| 摘要 |
<P>PROBLEM TO BE SOLVED: To make an ideal power supply for driving a magnetron and improve a power factor as well as the efficiency of power supply. <P>SOLUTION: A magnetron-driving power supply 30, provided with an inverter circuit 48 driving the magnetron 31, an input current detecting circuit 52 detecting input current, and a control circuit 50 controlling a switching element 44, further includes a power supply synchronization timing detection circuit 51 for detecting zero volt of an alternating-current power supply 41, and driving data for deciding an ON-time and an OFF-time of the switching element 44. The driving data is used with reference to the zero volt of the alternating-current power supply detected by the power supply synchronization timing detection circuit 51 directly after the magnetron 31 is driven, and, when the magnetron 31 is warmed up, it is controlled with the driving data in a long ON-time ratio state, at low-voltage part of the alternating-current power supply 41, and just before a peak part of the alternating-current power supply 41, the inverter 48 is controlled by the control circuit 50 so as to shorten the ON-time ratio of the driving data. <P>COPYRIGHT: (C)2010,JPO&INPIT |
