| 摘要 |
<p>A switched mode power supply comprises a half bridge circuit or a full bridge circuit. A resonant circuit is connected to the bridge circuit and comprises an inductive element (105, 208) :end a capacitive element (106, 209) connected in series, whereby the resonant circuit has a resonant frequency. The rate of change of a voltage across the resonant circuit is measured. A switching frequency of the switching elements is controlled for lowering the rate of change of the voltage across the resonant circuit to a predetermined minimum value. In ;:i no-load condition, the switching frequency of the switching elements is set to an operating f °equency which is higher than the resonant frequency of the resonant circuit. In a load cordition, the switching frequency of the switching elements is lowered to the resonant frequency of the resonant circuit.</p> |
