| 摘要 |
A control circuit is provided for controlling the on-time of a pair of switching transistors in a half bridge converter. The control circuit includes a first comparator for comparing the converter output voltage with a reference voltage. The control circuit also includes a circuit which generates a first signal indicative of the current through the primary winding of the converter output transformer. Also included is a circuit which generates a second signal indicative of the on-time of one of the switching transistors exceeding the on-time of the other switching transistor. The first and second signals are averaged and compared with the output voltage of the first comparator by a second comparator. The second comparator controls the on-time of the switching transistors. In this way, any imbalance in the on-time of the switching transistors is corrected by the control circuit.
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