Frequency modulation control of a buck-boost power converter

A control circuit for generating a control signal to operate a buck-boost power stage of a buck-boost power converter to convert an input voltage to an output voltage, the control circuit comprising:

• a feedback circuit operative to detect the output voltage to generate a feedback signal as a function of the output voltage;
• an error amplifier connected to the feedback circuit for amplifying a difference between the feedback signal and a reference voltage to generate an error signal;
• a waveform generator operative to provide a first ramp signal and a second ramp signal;
• a frequency controller connected to the error amplifier, operative to generate an oscillation signal according to the error signal;
• a clock generator connected to the frequency controller and the waveform generator for generating a clock signal according to the oscillation signal for the waveform generator to control frequencies of the first and second ramp signals;
• a PWM comparator connected to the error amplifier and the waveform generator for generating a first PWM signal and a second PWM signal according to the error signal and the first and second ramp signals;
• and
• a gate driver connected to the PWM comparator and the buck-boost power stage for generating the control signal according to the first and second PWM signals.