VBR across the bridge output capacitor 2022 at node 2023 that leads into the buck regulator 2024. For the embodiment of
Operation of the powering circuitry 2010 for “active power stealing” is now described. In the description that follows it will be assumed that the “Y” wire has been inserted and therefore that power is to be stolen from the Y-lead, with it being understood that similar counterpart operation based on the “W” lead applies if no “Y” wire has been inserted. During an active cooling call, it is necessary for current to be flowing through the HVAC cooling call relay coil sufficient to maintain the HVAC cooling call relay in a “tripped” or ON state at all times during the active cooling call. In the absence of power stealing, this would of course be achieved by keeping the Y-Rc FET switch 2006 in ON state at all times to short the Y and Rc leads together. To achieve active power stealing, the microcontroller 2008 is configured by virtue of circuitry denoted “PS MOD” to turn the Y-Rc FET switch OFF for small periods of time during the active cooling call, wherein the periods of time are small enough such that the cooling call relay does not “un-trip” into an OFF state, but wherein the periods of time are long enough to allow inrush of current into the bridge rectifier 2020 to keep the bridge output capacitor 2022 to a reasonably acceptable operating level. For one embodiment, this is achieved in a closed-loop fashion in which the microcontroller 2008 monitors the voltage VBR at node 2023 and actuates the signal Y-CTL as necessary to keep the bridge output capacitor 2022 charged. By way of example, during active power stealing operation, the microcontroller 2008 will maintain the Y-Rc FET switch in an ON state while monitoring the voltage VBR until it drops below a certain lower threshold, such as 8 volts. At this point in time, the microcontroller 2008 will switch the Y-Rc FET switch into an OFF state and maintain that OFF state while monitoring the voltage VBR, which will rise as an inrush of rectified current charges the bridge capacitor 2022. Then once the voltage VBR rises above a certain upper threshold, such as 10 volts, the microcontroller 2008 will turn the Y-Rc FET switch back into in an ON state, and the process continues throughout the active power stealing cycling. Although the scope of the present teachings is not so limited, the microcontroller 2008 is preferably programmed to keep the maximum current IBP(max) to a relatively modest level, such as 20 mA (corresponding to a maximum “safe” power stealing level of about 90 mW assuming 4.45 volts) throughout the active power stealing cycle. The circuit elements are designed and configured such that the ON-OFF cycling of the Y-Rc FET switch occurs at a rate that is much higher than 60 Hz and generally has no phase relationship with the HVAC power transformer, whereby the specter of problems that might otherwise occur due to zero crossings of the 24 VAC voltage signal are avoided. By way of example and not by way of limitation, for some embodiments the time interval required for charging the bridge output capacitor 2022 from the lower threshold of 8 volts to the upper threshold of 10 volts will be on the order 10 to 100 microseconds, while the time that it takes the bridge output capacitor 2022 to drain back down to the lower threshold of 8 volts will be on the order of 1 to 10 milliseconds. It has been found that, advantageously, at these kinds of rates and durations for the intermittent “OFF” state of the Y-Rc FET switch 2006, there are very few issues brought about by accidental “un-tripping” of the HVAC cooling call relay during active power stealing across a wide population of residential and commercial HVAC installations.
According to one embodiment, it has been found advantageous to introduce a delay period, such as 60-90 seconds, following the instantiation of an active cooling cycle before instantiating the active power stealing process. This delay period has been found useful in allowing many real-world HVAC systems to reach a kind of “quiescent” operating state in which they will be much less likely to accidentally un-trip away from the active cooling cycle due to active power stealing operation of the thermostat 2000. According to another embodiment, it has been found further advantageous to introduce another delay period, such as 60-90 seconds, following the termination of an active cooling cycle before instantiating the inactive power stealing process. This delay period has likewise been found useful in allowing the various HVAC systems to reach a quiescent state in which accidental tripping back into an active cooling cycle is avoided. Preferably, the microcontroller 2008 implements the above-described instantiation delays for both active and inactive power stealing by setting the maximum current IBP(max) to zero for the required delay period. In some embodiments, the operation of the buck regulator circuit 2024 is also shut down for approximately the first 10 seconds of the delay period to help ensure that the amount of current being drawn by the powering circuitry 2010 is very small. Advantageously, the rechargeable-battery-assisted architecture of the powering circuitry 2010 readily accommodates the above-described instantiation delays in that all of the required thermostat electrical power load can be supplied by the rechargeable battery 2030 during each of the delay periods.
