Packaging and details of a wireless power device
A wireless power system includes a power source, power receiver, and components thereof. A current sensor senses the amount of current through the antenna. That amount of current is then used to adjust characteristics of the transmitting or receiving.
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This application claims priority from provisional application No. 61/035,340, filed Mar. 10, 2008, the entire contents of which are herewith incorporated by reference.
BACKGROUNDOur previous applications and provisional applications, including, but not limited to, U.S. patent application Ser. No. 12/018,069, filed Jan. 22, 2008, entitled “Wireless Apparatus and Methods”, and U.S. patent application Ser. No. 12/398,179, filed Mar. 4, 2009 entitled “Packaging and Details of a Wireless power device”, the disclosures of which is herewith incorporated by reference, describe wireless transfer of power.
The transmit and receiving antennas are preferably resonant antennas, which are substantially resonant, e.g., within 10% of resonance, 15% of resonance, or 20% of resonance. The antenna is preferably of a small size to allow it to fit into a mobile, handheld device where the available space for the antenna may be limited. An embodiment describes a high efficiency antenna for the specific characteristics and environment for the power being transmitted and received.
One embodiment uses an efficient power transfer between two antennas by storing energy in the near field of the transmitting antenna, rather than sending the energy into free space in the form of a travelling electromagnetic wave. This embodiment increases the quality factor (Q) of the antennas. This can reduce radiation resistance (Rr) and loss resistance (Rl).
Our previous disclosures described different ways in which this can be done.
There are a number of different reasons why one might want to use wireless power for portable items. Wireless power avoids the tangle and clutter of wires. It also can allow the automatic recharge of a rechargeable system. Computer systems have used wireless keyboards and mice, to avoid the clutter of wires on a user's desk. However, users still need to occasionally change the batteries in such devices. The changing of batteries can be disruptive, and inconvenient.
SUMMARYThe present application describes aspects of a wireless desktop system. According to an embodiment, wireless power is integrated into elements on a user desktop such as a keyboard, mouse, speakers, and other similar components.
Our previous patent applications including U.S. patent application Ser. No. 12/351,845 filed Jan. 11, 2009; and U.S. patent application Ser. No. 12/353,851, describe use of wireless power to form a wireless desktop that allows attaching a wireless keyboard, mouse, or other peripherals. These previous applications have disclosed how a wireless desktop has advantages for wireless power.
These applications match the opportunities of vicinity coupling for wireless power technology. Proximity coupling and charging pad solutions have been known for using wireless power. However, these have the disadvantage of requiring that the materials be placed directly in the right spot.
Another advantage of wireless power on the desktop is that many parts already exist on the desktop which have the right form factor for transmission of wireless power, including, but not limited to, the mouse station, and the base for a display.
In different embodiments, the system can use a high frequency band of 13.56 MHz for transmission of power, or a low frequency band around 135 kHz.
The base, either the base of the PC screen or the discrete power base, each include a coil shown as 121 in parallel with a high voltage capacitor. The coil is connected to receive power from a power supply system that is powered by the AC power cord 123. The power supply system also drives auxiliary structure including an antenna current sense circuit shown as 125.
The ruleset can be created by experimentation for any specific circuit and configuration.
Another embodiment of the antenna system is shown in block diagram form in
Another embodiment may add additional components into the power base. The additional components may include the parts as shown in
Received current 520 is sensed, and a signal indicative thereof is sent to the control unit 510. The control unit correspondingly controls a tuning unit 530, rectifier 540, and a DC to DC converter 550. The rectifier carries out synchronous rectification, with an adaptive load. This can avoid the diode voltage drop that would otherwise occur across a conventional diode rectifier. In a synchronous-rectifier, an electronic switch such as a MOSFET forms a half-bridge configuration that clamps the switching node to −0.1V or less. The synchronous rectifier improves the efficiency by placing a low-resistance conduction path across the diode rectifier.
A load formed by the antenna can be changed by the control unit in order to improve the matching based on characteristics sensed by the control unit. For example, this can change capacitance and/ or inductance. The controller can also change the characteristics of the rectifier, e.g, the frequency of the synchronous rectification, or the characteristics of the adaptive load presented by the rectifier.
Similarly, the DC to DC converter 550 can carry out load adaptation based on specific sensed characteristics. Both the rectifier and the DC to DC converter 550 are controlled by the control unit 510.
