Abstract: A removable battery pack for powering a pen-based or portable computer system in which the battery pack blocks its terminals when inserted into an unknown system. The known system includes a power supply microcontroller which passes battery charge data back and forth between a memory located in the battery pack and the power supply microcontroller. A battery microcontroller, located in the battery pack, eavesdrops drops on the communication between the power supply microcontroller and the memory, and when it validates a known signature of this communication, the battery microcontroller then enables the terminals of the battery pack. A trickle discharge current flows from the battery pack whenever the battery pack is out of the known system to allow the power supply microcontroller to power up in the case of a dead auxiliary battery.

Abstract: A cordless device 11 comprises a load 13 and a multiple pack power supply 15 connected to load 13. A voltage detection circuit 23, 63, 64, 75, 76 is connected to supply 15 and detects when one of the batteries 17, 19 is charged and the other is discharged. Circuits 23, 63, 65, 75, 76 may also function as a voltage comparator circuit to identify when one of the batteries 17, 19 is defective. The detection or comparator circuit includes comparators 25, 33 for comparing the battery voltages. An indicator 41, 43, 65, 74, 81 is connected to the output of comparators 25, 33 and provides an end user identifiable signal responsive to the outputs of comparators 25, 33.

Abstract: A method and apparatus for receiving, monitoring and characterizing network power information in real time through the use of a specialized display system. A processor receives three phase current and voltage information from a network power relay, converts and scales that data into a two-dimensional vector having coordinates that are represented by, and displayed as, a single pixel on a display screen. The repeated monitoring provides a Feature Map (FM) of the network system that can be easily read and understood by operating personnel.

Abstract: A portable communication device with battery conservation capability is capable of sensing (223) its power source and suppressing a battery conservation circuit depending on an actual voltage determined (225) from an analog-to-digital converter. Two or more voltage ranges are defined (227) such that battery conservation is disabled when an external power source is operated in one of the predetermined voltage ranges.

Abstract: A testing instrument including a display element and two control paths that are separately activated. The display element has a display field shaped like a lightning bolt or zigzag and has at least three partial display fields which follow successively in a longitudinal direction of the display element. Each of adjoining partial display fields is connected to a different one of the two control paths.

Abstract: An on-vehicle electronic controller which controls the operation of a device of an automobile or an internal combustion engine is disclosed. A relay intermittently supplies power to a controlled apparatus. The controller first causes the apparatus to be operated for a predetermined period of time while the relay is off, thus ensuring that any residual voltage at the relay terminal is discharged. After the predetermined time, the relay terminal voltage is compared to a predetermined voltage. If the voltage is greater than the predetermined voltage, it is determined that the relay is welded shut.

Abstract: A combination electrical connector and power failure signal device, comprising a generally box-like housing having a front, a back and a chamber, a male electrical plug on the back, a female electrical plug on the front, an electrical circuit in the housing including conductors connecting the male plug to the female plug, an alarm circuit in the housing responsive to power in the electrical circuit maintaining a stand by condition, the alarm circuit including a sensor for sensing a failure of power in the electrical circuit and initiating a first alarm mode, and responsive to a predetermined time in the first alarm mode to terminate the first alarm mode and initiate a second alarm mode, and a battery for powering the alarm circuit during failure of power in the electrical circuit.

Abstract: A periodic system management interrupt (SMI) source is provided that includes a programmable timer for asserting an SMI a predetermined rate. A microprocessor is coupled to a periodic SMI source through a CPU local bus. The periodic SMI source may be programmed by executing an I/O write cycle which allows a count value and an enable bit to be loaded into an internal configuration register. When the enable bit is set, the programmable timer asserts a periodic system management interrupt at a fixed rate as determined by the count value within the configuration register. The periodic system management interrupt may be asserted, for example, at intervals of 16 milliseconds, 64 milliseconds, 245 milliseconds, 1 second, 16 seconds, or 1 minute. The periodic SMI source allows for the automatic generation of a periodic system management interrupt independently of software.

