Patent ID: 7489532

Claim:
A power converter with feed-forward voltage compensation for enabling a PFC circuit, comprising: a PFC circuit, generating a bus voltage in response to an input voltage; a power stage, coupled to said PFC circuit for generating an output voltage in response to said bus voltage; a feedback unit, coupled to said power stage for generating a feedback voltage in response to said output voltage; a voltage divider, generating a compensation voltage in response to said input voltage; an operation unit, coupled to said feedback unit and said voltage divider for generating a first threshold voltage in response to the sum of said feedback voltage and said compensation voltage; and a comparator, having two input ends and one output end, wherein the two input ends of the comparator connect to said operation unit and a reference voltage, and the output end of the comparator connects to said PFC circuit; said comparator is a hysteresis comparator that provides a hysteresis range in response to said reference voltage, said comparator generates said control signal to compare said hysteresis range with said first threshold voltage so as to activate said PFC circuit to perform power factor correction and boost procedure when the input power is the result of a high input voltage condition or a low input voltage condition, said reference voltage being constant.