Power wire selection circuitry 2140 can include input nodes 2141-2144, control node 2145, power node 2146, and switch electronics 2147. Power node 2146 is connected to switch circuitry 2147 and to full-wave bridge rectifier 2120. Control node 2145 is connected to switch circuitry 2147 and microcontroller 2108. Input nodes 2141-2144 are connected to switch circuitry 2147 and are electrically coupled to different wiring connectors 2114. In particular, node 2141 is connected to the common wire connector, node 2142 is connected to the W call relay connector, node 2143 is connected to the Y call relay connector, and node 2144 is connected to the G call relay wire. Although
Power wire selection circuitry 2140 is operative to selectively connect power node 2146 to one of input nodes 2141-2144 based on a signal received at control node 2145. Switch circuitry 2147 can include circuitry (e.g., FET switches) necessary to connect any one of input nodes 2141-2144 to power node 2146. In addition, switch circuitry 2147 can dynamically switch connection of power node 2146 from one input node to another in response to signals received at control node 2145. For example, microcontroller 2108 may initially instruct selection circuitry 2140 to connect power node 2146 to input node 2143, and then at a later time period, microcontroller 2108 can instruct selection circuitry 2140 to connect power node 2146 to input node 2144. Determination of which input node is selectively coupled to power node 2146 is based, in part, on an HVAC wiring scheme, discussed below.
Thermostat 2100 is operable to function regardless of which HVAC wiring scheme is connected to wiring connectors 2114. HVAC wiring schemes can include three general classes of schemes: a single circuit system with no common wire, a multiple circuit system with no common wire, and a common wire system. A single circuit system with no common wire includes wiring configurations in which only one call relay wire (e.g., W, Y, G, O/B, or AUX) and its associated return relay power wire (e.g., Rh or Rc) are connected to wiring connectors 2114, and no “C” power wire (e.g., common wire) is connected to wiring connectors 2114. The “single” designation implies that only one call can be made by thermostat 2100 for this particular HVAC wiring scheme. A specific example of a single circuit system is when a W (heating) call relay wire, a Rh (heat call relay power wire), and no other HVAC wires are connected to wiring connectors 2114. Such a circuit permits thermostat 2100 to make a heating call, but no other calls. Another specific example of a single circuit system is when a Y (cooling) call relay wire, a Rc (cool call relay power wire), and no other HVAC wires are connected to wiring connectors 2114. Such a circuit permits thermostat 2100 to make a cooling call, but no other calls.
A multiple circuit system with no common wire includes wiring configurations in which at least two different call relay wires (e.g., W, Y, G, O/B, or AUX) are connected to wiring connectors 2114, but no “C” power wire is connected. Connections of Rh and Rc depend on which call relay wires are connected, and has no bearing on whether the HVAC wiring scheme is a multiple circuit system. The “multiple” designation implies that thermostat 2100 can call at least two different calls. A specific example of a multiple circuit system is when the W and Y call relay wires, but no common wire, are connected to wiring connectors 2114. Another example of a multiple circuit system is when the Y and G call relay wires, but no common wire, are connected to the wiring connectors 2114. Yet another example is when the W, Y, and G call relay wires, but no common wire, are connected to wiring connectors 2114.
A common wire system includes a wiring configuration in which a “C” common power wire and any combination of call relay and relay power wires are connected to wiring connectors 2114. For example, a common wire system can exist when the C common wire, W call relay wire, and Rh relay power wire are connected to wiring connectors 2114.
At step 2220, a power scheme is implemented based on the determined HVAC wiring scheme. If at, step 2230, the determined HVAC wiring scheme is the single circuit system, the thermostat can implement a power scheme that uses active and inactive power stealing on the single circuit system, as indicated by step 2232. In addition, at step 2234, power wire selection circuitry is instructed to select which wiring connector is connected to the power node. In particular, it selects an input node associated with the call relay wire connected to the wiring connector of the single circuit system.
