Patent ID: 9008528
Filing Date: 2015-04-14
Classification: G03G,H05B

Abstract:
1. An induction heating fusing device comprising: a serial resonance circuit having an induction coil and a condenser; a phase comparator, a phase controller, a resonance frequency tracking oscillator, and a PWM (pulse width modulation) signal generator, wherein the phase comparator compares a phase of a pulse outputted by the PWM signal generator with a phase of current flowing through the induction coil, outputs a comparison result obtained by the comparing to the phase controller when controlling the phase, and outputs the comparison result to the resonance frequency tracking oscillator when performing PWM control, the phase controller outputs a frequency control signal which has a predetermined phase value based on an output of the phase comparator and a predetermined coil current phase amount, the resonance frequency tracking oscillator changes an oscillation frequency by using an output of the phase controller such that a driving frequency of the serial resonance circuit tracks the resonance frequency, the PWM signal generator generating a pulse to drive the serial resonance circuit based on the resonance frequency by the resonance frequency tracking oscillator, and the phase comparator, the phase controller, the resonance frequency tracking oscillator, and the PWM signal generator are digitally controlled.