System and method for phase dropping and adding

A multi-phase voltage regulator comprising:

• a master phase comprising:
• an error amplifier to generate a compensation signal based on a difference between a reference voltage and a signal representative of a voltage at an output node of the multi-phase voltage regulator;
• a current supplying stage to supply a master output current equaling at least a portion of a load current output from the multi-phase voltage regulator;
• and
• a master control circuit to calculate a control signal based on the compensation signal and a sampled current representative of the master output current, wherein operation of the current supplying stage is controlled by the control signal;
• and
• one or more additional phases, wherein each of the one or more additional phases comprises:
• a current supplying stage to supply a respective local output current equaling at least a portion of the load current;
• and
• a control circuit to calculate a control signal based on the compensation signal, a sampled current representative of the respective local output current, and a sampled current representative of the master output current;
• wherein the control circuit is configured to disable the respective current supplying stage gradually based on a comparison of a respective first predetermined level with a sum of the respective local output current and the master output current.

A system comprising:

• a power source to provide a voltage signal;
• a multi-phase voltage regulator having a plurality of phases and configured to regulate the voltage signal from the power source;
• and
• a load coupled to the multi-phase voltage regulator to receive the regulated voltage signal;
• wherein the multi-phase voltage regulator is further configured to gradually drop one of the plurality of phases based, at least in part, on the level of current output by the dropped phase;
• and
• wherein the multi-phase voltage regulator is further configured to immediately add the dropped phase based, at least in part, on the level of current output by one of the other phases.

A control circuit for a phase in a multi-phase voltage regulator, the control circuit comprising:

• a first summation circuit to calculate a combined output current representative of a sum of a master output current and a local output current of the respective phase;
• a difference circuit to calculate a difference signal representative of a difference between the master output current and the local output current;
• threshold circuitry to compare the combined output current with a first predetermined level;
• a second summation circuit to sum the difference signal with a signal from the threshold circuitry;
• and
• an integrator to integrate an output of the second summation circuit;
• wherein, when the combined output current is below the first predetermined level, the signal from the threshold circuitry has an offset value which causes the output of the integrator circuit to grow larger gradually until the respective phase is disabled.