| 摘要 |
<p>The invention relates to a dual DC voltage power supply providing positive and negative DC voltages including soft turn-on circuitry to limit inrush current to substantially uncharge capacitive loads. The power supply includes a plurality of rectifier circuits providing at least one positive DC voltage level and at least one negative DC voltage level from at least one AC input voltage. A plurality of power terminals receive the rectified voltage, and an output terminal is provided for each DC voltage level. A reference terminal is provided for connection to a point of reference potential. A control for each DC voltage level is coupled in parallel relationship with the capacitive load and is responsive to the voltage developed across the load attaining a predetermined value whereupon the control provides a firing signal. A turn-on current suppressor is provided for each DC voltage level, the suppressor having a relatively high impedance connected between one of the power terminals and the output terminal wherein the impedance limits the magnitude of current supplied to the load in the absence of the control firing signal. A switch, having a main current conduction path coupled in parallel with each suppressor impedance, is responsive to the control firing signal to provide a low impedance bypass across the suppression impedance.</p> |
