PHASE-CONTROL POWER CONTROLLER WITH ANALOG RMS LOAD VOLTAGE REGULATION

摘要

A phase-control power controller that converts a line voltage to an RMS lo ad voltage includes an analog load voltage sensor that includes a light emitter that provides an optical output related to an RMS load voltage, and a phase-control circui t that has a comparison circuit that varies a resistance in the phase-control circuit responsive to the optical output. The comparison circuit includes an optically coupled transistor that senses the optical output from the light emitter, a load sensitive resistor that emits an amount of thermal energy corresponding to an amount of optical energy sensed by the optically coupled transistor, and two thermally dependent resistors connecte d in series, where one of the two resistors has a resistance that corresponds to the amou nt of thermal energy emitted by the load sensitive resistor and that varies the resistance in the phase-controlled dimming circuit.