Abstract: When the remote controller battery is exhausted to a low state, the state is detected and displayed on a display device located at the apparatus which is controlled by the commands from the remote controller. The voltage state of the battery is detected upon the actuation of a key of the remote controller. If a low state is detected, a low battery data code is added to the command code generated as a result of actuation of the key, and both kinds of data are transmitted to the controlled electronic device. The transmitted data is received at the controlled electronic device. The low battery data is detected and displayed on a display device of the remotely controlled electronic device.

Abstract: A smoke detector having an audible missing primary power source indicator, capable of indicating the absence of a primary power source powering the detector is provided. A missing power source circuit, including a supplementary power source having an effective voltage below a predetermined reference value is connected in parallel with the primary power source of the smoke detector. Additionally, the smoke detector contains low voltage detection and alarm circuitry, connected to the primary and supplementary power sources, to produce an audible warning when the effective voltage powering the smoke detector is determined to be below a predetermined reference value. Primary power to the detector may be supplied by a DC battery, a DC power source which has been converted from AC power or by a combination of the two.

Abstract: A detection and alarm circuit for protection of electronic components includes a fan motor current sensing resistor for producing a pulse that is amplified and introduced to a frequency-to-voltage converter for generating a filtered and processed voltage level for application to a voltage comparator. A reference voltage circuit supplies a voltage level to the comparator for matching with the filtered and processed voltage level and depending on the mismatch, an output signal is introduced to a transistor switch for operating an alert alarm device.

Abstract: In a computer system having a computer bus drive circuit capable of providing drive current to an individual line of a computer bus coupled thereto, a circuit for determining a proper level for the drive current and a method of making such determination. The circuit comprises: (1) a detection circuit, coupled to the individual line of the bus, for monitoring a response of the individual line of the bus to changes in state thereof during an operation of the computer system and providing an indication of the response and (2) a drive current establishment circuit, coupled between the detection circuit and the computer bus drive circuit, for establishing the proper level for the drive current in response to the indication produced by the detection circuit during an operation of the computer system.

Abstract: Air bags are deployed by firing circuits each containing a squib in series with a common control switch, and a control containing an accelerometer and a microprocessor for operating the switch to deploy the air bags. To diagnose shorts, a current source feeds a trickle current through each squib and a current limited voltage regulator across the switch passes the combined trickle currents to ground. The microprocessor senses the voltage across the switch via an A/D converter. That voltage goes low for a short to ground and high for a short to battery voltage.

Abstract: The present invention relates to an LED traffic signal light containing numerous LEDs and a voltage compensation circuit which allows the traffic light to operate over a wide range of input power voltages, while generating sufficient light intensity to control traffic at a highway intersection. The voltage compensation circuit achieves these objectives without substantially increasing the power consumption, overall cost, or failure rate of the LED traffic signal light. In the preferred embodiment, the voltage compensation circuit disables or rearranges a first and then a second set of LEDs in the traffic light, as the input power voltage drops below a first and then a second threshold voltage, so that the remaining LEDs will be driven by an increased current and generate a greater overall light intensity than if all of the LEDs were driven by the decreased current that would result from the decreased input power voltage.

Abstract: A paging receiver with a motor and buzzer for saving a battery voltage by alerting a low voltage state of the battery. A low voltage detector compares the battery voltage with a reference voltage to generate a low voltage detection signal when the battery voltage is less than the reference voltage. In this case, an alerting driver is switched by the low voltage detection signal for cutting off the electrical passage between a motor and the battery and connecting the tone generator to the buzzer so as to generate alert tone.

Abstract: The specification discloses a circuit for monitoring the status of an ultraviolet (UV) light bulb in a water treatment system. The circuit uses either transformers or zener diodes with opto-isolators to monitor the voltage across the bulb. A logic signal is emitted when abnormally high voltage is detected, for example, indicating that the bulb is burned out, broken, or missing. A logic signal also is emitted when abnormally low voltage is detected, for example, indicating that the starter circuit is short circuited or that power is interrupted.

