Patent ID: 7199532

Claim:
A lamp comprising a phase-control power controller within the lamp and connected to a lamp terminal, said phase-control power controller including an analog load voltage sensor that provides an optical output related to an RMS load voltage and a phase-controlled dimming circuit that has a comparison circuit that varies a resistance in said phase-controlled dimming circuit responsive to the optical output from said load voltage sensor, said analog load voltage sensor comprises a first light emitting diode that emits the optical output, and said comparison circuit comprises a first optically coupled transistor that senses the optical output from said first light emitting diode, a first load sensitive resistor that emits an amount of thermal energy corresponding to an amount of optical energy sensed by said first optically coupled transistor, and two resistors connected in series, one of said two resistors having a resistance that corresponds to the amount of thermal energy emitted by said first load sensitive resistor and that varies the resistance in said phase-controlled dimming circuit.