Patent ID: 6936800

Claim:
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; a plurality of inverter circuits each comprising a resonance circuit composed of an electromagnetic induction coil and a resonance capacitor connected to an output side of the rectifying circuit and a switching element that excites the resonance circuit; and a plurality of drive circuits each supplying a drive signal to the associated switching element of the associated inverter circuit, the heating device comprising: a first control section that effects a control to select one of the plurality of drive circuits and to enable the selected drive circuit to supply the drive signal; 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 is supplied from the drive circuit selected by the first control section and a time at which the other drive circuit is selected and the supply of the drive signal is switched to supply the drive signal from said other drive circuit.