Patent ID: 6822427
Filing Date: 2004-11-23
Classification: H02M,Y02B

Abstract:
A zero voltage switching cell comprising,a first cell terminal, a coupled inductor having a primary winding and a secondary winding with a dotted terminal of said primary winding of said coupled inductor connected to said first cell terminal, a rectifier having first and second terminals with said first terminal of said rectifier connected to an undotted terminal of said primary winding of said coupled inductor, a second cell terminal connected to said second terminal of said rectifier, an active reset network having a first terminal and a second terminal with said first terminal of said active reset network connected to a dotted terminal of said secondary winding of said coupled inductor and with said second terminal of said active reset network connected to an undotted terminal of said coupled inductor, comprising a series connection of, a capacitor, and switch means, operable substantially in synchronization with said rectifier, being on when said rectifier is on and being off when said rectifier is off, except for timing variations at the switching transitions, which timing variations are sufficiently long to enable a transition of said switch means from a non-zero applied voltage in an off state to zero applied volts, whereby said zero voltage switching cell, when substituted for the main rectifier in a hard switching power converter circuit having a single main switch, a single main rectifier, and a main dc magnetic energy storage element, provides zero voltage switching for said single main switch by using energy stored in said coupled inductor to drive a zero voltage turn on transition for said single main switch.