The DC to DC converter also carries out charging current control to the device battery, 560, to avoid overcharging that battery or charging it too aggressively.
One important aspect of this system is the adaptive control. For example, because the current through the antennas is sensed, the operation can allow more aggressive control of the battery charging during low power times than during high-powered times. For example, if the receiver is receiving low amounts of current, then rectifier more aggressively steps up the power. This causes the DC to DC converter to step up the power to a sufficiently high voltage to drive the battery. Sensing the current through the antenna can be used to control the different items in the circuit and to determine how these different items should operate.
Although only a few embodiments have been disclosed in detail above, other embodiments are possible and the inventors intend these to be encompassed within this specification. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way. This disclosure is intended to be exemplary, and the claims are intended to cover any modification or alternative which might be predictable to a person having ordinary skill in the art. For example, other sizes, materials and connections can be used. Other structures can be used to receive the magnetic field. In general, an electric field can be used in place of the magnetic field, as the primary coupling mechanism. Other kinds of antennas can be used. Also, the inventors intend that only those claims which use the-words “means for” are intended to be interpreted under 35 USC 112, sixth paragraph. Moreover, no limitations from the specification are intended to be read into any claims, unless those limitations are expressly included in the claims.
Where a specific numerical value is mentioned herein, it should be considered that the value may be increased or decreased by 20%, while still staying within the teachings of the present application, unless some different range is specifically mentioned. Where a specified logical sense is used, the opposite logical sense is also intended to be encompassed.
Claims
1. A wireless power transmitter, comprising
- a magnetically resonant antenna;
- a transmit system that creates a driving signal at a frequency that is substantially resonant with said magnetically resonant antenna;
- a current sensor, sensing an amount of current that flows through said magnetically resonant antenna and creates a current sense signal indicative thereof; and
- wherein said signal indicative of current is used by said transmit system to change said driving signal based on a characteristic of transmitting by said magnetically resonant antenna.
2. A transmitter as in claim 1, wherein said antenna is tuned to 13.56 Mhz.
3. A transmitter as in claim 1, wherein said antenna is tuned to 135 Khz.
4. A transmitter as in claim 1, further comprising a controller that monitors said current sense signal, and uses said signal to change said driving signal.
5. A transmitter as in claim 4, further comprising a power indicator meter, and wherein said controller changes said signal based on an output of said power indicator meter.
6. A transmitter as in claim 4, further comprising an inverter that creates said signal at said frequency of said antenna.
7. A transmitter as in claim 6, wherein said controller controls characteristics of said inverter.
8. A transmitter as in claim 7, wherein said controller controls pulse width and electronic fine-tuning of said inverter.
9. A transmitter as in claim 1, wherein said magnetically resonant antenna includes at least one component with a specified voltage and/or current rating, and further comprising an overload protection part, responsive to said amount of current, that prevents currents higher than a predetermined level based on ratings of electronic components.
10. A wireless power receiver, comprising
- a magnetically resonant antenna;
- a receive system that receives a signal at a frequency that is substantially resonant with said magnetically resonant antenna, and creates electrical power from said signal;
- a current sensor, sensing an amount of current that flows through said magnetically resonant antenna and creates a signal indicative thereof; and
- wherein said signal indicative of current is used by said receive system to change a characteristic of receiving based on said signal from said current sensor.
11. A receiver as in claim 10, wherein said antenna is tuned to 13.56 Mhz.
12. A receiver as in claim 10, wherein said antenna is tuned to 135 Khz.
13. A receiver as in claim 10, further comprising a controller that monitors said signal from said current sensor, and uses said signal to change said driving signal.
14. A receiver as in claim 13, further comprising a power indicator meter, and wherein said controller also changes said signal based on an output of said power indicator meter.
15. A receiver as in claim 13, wherein said receive system further comprises a rectifier that rectifies an said signal to create said electrical power, said rectifier having characteristics of rectifying, that are controlled by said controller.
16. A receiver as in claim 15, wherein said rectifier is a synchronous rectifier, and said controller controls a frequency of the synchronous rectification.
17. A receiver as in claim 15, wherein said rectifier is a synchronous rectifier, and said controller controls characteristics of the adaptive load presented by the rectifier.