Referring briefly to
Upon making the HVAC wiring scheme determination, microcontroller 2108 can instruct power wire selection circuitry 2140 to connect power node 2146 to the W wiring connector. The line contained within switch circuitry 2147 that connects the W input node 2142 to power node 2146 illustrates the result of this instruction. In addition, based on the determined HVAC wiring scheme, microcontroller 2108 is operative to enable a power scheme that uses active and inactive power stealing. Active and inactive power stealing have been discussed above in connection with the description accompanying
Referring now back to
After the power node is initially connected to one of the wiring connectors, the current and future states of the thermostat are monitored to determine which, if any, HVAC circuits are changing or about to change from an enabled state to an non-enabled state, or vice versa, as indicated by step 2246. For example, the microcontroller can be aware of which circuits are active or enabled. In addition, the microcontroller can also be aware of which wiring connector is connected to the power node by virtue of controlling which input node is connected to the power node. At step 2247, a determination is made whether the power node is connected to a wiring connector that is changing or about to change its state. If YES, then at step 2248, power wire selection circuitry 2140 is instructed to couple the power node to a wire connector associated with one of the HVAC circuits that is not enabled or active. After step 2248, the process loops back to step 2246 and repeats. If the determination at step 2247 is NO, then no steps are taken and the process loops back to step 2246 and repeats.
Referring now briefly to
Upon making the HVAC wiring scheme determination, microcontroller 2108 can instruct power wire selection circuitry 2140 to connect power node 2146 to the W wiring connector, the Y wiring connector, or the G wiring connector by causing switch circuitry 2147 to select the appropriate input nodes (e.g., nodes 2142-2144). In addition, the determination that the HVAC wiring scheme is a multiple circuit system enables the thermostat to enable a power scheme that uses only inactive power stealing. Referring now specifically to
The timing of when power wire selection circuitry 2140 switches from one input node to another in response to knowledge that the currently selected input node is or is about to be associated with an enabled HVAC circuit is important to ensure inactive power stealing is the only power stealing method used in connection with the multiple circuit system. At any given time, the thermostat knows which HVAC circuits are enabled and which input node is coupled to the power node. The thermostat also knows when there will be changes in the status of the HVAC circuit (e.g., whether a particular HVAC circuit will switch from an enabled state to a non-enabled state and vice versa). Having knowledge of such status, the thermostat can time the selection of the input node with the change in state of an HVAC circuit to ensure compliance with the inactive power stealing scheme. For example, if it is known that the selected input node is connected to the Y wiring connector and a Y cooling call is about to be requested, microcontroller 2108 can cause switch circuitry 2147 to switch to another node (e.g., node 2142) before it turns switch 2162 ON or it can cause switch circuitry 2147 to switch to another node consistent with the activation of switch 2162.
Referring now back to
Referring back to
Whereas many alterations and modifications of the present invention will no doubt become apparent to a person of ordinary skill in the art after having read the foregoing description, it is to be understood that the particular embodiments shown and described by way of illustration are in no way intended to be considered limiting. By way of example, it is within the scope of the present teachings for one or more of the above teachings to be advantageously combined with one or more features described in one or more of the following patent applications, each of which is incorporated by reference herein: U.S. Ser. No. 13/267,871 filed Oct. 6, 2011; U.S. Ser. No. 13/467,029 filed May 8, 2012; U.S. Ser. No. 13/624,878 filed Sep. 21, 2012; and U.S. Ser. No. 13/632,148 filed Sep. 30, 2012. Therefore, reference to the details of the preferred embodiments is not intended to limit their scope.
Claims
1.-27. (canceled)
28. A thermostat for use in connection with a HVAC (heating, ventilation, and air conditioning) system, the HVAC system having a single circuit system, a multiple circuit system, or a common wire system, the thermostat comprising:
- insertion sensing circuitry operative to provide insertion sensing signals indicative of a wiring scheme associated with the HVAC system being connected to the thermostat; and
- control circuitry operative to: receive the insertion sensing signals; and engage in single circuit power stealing, multi-circuit power stealing, or common wire power utilization for obtaining power from the HVAC system based on the received insertion sensing signals, wherein: the single circuit power stealing is characterized by using both active and inactive power stealing from a single HVAC control wire; the multi-circuit power stealing scheme is characterized by only using inactive power stealing on a non-enabled circuit within the multiple circuit system; or the common wire system is characterized by using neither active power stealing nor inactive power stealing.
29. The thermostat of claim 28, wherein the active power stealing is characterized in harvesting power from the HVAC system while it is engaged in an active HVAC function.