Abstract: In a hand-held electronic apparatus, such as radio display pager, a control circuit is powered by a first battery to produce an control signal for operating an inductive device such as vibrator. A second battery is provided having an internal resistance lower than the internal resistance of the first battery. A capacitor is connected in parallel with the inductive device and the voltage developed thereacross is monitored by a voltage sensor, which produces a sensor output when the voltage exceeds a prescribed level. A first switching circuit is responsive to the control signal for coupling the inductive device to the second battery and responsive to the sensor output for decoupling it from the second battery. A second switching circuit also responds to the sensor output for coupling the inductive device to the first battery until the control signal ceases to exist.

Abstract: A battery charge monitor for automotive vehicles that includes electronic circuitry for connection to the vehicle battery and responsive to battery voltage to provide a first electrical signal when battery voltage decreases to a selected threshold level. A latching relay includes relay contacts for connection between the vehicle battery and vehicle battery loads, including the starter. A first relay coil is operatively coupled to the relay contacts and responsive to the first signal from the electronic circuitry to open the relay contacts and disconnect the battery from the battery loads including the starter. A second relay coil is operatively coupled to the relay contacts and responsive to a second electrical signal from an operator reset switch for reclosing the relay contacts and connecting the battery to the loads. Thus, when battery charge reaches a level below which starting may be difficult, the electronic circuitry cooperates with the latching relay to disconnect the battery from the loads.

Abstract: The invention continuously monitors the current drawn from the on board battery system of a recreational vehicle or marine vessel. The device calculates and displays the energy remaining as a portion of the total capacity by accumulating over time the net energy drawn out of the battery. The device accurately accounts for the known effect of effectively lower battery capacities at higher current draws, and also allows the user to re-initialize the battery system capacity to reflect either degradation of the battery capacity with time or upgrades to the battery system.

Abstract: A temperature limit circuit has a pair of comparators for producing an output signal when a sensed temperature either exceeds of falls below a permissible range. A common impedance circuit uses a single output pin to establish both the upper and lower temperature limits and a hysteresis level at each end of the range. A hysteresis circuit includes two branches, one of which directs a hysteresis current in one direction to a hysteresis resistor at a common input to the comparators to set the hysteresis at one end of the temperature range, and the other of which directs the hysteresis current through the hysteresis resistor in the opposite direction to set the hysteresis at the other end of the temperature range; the oppositely directed current flows establish hysteresis differentials of opposite polarities. A voltage reference circuit that includes a feedback circuit is preferably used for both temperature sensing and to establish a reference current upon which the hysteresis current is based.

Abstract: A low voltage detection circuit includes bandgap and differential comparator circuits for generating a first signal proportional to the level of the supply voltage when it exceeds a predetermined range, and an output driver responsive to the first signal for generating an output indication representative of a low or failure condition of the supply voltage.A supplemental current source provides a bias current to the output driver in opposition to and much smaller than the first signal in order to proactively switch the output driver into the low or failure condition when the supply voltage, and the first signal representative thereof, fall below a predetermined minimum range.

Abstract: An electric power circuit with line voltage failure detection includes a pair of DC conductors for receiving a DC voltage, a capacitor connected across these conductors, and a main power converter connected to produce an output voltage on a main power bus in response to the DC voltage on the power conductors. A circuit branch connected across the power conductors includes the series connection of a primary winding of a transformer and a switching device. The switching device is operated to produce a series of voltage pulses across the secondary winding of the transformer. These voltage pulses are used to produce a second output voltage. The magnitude of these voltage pulses which occur during time when the switching device is off, is detected and a line failure indicating signal is produced when this magnitude falls below a predetermined value.

Abstract: A circuit breaker has leakage current detecting functions, that is leakage detection, leakage alarm and disconnection the circuit in the leakage state from the power source side; in order to conduct such functions, the circuit breaker comprises a magnetic release device for disconnecting a circuit in the leakage state, a zero-phase current transformer for detecting a leakage current, a sensitivity selector, an amplifier and a leakage relay for issuing a leakage alarm signal.

Abstract: Method and apparatus for periodically checking the ground path resistance value of a crash sensor connection to chassis ground and determining if the resistance exceeds a predetermined maximum acceptable value.

