Fairchild Semiconductor Corporation

Acme Electric Corporation

Ronald H Randall

Sampat Shekhawat

Donghye Cho

Dong-Young Huh

In one embodiment, a power converter system includes a first input terminal and a second input terminal operable to connect to an alternating current (AC) power source, and an output terminal at which an output voltage can be provided to a load. A first inductor and a first diode are connected in series between the first input terminal and the output terminal. A second inductor and a second diode are connected in series between the second input terminal and the output terminal. A first switch is connected to the first inductor and the first diode, and a second switch is connected to the second inductor and the second diode. The first switch and the second switch alternately function as a boost switch and a synchronous rectifier for charging and discharging the first and second inductors during operation of the power converter system. An auxiliary network is operable to provide for zero voltage switching (ZVS) and zero current switching (ZCS) conditions for both the first and second switches during operation of the power converter system.

High-efficiency power converter system

A synchronous full bridge rectifier is controlled to provide a power factor near unity. The full bridge rectifiers are transistors each with a controlling input. The AC input signal and currents within the circuit are sensed and sent to a controller. In response, the controller output control signals to turn on/off the rectifying MOSFETS on a timely basis to form a power factor of near one with respect to the AC input signal. The full wave rectifier is made of N-channel MOSFET's, some with fast body diodes. The MOSFET's are rectifiers and PFC control elements. The result is a one stage synchronous rectifier with PFC. A solid state precision analog differential amplifier senses the AC line waveform and high frequency current transformers sense the currents. The controller accepts the inputs of the amplifier and the sensed currents and outputs control signals that turn on and off the four MOSFET's. The timing of turning on/off is arranged so that the current drawn from the AC source is sinusoidal and matches the phase of the sinusoidal AC source.

Vrms and rectified current sense full-bridge synchronous-rectification integrated with PFC

An inverter circuit is disclosed in which the alternating current output is rectified to become a DC power supply with a regulated output voltage. The inverter is controlled to limit the peak current conducted by the power semiconductors and a current limit circuit is provided to limit the DC output current. The invention provides an output current sensing circuit utilizing a current transformer, with the primary winding thereof connected in the alternating current portion of the inverter circuit and with current flow in the primary winding proportional to the DC output. Rectifier means is provided to rectify the output of the secondary winding of the current transformer, and this is supplied across a first resistor. There is means to sample the voltage across this first resistor only during the conduction period of the power semiconductors. An integrating means is provided to integrate the sampled voltage and develop an output current signal for control of the output current from the inverter circuit. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

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Cuba, NY, United States of America

Ronald H Randall