Abstract: A sensor circuit detects a current supplied to a set of light-emitting diodes and produces a current reading dependent on the temperature of operation of these light-emitting diodes. The sensor circuit comprises first and second serially interconnected resistors also connected in series with the set of light-emitting diodes. The sensor circuit also comprises a temperature-dependent impedance connected in parallel with one of the first and second resistors. At least a portion of the current through the set of light-emitting diodes flows through the sensor circuit to enable the first and second serially interconnected resistors and the temperature-dependent impedance to produce a variable voltage signal representative of the current through the set of light-emitting diodes, this variable voltage signal being dependent upon temperature. The above sensor circuit finds application in a substantially constant intensity light source.

Abstract: A modular power supply which distributes responsibility for supplying current to a load among two or more power supply modules having a common output node. One of the power supply modules which supplies the lowest level of current to the load functions as the master while the remaining power supply modules each function as a slave. A load share bus which interconnects all the power supply modules is driven by the master with a signal representative of the level of current supplied by the master. Each slave module attempts to reduce its output current to a level which is a predetermined offset above the level of current supplied by the master while a regulated voltage is maintained at the common output node. Any one of the modules can become the master, though once the system is operating, the predetermined offset generally prevents the roles from changing. Should one of the power supply modules fail such that its output current is uncontrolled, this power supply module will not be the master.

Abstract: A system and method for adjusting the maximum allowable current limit for each of a plurality of parallel power supplies within an N+1 power supply system in response to dynamic variations in the total supply current capacity of the N+1 power supply system. A plurality of parallel supplies make up the N+1 power supply which provides power to a load. A sensor within each of the parallel power supplies determines an operating status of each of the parallel power supplies. A detector circuit in communication with the sensors translates the operating status determination into a supply current capacity signal. Finally, a current limit adjustment circuit generates a current limit signal in response to the supply current capacity signal, such that the maximum allowable current limit for each parallel power supply is adjusted while maintaining the overall power supply VA limit for the N+1 power supply.

Abstract: Regulator circuits and regulation techniques that provide sufficient power for a given load requirement even where no single power supply in the system is adequate to satisfy the given load requirement. Circuits and techniques according to the invention use multiple switching regulators having inputs at different voltages and having a single combined output. A current-sense circuit allocates power provided to the output by the switching regulators such that each switching regulator provides a portion of the total output current, and therefore, power to the switching regulator.

Abstract: A constant-current regulator regulates and monitors the current fed to one or more downstream loads. It also serves to even out the current fed to the downstream load or loads at the control level or when there is a change in the control level. In order to enhance the security and reliability of operation of such a constant-current regulator when installed in a control and monitoring circuit, control signals having a similar regulating/monitoring content are applied to the constant-current regulator by means of two separate busses (3, 4) in a mutually independent manner. The constant-current regulator is used to carry out a separate plausibility/conformity check of the control signals from the first bus (3) and the control signals from the second bus (4). If a lack of plausibility/conformity is ascertained for the control signals of the first bus (3), the control signals of the second bus (4) are taken as the basis for operation of the constant-current regulator.

Abstract: A current control circuit is provided which is capable of maintaining a constant DC current flowing in a load resistor irrespective of the resistance value of a load resistor connected to a connection terminal. To this end, a constant current circuit (21) is connected to a RING terminal (2), which acts as the connection terminal. The constant current circuit (21) controls a current drive circuit (6) in response to a voltage at the RING terminal (2) to ensure that a DC current flowing in a power feed resistor (4) is kept constant. Due to the fact that DC current flowing in the load resistor irrespective of the resistance value of the load resistor is kept constant, the burden placed on a power supply of a subscriber line interface in a telecommunications network is no longer increased. Also, there no longer arises a need for increasing a power feed resistance and the rating of a power feed transistor, which, in turn, leads to a reduction in manufacturing cost.

