The invention relates to a high
power factor DCM Boost PFC converter comprising a main power circuit and a
control circuit. The main power circuit comprises an input
voltage source vin, an EMI filter, a
diode rectification circuit RB, a Boost
inductor Lb, a switch tube Qb, a
diode Db, an output
capacitor Co and a load RLd. The high
power factor DCM Boost PFC converter is characterized in that the
control circuit adopts an output
signal which adopts duty ratio as changing rule to drive the switch tube Qb. Adopting the varying duty ratio control, the high
power factor DCM Boost PFC converter can improve the PF value to about 1 in the AC input
voltage range of 90-265 V, increase the
inductance capacity, obviously decrease the inductive current
ripple, obviously reduce the effective value of the inductive current and correspondingly reduce the effective value of the current of the switch tube, has
high input power factor and small output
voltage ripple and contains less input current
harmonic waves. The
conduction loss of the high power factor DCM Boost PFC converter is reduced, and the efficiency is improved.