Generally, power supply IC constantly monitors the output voltage to ensure stable power supply functionality and includes a feedback circuit that fine-tunes the output voltage by comparing with an internal reference voltage. Providing faster response makes it possible to reverse changes in the output voltage caused by fluctuations in input voltage and/or load current in a shorter time. On the other hand, shortening the response time too much can cause the circuit operation to become unstable and the output voltage to oscillate, and as the response speed is also affected by output capacitance, until now it has been difficult to achieve the desired response performance.