| 摘要 |
PURPOSE:To lower the breakdown voltage of a holding circuit and enable the miniaturization and weight reduction by charging a holding circuit at a constant voltage by DC/DC converter and limiting the current thereby limiting an inrush current too. CONSTITUTION:A holding circuit 4 is connected so that it can be charged by a DC/DC converter, without being connected directly to a rectifying circuit 2, and is connected so that it can supply voltage to a DC/DC converter 5 only when the voltage being rectified by the rectifying circuit 2 falls below a certain value. And, the full waves of the AC voltage of input 1 are rectified by the diode 21 of the rectifying circuit 2, and it is connected to the DC/DC converter as it is, and the DC/DC converter 5 applies switching voltage to a transformer 51, being switched by a switching transistor 52. And, the secondary voltage is smoothed by a diode 54 and a capacitor 55, and is supplied to an output 6, and the pulse width of the transistor 52 is controlled with a control circuit 53 for detecting and stabilizing the voltage at the output 6. |
