Patent ID: 6349023
Filing Date: 2002-02-19
Classification: H05B,Y02B

Abstract:
A power control system for controlling a power switch for selectively connecting and disconnecting a power source to a resistive load to prevent said resistive load from exceeding a predetermined high temperature limit, said power control system comprising:a current sensing resistor wired in series with said resistive load for registering a voltage proportional to an instantaneous current passing through said resistive load, said instantaneous current being proportional to instantaneous power in said resistive load; a load temperature modeling circuit for producing an output voltage proportional to a present temperature of said resistive load; and a temperature comparison circuit for selectively comparing said temperature modeling circuit output voltage to one of a plurality of reference voltage setpoint devices producing voltages proportional to said predetermined high temperature limit and a base temperature, said temperature comparison circuit also for controlling said power switch to disconnect said power source from said resistive load when said high temperature limit is reached and to re-connect said power source to said resistive load when said base temperature is reached and a second switch for selecting one of said reference voltage setpoint devices to connect to said temperature comparison circuit.