ABSTRACT
A feedback amplifier generates a control signal based on an output voltage and a reference voltage. A ?rst ramp signal generating circuit generates a ?rst ramp signal that synchroniZes With a pulse signal from an oscillator. A second ramp signal generating circuit generates a second ramp signal according to the state of a latch circuit. A comparator generates a reset signal When the total of the signal repreSenting an inductor Current and the respective levels of the level of the control signal. The latch circuit is set by the pulse signal from the oscillator and is reset by the reset
signal. A driver circuit comprises a boost capacitor, and drives the sWitch according to the state of the latch circuit.