POWER REGULATOR FOR A RESISTIVE LOAD
Original Publication Date: 1978-Dec-31
Included in the Prior Art Database: 2004-Mar-31
Xerox Disclosure Journal
A circuit is disclosed for regulating the level of current supplied to an incandescent lamp or fuser heater resistive load without causing disturbances on the incoming power line that would otherwise exceed predetermined limits. The circuit includes a full-wave rectifier 10 operative to receive an alternating current signal for conversion to a pulsating unidirectional power signal which is supplied to a series circuit including the resistive load 12, a transistor 14 and a sampling resistor 16. A control signal developed across the sampling resistor 16 is supplied to a pulse width modulator 18 which has its output connected to the base of transistor 14 whereby the pulsating unidirectional power signal is chopped into pulses that have a high frequency relative to that of the alternating current signal and have uniform duration through a given cycle of the alternating current signal whereby a power factor approaching one is achieved.