Patent ID: 7969225
Filing Date: 2011-06-28
Classification: H03K

Abstract:
1. A circuit of reducing power loss of a switching device, comprising: a pair of auxiliary switching devices, said pair of auxiliary switching devices being connected to a direct voltage, said pair of auxiliary switching devices comprising a top leg auxiliary switch and a bottom leg auxiliary switch, said top leg auxiliary switch and said bottom leg auxiliary switch being serially connected with each other, each of said top leg auxiliary switch and said bottom leg auxiliary switch being an auxiliary metal-oxide semiconductor field-effect transistor (MOSFET); a pair of diodes, said pair of diodes being connected with said pair of auxiliary switching devices, said diodes comprising a first diode and a second diode; a pair of switching devices, said pair of diodes comprising a top leg switch and a bottom leg switch, said top leg switch and said bottom leg switch being serially connected with each other, said top leg switch and said bottom leg switch being switching MOSFETs, each of said top leg switch and said bottom leg switch being connected with a resonant capacitor parallelly; a pair of auxiliary inductors, said pair of auxiliary inductors being connected with said pair of auxiliary switching devices and said pair of switching devices, said pair of auxiliary inductors comprising a first inductor and a second inductor, said first inductor and said second inductor being parallelly connected with each other, each of said first inductor and said second inductor having a first terminal and a second terminal; and a load circuit, said load circuit being connected with said pair of switching devices, said load circuit comprising a load inductor and a plurality of load capacitors, wherein an auxiliary switching circuit comprising said pair of auxiliary inductors, said pair of auxiliary switching devices and said pair of diodes is obtained to fix each turn-on time of said top leg auxiliary switch and said bottom leg auxiliary switch, wherein, said auxiliary switching device is turned on after a drain-source voltage of a parallel capacitor of a corresponding MOSFET is totally discharged.