Power dimmer

A circuit for controlling power in a load supplied by an A.C. supply voltage and directly connected to a first terminal of application of the A.C. supply voltage, comprising:

• two isolated-gate bipolar transistors, connected in anti-parallel between a second terminal of application of the A.C. voltage and the load;
• means for detecting a zero crossing of the A.C. supply voltage in a first direction;
• means for generating, at each period of the A.C. supply voltage, a pulse of a predetermined time duration for controlling a first transistor of said isolated-gate bipolar transistors, a time of occurrence of the pulse being conditioned by the detection of the zero crossing of the A.C. supply voltage and by a desired power reference setting a variable delay of occurrence of the pulse with respect to the detected zero crossing;
• and
• means for inverting and transferring said pulse to a second transistor of the isolated-gate bipolar transistors.