Patent ID: 7643313

Claim:
A PWM controller for compensating a maximum output power of a power converter, comprising: a PWM unit for generating a PWM signal for controlling a power switch to switch a power transformer, wherein the power switch is coupled to a primary winding of the power converter, the power transformer is supplied with an input voltage of the power converter, and a pulse width of the PWM signal is correlated to an amplitude of the input voltage; and a compensation circuit coupled between the PWM unit and a current-sense device for generating a current boost signal in response to the PWM signal and a current-sense signal, wherein the current-sense signal is generated by the current-sense device in response to a primary-side switching current of the power transformer, the current boost signal is generated by pushing up a peak value of the current-sense signal, and a peak value of the current boost signal is adjusted by the pulse width of the PWM signal for compensating a difference of the maximum output power caused by the amplitude of the input voltage.