| 摘要 |
A high-voltage AC to low-voltage DC converter includes a rectifier circuit for providing a pulsating high-voltage DC signal from the high-voltage AC input and a switch having its main current path coupled between the rectifier circuit output and an output terminal of the converter. A filter capacitor is coupled to the output terminal to filter the low-voltage DC output, and first and second voltage sensors are coupled to the rectifier output and the low-voltage DC output terminal of the converter circuit, respectively. The first voltage sensor is set to sense a low (typically zero) voltage, and the second voltage sensor is set to sense the desired low-voltage DC output level. The outputs of the first and second voltage sensors are coupled to the set and reset inputs, respectively, of a latch circuit, with the output of the latch circuit being coupled to a control terminal of the switch in order to turn on the switch upon receiving a set input from the first voltage sensor and then turn off the switch on receiving a reset input from the second voltage sensor. This converter configuration provides a compact and highly-efficient circuit.
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