Patent ID: 7885086

Claim:
A forward converter with self-driven synchronous rectifiers, comprising: a transformer comprising a primary winding, a secondary driving winding and a secondary power winding, wherein the primary winding is connected with an external power supply; a master power loop comprising a forward rectifier, a freewheeling rectifier and a power inductor and connected to the secondary power winding of the transformer, wherein the master power loop comprises a master voltage output terminal and a ground terminal, a filter capacitor is connected between the master voltage output terminal and the ground terminal, first terminals of the freewheeling rectifier and the forward rectifier are respectively connected to a first terminal and a second terminal of the secondary power winding, second terminals of the freewheeling rectifier and the forward rectifier are connected at a connection point, the connection point is connected to the ground terminal, and a power inductor is serially connected between the first terminal of the secondary power winding and the voltage output terminal; and a signal distributor comprising a first output terminal, a second output terminal and a common connection terminal, wherein the first output terminal and the second output terminal are respectively connected to control terminals of the freewheeling rectifier and the forward rectifier, the common connection terminal is connected with the connection point of the second terminals of the forward rectifier and the freewheeling rectifier, wherein that the common connection terminal is conducted to the first terminal or the second terminal depends on a voltage difference between the first output terminal and the second output terminal to distribute a voltage signal to the control terminal of the forward rectifier or the freewheeling rectifier, wherein the signal distributor comprises a first diode and a second diode, anodes of the first diode and the second diode are connected with the common connection terminal, and cathodes of the first diode and the second diode serve as the first output terminal and the second output terminal, respectively, and the signal distributor is connected directly or through a level shifter to the secondary driving winding.