| 摘要 |
A first-order feedback control power supply apparatus being arranged in such a manner that when the apparatus is driven under light load condition, a current flowing through an inductor is detected by employing a second CR smoothing filter; when the present load condition is judged as a light load condition based upon the detected inductor current, both upper-sided/lower-sided power MOSFETs and a PWM oscillator are turned OFF so as to be brought into sleep states; when an output voltage of the power supply apparatus is lowered and the lowered output voltage reaches a lower limit threshold of a transient variation detecting circuit, the upper-sided power MOSFET is turned ON to recover the output voltage; and when the output voltage of the power supply voltage reaches a predetermined voltage, the upper-sided power MOSFET is turned OFF so as to be again brought into the sleep state.
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