Patent ID: 9301346
Filing Date: 2016-03-29
CPC Classification: H05B

Claim Text:
1. A power supply for a high frequency heating that drives a magnetron by carrying out a high frequency switching operation by a semiconductor switching element using a commercial power source, wherein a control signal for an input current is used to suppress an over-shoot of the input current immediately after the magnetron begins oscillating, the power supply comprising a deciding part, wherein the control signal is set based on comparing, by the deciding part, the input current with a threshold value for the input current for deciding a non-oscillation (a start mode) and an oscillation (a steady mode) of the magnetron by the deciding part based on said comparing, wherein the deciding part receives a signal representative of the input current, and provides to a pulse width modulator (PWM) setting part of the power supply, an output signal indicating whether the magnetron is presently oscillating or not oscillating, the output signal being determined based on comparing the input current with the threshold value for the input current by the deciding part such that the output signal indicates that the magnetron is presently oscillating when the input current is greater than the threshold value, wherein the control signal for the input current sets different values in the non-oscillation (the start mode) and the oscillation (the steady mode) of the magnetron, and a setting value of the start mode of the control signal for the input current is less than a setting value of the steady mode.