30. The thermostat of claim 28, further comprising a switching circuit for controlling a HVAC function, wherein a closed switching circuit activates the HVAC function, wherein the active power stealing is performed during times when the HVAC function is active, wherein during active power stealing, the switching circuit opens for a time interval, wherein:
- power is harvested from the HVAC system during the time interval; and
- the time interval is short enough that the HVAC function remains active without interruption during the time interval.
31. The thermostat according to claim 28, wherein active power stealing is characterized by momentarily opening a closed contact during an enabled phase of the single circuit system.
32. The thermostat according to claim 31, wherein the contact is closed during a majority of each duty cycle when the single circuit system is in the enabled phase.
33. The thermostat according to claim 28, wherein active power stealing is characterized by receiving power from an enabled HVAC relay circuit in a manner that does not untrip the enabled HVAC relay circuit.
34. The thermostat according to claim 28, wherein inactive power stealing is characterized by receiving power from a non-enabled HVAC relay circuit in a manner that does not trip the non-enabled HVAC relay circuit.
35. A thermostat for use in connection with a HVAC (heating, ventilation, and air conditioning) system, the HVAC system having a single circuit system, a multiple circuit system, or a common wire system, the thermostat comprising:
- insertion sensing circuitry operative to provide insertion sensing signals indicative of a wiring scheme associated with the HVAC system being connected to the thermostat; and
- control circuitry operative to: receive the insertion sensing signals; and engage in single circuit power stealing, multi-circuit power stealing, or common wire power utilization for obtaining power from the HVAC system based on the received insertion sensing signals, wherein: the single circuit power stealing is characterized by using both active and inactive power stealing from a single HVAC control wire, wherein active power stealing is characterized in harvesting power from the HVAC system by fast switching a transistor; the multi-circuit power stealing scheme is characterized by only using inactive power stealing on a non-enabled circuit within the multiple circuit system, wherein inactive power stealing is characterized in harvesting power from the HVAC system by not fast switching the transistor; or the common wire system is characterized by using neither active power stealing nor inactive power stealing.
36. The thermostat of claim 35, wherein an HVAC function is activated when the transistor is closed, wherein the active power stealing is performed during times when the HVAC function is active, wherein during active power stealing, the transistor opens for a time interval, wherein:
- power is harvested from the HVAC system during the time interval; and
- the time interval is short enough that the HVAC function remains active without interruption during the time interval.
37. The thermostat of claim 36, wherein a length of the time interval is determined by:
- monitoring a voltage associated with a charge level of a capacitive element;
- beginning the time interval when the voltage is below a lower threshold;
- charging the capacitive element during the time interval; and
- ending the time interval when the voltage exceeds an upper threshold.
38. A thermostat for use in connection with a HVAC (heating, ventilation, and air conditioning) system, the HVAC system having a single circuit system, a multiple circuit system, or a common wire system, the thermostat comprising:
- insertion sensing circuitry operative to provide insertion sensing signals indicative of a wiring scheme associated with the HVAC system being connected to the thermostat; and
- control circuitry operative to: receive the insertion sensing signals; and engage in single circuit power stealing, multi-circuit power stealing, or common wire power utilization for obtaining power from the HVAC system based on the received insertion sensing signals, wherein: the single circuit power stealing is characterized by using both active and inactive power stealing from a single HVAC control wire, wherein active power stealing is characterized in harvesting power from the HVAC system by duty cycling a field effect transistor; the multi-circuit power stealing scheme is characterized by only using inactive power stealing on a non-enabled circuit within the multiple circuit system, wherein inactive power stealing is characterized in harvesting power from the HVAC system by not duty cycling switching the field effect transistor; or the common wire system is characterized by using neither active power stealing nor inactive power stealing.
Type: Application
Filed: Aug 26, 2016
Publication Date: Jul 25, 2019
Patent Grant number: 10452083
Inventors: Daniel Adam Warren (San Francisco, CA), Hugo B. Fiennes (Palo Alto, CA), Jonathan Alan Dutra (Saratoga, CA), David Bell (Los Altos Hills, CA), Anthony Michael Fadell (Woodside, CA), Matthew Lee Rogers (Los Gatos, CA), Ian C. Smith (Palo Alto, CA), Edwin H. Satterthwaite, JR. (Palo Alto, CA), Grant Michael Erickson (Sunnyvale, CA), Andrea Mucignat (Burlingame, CA), Joseph E. Palmer (San Jose, CA)
Application Number: 15/248,725
