| 摘要 |
Disclosed is a circuit design and method for providing an open loop, single-output, high efficiency AC-DC regulated power supply. The circuit is designed with two boost stages (or a two-stage boost) coupled to a zero-voltage switched (ZVS) synchronous rectifier. The first boost stage comprises an inductive switching component coupled to a first capacitor and a pulse width modulator (PWM) via a diode and transistor, respectively. The second boost stage comprises the inductive component coupled to a MOSFET, diode, and capacitor. The second boost state runs at substantially 50% duty cycle for low line conditions and substantially 10% duty cycle for high line conditions, whereby the overall efficiency of the two-stage boost is substantially equal to a conventional boost stage. The circuit includes a DC-DC regulator section, which operates in ZVS mode at approximately 100% duty cycle.
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