Patent ID: 8154267

Claim:
A current mode control type switching regulator for converting an input voltage into an output voltage that is a predetermined constant voltage, comprising: a switching element; an inductor energized by the input voltage in response to switching of the switching element; a rectifier element for discharging the inductor; and a slope voltage generating circuit unit configured to generate and output a slope voltage having an inclination responsive to a current flowing through the inductor, said current mode control type switching regulator being configured to amplify a voltage difference between a predetermined reference voltage and a divided voltage obtained by dividing the output voltage; compare the amplified voltage and the slope voltage to generate a pulsed signal having a duty cycle determined by the comparison; and control switching of the switching element in response to the pulsed signal, wherein the slope voltage generating circuit unit includes an inductor current detecting circuit for detecting a current flowing through the inductor when the switching element is on to energize the inductor and converting the detected current into a voltage; and a ramp voltage generating circuit for generating and outputting a ramp voltage having a predetermined inclination, said slope voltage generating circuit unit being configured to add the voltage obtained by the inductor current detecting circuit and the ramp voltage to generate the slope voltage; the ramp voltage generating circuit includes a constant current circuit for generating and outputting a predetermined constant current; an offset voltage generating resistor through which the constant current outputted by the constant current circuit flows; and a ramp capacitor charged by the constant current outputted by the constant current circuit through the offset voltage generating resistor, said ramp voltage generating circuit being configured to add a voltage drop caused by the offset voltage generating resistor to a terminal voltage of the ramp capacitor to generate and output the ramp voltage.