Patent ID: 7679348

Claim:
A switching regulator operating in one of a PWM control mode and a PFM control mode, comprising: a switching unit that performs switching between the PWM control mode and the PFM control mode; an error amplification circuit that amplifies an error voltage between a voltage proportional to an output voltage and a first reference voltage; a slope circuit that generates a slope signal when activated by a control signal used to turn on an output switching transistor, said slope circuit outputting a predetermined offset voltage when the control signal turns the output switching transistor off; a reference voltage generation circuit that generates a second reference voltage for determining a time interval of an ON state in the PFM control mode; a multiplexer that outputs one of the second reference voltage and an output voltage from the error amplification circuit; a comparison circuit that compares an output voltage from the slope circuit to an output voltage from the multiplexer; and an oscillation circuit that determines a timing of the ON state in the PWM control mode.