Patent ID: 7880329

Claim:
A step-up type switching regulator that raises a voltage of an input voltage and generates output voltages in a plurality of channels, comprising: an inductor and a main transistor that are disposed in series between an input terminal to which the input voltage is applied and a fixed voltage terminal; a plurality of output capacitors that are disposed for respective output terminals of a plurality of channels; a plurality of rectification circuits that are disposed between respective output terminals and a switching terminal which is a connection point of the inductor and the main transistor, for respective output terminals of the plural channels; and a controlling unit that generates a pulse signal whose duty ratio is controlled so that the output voltage of each channel will be constant, and controls the main transistor and the rectification circuit of each channel in accordance with the pulse signal, wherein the rectification circuit of at least one channel includes a first synchronous rectification transistor and a second synchronous rectification transistor that are disposed in series between a corresponding one of the output terminals and the switching terminal, where the first synchronous rectification transistor is disposed in a direction such that a cathode of a body diode thereof is on the switching terminal side, and the second synchronous rectification transistor is disposed in a direction such that a cathode of a body diode thereof is on the output terminal side, and the controlling unit first turns on the first synchronous rectification transistor, and then turns on the second synchronous rectification transistor for a period of time in accordance with a pulse width of the pulse signal.