18. A receiver as in claim 10, further comprising an overload protection part, responsive to said amount of current, that prevents currents higher than a predetermined level based on ratings of electronic components.
19. A receiver as in claim 18, wherein said ratings are ratings of components forming the antenna.
20. A method, comprising using an antenna which is tuned to have a magnetic resonance at a first frequency to receive a wireless magnetic signal;
- using electrical circuitry connected to said antenna to convert the received magnetic signal to electrical power;
- sensing an amount of current that flows through said antenna and creating a current sense signal indicative thereof; and
- said electrical circuitry changing a way that it interfaces with said antenna, based on said current sense signal, wherein said current sense changes the characteristics of said wireless power receiving based on a sensed current, where said changing changes an amount of received power between a source and a recipient.
21. A method as in claim 20, wherein said using comprises using said antenna to receive wireless power.
22. A method as in claim 20, wherein said antenna is tuned to 13.56 Mhz.
23. A method as in claim 20, wherein said antenna is tuned to 135 Khz.
24. A method as in claim 20, wherein said antenna includes at least one component with a specified voltage and/or current rating, and further comprising an overload protection part, responsive to said amount of current, that prevents currents higher than a predetermined level based on ratings of electronic components.
25. A method, comprising
- using electrical circuitry to convert electrical power to a magnetic signal at a first frequency;
- using an antenna which is tuned to have a magnetic resonance at said first frequency to transmit a wireless magnetic signal based on said magnetic signal;
- sensing an amount of current that flows through said antenna and creating a current sense signal indicative thereof; and
- said electrical circuitry changing a way that it interfaces with said antenna based on said current sense signal, wherein said current sense changes the characteristics of said wireless power transmitting based on a sensed current, where said changing changes an amount of transmitted power between a source and a recipient.
26. A method as in claim 25, wherein said antenna is tuned to 13.56 Mhz.
27. A method as in claim 25, wherein said antenna is tuned to 135 Khz.
28. A method as in claim 25, wherein said antenna includes at least one component with a specified voltage and/or current rating, and further comprising an overload protection part, responsive to said amount of current, that prevents currents higher than a predetermined level based on ratings of electronic components.
29. A wireless power receiver, comprising
- a magnetically resonant antenna;
- a receive system that receives a signal at a frequency that is substantially resonant with said magnetically resonant antenna, and creates electrical power from said signal, said receive system including a power supply that changes a characteristic of creation of electrical power to improve matching with the antenna.
30. A receiver as in claim 29, wherein said receive system includes a synchronous rectifier.
31. A receiver as in claim 30, wherein said receive system changes a frequency of said synchronous rectifier to change said matching.
32. A receiver as in claim 29, wherein said receive system includes a DC to DC converter.
33. A receiver as in claim 32, wherein said receive system changes a characteristic of said DC to DC convert to change said matching.
34. A receiver as in claim 32, further comprising a current sensor, sensing an amount of current that flows through said magnetically resonant antenna and creates a signal indicative thereof.
35. A receiver as in claim 34, wherein said receive system more aggressively receives power during a time when said signal indicative of current indicates that more power is being received.
36. A receiver as in claim 29, wherein said antenna is tuned to 13.56 Mhz.
37. A receiver as in claim 29, wherein said antenna is tuned to 135 Khz.
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- “Wireless Non-Radiative Energy Transfer”, MIT paper, publication and date unknown, believed to be 2007.
- “Efficient wireless non-radiative mid-range energy transfer”, MITpaper, publication and date unknown, believed to be 2007.
- “Wireless Power Transfer via Strongly Coupled Magnetic Resonances”, Kurs et al, Science Express, Jun. 7, 2007.
- “Wireless Power Transfer via Strongly Coupled Magnetic Resonances”, Kurs et al, scimag.org, Jul. 6, 2007.
Type: Grant
Filed: Mar 9, 2009
Date of Patent: Apr 26, 2011
Patent Publication Number: 20090224609
Assignee: QUALCOMM, Incorporated (San Diego, CA)
Inventors: Nigel P. Cook (El Cajon, CA), Lukas Sieber (Olten), Hanspeter Widmer (Wohlenschwil)
Primary Examiner: Robert L. Deberadinis
Attorney: Ramin Mobarhan
Application Number: 12/400,703
International Classification: H02J 1/10 (20060101);