| 摘要 |
A power supply circuit is provided for generating a low voltage for powering a control circuit. The power supply circuit is connected to a voltage source having a high voltage relative to the output voltage of the power supply circuit. The power supply circuit includes a power supply capacitor and a charging capacitor connected to the power supply capacitor which charges the power supply capacitor when the power supply circuit is connected to the high voltage source. The power supply also includes an inductor connected to the power supply capacitor which charges the power supply capacitor by resonant action when the power supply circuit is disconnected from the voltage source, so that the power supply capacitor is continuously charged. A pair of diodes are also provided. The first diode is connected between the charging capacitor and the power supply capacitor. The second diode is connected in series with the inductor. The power supply circuit further includes a zener diode connected to the power supply capacitor for regulating the voltage across the power supply capacitor. <IMAGE> |
