Abstract: A power converting apparatus controls switching of self turn-off type semiconductor devices so as to perform power conversion. The apparatus comprises a plurality of switch units each having first and second self turn-off type semiconductor devices, first and second diodes, and a capacitor. The cathode of the first self turn-off type semiconductor device is connected to the anode of the first diode, and the cathode of the second diode is connected to the anode of the second self turn-off type semiconductor device. The capacitor is connected between a common junction between the cathode of the first self turn-off type semiconductor device and the anode of the first diode and a common junction between the cathode of the second diode and the anode of the second self turn-off type semiconductor device.

Abstract: An inductor is connected in parallel with an electrical load which, together with the capacitive components of the load, forms a resonant circuit. An auxiliary inductance coupled to the aforesaid conductor is energized periodically. During the oscillations, the resonant circuit delivers the energy to the load. The power dissipation of the switches is very low, due to the auxiliary inductance and the resonant circuit. The high-voltage generator is particularly suitable for gas lasers.

Abstract: A full bridge switching power supply is coupled to an ozonator load via a series resonant circuit having a resonant frequency above the switching frequency. Power output is controlled by varying the duration of the times when diagonal switches are conducting, and the output voltage has a longer rise time than fall time due to there being intervals between the conduction periods of diagonal switches during which one of the switches is turned on to permit resonant current flow. The driving voltages for attaining this action are symmetrical rectangular waves of identical shape having different phases that are derived from out of phase pulses where width is varied by the timing of their trailing edges.

Abstract: A modular switching system includes a transistor operative in a switching mode for applying current to a load. Adaptation of the system to accommodate different values of load is attained by coupling an input drive ,signal to a base terminal of the transistor via a variable gain amplifier wherein the gain is established by a load-adaption signal to meet the requisite base current drive signal for the load. Plural emitter terminals of the transistor connected to separate branches of a monitoring circuit, each branch having its own threshold detector, for monitoring of minimum and maximum values of load current.

Abstract: A current mode power supply having a switching topology with a pulse width modulated duty cycle with a current sensing resistor is short circuit protected by a current limit circuit. The current limit circuit has inputs coupled to the current sensing resistor and the dc source input. The current limit circuit provide an output signal connected to the pulse width modulator, for shortening the duty cycle in dependence upon the sum of voltage signals from the current sensing resistor and the dc source input.

Abstract: A power source device is disclosed with a transformer having a plurality of windings provided with the secondary of the transformer, first and second smoothing means connected to a predetermined winding in the plurality of windings, a first voltage detection means for detecting a change of an output voltage from the first smoothing means and means for superimposing an output from the first voltage detection means on an output from the second smoothing means and feeding back a superimposed value to the primary of the transformer. The disclosed power source device has less ripple in the output and is stably responsive to an abrupt change of load.

Abstract: A voltage control system has a pair of clockwise and counterclockwise interleaved coils on a portion of a transformer core, the coils having multiple spaced turns providing sets of co-planar alternate electrical contact pairs extending linearly to form a tapping system for varying the output voltage of the transformer. A conductive electrical bridging member is movable in the linear direction of extension of the contacts and bridges a selected pair of contacts, one contact from each coil, to alter the effective number of electrical turns of the two coils between a minimum and maximum output voltage. An adjunctive feature is to provide both a contact lead to the bridging member and appropriate rectification at output ends of the pair of coils in order to produce a direct current output.

Abstract: An inrush current limiting circuit includes a power FET switch connected between power source and load and a control circuit. The power FET switch includes one or more parallel-connected power FETs, each having low individual conductive resistances. The control circuit, connected between the power inputs and the gate of power FET switch, includes a voltage supply for providing sufficient voltage to turn the power FET switch on and a time constant circuit for controlling the rate at which the power FET means is turned on. With the voltage supply connected to an optional enable terminal, a DC enable signal can control powering of the load. A second time constant circuit controls the rate of power down.

Abstract: In a power unit, an output current supplied from the power unit to a load device is constantly detected as a load current. When the detected load current exceeds a predetermined current value, output power supplied from the power unit to the load device is reduced or cut off. An output voltage supplied from the power unit to the load device is constantly detected. When the detected output voltage has continued to be lower than a predetermined voltage value over a predetermined time period, the output power is reduced or cut off.

Abstract: A voltage control circuit comprises a transformer (18) having primary (17) and secondary (20, 21) windings, an input coupled to said primary winding, first and second switch devices (11, 12) each coupled to said primary winding of the transformer, and a clamping capacitor (28) coupled to the transformer and at least one of the first and second switches. An output filter (25, 26) is coupled through a rectifier (23, 24) to the secondary winding of the transformer and an output is taken from the output filter. Means comprising a feedback circuit (13, 14, 15) coupled on one side to the output filter and on the other side to control terminals of the first and second switches cause the first and second switches to conduct current alternately. Operation of the circuit is stabilized by including an interconnection (29) of the clamping capacitor to the feedback circuit for generating a signal that modifies the energy applied by the feedback circuit to the control terminals of the first (11) and second (12) switches.

Abstract: A transformer having a primary winding and a secondary winding across which load is coupled is compensated. A third winding is provided on the transformer. A first output terminal of an amplifier is coupled to a first terminal of the primary winding. A first terminal of the third winding is coupled to the second terminal of the primary winding. A second terminal of the third winding is coupled to an input terminal of the amplifier.

