| 摘要 |
A circuit incorporating a circuit element for recovering the energy stored in the parasitic input capacitance of a power transistor at turn-on. The circuit includes a resonating element, such as a transformer, and a diode coupled between a voltage source and a power transistor, such as a field effect transistor. A switching device is switchably coupled between the input of the power transistor and the voltage source, and between the input of the power transistor and the resonating element. The resonating element is adapted to recover and store the energy stored in the parasitic capacitance of the power transistor when it is turned on, thus improving the efficiency of the circuit. The diode is adapted to avoid loading of the power source. The energy is recovered and stored until a new turn-on interval is required or until there is a need for other power requirements. This improves the operating efficiency of a system using the circuit. For a given loss, the recovery of this energy permits operation at a higher frequency for size reduction and/or improved performance, or the use of large die for reduced conduction loss. The advantages are the same for FETs when they are used as the control element or as a rectifier element, but the gains in efficiency are most notable in rectifier applications.
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