Abstract: An integrated circuit is shown in which provision is made for terminating or locking out the operating circuitry when the supply voltage has fallen below a level that can cause anomalous or unreliable operation. Certain selected transistors are provided with saturation sensors which operate to produce a current when the transistors go into collector saturation. When any of the sensors indicates the onset of saturation, clamping circuitry is energized to provide lock out. In addition, a temperature compensated dummy bandgap circuit is included to sense extremely low supply voltages and provide the lockout function under conditions where a reliable saturation indication might not be available.

Abstract: A circuit arrangement for monitoring two operating voltages of different polarity detects and indicates the deviation of either operating voltage from its nominal value beyond a predetermined tolerance limit. A transistor is provided, whose base is connected to the positive operating voltage across a first zener diode and to the negative operating voltage through a first resistor, and whose emitter is connected to the negative operating voltage through a series connection of a second zener diode and a second resistor, and to a reference potential across a diode.

Abstract: A direct current power supply device which generates an alarm signal when a power failure occurs in an alternating current power supply connected as an input to the device. A power failure detector circuit is connected at the input of the device and signals the failure of the AC power supply. In order to compensate for different time delays in the fall of the DC output due to varying loads at the output of the device, a reset signal generating circuit is used which is controllable in accordance with the size of the load. The circuit receives as an input, a signal identifying a power failure from the power failure detector circuit and a signal identifying the load current value from a load current value detector circuit, connected between the load and the AC/DC converter. The reset signal generating circuit, using analog or digital components, will generate a reset signal at a timing determined by the size of the load.

Abstract: A voltage drop detection circuit (1) able to detect a drop in an output voltage of a switching regulator which includes an error detection circuit for detecting a difference between the output voltage and a predetermined value and a feedback circuit (PC1, R1) for controlling a control circuit (2) of a switching transistor in response to an output signal from the error detection circuit (R2, R4, R5, IC1). The voltage drop detection circuit (1) is constructed to operate by using the output of the error detection circuit (R2, R4, R5, IC1) as a control input. When the output voltage becomes lower than the predetermined value, the current of a shunt regulator (IC1) is cut off, a transistor (Q2) is turned off, and a voltage drop is output from terminals (E1, E2).

Abstract: An on-chip power supply regulation system for a VLSI circuit such as a dynamic RAM is disclosed. The system includes a high power supply voltage detection circuit and a power supply clamp circuit, where a clamped voltage generated by the clamp circuit biases the functional circuitry when the high power supply voltage detection circuit detects an overvoltage conditions. The bias voltage applied to the functional circuitry in the normal operating condition can be a regulated voltage generated from the power supply voltage. Further included in the disclosed circuit is a burn-in voltage generation circuit and a burn-in voltage detection circuit, which can apply an accelerated voltage which depends upon the applied power supply voltage, when the power supply voltage is higher than during normal operation but lower than in the overvoltage condition enabling the clamp operation.

Abstract: Low voltage inhibit control apparatus used in conjunction with a microprocessor system having a power supply, comprising a low voltage inhibit circuit providing a power down reset signal in response to the voltage dropping of the power supply, and control circuitry for preventing the power down reset signals from being supplied to the microprocessor system in response to receiving DATA and WRITE signals from the microprocessor.

Abstract: A low voltage warning apparatus is adapted to energize a low voltage indicator in response to a test voltage signal falling below the magnitude of a reference voltage signal. The test voltage signal and reference voltage signal are connected to be received by a comparator circuit so that the comparator circuit output is connected to ground when the test voltage falls below the value of the reference voltage. The low voltage indicator is connected between an indicator power supply and the comparator output so that when the comparator output is connected to ground, a low voltage indicator energizing current flows through the low voltage indicator to provide the desired low voltage indication.

Abstract: A circuit for protecting electronic equipment such as computers, laser printers, fax machines, and the like from damage due to electrical transients associated with a temporary power interruption is connectable between a source of A.C. power and the electronic equipment. The circuit disconnects the equipment from the power source during a temporary power outage and maintains the equipment disconnected from the A.C. power until transients in the line voltage have abated. The circuit reconnects the equipment to the A.C. power source after a preselected time delay from the initial power interruption. The circuit keeps track of time during a power interruption without the use of batteries.