Abstract: A steering wheel control system (10) that employs a method for passing push-button commands from a steering wheel to a vehicle system, wherein the method is not dependant upon the contact resistance of a sliding contact (32) located in the steering wheel column. The control system (10) includes a constant current source circuit (20) that generates a unique constant current corresponding to each command. The sliding contact (32) passes the constant current between the steering wheel and the vehicle system, and a calibrated resistance circuit (40) converts the unique constant current into a discrete voltage. The discrete voltage is also converted into a digital signal for use by a microcontroller (60) to activate the vehicle systems. The use of constant currents therefore avoids operational problems associated with decreases in the overall system noise margin due to large voltage drops across the sliding contact (32).

Abstract: A flywheel energy conversion device provides highly efficient conversion between kinetic and electrical energy. The flywheel produces increased output by providing armature coils in an air gap formed about the flywheel (both radial and axial embodiments are described). In preferred embodiments, field coils of a magnetic circuit are energized with DC drive current that creates homopolar flux within a rotating solid rotor having teeth cut from a flat disk. The total reluctance of the magnetic circuit and total flux remain substantially constant as the rotor rotates. The flux may travel radially outward and exit the flat disk through the teeth passing across an armature air gap. Airgap armature coils are preferably utilized in which the changing flux density (due to the rotating teeth) induces an output voltage in the coils.

Abstract: Parallel circuit of power supplies, the output voltage of each power supply, in the event of the nominal current being exceeded during simultaneous operation of all the power supplies, becoming less by a predetermined amount which is greater than the tolerance of the output voltages at the nominal current.

Abstract: An ECU for executing serial communication via a transmission line has a driver circuit. The driver circuit includes an integrator for integrating a transmission signal and a power source for generating a current which corresponds to the integrated value of the transmission signal and releasing the current to the transmission line. A terminal circuit for receiving a constant current smaller than a maximum current that the driver circuit can discharge is connected to the transmission line. Since the amount of output current from the driver circuit is gradually changed, the generation of noise in the transmission line can be prevented. Further, since the voltage of the transmission line immediately changes to either a high or low level depending on the amount of output current, accurate data communication can be performed.

Abstract: In the described embodiments, a spacecraft is powered by paralleled solar panels, which supply power to a load. The panels are ORed together, and each is controlled by a switched shunt, which provides coarse control of the load voltage. A control loop senses the load voltage, and logic selects those shunts which are conductive at any particular time in a manner which tends to maintain the load voltage constant. The control loop may undesirably become unstable because of gain changes caused by changes in solar panel insolation. A further controller adjusts the clock frequency at which the shunts are switched in a manner which tends to stabilize the loop. The further controller responds (a) to the current of one or more of the panels, (b) to the frequency of oscillations across the load, or (c) to both.

Abstract: Fire control systems and release mechanisms. The release mechanisms of the present invention comprise a digital logic circuit for processing signals which are indicative of a condition in an outside environment, and for providing a trigger that will actuate the mechanical release mechanism in response to the condition, a power circuit for providing regulated power to the electronic circuit in response to the input power, the regulated power being used to operate the digital logic circuit, and a power backup circuit interfaced to the power circuit for providing the regulated power for a predetermined time in the event of an input power failure so that the digital logic circuit can be operated for the predetermined time during the input power failure.

Abstract: When a computer is not externally powered, it operates from installed first and second batteries. In top surface of the computer, LEDs are provided which indicates three states of each battery; need of charging, during charging, and completion of charging.

Abstract: A system for regulating the transfer impedance of a plurality of current-to-voltage converters to a substantially equal value includes a reference voltage source and a reference impedance for providing a reference current. A reference current-to-voltage converter is responsive to the reference current and provides an output voltage. A comparator is responsive to the reference voltage and the output voltage and provides a control signal to the reference current-to-voltage converter and to all the other current-to-voltage converters to maintain the transfer impedance of all the current-to-voltage converters constant.

