Patent ID: 7094997
Filing Date: 2006-08-22
Classification: G03G

Abstract:
1. A heating device including an AC power supply; a rectifying circuit that converts an AC current from the AC power supply to a DC current; an inverter circuit comprising a first resonance circuit composed of an electromagnetic induction coil with a first resonance frequency and a resonance capacitor connected to an output side of the rectifying circuit, a second resonance circuit composed of an electromagnetic induction coil with a second resonance frequency and a resonance capacitor connected to the output side of the rectifying circuit, and a switching element that excites the first and second resonance circuits; and a drive circuit that supplies a drive signal to the switching element of the inverter circuit, the heating device comprising: a first control section that effects a control to enable the drive circuit to supply a drive signal with a first drive frequency corresponding to the first resonance frequency or a drive signal with a second drive frequency corresponding to the second resonance frequency; and a second control section that effects a control to set a minimum time interval for switching at 1/(half-wave length of a frequency of the AC power supply) or more, the minimum time interval being defined between a time point at which the drive signal with the first drive frequency or the drive signal with the second drive frequency is supplied by the control of the first control section and a time at which the supply of the drive signal is switched between the drive signal with the first drive frequency and the drive signal with the second drive frequency.