Abstract: The present invention provides a full-resonant power circuit device for receiving a variable input voltage that a power factor correcting circuit for separating a variable input voltage AC into a plurality of supply voltages, and the input voltage sections are detected to separately switch corresponding switch transistors for suitably adding resonance inductors to the input voltage sections to be used by the full-resonant power circuit device to reduce the large voltage difference of a conventional power factor corrector so as to improve the efficiency of the power circuit device and improve a half-bridge resonance circuit that is only operated in a fixed voltage source.

Abstract: A switch-mode self-coupling power device additionally increases a set of high voltage auxiliary winding in the transformer and increases a control circuit and an energy transmitting circuit in the primary side circuit of the conventional circuit. When the load is too low, the control circuit may control the energy transmitting circuit according to the variation of the load so that the voltage of the high voltage auxiliary winding can be transmitted to a controller for operation through the energy transmitting circuit. Therefore, the design of PWM controller (pulse width modulation controller) auxiliary power circuit according to the present invention, which is not limited by the magnitude of a dummy load at the secondary side of the transformer, can conform to international regulations and is a product with industrial purpose and conforming to green mode.

Abstract: A forward power converter with a self-excited synchronous rectifying circuit makes use of the self-excitation function of a transformer to generate electric energy at a secondary side winding coil of the transformer, hence controlling an n-channel FET to accomplish synchronous rectification. In the synchronous rectifying circuit, the drain of the n-channel FET is connected to an end of the secondary side of a first transformer, the source of the n-channel FET is connected to a positive end of a flywheel diode, the negative end of the flywheel diode is connected to the other end of the secondary side of the first transformer, a control end of the n-channel FET is connected to an end of an induction coil via a resistor and a capacitor, and the other end of the induction coil is connected to the source of the n-channel FET.

Abstract: A forward power converter with a self-excited synchronous rectifying circuit makes use of the self-excitation function of a transformer to generate electric energy at a secondary side winding coil of the transformer, hence controlling an n-channel FET to accomplish synchronous rectification. In the synchronous rectifying circuit, the drain of the n-channel FET is connected to an end of the secondary side of a first transformer, the source of the n-channel FET is connected to a positive end of a flywheel diode, the negative end of the flywheel diode is connected to the other end of the secondary side of the first transformer, a control end of the n-channel FET is connected to an end of an induction coil via a resistor and a capacitor, and the other end of the induction coil is connected to the source of the n-channel FET.