Patent ID: 6396714
Filing Date: 2002-05-28
Classification: H02M,Y02B

Abstract:
An active clamp forward converter capable of switching a direct current supplied to a primary coil of a transformer between zero current and zero voltage, and inducing a voltage in a secondary coil after rectifying and smoothing said voltage, comprising:a first FET (field effect transistor) connecting a first end of said primary coil to a positive terminal of a direct current power supply; a second FET connecting a second end of said primary coil to a negative terminal of the direct current power supply; a third FET connecting the first end of said primary coil to the negative terminal of the direct current power supply via a first capacitor; and a fourth FET connecting the second end of said primary coil to the positive terminal of said direct current power supply via a second capacitor; wherein, said zero current/zero voltage switching of said direct current supplied to said primary coil of said transformer is performed by alternately controlling a first pair of transistors comprising said first and second FETs and a second pair of transistors comprising said third and fourth FETs to on and off states, said alternate on and off states being sandwiched between time periods during which both pairs are controlled to be in the off state.