Abstract: A power supply circuit includes a cascade arrangement of a full-wave rectifier and a first and a second switched voltage converter. The input terminals of the first voltage converter receive a rectified supply voltage. The second switched voltage converter has input terminals connected to a first storage capacitor of the first voltage converter. The second voltage converter includes the output terminals of the power supply circuit. A control circuit controls the period of conductance of the controlled switches of the switched voltage converters with a switching period which is much shorter than the cycle period of the AC supply voltage. A first inductive element is connected via a first controlled switch across the output terminals of the full-wave rectifier during a part of the switching period.

Abstract: A digital controlled inverter (100) for inverting an input signal to an alternating current signal having a clock generator (104) for generating a high frequency clock timing signal and a latch (106) for controlling the passage of the clock timing signal to a power stage (102). The power stage (102), which provides a low distortion alternating current signal, is controlled by the latch (106). A control loop (108) is provided for sensing and converting the alternating current signal to a command signal. The command signal controls the state of the latch (106). The latch (106) is reset at the rate of the clock timing signal and updated with the command signal to provide pulse-to-pulse regulation of the alternating current signal. The inverter (100) comprises a transient response to variations in load proportional to the clock timing signal. In a preferred embodiment, the latch (106) functions as a switch for controlling the power output stage (102).

Abstract: A microprocessor-controlled DC-DC converter includes a controllable switch for generating at least one output voltage (Ua). The duty cycle of the controllable switch is controllable depending upon the output voltage. Despite the use of an inexpensive and hence "slow" microprocessor, the control stability of the DC-DC converter will still be adequate if, during the computation time of the microprocessor that is available for the calculation of the duty cycle of the controllable switch, the output voltage is sampled more than once. The duty cycle of the controllable switch is presettable as discrete values (Df) determined by means of an output unit of the microprocessor. These discrete values are formed, from the respective duty cycle determined, by a coarse quantization which corresponds to the temporal resolution of the microprocessor and by a fine quantization associated with each quantization step of the coarse quantization.

Abstract: An apparatus and method is disclosed for an improved control system for a series resonant converter for transferring power between a source and a load. The control system comprises a series resonant circuit including a capacitor and an inductor with a first and second switching matrix connecting the series resonant circuit to the source and the load, respectively. A controller selects a combination of switches for transferring power between the source and the load using a single segment half-cycle resonant waveform that produces a final voltage on the capacitor within a preselected boundary.

Abstract: A method employing a precharging pulse to adjust and/or to equalize the peak voltages of a discontinuous bipolar pulse waveform used for powering a corona in an ozone generator system. This precharging pulse is generally opposite in polarity to the first unipolar pulse of the bipolar pulse waveform, and precharges the inductances and capacitances of the system to provide priming energy for the first corona pulse and to compensate for skewing of the waveform due to resonances. This method enables the corona to be operated at the optimum voltage for efficient ozone generation, and provides the ability to fine-tune each system to best match high-voltage transformers to corona cells.

Abstract: A rectifier circuit is constructed entirely with field-effect transistors of the same conductivity type and which provides rectification with a small voltage drop and hence a high efficiency. A normally-off FET is coupled between an alternating voltage input and a direct voltage output. A bias circuit biases the gate of this FET so as to reduce the effective threshold voltage of the FET substantially to zero. Bridge rectifier circuits, based on this principle make it possible to obtain both half-wave and full-wave rectification with a very small voltage drop. Various circuits for generating the gate bias are disclosed.

Abstract: A bidirectional voltage to current converter circuit with extended dynamic range includes a first and second operational amplifier in which the input voltage terminal is connected to the negative input of both operational amplifiers. The outputs of the operational amplifiers each directly drive the gates of two transistors which operate as a current mirror circuit. The current mirror transistors associated with the first operational amplifier are p-channel transistors with their sources connected to VDD, and the two transistors driven by the second operational amplifier are n-channel transistors with their sources connected to ground. The drains of the first p-channel transistor and the first n-channel transistor are coupled back to the positive inputs of the first and second operational amplifiers respectively; and also each drain is separately connected to one end of a resistor, the other ends of the two resistors are connected together and to a reference voltage.

Abstract: The operation of an electromechanical relay is synchronized with the power line waveform where an electrical power supply is supplied from a source to an electrical load. The current voltage supplied to the load is characterized by a power line waveform. An electromechanical relay is positioned between the power supply and the load where contacts of the relay are opened and closed to interrupt and supply power to the load. A microcontroller is positioned between a power source and the electromechanical relay and actuates the relay so that when the contacts are closed or opened the contacts are not exposed to an undesired voltage. A feedback control circuit senses the opening and closure of the contacts so that in the event the contacts, for example close at an undesireable point on the load current waveform the microcontroller adjusts for the necessary delay to cause the actuation of the relay to occur such that the contact closure is at the desired point in the load current waveform.

Abstract: A start circuit for starting the generation of pulse width modulated switching pulses is disclosed for use in a DC/DC switching converter power supply. The starting circuit is responsive to the initiation of a DC voltage source and starts the operation of a pulse generator. The starting circuit also includes a relaxation oscillator connected to the DC voltage source for periodically generating a start pulse at a predetermined frequency. Ongoing power is coupled to the pulse generator once the generator begins operation. The relaxation oscillator is selectively disabled when the pulse generator is powered by the ongoing power supplied by the power supply during normal operation. The start circuit further includes a delay function for delaying the disabling of the relaxation oscillator for a preselected period after shutdown of the power supply and includes a rapid start function for reducing the time between restoration of input power and the operation of the start circuit.