Method and apparatus for an efficient multiphase switching regulator

A multiphase switching regulator with forced current sharing comprising:

• at least a first inductor and a second inductor having respective input terminals and respective output terminals, said output terminals connected together;
• at least a first switch circuit connected to said input terminal of said first inductor and a second switch circuit coupled to said input terminal of said second inductor;
• at least one voltage source coupled to said first and second switch circuits;
• a controller to control operations of said first and second switch circuits to alternately connect said input terminals of the respective inductors to said respective voltage source and ground, and wherein said controller adjusts duty cycles of respective voltage waveforms across the respective inductors to achieve equal sensed voltages representative of respective voltages at the input terminals of the inductors;
• said controller comprises a control voltage circuit and at least two pulse-width modulation circuits;
• said control voltage circuit produces control voltages to control duty cycles of respective outputs of the respective pulse-width modulation circuits;
• and
• said control voltage circuit further comprises:
• an error amplifier configured to compare a feedback voltage proportional to an output voltage with a reference voltage;
• a first feedback amplifier configured to buffer output of said error amplifier and provide a first control voltage;
• an offset amplifier configured to compare a first sensed voltage with a second sensed voltage;
• and
• a second feedback amplifier configured to sum an output of said offset amplifier with an output of said error amplifier and provide a second control voltage.

A method of forced current sharing in a multiphase switching regulator comprising the acts of:

• converting voltages at respective input terminals of inductors into sensed voltages, wherein said sensed voltages are proportional to respective duty cycles of respective voltage waveforms across said respective inductors, one of said sensed voltages being a master sensed voltage and the others of said sensed voltages being slave sensed voltages;
• comparing said slave sensed voltages to said master sensed voltage;
• generating respective offset voltages based on respective differences between each of said slave sensed voltages and said master sensed voltage;
• and
• adjusting duty cycles of said voltage waveforms in accordance with respective offset voltages to achieve equal sensed voltages.

A multiphase switching regulator with forced current sharing comprising:

• means for converting voltage waveforms at respective input terminals of respective inductors into respective sensed voltages;
• means for comparing said sensed voltages;
• and
• means for adjusting duty cycles of said respective voltage waveforms to achieve equal sensed voltages.