| 摘要 |
The objective of this invention pertains to a drive signal supply circuit for a switching regulator. Switching regulator 1 of the present invention has amplitude center adjusting circuit 20. In switching regulator 1, a sawtooth wave and the output signal of error amplifier 11 are input to comparator 12, and a pulse signal that sets the ON/OFF state of switching transistor 2 is generated. Since the amplitude center voltage of the sawtooth wave is adjusted corresponding to the power source voltage Vcc, even when power source voltage Vcc is changed rapidly, the amplitude center adjusting circuit 20 can adjust the amplitude center voltage of the sawtooth wave at a high speed matching the rapid fluctuations, and this signal is output to comparator 12. Consequently, the pulse signal output from comparator 12 can follow the rapid fluctuations of power source voltage Vcc. As a result, the output voltage can follow the rapid fluctuations of the power source voltage. Consequently, the problem in the prior art, that is, instability due to the output voltage not being able to follow the fluctuations of the power source voltage Vcc, can be solved.
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