Patent ID: 6882132
Filing Date: 2005-04-19
Classification: H02M

Abstract:
1. A DC voltage chopper, comprising: a power switch device having a drive circuit and a main circuit connected to and driven by said drive circuit; an LC filter circuit connected to said main circuit, said LC filter circuit having an output terminal functioning as an output terminal of the DC voltage chopper; a commutating circuit connected in parallel to said LC filter circuit; a reference voltage generator outputting a reference voltage; and a comparison circuit having a hysteretic function and an output coupled to said drive circuit, said comparison circuit having a first input terminal connected to said output terminal of the DC voltage chopper and a second input terminal connected to said reference voltage generator and receiving the reference voltage; said drive circuit containing a logic circuit having a first input connected to said output of said comparison circuit for receiving a switch-off signal for said power switch device and a second input for receiving a switch-on signal for said power switch device, said second input receiving a trigger clock signal with a fixed frequency as the switch-on signal, said logic circuit generating an output signal for switching said power switch device on after a constant period of time being determined by the fixed frequency of the trigger clock signal, said logic circuit switching said power switch device off as soon as an output voltage of the DC voltage chopper reaches the reference voltage.