Patent ID: 7145108

Claim:
A controller for a heating device for controllably applying power to a heating device and controlling the heating device temperature by varying the duty cycle characteristics of a periodic control signal, comprising: an oscillator circuit operable to output a frequency signal; a counter connected to the oscillator circuit operable to count oscillations of the frequency signal and output a periodic control signal based on said frequency signal; a power supply circuit including a switch to thereby energize and de-energize said heating device; an actuating circuit controlling said switch, said actuating circuit controlled by said periodic control signal, wherein said actuating circuit is operable to control said switch to energize said heating device during a portion of said periodic control signal; a user controlled temperature adjustment circuit connected to the oscillator circuit, including means for varying the frequency of said frequency signal, whereby said periodic control signal is varied to thereby vary the heating device temperature, wherein said means for varying the frequency includes means for varying an impedance included in said oscillator; and a plurality of LEDS connected to said user controlled temperature adjustment circuit wherein said LEDS provide a means for selecting available heating modes of said controller, such that said controller provides for at least one heat mode by detecting the presence of at least one of said plurality of LEDS, and deactivates a heat mode in response to the absence of said at least one of said plurality of LEDS.