Multi-phase DC-DC converter and controlling method thereof

A multi-phase DC-DC converter, coupled to a plurality of output inductances, the multi-phase DC-DC converter comprising:

• a plurality of output units each coupled to one corresponding output inductance of the output inductances, and each of the output units and the corresponding output inductance comprising a phase node therebetween;
• a sensing unit coupled to the phase nodes and acquiring an output current of each of phases and providing a plurality of difference voltages that respectively represent current differences of the phases, wherein a value of each of the difference voltages is not zero;
• and
• a pulse width modulation (PWM) controller coupled to the output units and the sensing unit,
• wherein the number of the output inductances and the number of the output units are both N, and N is a natural number greater than or equal to 2,
• wherein the number of the difference voltages provided by the sensing unit is N, and when output currents of the phases are respectively denoted by I1, I2 . . . , and IN;
• and the N difference voltages are respectively denoted by Vdiff1, Vdiff2 . . . , and VdiffN,
• Vdiff1=I1−(accumulation of the output currents of the phases,excluding I1)/(N−1),
• Vdiff2=I2−(accumulation of the output currents of the phases,excluding I2)/(N−1), and
• VdiffN=IN−(accumulation of the output currents of the phases,excluding IN)/(N−1),
• wherein the PWM controller comprises an on-time calculating circuit coupled to the sensing unit and the output units to generate an on-time pulse to the output units according to at least one of the difference voltages.

A multi-phase DC-DC controlling method, comprising:

• acquiring an output current of each of phases on a plurality of output inductances;
• providing a plurality of difference voltages that respectively represent current differences of the phases according to the acquired output currents of the phases, wherein a value of each of the difference voltages is not zero;
• and
• adjusting a duty cycle of a PWM signal corresponding to each of the phases according to each of the difference voltages to control a channel current for power conversion of each of the phases,
• wherein the number of the difference voltages provided is N and N is a natural number greater than or equal to 2, and when output voltages of the phases are respectively denoted by V1, V2 . . . , and VN;
• the N difference voltages are respectively denoted by Vdiff1, Vdiff2 . . . , and VdiffN;
• and an average voltage is denoted by Vave,
• Vdiff1=A×V1−B×Vave,
• Vdiff2=A×V2−B×Vave, and
• VdiffN=A×VN−B×Vave,
• wherein Vave=(accumulation of V1 to VN)/N, and A and B are coefficients respectively.

A multi-phase DC-DC controlling method, comprising:

• acquiring an output current of each of phases on a plurality of output inductances;
• providing a plurality of difference voltages that respectively represent current differences of the phases according to the acquired output currents of the phases, wherein a value of each of the difference voltages is not zero;
• and
• adjusting a duty cycle of a PWM signal corresponding to each of the phases according to each of the difference voltages to control a channel current for power conversion of each of the phases,
• wherein the number of the difference voltages provided is N and N is a natural number greater than or equal to 2, and when output currents of the phases are respectively denoted by I1, I2 . . . , and IN;
• and the N difference voltages are respectively denoted by Vdiff1, Vdiff2 . . . , and VdiffN,
• Vdiff1=I1−(accumulation of the output currents of the phases,excluding I1)/(N−1),
• Vdiff2=I2−(accumulation of the output currents of the phases,excluding I2)/(N−1), and
• VdiffN=IN−(accumulation of the output currents of the phases,excluding IN)/(N−1).