Systems and methods for regulating output currents of power conversion systems

A system controller for regulating a power conversion system, the system controller comprising:

• a jittering-signal generator configured to generate a random jittering signal;
• a ramp-signal generator configured to receive the random jittering signal and generate a ramping signal based on at least information associated with the random jittering signal, the ramping signal being associated with a ramping slope;
• a first controller terminal configured to provide a compensation signal based on at least information associated with a first current flowing through a primary winding of a power conversation system;
• a comparator configured to receive the ramping signal and the compensation signal and output a comparison signal based on at least information associated with the ramping signal and the compensation signal;
• and
• a driving component configured to generate a drive signal based on at least information associated with the comparison signal and output the drive signal to a switch to affect the first current, the drive signal being associated with multiple modulation cycles corresponding to a modulation frequency related to a modulation period;
• wherein the system controller is further configured to:
• change the ramping slope based on at least information associated with the random jittering signal so that the ramping slope is changed by random magnitudes corresponding to the multiple modulation cycles respectively;
• and
• adjust the modulation frequency based on at least information associated with the ramping slope changed by the random magnitudes.

A method for regulating a power conversion system, the method comprising:

• generating a jittering signal associated with multiple jittering cycles corresponding to a predetermined jittering frequency related to a predetermined jittering period;
• receiving the jittering signal;
• processing information associated with the jittering signal;
• generating a ramping signal based on at least information associated with the jittering signal, the ramping signal being associated with a ramping slope;
• providing a compensation signal based on at least information associated with a first current flowing through a primary winding of a power conversation system;
• receiving the ramping signal and the compensation signal;
• processing information associated with the ramping signal and the compensation signal;
• outputting a comparison signal based on at least information associated with the ramping signal and the compensation signal;
• processing information associated with the comparison signal;
• generating a drive signal based on at least information associated with the comparison signal;
• and
• outputting the drive signal to a switch to affect the first current, the drive signal being associated with multiple modulation cycles corresponding to a modulation frequency related to a modulation period;
• wherein the generating a ramping signal includes:
• changing the ramping slope based on at least information associated with the jittering signal so that, within a same jittering cycle of the multiple jittering cycles, the ramping slope is changed by different magnitudes corresponding to the multiple modulation cycles respectively;
• wherein the changing the ramping slope is performed to adjust the modulation frequency based on at least information associated with the changed ramping slope.

A method for regulating a power conversion system, the method comprising:

• generating a random jittering signal;
• receiving the random jittering signal;
• generating a ramping signal based on at least information associated with the random jittering signal, the ramping signal being associated with a ramping slope;
• providing a compensation signal based on at least information associated with a first current flowing through a primary winding of a power conversation system;
• receiving the ramping signal and the compensation signal;
• processing information associated with the ramping signal and the compensation signal;
• generating a comparison signal based on at least information associated with the ramping signal and the compensation signal;
• generating a drive signal based on at least information associated with the comparison signal;
• and
• outputting the drive signal to a switch to affect the first current, the drive signal being associated with multiple modulation cycles corresponding to a modulation frequency related to a modulation period;
• wherein the generating a ramping signal includes:
• changing the ramping slope based on at least information associated with the random jittering signal so that the ramping slope is changed by random magnitudes corresponding to the multiple modulation cycles respectively;
• wherein the changing the ramping slope is performed to adjust the modulation frequency based on at least information associated with the ramping slope changed by the random magnitudes.