A voltage converter circuit includes a voltage converter controller which generates a PWM signal to operate a power switch for voltage conversion. The voltage converter controller includes a sensing pin for sensing a current and the voltage converter controller receives a power supply. A parameter setting method for the voltage converter circuit includes: during a start-up stage, when the power supply increases above a predetermined reference level, the voltage converter controller outputting a current through the sensing pin; and setting at least one parameter of the voltage converter controller according to a voltage at the sensing pin.