摘要 |
Control of an output pulse width by a PWM control circuit is stopped and the initial pulse string having a fixed pulse width is outputted in order to obtain a power supply voltage rise within a predetermined time period at the time of turning on the power. During normal operation, the voltage detected by a voltage detecting circuit is captured by a PWM control circuit, and the pulse width of the output pulse string is adjusted according to the detected voltage in order to keep the power supply voltage constant.
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