| 摘要 |
A green-mode flyback pulse width modulation apparatus adopting a bipolar transistor structure IC process is used in a power supply. An oscillator circuit outputs a periodic clock signal to a control terminal of a power switch through an amplifier circuit for periodically turning on the power switch. A latch circuit is connected to the oscillator circuit, the amplifier circuit, the power switch and a feedback terminal of the power supply for periodically pulling down the potential at a control terminal of the power switch in response to a feedback signal generated by the feedback terminal to turn off the power switch and continue suspending the operation of the oscillator circuit when the power supply is at a light load, and will resume the output of the oscillator circuit till the potential of the feedback signal potential drops, so as to achieve the green-mode function.
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