Patent ID: 7095635

Claim:
A dc-ac converter, comprising: a dc power supply; a transformer having a primary winding and at least one secondary winding; a semiconductor switch circuit for passing a current alternately in a first direction and a second direction from said dc power supply to said primary winding; a load connected to said secondary winding; a current detection circuit for detecting the current flowing through said load to generate a current detection signal indicative of the current detected; a PWM triangular wave signal generation circuit for generating a triangular wave signal for use in PWM (said triangular wave signal referred to as PWM triangular wave signal); a PWM control signal generation circuit for generating a PWM control signal upon receipt of said PWM triangular wave signal and current detection signal by generating an error signal based on said current detection signal; and comparing said error signal and PWM triangular wave signal to generate said PWM control signal; and an intermittent operation control circuit for setting the level of said error signal to substantially zero based on an intermittent operation signal during an off-duty period of said intermittent operation, wherein said semiconductor switch is switched on and off in accordance with said PWM control signal.