| 摘要 |
PROBLEM TO BE SOLVED: To provide a control power circuit which has high stability against variations of power supply and a load, suppressing power losses generated by the components of the control power circuit in an inverter unit having a self-excited control circuit. SOLUTION: A rectifying circuit DB for rectifying an AC power supply voltage, an inverter circuit 1 provided with a pair of switching devices Q1, Q2 connected in series between the output terminals of the rectifying circuit DB and a resonance load circuit 3 connected to the junction of the switching devices via a DC cutting capacitor C3, a self-excited control circuit 4 for turning on/off the switching devices Q1, Q2 of the inverter circuit 1 alternately, and a power circuit 2 comprising a smoothing capacitor C1, are provided. A supply voltage Vcc for the control circuit 4 is supplied from a spot where a first voltage having a positive characteristic with respect to AC power supply variation is generated, and from a spot where a second voltage having a negative characteristic with respect to the AC power supply variation is generated. |
