Switching regulator and operation control method thereof

摘要

A non-isolated type switching regulator having an inductor includes: a switch element; a rectification element; an error amplifying circuit section amplifying a voltage difference between a feedback voltage and a first reference voltage and outputting as an error voltage; a first voltage comparison circuit section performing a voltage comparison of a ramp voltage which performs a voltage change set beforehand with the error voltage to be synchronized with the switching of the switch element and producing and outputting a first comparison signal; a second voltage comparison circuit performing a voltage comparison of the error voltage with a second reference voltage and producing and outputting a second comparison signal; an oscillation circuit section starting an oscillation based on the second comparison signal and producing and outputting a clock signal; and a control circuit section performing a switching control of the switch element based on the clock signal and the first comparison signal.

主权项

1. A switching regulator which supplies an output voltage for an inductor and is a non-isolated type, the switching regulator converting an input voltage to a predetermined constant voltage and outputting as the output voltage and automatically performing a switching of a PWM control and a VFM control, comprising:
a switch element which performs a switching based on a control signal inputted to a control electrode and a charge to the inductor by the input voltage; a rectification element which performs a discharge of the inductor when the switch element is turned off and the charge to the inductor is stopped; an error amplifying circuit section which amplifies a voltage difference between a feedback voltage proportional to the output voltage and a predetermined first reference voltage and outputs as an error voltage; a first voltage comparison circuit section which performs a voltage comparison of a ramp voltage which performs a voltage change set beforehand with the error voltage to be synchronized with the switching of the switch element and produces and outputs a first comparison signal which indicates a result of the comparison; a second voltage comparison circuit section which performs a voltage comparison of the error voltage with a predetermined second reference voltage and produces and outputs a second comparison signal which indicates a result of the comparison; an oscillation circuit section which includes an oscillation circuit which starts an oscillation operation based on a control signal provided by the oscillation circuit section to an input of the oscillation circuit, wherein the oscillation circuit produces and outputs a clock signal of a predetermined frequency, and the oscillation circuit section controls the oscillation operation of the oscillation circuit based on the second comparison signal; and a control circuit section which performs a switching control of the switch element based on the clock signal and the first comparison signal, wherein the oscillation circuit section starts the oscillation operation of the oscillation circuit based on the second comparison signal and stops the oscillation operation of the oscillation circuit based on the second comparison signal when the clock signal produced by the oscillation circuit is in a state opposite to a state where the switch element is turned on and the charge to the inductor is performed.