Patent ID: 8552699

Claim:
An electromagnetic interference reduction network for a converter, wherein the converter includes upper and lower power switches having current terminals coupled together at a phase node and provided in series between an input voltage node and a reference node, said electromagnetic interference network comprising: an inductance for coupling between the input voltage node and the upper power switch at a first node; an auxiliary power switch having current terminals coupled between said first node and a second node; a capacitance for coupling between said second node and the reference node; and a controller for controlling switching of the upper and lower power switches and said auxiliary power switch based on a pulse control signal which toggles between first and second states, wherein said controller operates to: provide a first control signal to turn the upper power switch on in response to the pulse control signal switching to the second state and to turn the upper power switch off in response to the pulse control signal switching to the first state; provide a second control signal to turn the lower power switch on after the upper power switch is turned off and to turn the lower power switch off approximately when the voltage on the phase node goes positive while the upper switch is on; and provide a third control signal to turn said auxiliary power switch on after the lower power switch is turned off and to turn said auxiliary power switch off after the upper power switch is turned off.