Patent ID: 8508196

Claim:
A switching regulator with a soft-start function comprising: a first oscillation circuit for outputting a start-up switching signal when an output voltage of the switching regulator is lower than a predetermined voltage; a reference voltage circuit for outputting a gradually-increasing reference voltage at start-up of the switching regulator; an operational amplifier for comparing the gradually-increasing reference voltage with a feedback voltage determined based on the output voltage of the switching regulator; a second oscillation circuit for outputting a switching signal; a PWM comparator for comparing an output signal of the operational amplifier with the switching signal; a switch circuit for selectively outputting the start-up switching signal and an output signal of the PWM comparator based on the output voltage of the switching regulator; and a control circuit for controlling the gradually-increasing reference voltage, wherein the gradually-increasing reference voltage follows and matches a voltage across a capacitive element, wherein when the output voltage is below the predetermined threshold, the control circuit controls the voltage across the capacitive element to follow and match the feedback voltage, and when the output voltage exceeds the predetermined voltage, the control circuit controls the capacitive element to charge based on current sourced from a constant current source circuit.