| 摘要 |
A power supply for producing a regulated dc output from an ac primary input incorporates a convention rectifying and filtering circuitry feeding a switching circuit for providing a high frequency, substantially rectangular voltage waveform to a high frequency transformer. The output of the transformer is provided to a synchronous buck converter having a grounded line and an ungrounded line, with a first FET switch in the ungrounded line and a second FET switch connected from the output of the first FET switch to the grounded line. A controller in the synchronous buck converter switches the FETs according to the input voltage waveform to achieve rectification. In another aspect, two FETs are placed in opposite polarity in the ungrounded line and switched together, and the controller also alters the duty cycle of the switching in accordance with the magnitude of a regulated output produced from the output of the synchronous buck converter, to achieve precise regulation. Power supplies are provided with multiple outputs of different regulated voltage, which may be externally enabled and disabled.
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