Abstract: Monitoring an electric power distribution circuit having a rated load capacity includes continually sensing an intensity of electric power supplied through that circuit. In response to that sensing a first signal indicating when electric power is supplied through that circuit at a predetermined maximum current usage below rated load capacity is provided. A second signal indicating a safe loading condition is provided when the sensed intensity is substantially below that maximum current usage. A third signal is provided when the mentioned intensity is at a value between the safe loading condition and the maximum current usage.

Abstract: A power supply monitoring circuit for operating in a plurality of modes comprising first and second single input comparators coupled to first and second inputs, respectively, for sensing the voltage levels thereof. A reference circuit for generating a reference voltage at a first output. A programming circuit coupled to the outputs of the first and second single input comparators and being responsive to a third input for providing the selection of plurality of operation modes and for providing second and third outputs which are function of the voltage levels appearing at the first and second inputs.

Abstract: A low battery detect circuit shuts down high current circuitry in the system in the event that battery voltage drops to a level such that the regulated output voltage is endangered. The trigger voltage is dependent upon capacitor ratios and a reference voltage. The output of the detection circuitry is a digital signal which can be used to disable high current circuitry in an implantable medical device and, thus, allow the battery voltage to recover. Alternatively, the output of the detection circuitry can be used as a battery status indicator flag.

Abstract: A power controller comprises a manually-on circuit breaker having an electrically-actuatable trip coil which enables the circuit breaker to be tripped-off electrically. The circuit breaker is connected to a voltage source and provides operating voltage to a power outlet. A line voltage monitor provides a voltage indication to a logic control circuit when operating voltage moves outside a predetermined range established by setting upper and lower operating voltage limits. In response to receiving such a voltage indication, the logic control circuit deenergizes a relay, thereby connecting a charged capacitor to the tripping coil of the circuit breaker to cause the breaker to be tripped-off even when the voltage to the circuit breaker drops to zero volts. Other signals provided to the control logic circuit also cause the deenergizing of the relay controlling the circuit breaker tripping capacitor.

Abstract: An automatic switching apparatus is disclosed for a system employing a battery and a charging device. A load is automatically disconnected in response to the decrease in voltage caused by an inactivation of the charging device so that the battery will not be undesirably discharges if the load is not turned off. An override switch is provided to allow the load to draw power even when the charging device is not operating.

Abstract: A power source failure detecting system for detecting failure in a power source for an electronic control system for a vehicle determines that a failure occurs in the power source and outputs a signal when the vehicle speed continues to be higher than a predetermined value (e.g., 40 Km/h) for a predetermined time interval (e.g., 10 seconds) and at the same time, the power source voltage is lower than a predetermined value (e.g., 9 v).

Abstract: Voltage monitor for monitoring the output voltage of a power source which can be connected to a power load, which includes a reference voltage source, comparators for comparing the power source voltage with the reference voltage, switches between the power source and the load, which can be controlled by an output from the comparators, such that the switches can be closed only when the power source voltages are within certain voltage limits and meet certain conditions, and also such that the load is disconnected when the power source voltages go beyond certain voltage or frequency limits. A timing circuit may also be provided for timing various voltage conditions.

Abstract: Electrical circuits for detecting intermittent and continuous electrical parameters such as continuity for open or closed circuits, AC power interruption or decrease in frequency, DC power interruption, missing electrical pulses; and voltage, resistance, and current levels that are greater than or less than present high and low limits. This invention also detects temperature and light (illumination) that is greater or less than present limits. The invention has a memory and both a (variable time delayed) automatic, and a manual memory reset. It provides both visual and a defeatable audio indicators or alarms. The advantage of said invention is that it detects intermittent conditions as brief as fractions of microseconds that may occur as frequently as milliseconds apart or as infrequently as days apart; it also detects steady state conditions.

