| 摘要 |
<p>A power supply circuit comprises: an output terminal 3; an inductor L1; first and second capacitors C1, C2; a resistor R1; first and second diodes D1, D2; a switch S1; control means 1 to control the switch; and a ground rail 2. The diodes are connected in series between the ground rail and a terminal of the second capacitor which is also connected to the output terminal, the other terminal of the second capacitor being connected to the ground rail. The inductor, first capacitor and resistor are connected in series between the ground rail and a node N between the diodes. The switch is connected in series with the first diode, the inductor, the resistor and the first capacitor from the ground rail and back to the ground rail, and is switchable between a first state in which it permits the first capacitor to charge in response to a voltage of a first polarity across the inductor, and a second state, in which it prevents the first capacitor from charging. The control means controls the switch dependent upon a voltage at the output terminal, whereby the first capacitor charges the second capacitor in response to a voltage of a second, opposite polarity across the inductor.</p> |
