Power supply device

A power supply device, comprising:

• a first delay circuit which delays a first clock signal and outputs a second clock signal;
• a pulse signal generating circuit which generates a first pulse signal in synchronization with the first clock signal;
• a first transistor which connects an output node to a power supply potential node according to the first pulse signal;
• a second transistor which connects the output node to a reference potential node according to the first pulse signal;
• an integration circuit which integrates and outputs a signal of the output node;
• and
• a comparator which compares an output signal of the integration circuit and the reference signal, wherein
• the first transistor and the second transistor perform on and off operations which are reverse to each other,
• the pulse signal generating circuit sets the first pulse signal to first level in synchronization with the first clock signal, sets the first pulse signal to second level in synchronization with the second clock signal, and sets the first pulse signal to the second level in synchronization with an output signal of the comparator, and
• the frequency of the first pulse signal is constant irrespective of voltage of the output node.