Control Circuit of Variable-Frequency Switching Converter and Variable-Frequency Switching Converter

A control circuit of a variable-frequency switching converter, comprising a duty ratio modulation signal generation module, a Constant On Time (COT) trigger signal generation module, and a control module;

• wherein the duty ratio modulation signal generation module is configured to output a duty ratio modulation signal to a first end of the control module;
• the COT trigger signal generation module is configured to output a COT trigger signal to a second end of the control module when a ripple voltage is less than a ripple reference voltage;
• the control module is configured to generate a fixed on frequency pulse width signal based on the duty ratio modulation signal and a clock signal when the COT trigger signal is not received, generate a control signal based on the fixed on frequency pulse width signal, generate a COT pulse width signal based on the control signal and the COT trigger signal when the COT trigger signal is received, and generate a target pulse width signal based on the fixed on frequency pulse width signal and the COT pulse width signal;
• wherein the ripple voltage is generated based on a ripple voltage generation circuit, the ripple voltage generation circuit is configured to generate a first ripple voltage, and superpose a feedback voltage on an output voltage feedback node and the first ripple voltage to generate the ripple voltage, and the first ripple voltage is related to the target pulse width signal output by the control module.