| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit which is excellent in high-speed responsiveness to load fluctuation.SOLUTION: A power supply circuit includes: an LDO regulator for generating an output voltage corresponding to an input voltage; and a booster circuit for improving the responsiveness of the LDO regulator to the fluctuation of the output voltage. The LDO regulator includes: an amplifier for outputting a voltage corresponding to the fluctuation of the output voltage; and a first transistor for outputting an output voltage in a voltage level corresponding to a voltage output by an amplifier. The booster circuit includes: a second transistor for feeding output currents proportional to the output currents of the first transistor; a first differential amplifier for outputting a voltage signal corresponding to a voltage difference between a voltage corresponding to the output currents of the second transistor and a first reference voltage; and a control circuit for controlling the responsiveness of the amplifier in accordance with the voltage signal corresponding to the voltage difference.SELECTED DRAWING: Figure 1 |