Abstract: The duration of time during which an AC power voltage sinusoidal waveform remains between negative voltage threshold -V1 volts, nominally 5% of negative peak voltage -V2 volts, and positive voltage threshold +V1 volts, nominally 5% of peak positive voltage +V2 volts, is detected. By the change in voltage with time exhibited by a sinusoidal waveform in the region of zero voltage crossing, the expected time duration between voltage thresholds in approximately 5% of one-half period of such sinusoidal waveform. If the actual time between voltage thresholds exceeds (nominally) twice this value, or 10% of one-half period, then a power black-out condition is sensed, and a power fault signal is produced.

Abstract: Safety appparatus for sensing an electrically powered device connected to an AC power source to prevent the start-up of the device upon power restoration when the power device is in its "ON" operative condition includes a current sensing circuit that is responsive to reconnection of such a load to prevent the establishment of an electrical circuit path through the device. Included are circuits for sensing the presence of the AC power and for the generation of the sensing current are also presented.

Abstract: A switching module having a plurality of switching channels responsive to a microcontroller for coupling electrical power to a load, and decoupling electrical power in the event an undesired operating condition is sensed. Each switching channel includes a switching transistor and transistor driver. Monitoring circuitry senses the actual voltage drop across the load to provide the controller with an indication of undesired operation. A limiting resistor limits the transistor drive such that the transistor is forced out of satuaration during a high power condition, thereby avoiding undesired power dissipation which would otherwise occur if operation in the saturated condition continued.

Abstract: A threshold comparator having hysteresis wherein the repeatable threshold levels are established by multiple current paths and resistance ratios, which provides an under-voltage lock-out signal. The current paths are established by transistors fabricated on a common substrate and include a split collector P-N-P transistor that provides the distribution of the input signal to the various current paths. The turn-on and turn-off threshold points of the circuit according to the present invention are established by resistance ratios which are more easily maintained than are absolute resistance values. Similarly, when implemented on a common substrate, the remaining component values may be selected so that the thresholds values are nearly independent of temperature, providing an easily manufactured, high yield circuit.

Abstract: An apparatus for visually indicating abnormal phase relationships between incoming or outgoing phases for a plural phase device, comprised of a plurality of light emitting means interconnected between phases by a logic circuit arrangement whereby the various combinations of on/off indicators present a coded, visual presentation representing the specific mismatch condition of the network. The invention encompasses the concept of incorporating the indicating circuitry within the multiple phase device enclosure and providing an aperture in the enclosure so that the indicators may be viewed without the necessity of gaining access to the interior of the device and exposing individuals to the danger of high voltage/current circuits.

Abstract: The alert circuit includes a minimum number of inexpensive descrete electronic components to provide a flashing alert when battery voltage drops below a predetermined trigger voltage. A single unijunction transistor circuit functions as a combination low voltage detector and oscillator to output periodic pulses to an LED annunciator circuit when battery voltage is low.

Abstract: A scheme for detecting reduced source of voltage of a controlled switching power supply including a transformer employs the inherent insolation characteristics of the transformer to yield an isolated alarm signal indicative of a failed or inadequate source voltage.

Abstract: A potential indicating device for indicating the presence of a voltage on a connector in a high voltage electrical distribution system, the connector including a conductor, a semiconductive shield and a test point terminal. The device comprises two separate indicator circuits, each energized by a different voltage capacitively coupled to the conductor. When a voltage is present in the conductor, first circuit means transmits a voltage capacitively coupled to the test point terminal to a visible indicator which flashes intermittently, and second circuit means transmits a voltage capacitively coupled to the semiconductive shield to an audible indicator when switching means closes the second circuit means. Preferably switching means comprises a photosensitive transistor normally shielded from light by a removable plug.

Abstract: A DC power monitor includes a reference voltage and voltage dividers for obtaining voltages which are respectively above and below the reference level when the voltages being monitored are at their nominal value. Comparators compare the divided voltages with the reference and the comparator outputs are Anded and coupled through a flip flop to a bicolor LED which is one color when the voltages are in tolerance and another color when out of tolerance.

Abstract: A method and apparatus for detecting voltage losses in a power distribution line wherein a plurality of voltage sensing devices are used to generate an alarm signal which identifies the phases and locations corresponding to points at which voltage losses are detected.