| 摘要 |
PURPOSE:To provide a charger in which the number of components to be used is small although a high power factor is provided and whose circuit constitution is extremely simple. CONSTITUTION:A power-supply circuit is provided with a DC-DC converter 13 in which full-wave-rectified waves obtained by a rectifier diode 12 are transformed into full-wave-rectified waves having a different voltage level and with a step-up-type active filter 14 in which energy stored in a choke coil 14a in the ON-operation of a switching transistor 14c is discharged to a battery 15 through a diode 14b in its OFF-operation. In addition, it is provided with a current sensor 14d which detects a current given from the DC-DC converter 13 in the ON/OFF-operation of the switching transistor 14c and with a control circuit 16 which controls the phase of the detected current by the current sensor 14d so as to coincide with the phase of the voltage of the full-wave-rectified waves and which, when the detected current is lowered, performs a control operation to raise a transformation ratio in the DC-DC converter 13. |
