Switching power converter and control method thereof

A control method for controlling a switching power converter which includes a power stage circuit, wherein the power stage circuit includes a first transistor and a second transistor which are coupled to a first end of an inductor at a switching node, wherein the first transistor and the second transistor are controlled, through pulse width modulation, to switch electrical connections of the switching node with a synchronous mode or an asynchronous mode according to a mode control signal, so as to convert an input voltage to generate an output voltage;

• the control method comprising:
• amplifying a difference between a feedback signal related to the output voltage and a regulation reference signal to generate an error amplified signal;
• generating a ramp signal;
• generating a primary modulation signal by comparing the error amplified signal and the ramp signal;
• generating a skipping reference signal;
• generating a pulse skipping control signal by comparing the error amplified signal and the skipping reference signal, wherein the skipping reference signal has a predetermined reference level during a steady state in the synchronous mode;
• and
• masking the primary modulation signal according to the pulse skipping control signal to generate an adjusted modulation signal to control the power stage circuit;
• wherein the step of generating the skipping reference signal includes:
• turning the skipping reference signal to the predetermined reference level superposing a compensation reference level when the synchronous mode is changed to the asynchronous mode;
• and
• subsequently, gradually returning the skipping reference signal to the predetermined reference level within a first predetermined period, thereby compensating fluctuation of the error amplified signal incurred during transition from the synchronous mode to the asynchronous mode, so as to decrease fluctuation of the output voltage.