| 摘要 |
PROBLEM TO BE SOLVED: To reduce a required operation current by a ramp generator using capacitive addition. SOLUTION: Ramp voltage VRAMP is generated by a ramp engine constituted of combining 1st and 2nd capacitor dividers C1A, C1B, C2A, C2B for generating a ramp waveform and plural switches S1 to S6. A ramp waveform related to the ramp voltage VRAMP is compared with reference voltage VREF2, the switching of the switches S1 to S6 is controlled so as to generate a repeated ramp waveform and a signal obtained by feeding back the output voltage of a power train for supplying an output through a feedback network is compared with the ramp voltage VRAMP by a high speed comparator X1 to obtain output voltage whose duty cycle or the like is adjusted.
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