Patent ID: 6897636

Claim:
A multi-phase DC—DC converter producing an output voltage at an output node comprising: a plurality of converter channels, each of said plurality of converter channels including a converter channel input, and a converter channel output coupled to said output node, each of said plurality of converter channels being operative to generate a converter channel current and to adjust said converter channel current in response to a control signal electrically connected to each said converter channel input; and a control circuit, comprising: an error signal comparator that is operative to generate an error signal in accordance with a prescribed relationship between said output voltage and a reference voltage; and a plurality of control circuit channels, each of said plurality of control circuit channels corresponding to one of said plurality of converter channels, each respective one of said plurality of control circuit channels including a channel current sensor that is operative to generate a channel current signal representative of a corresponding converter channel current; a differential combiner that is operative to generate a differential channel current signal representative of a difference between said channel current signal and an average of an overall average current for said plurality of converter channels; a differential error signal generator that is operative to generate a differential error signal representative a difference between said error signal and said differential channel current signal; and a pulse width modulator coupled to receive a ramp voltage having an amplitude proportional to a respective input voltage for said respective one of said control circuit channels and said differential error signal, and producing a pulse width modulated output voltage in accordance with a comparison of said ramp voltage with said differential error signal; outputs of said pulse width modulators being combined to provide a composite output current at said output node; and wherein ramp voltages of said pulse width modulators of said plurality of control circuit channels have different input voltages; and said plurality of control circuit channels are configured to balance said converter channel currents.