Abstract: An electric power system having power supplies connected in parallel to a common bus includes a voltage feedback and current feedback loop for each supply. A voltage feedback signal and a current feedback signal are combined with a reference signal to produce an error signal. The output voltage of each supply is controlled in response to its corresponding error signal, to achieve current sharing and redundancy without interconnections among the control circuits of the various supplies.

Abstract: This application concerns a simple passive circuit that improves current balance in paralleled power MOSFETs that are not precisely matched and that are operated in their active region from a common gate drive. A nonlinear circuit consisting of diodes and resistors generates a differential gate potential required to correct for unbalance while maintaining low losses over a range of current.

Abstract: A power supply control system controls at least two variable power supplies feeding a common load connected to a common output terminal. A sensor monitors the current drawn by each power supply in dependence upon the difference detected in a sense to reduce the difference to zero. A summing circuit sums the outputs of all the comparators. Another comparator compares the output of the summing circuit with a zero level and produces an output to modify the reference signal. The loops comprising each comparator and the further comparator each act in a sense to reduce the output of the summing circuit to zero and in this way the system tends to maintain a balanced output from all supplies so that each supply shares the power requirement of the load according to its capacity while at the same time maintaining the output voltage at a level corresponding to the average of the nominal voltages of the individual supplies.

Abstract: A switch connected between two voltage sources and responsive to a sensing circuit. The switch includes a transistor which operates to interchange the electrical connection of the two voltage sources from parallel to series upon the sensing circuit signals the need for more voltage. The two sources are normally in parallel to increase the cost efficiency and energy efficiency of the amplifier and power supply.

Abstract: A load share system which connects to the power outputs of two power supplies to determine any deviation of the output currents relative to each other and provides a correction signal representative of the deviation. The system generates two balance signals of similar magnitude and opposite polarity and delivers one of the balance signals to a sense input of one power supply and the other signal to a sense input of the other power supply to balance the power outputs.

Abstract: A system and method of connecting power supplies in parallel that provides desired voltage regulation at the load and current sharing between the power supplies. The power supplies are connected in parallel at the load. Each power supply also has a sense line connected at the load. Each power supply includes means for measuring the current delivered to the load. Each supply also includes an electronically controlled variable resistive element in its respective sense line. The amount of current being supplied by each power supply to the load is measured. A controller determines if an unacceptable imbalanced current condition exists, i.e., it determines which power supply is supplying too much or too little current and the controller selectively changes the value of the appropriate variable resistive element in the sense line of that power supply in order to change the current being delivered to the load in a direction that corrects for the imbalanced condition.

Abstract: An electric power source for use in an electrostatic precipitator includes a first high voltage DC source having an output terminal adapted to be connected to discharge electrodes of the electrostatic precipitator. An inductor is connected at its one end through a coupling capacitor to the output terminal. A controlled rectifier is connected at its an anode to the other end of the inductor and has a grounded cathode. A diode is connected in a reversed parallel to the controlled rectifier. There is also provided a second high voltage DC source having a high output impedance and connected to the inductor, and the controlled rectifier is turned on and off by a controller.

Abstract: An inductor generator for welding in which: a plurality of generator elements are combined and incorporated in a single generator and respectively provided with excitation windings to render the generator elements self excitable; a constant-current control circuit is inserted between each excitation winding and corresponding field winding in order to stabilize the field current which has been once set. The constant-current control circuits are so mutually connected that compensation operation is possible so that, when the field current of any of the generator elements is varied, fluctuations of the output values of the other generator elements are prevented, these fluctuations otherwise being due to various effects acting mutually between the generator elements, particularly magnetic effect, in spite of the fact that the field currents of the other generator elements are being maintained at their set values. As a result the above described problems of the prior art are overcome.

