Abstract: A full bridge integrable dc-to-dc converter is described which includes four FET switching devices wherein the parasitic capacitors of the switching devices exchange energy with the leakage and magnetizing inductances of the converter transformer. Since energy is exchanged between the passive components of the circuit, the switching is accomplished in a substantially lossless manner. Energy not transmitted to the load is returned to the source rather than being dissipated in the active devices of the converter. Further, single frequency operation is accomplished over a broad range of output conditions by phase shifting the converter legs relative to one another.

Abstract: A high-frequency DC-DC Converter uses a single, primary-side power switching transistor and all of the circuit parasitic elements to achieve high efficiency and small size while operating from no-load to full-load with a relatively narrow operating frequency variation of only about 1.35:1 maximum, and with a reasonably low peak switching device voltage which is only about 3 times the input voltage. The energy stored in the switching device output capacitance is not lost during each high-frequency cycle, but is resonated back to the supply or load circuit. A single-ended-parallel, multi-resonant-converter (SEP-MRC) utilizes a control circuit for controlling the conduction, or "on", time of the single primary-side device, to adjust and regulate the load voltage.

Abstract: A resonant power converter has a plurality of transformers, each having a primary winding and a secondary winding coupled thereto; the primary windings of all of the plurality of transformers are connected in series. The plurality of transformer secondary circuits are effectively connected in parallel, for current addition. a relatively small portion of the resonance capacitor is placed across each primary winding to insure a low impedance which causes the secondary-winding-connected rectifiers to commutatively switch substantially independently and share the entire output current substantially equally. A plurality of lower power transformers are thus utilized to replace a single high power transformer, so that leakage inductance is reduced and a higher operating frequency can be maintained.

Abstract: A high-frequency resonant power converter transforms a relatively low D.C. input voltage to a relatively high A.C. link voltage to drive a resonant circuit. The high A.C. voltage appearing across a resonance circuit high-voltage capacitor is then transformed down to a relatively low value and rectified to obtain a desired relatively low D.C. output voltage. Use of a high A.C. link voltage eliminates low voltage operation of the resonance circuit, which would require very large resonant capacitors having high current ratings. Composite magnetic structures which combine a resonant inductor and a transformer are also disclosed.

Abstract: A control circuit for insuring super-resonant operation of a DC-to-AC resonant converter, having a resonance circuit with a resonant frequency F.sub.r, in which a circulating current i.sub.r flows between a first node A, alternatingly connected between an input potential and a primary common potential at an operating frequency F, and a second node B, includes: a subcircuit for generating a first signal representative of the phase of the circulating current i.sub.r ; another subcircuit for generating a second signal representative of the phase of a potential V.sub.AB between the first and second nodes; and a comparator which compares the first and second signals to increase the operating frequency F if the phase of the circulating current i.sub.r leads the phase of the node-to-node potential V.sub.AB.

Abstract: An integrated circuit contains the gate drivers and the control components for constructing a DC power supply in any of the most popular converter topologies. Multi-function elements in the control circuit minimize the area of the chip. The integrated circuit drives both the upper and lower switches of a half-bridge converter and separately regulates two power supply output voltages, one by pulse width modulation and the other by frequency modulation.

Abstract: A resonant converter feeds five load circuits while maintaining excellent voltage regulation. The power converter features a non-bifilar wound transformer with the resonant capacitors serving the dual function of suppressing diode voltage switching transients while forming the resonant circuit in conjunction with the transformer. Overcurrent circuit protection is also provided.

Abstract: A digital data detector is part of the primary side control electronics in a high voltage integrated circuit for regulating a power supply secondary side output potential; the detector output is responsive to the transitions of digital error data received from the supply secondary side via an electrically-isolated data transmission means. Only the transition edges are utilized by the detector, so that any non-linearity after each transition of the transmission means is immaterial. If the isolation device is a pulse transformer, the transformer core can be of relatively small volume, as full-pulse reproduction is unimportant and pulse saturation is tolerable. A multiplexer allows the primary side control electronics to initiate power supply operation; control is switched to the secondary side responsive to signal edges therefrom being detected by the digital data detector.

Abstract: An integrated circuit contains the gate drivers and the control components for constructing a DC power supply in any of the most popular converter topologies. Multi-function elements in the control circuit minimize the area of the chip. The integrated circuit drives both the upper and lower switches of a half-bridge converter and separately regulates two power supply output voltages, one by pulse width modulation and the other by frequency modulation.

