| 摘要 |
A power converter including a complementary regeneration circuit for eliminating oscillations and conserving leakage energy to increase the efficiency of a flyback power converter. The complementary regeneration circuit includes a regeneration capacitor, a regeneration switch, a diode and appropriate timing circuitry to switch the regeneration capacitor in and out of the circuit at the appropriate times. Due to the operation of the regeneration switch, the capacitance of the regeneration capacitor is much larger than a typical snubber/clamp capacitor, so that it overdamps the circuit eliminating voltage overshoot typically appearing across the primary switch. The regeneration capacitor charges with regeneration energy and drives negative current into the primary inductor, holding the voltage across the primary switch constant when the secondary current goes to zero. When the regeneration switch is turned off, the negative current in the primary inductor drains the capacitance in the primary switch, which activates the inherent diode of the primary switch causing low voltage across the primary switch when it is turned on. A simple resistor or transistor circuit may be added between the input voltage and the PWM timing circuit to change the frequency of operation to compensate the regeneration energy for changes in the input voltage. Similarly, a resistive element coupled between the PWM timing circuit and an auxiliary voltage having a voltage proportional to the output voltage changes the operating frequency to compensate the regeneration energy for changes in the output voltage.
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