Switching regulator and operation clock signal generator circuit and control method thereof

Abstract

A switching regulator includes: a power stage circuit; a control circuit; and an operation clock signal generator circuit configured to generate plural test clock signals during a clock determination period and generate an operation clock signal during a normal operation period. When the switching regulator operates during the clock determination period in a discontinuous conduction mode, the control circuit alternatingly generates plural PWM signals corresponding to the test clock signals generated by the operation clock signal generator circuit and an output voltage, wherein each PWM signal corresponds to one test clock signal, so that the power stage circuit generates corresponding phase node voltages at a phase node, wherein among the plural test clock signals, the operation clock signal generator circuit selects one test clock signal corresponding to a minimum phase node voltage as the operation clock signal during the normal operation period.