| 摘要 |
<p>A high-voltage power supply apparatus includes a transformer, and an input winding is turned on and off repeatedly by a switching element, and thereby an alternating current (AC) is generated in the input winding. By varying the duration of a turned-on state or a turned-off state of the switching element, an output voltage from the output winding of the transformer is regulated. A series connection of a first resistor and a transistor is connected between one end of the output winding and a reference potential. A second resistor is connected in parallel with the series connection. A medium voltage circuit is connected through a diode between the other end of the output winding and the reference potential, and a high voltage circuit is connected between a connection point of the medium voltage circuit and the diode and the reference potential. When the high voltage circuit is to be operated, the transistor is turned on, and a state of the switching element, and thereby, an input voltage of the transformer, is controlled based on a current flowing through the first and second resistors. When the high voltage circuit is not to be operated, the transistor is turned off, and the input voltage is controlled based on a current flowing through the second resistor.</p> |
