Abstract: A circuit for converting a DC voltage to a pulsating DC voltage useful as a power source for operating an AC machine. The circuit includes means for controlling the amplitude of the pulsating DC voltage as the load changes and means for controlling the duration of the pulses comprising the pulsating DC voltage.

Abstract: An overvoltage protection power supply circuit for preventing an overvoltage from being applied directly to the flat panel display elements when the overvoltage is induced by a power supply, said overvoltage protection power supply circuit comprising a voltage regulating circuit for receiving an unregulated DC voltage and outputting a regulated DC voltage; a DC to AC voltage converting circuit for receiving the regulated DC voltage and converting the same to an AC voltage for driving flat panel display elements; a rectifying circuit for rectifying the output voltage of said inverting circuit; an overvoltage check circuit for identifying the existence of an overvoltage condition; and a switching circuit for determining a voltage on an adjusting terminal of said voltage regulating means, said switching circuit being controlled by said overvoltage check means whereby the output voltage from said DC to AC voltage converting circuit is fedback to said adjusting terminal of said voltage regulating means via said re

Abstract: A switching power supply for controlling an output voltage to a constant value with respect to fluctuations in input or in load, wherein are provided a DC power supply; two dividing capacitors connected in series to both ends of the DC power supply; two semiconductor switches connected in series to both ends of the DC power supply; a transformer having a primary winding, one end of which is connected to a connecting point of the two dividing capacitors; and a T type circuit comprising two inductors connected in series between the connecting point of the two semiconductor switches and the other end of the primary winding; and a capacitor connected between the connecting point of the two inductors and the other end of the primary winding. The control characteristics of the switching power supply are improved by reducing the dependency of the output voltage on fluctuations in the load.

Abstract: Disclosed is a device power supply in a semiconductor test system for supplying programmed test pattern voltages to a semiconductor device under test and for current range switching of current range resistors without effecting the output voltage of the device power supply.

Abstract: A pulse-width-modulated inverter in which equations relating switching angles, d.c. link distortion and a.c. inverter output distortion are determined empirically or by computer modeling. The amplitude of a d.c. link harmonic is the equation variable and stored constants particularize the equation for the phase of the harmonic and each switching angle which is to be controlled in response to d.c. distortion. As the d.c. link harmonics change, switching angle modifications are calculated using the stored constants.

Abstract: A voltage multiplier selectively couples an input voltage potential (10) from a voltage source (Vin) to an energy storage device (22) in response to a first control circuit (18). A second switching circuit (26) is used to selectively serially couple the first energy storage device (22) and the voltage source (10) to provide an intermediate voltage potential (Vin), which is selectively coupled to a second energy storage device (30) in response to a second control signal (28') that is provided by a second control circuit (38) coupled to the intermediate voltage potential (Vim). The output of the second energy storage device (30) comprises an output voltage potential (Vout) being greater than the input voltage potential (Vin).

Abstract: A circuit is provided that generates a predetermined regulated voltage between first and second terminals that is positioned between first and second power supply voltage rails wherein the predetermined regulated voltage is substantially independent of temperature and power supply variation. The circuit includes a bandgap circuit for providing a predetermined reference potential that is substantially independent of temperature and power supply variation. A resistive circuit provides first and second voltages which are referenced with respect to the first supply voltage rail. A level translator circuit translates the second voltage provided by the resistive circuit to a third voltage which is referenced with respect to the second supply voltage rail.

Abstract: A control system for poly-phase power inverters that uses feedback sensed voltages and currents to control the switching of solid state power switches in the inverter bridges, producing a nearly ideal sinewave voltage output regardless of load induced or switching harmonic voltages. The system operates in combination with the inverter power switches and switch drivers, particularly incorporating a digital programed optimal controller with virtually no delay in implementing the feedback control, and automatically correcting for any sensed line voltage distortions. The system inherently provides a high recovery speed for voltage transients.

Abstract: The control for an AC inverter includes a low voltage microcontroller referenced to ground potential and a waveform generator coupled to the microcontroller through a serial data link including optical isolation devices. The waveform generator floats at the negative bus potential of the DC source for the inverter. The waveform generator produces switching signals for the inverter under control of the microcomputer. The waveform generator, serial communications circuitry and other support circuits are all part of a single application specific integrated circuit.

