Patent ID: 7034473

Claim:
A phase-control power controller that converts a line voltage to an RMS load voltage, the controller comprising: line terminals for a line voltage and load terminals for a load voltage; a phase-control circuit connected to said line and load terminals and having an RC network that clips the load voltage; a load sensing circuit connected across said load terminals that senses the load voltage and provides a DC signal that is related to an RMS load voltage; and a comparison circuit connected to said phase-control circuit and said load sensing circuit and that compares the DC signal to a reference and adjusts a resistance of said RC network in response to the comparison of the DC signal to the reference to control the RMS load voltage, said comparison circuit comprising a first energy emitter that emits energy is response to the comparison of the DC signal to the reference, a first energy sensor that senses energy emitted from said first energy sensor, and two resistors connected in series and with said RC network connected between said two resistors, one of said two resistors having a resistance that corresponds to an amount of energy sensed by said first energy sensor.