Method and apparatus for multi-phase DC-DC converters using coupled inductors in discontinuous conduction mode

A multiphase voltage converter, comprising:

• N inductors, each inductor having a first and a second terminal, at least two of the N inductors being magnetically coupled to each other, N being an integer greater than one;
• a filter connected to the second terminal of each of the N inductors, the filter including at least one capacitor;
• N high-side switches, each of the high-side switches being connected between a power source and the first terminal of a respective one of the N inductors;
• N low-side switches, each of the low-side switches being connected between the first terminal of a respective one of the N inductors and ground;
• and
• a converter controller for controlling operation of the voltage converter, the converter controller operating the voltage converter in a rotating phase discontinuous conduction mode when an output load value is within a first range of output load values, at least two of the N high-side switches alternating conduction of current pulses in the rotating phase discontinuous conduction mode.

A multiphase voltage converter, comprising:

• N inductors, each inductor having a first and a second terminal, at least two of the N inductors being magnetically coupled to each other, N being an integer greater than one;
• a filter connected to the second terminal of each of the N inductors, the filter including at least one capacitor;
• N high-side switches, each of the high-side switches being connected between a power source and the first terminal of a respective one of the N inductors;
• N low-side switches, each of the low-side switches being connected between the first terminal of a respective one of the N inductors and ground;
• and
• a converter controller for controlling operation of the voltage converter, the converter controller operating the voltage converter in a first discontinuous conduction mode when an output load value is within a first range of output load values, at least two of the N high-side switches being simultaneously closed during a switching period in the first discontinuous conduction mode.

A multiphase voltage converter, comprising:

• N inductors, each inductor having a first and a second terminal, at least two of the N inductors being magnetically coupled to each other, N being an integer greater than one;
• a filter connected to the second terminal of each of the N inductors, the filter including at least one capacitor;
• N high-side switches, each of the high-side switches being connected between a power source and the first terminal of a respective one of the N inductors;
• N low-side switches, each of the low-side switches being connected between the first terminal of a respective one of the N inductors and ground;
• and
• a converter controller for controlling operation of the voltage converter, the converter controller operating the voltage converter in a first discontinuous conduction mode when an output load value is within a first range of output load values, the converter controller operating the voltage converter in a second discontinuous conduction mode when the output load value is within a second range of output load values, at least part of the second range of output load values being greater than the first range of output load values;
• at least one of the N high-side switches remaining quiescent and the remaining high-side switches conducting current pulses in the first discontinuous conduction mode, and
• at least two of the N high-side switches alternating conduction of current pulses in the second discontinuous conduction mode.