Abstract: An electrical power converter including both DC and AC power terminals which are respectively connected to a DC current source and an AC voltage source, the latter comprising the grid of an AC power utility. A capacitor is coupled to the AC terminals along with a load. A control and gating circuit is coupled to the converter for supplying control signals for the thyristors of a converter bridge included in the polyphase converter. When disconnected from the utility grid, a relatively fast acting control loop is coupled to the control and gating circuit and is responsive to the current flowing in the capacitor and an AC reference voltage to accommodate the current source characteristics of the converter for maintaining an output voltage of substantially constant amplitude across the AC terminals.

Abstract: A PWM converter apparatus having phase detection means including an error detection protection device for outputting an estimate value as a present phase signal when a phase signal in each computation cycle deviates for a predetermined value or more from the estimate value obtained according to the former phase signal, the frequency of a power voltage, and a computation cycle.

Abstract: A parallel multi-inverter system including a plurality of inverters connected in parallel to each other through one or more parallel reactors, wherein output voltages of the inverters are controlled on the basis of the polarity of an output voltage command signal and a comparison result between a value obtained by converting the output voltage command signal into a positive one and a carrier signal to reduce harmonic components of the line-to-line voltages, and further two different switching modes to set the output voltage of the system zero are equally used to prevent a circulating current from flowing through the parallel reactors during each zero potential period of the output voltage of the system.

Abstract: A regulator circuit is connected to a transformer. The transformer has a primary winding connected to a rectified D.C. voltage signal and has a feedback winding. A feedback capacitor is coupled across the feedback winding of the capacitor. The regulator circuit includes a high voltage switching transistor, a pulse width modulator which controls the high voltage switching transistor and a high voltage power up transistor. At power up, the high voltage power up transistor connects the single high voltage pin to the feedback capacitor allowing the feedback capacitor to begin charging. When the feedback capacitor has charged past a first threshold voltage the pulse width modulator alternately turns the high voltage switching transistor on and off. When the high voltage switching transistor is turned on, the high voltage pin is connected to ground and current passes through the primary winding of the transformer, and thus current is generated through the feedback winding into the feedback capacitor.

Abstract: A single quadrant chopper timing control circuit is used with unidirectional power flow chopper arrangements in a power inverter to maintain current oscillation between positive and negative threshold levels of a hysteresis controller. The single quadrant chopper timing control circuit creates a mimic current when the current in the power inverter becomes zero or less. The mimic current allows the unidirectional power arrangement to continue oscillating so that there is little or no discontinuity in the timing. The device will continue to operate and provide a high bandwidth to ensure that the device will function during an overload or load dump condition.

Abstract: An autoconverter has an electronic switch activated by turn-on pulses and a circuit arrangement for the formation of the actual value of the current in a primary input circuit. Inrush currents are suppressed within an optimally-broad range of current by providing an electronic switch in the circuit arrangement which forms the actual value of the current, the electronic switch being inhibited during initial power peaks of the current flowing through a current sensor in the primary input circuit.

Abstract: A two-phase bang-bang current control synchronizer for synchronizing two current streams which pass within a hysteresis controller. Synchronization occurs by summing a fixed hysteresis threshold voltage from a master chopper and a sawtooth wave voltage corresponding to a synchronization and outputting a summed signal to an integrator controller which integrated the summed signal and outputs an intergrates signal. A synchronization circuit receives the integrated signal and generates a sawtooth waveform corresponding to an average value of the fixed hysteresis threshold voltage. The sawtooth waveform is fed to the slave chopper and synchronizes the master chopper and the slave chopper.

Abstract: An inverter controller adjusts a selected switching pattern to accommodate minor variations and loads in the neighborhood of that pattern. The controller realizes in real-time the equivalent of an iterative solution of predetermined patterns. A number of representative pulse width modulated (PWM) patterns are selected for a range of loads and link ripple. A portion of the fundamental output is inserted onto the d.c. link to control one or more higher harmonics.