Abstract: A stabilized power source parallel operation system in which the composite output current is maintained at a predetermined level even if a plurality of the parallel power sources are deenergized. Each power source has a voltage comparator, a current converter and a current comparator. The outputs of each of the voltage comparators are interconnected by an inter-power source voltage bus so that each of the current comparators compare the same current.

Abstract: A power supply arrangement is disclosed wherein the power supplies (12, 14) share the power requirements of a common load (20) approximately equally and wherein either of the power supplies (12, 14) can act as the "master" while the other power supply acts as the "slave". The arrangement utilizes an integrating differential error amplifier (54), an inverting amplifier (56), and a non-inverting amplifier (58) which are electrically connected between the common load (20) and the power supplies (12, 14) to detect any difference in the output current of the power supplies (12, 14) due to a difference in output voltage, and correct same by increasing the output voltage of the power supply having the lower output voltage until the difference is eliminated. In this manner, either power supply (12, 14) can act as the "master" while the other power supply acts as the "slave".

Abstract: A stabilized DC power outputs supply devices for providing a plurality of DC power outputs which are selectively consumed, is provided by use of a single power control circuit. A plurality of DC power outputs are taken out from the single power control circuit through rectifier circuits and low-pass filter circuits. A voltage of each of the DC power outputs is sensed by a corresponding voltage sensing circuit and is compared with a corresponding reference voltage at a corresponding voltage comparing circuit. Detecting circuits for detecting one of the DC power outputs which is being consumed are provided to apply to a control signal generator the output of one of the comparing circuits which is corresponding to the DC power output detected by the detecting circuits. The control signal generator provides a control signal to the single power control circuit to stabilize the voltage of the DC output which is being consumed.

Abstract: A DC to DC converter has an unregulated input and provides a pair of regulated outputs which independently provide variable power on demand to two independent loads at a substantially constant output voltage. The converter includes three major sections, the input oscillator and pulse width modulation section, the isolated negative DC regulator and the isolated positive DC regulator. Each of the DC regulators is current limited and each is provided with overvoltage protection. One of the output regulators provides improved efficiency through the use of a pair of appropriately connected catch diodes which decrease current change through a filtering inductor, and through implementation of a combined regulator preload resistor and AC pulse width modulating switching transistor drive current source. The converter is a compact modular unit having a low profile with circuit components arranged to minimize temperature instability.

Abstract: A power supply employing a clock-driven D.C.-A.C.-D.C. converter having a current transformer in the A.C. section to develop a trapezoidal current feedback pulse train which is then converted to a trapezoidal voltage pulse train. A comparator compares the trapezoidal voltage pulse train to a voltage reference level set such that it is normally crossed by the ramp portion of each trapezoidal voltage pulse. Upon occurrence of a ramp crossing, which varies with the level of the output current, a control pulse is produced by the comparator and supplied to gating logic which develops driving pulse trains for the D.C.-A.C.-D.C. converter and cuts off each driving pulse upon occurrence of a control pulse. The resulting power supply constitutes a voltage-controlled constant current power supply which may be connected with an arbitrary number of other such supplies to a power bus and a common feedback-controlled voltage reference source.

Abstract: A constant current driving circuit for driving light emitting diodes, wherein a variation detecting circuit comprising a resistor and a field effect transistor is provided and the output voltage of the detecting circuit is effectively used to control the variation of electric current which flows through the driving transistor.

Abstract: A system for controlling and maintaining the power output of a broadcast transmitter under varying line voltage conditions, including a pulse width modulator wherein a triangular wave acting as a reference input is compared to the audio input. Power is controlled by varying the amplitude of the triangular wave relative to the audio input which additionally includes a DC bias thereby increasing or decreasing the comparator square wave output duty cycle which output is used to control the transmitter's RF power amplifier. Three separate DC control inputs, respectively, for automatic power control, remote or local manual power control, and a slow start control are summed and fed to an operational DC amplifier which provides a composite DC output which is fed to a triangular waveform generator in order to control the amplitude of the triangular waveform generated thereby.