| 摘要 |
<p>PURPOSE: To enhance the output efficiency for a load variable over a wide range by compensating for the fluctuation of load current through regulation of the duty cycle of a square wave generator and turning the square wave generator off completely over a significantly large part of the operating time of a power supply when the current demand level is low. CONSTITUTION: Upon receiving an output signal from a programmable reference generator 45 and an operation mode signal from a controller 50, a switching regulator 15 outputs a square wave to the primary coil 22 of a transformer 20 which produces a DC output voltage through the secondary coil thereof. In full-on constant voltage mode, a constant voltage output is sustained by varying the duty cycle of the square wave continuously with a feedback signal generated from a reference voltage generator 45. The controller 50 monitors the load demand level and when it drops below a specified level, a transition signal to burst mode is delivered and the switching regulator 15 is paused except the charging interval of capacitors 61, 63.</p> |
