Dual-mode control of a switch mode power supply

A method for controlling a multi-phase core supply, the method comprising:

• sensing phase currents of each phase of the multi-phase core supply;
• comparing the phase currents to a phase-current limit to determine a heavy load condition or a normal load condition;
• selecting, for an output of a multi-mode error amplifier, an error signal based on the determined load condition, the error signal selected being an output voltage error signal when the normal condition is determined and the error signal selected being the larger of the output voltage error signal and an overall current error signal when the heavy load condition is determined;
• and
• controlling switching of each phase of the multi-phase core supply based on the selected error signal.

A switch mode power supply comprising:

• a pulse width modulator (PWM) controller configured to generate a switching signal based on an error signal;
• a buck converter coupled to the PWM controller configured by the switching signal to output a voltage and a current to a load;
• and
• a feedback control circuit configured to:
• upon detecting that the current is at or above a saturated level, selecting as an output the larger of an output voltage error signal and an overall current error signal as the error signal;
• and
• upon detecting that the current is below the saturated level, selecting as an output the output voltage error signal as the error signal.