Patent ID: 7538536

Claim:
A controller IC for controlling the ac power to be supplied to a load by driving a semiconductor switch circuit, said controller IC comprising: a current detection signal input terminal for receiving a current detection signal formed on the basis of the current through said load and for coupling with one end of a capacitor; a PWM control signal generation circuit adapted to generate an error signal based on said current detection signal inputted into said current detection signal input terminal, and generate a PWM control signal for switching on and off said semiconductor switch circuit based on said error signal; an intermittent operation signal generation circuit for generating an intermittent operation signal that intermittently changes its state between a first and a second state; and an intermittent operation control circuit for receiving said intermittent operation signal, said intermittent operation control circuit adapted to charge said capacitor via said current detection signal input terminal when said intermittent operation signal is in said first state.