Abstract: In a converter for a switched reluctance motor, a dump capacitor receives freewheeling current from each phase and resupplies the charge to the dc supply. In this manner, residual magnetic energy is recovered and phase current quickly reduced while the converter requires only one main switching device and one freewheeling device per phase and the converter allows a unipolar source to be used.

Abstract: A resonant inverter is operated in a manner to provide a substantially constant output voltage to a load. The inverter is controlled using either a frequency control mode or a phase shift control mode. In the frequency control mode, a constant output voltage is maintained through frequency variation of the rectangular wave signal applied to the resonant circuit of the inverter. In the phase shift control mode, constant output voltage is maintained by phase shifting one component signal of the rectangular wave signal relative to another component signal thereof while maintaining constant the frequency of both component signals. Mode switching occurs automatically at the extremities of the operating frequency range of controllable switch means in the resonant inverter.

Abstract: A single power converter is capable of drawing low distortion current from an AC line and delivering DC or AC power to a load. The single power converter is used to independently control the input current and the output current. The power converter transformer has an output winding which is controlled by pulse-width modulation (PWM) and a frequency controlled boost winding for controlling input current.

Abstract: A single DC power switching converter feeds two DC load circuits from two transformer secondary windings. One winding is tightly coupled to the primary and its output voltage is controlled using pulse-width modulation. The other secondary winding is loosely coupled to the primary so that its leakage inductance resonates with a secondary capacitor such that its output is controlled by converter frequency adjustment. Thus, both output voltages are controlled using a single power switching stage.

Abstract: A bipolar emitter switching transistor in an emitter switched gate turn-off thyristor (GTO) arrangement has a controllable switching device coupled between the base of the emitter switching transistor and the anode of the GTO so that base current needed for the bipolar emitter switching transistor, to obtain a low collector-emitter voltage drop during transistor conduction, is derived from the load circuit, resulting in a greatly reduced base drive power supply requirement.

Abstract: A control for a voltage fed series resonant inverter includes controllable switch means which supplies square wave voltage signals to a resonant series circuit. The output of the inverter is coupled to a rectifier to provide dc power to a load. The control comprises summer means for comparing a commanded dc voltage to an actual dc output voltage and providing an error signal. An oscillator responsive to the error signal generates a frequency signal that is coupled to the controllable switch means to vary the frequency of the square wave voltage supplied to the resonant circuit. The duty cycle of the frequency signal is adjusted so that the frequency signal is provided in bursts during low load conditions thereby minimizing circulating currents while maintaining the output voltage with closed loop frequency control.

Abstract: A resonant dc-dc converter employing power transistors as the switching elements generates a high dc output voltage (150 kilovolts) to drive an X-ray tube. The converter is configured such that the resonating circuit elements can be realized using the transformer parasitic elements. Voltage step up is achieved due to the transformer turns ratio as well as the resonant rise of voltage across the energy storage elements of a series resonant circuit.

Abstract: A dc-dc converter employs a series resonant circuit which is driven by square waves of current. By adjusting the frequency of the square waves of current above the resonant point or by holding the frequency constant and varying the current supplied to the converter, the voltage on the resonant components can be stepped up and controlled. Switching losses in the inverter gate turn-off devices are low since the inverter feeds a lagging load which allows the use of lossless snubbers.

Abstract: A dc-dc converter employs a parallel resonant circuit which is driven by square waves of current. By adjusting the frequency below the resonant point, the voltage on the resonant components can be stepped up. Switching losses in the inverter devices are low since the inverter feeds a lagging load allowing lossless snubber operation which allows the use of lossless snubbers.

Abstract: A high gain latching Darlington transistor comprises a gate turn-off thyristor and a load transistor coupled in Darlington configuration. Circuit means including a diode are coupled to the gate turn-off thyristor and the transistor to provide a low loss path for load transistor current which reverse biases the gate-cathode junction of the thyristor at thyristor turn-off to prevent premature device conduction. The latching Darlington transistor configured in this manner thus operates as a conventional gate turn-off thyristor, capable of being pulsed into and out of conduction, but yet exhibits improved dv/dt capability and increased turn-off gain, typically between 10 and 100 times the turn-off gain of the individual gate turn-off thyristor.

Abstract: A transistor is operated in the PWM mode such that a hlaf sine wave of current is delivered first to one-half of a distribution transformer and then the other as determined by steering thyristors operated at the fundamental sinusoidal frequency. Power to the transistor is supplied by a dc source such as a solar array and the power is converted such that a sinusoidal current is injected into a utility at near unity power factor.