| 摘要 |
<p>An electric power unit capable of operating from different AC input power source voltages in which changes in the AC input voltage are compensated for automatically and rapidly. The power unit includes a rectifier circuit having both a voltage-multiplying rectification function and a non-voltage-multiplying rectification function. A switching circuit is provided for selecting as the operating rectification function one of the voltage-multiplying rectification function and the non-voltage-multiplying rectification function. A switching control circuit, operating with the AC input to the rectifier circuit as a reference potential, controls the switching circuit according to the value of the AC input voltage. An auxiliary power source establishes a voltage for powering the switching control circuit before the operation of the switching control circuit to select the rectification function is effected.</p> |
