A regulator includes a first resistor and a second resistor that are connected between a ground node and an output node, an amplifier that outputs an amplification voltage by comparing a reference voltage to a feedback voltage between the first resistor and the second resistor, and amplifying a difference between the reference voltage and the feedback voltage, an analog-to-digital converter that converts the amplification voltage to a digital code, and a plurality of transistors that are connected between a power node supplied with a power supply voltage and the output node and which adjusts a current being supplied to the output node in response to the digital code.