Multi-phase converter with balanced currents

A method of balancing a plurality of channel currents, each of said plurality of channel currents flowing in a corresponding one of a plurality of channels in a multi-phase DC/DC converter, said DC/DC converter having an output voltage, said method comprising the steps of:

• sensing each of said plurality of channel currents to thereby determine a plurality of channel current signals;
• averaging together said plurality of channel current signals to thereby determine an average channel current signal;
• comparing each of said plurality of channel current signals to said average channel current signal to thereby determine a respective differential channel current signal for each of said plurality of channels;
• further comparing said output voltage to a reference voltage to thereby determine an error signal;
• furthermore comparing each said differential channel current signal to said error signal to thereby determine a respective differential error signal for each of said plurality of channels;
• and
• adjusting each of said plurality of channel currents based at least in part upon a corresponding said differential error signal to thereby make each of said plurality of channel currents substantially equal to each other.

A multi-phase DC/DC converter, comprising:

• a converter output;
• a plurality of converter channels, each of said plurality of converter channels having a respective converter channel input and a respective converter channel output, each said converter channel output being electrically connected to said converter output, each of said plurality of converter channels being configured for sourcing a respective channel current, each of said plurality of converter channels being configured to adjust a corresponding said channel current in response to a control signal electrically connected to a corresponding said converter channel input;
• and
• a control circuit, comprising:
• a summing circuit having a plurality of summing circuit inputs and a summing circuit output;
• a plurality of current feedback paths, each of said plurality of current feedback paths electrically connecting a respective said converter channel output to a corresponding one of said plurality of summing circuit inputs;
• a scaling circuit having a scaling input and a scaling output, said scaling input being electrically connected to said sing circuit output;
• a plurality of first subtraction circuits each having a first input, a second input and a first subtraction circuit output, each said second input being electrically connected to said scaling output, each said first input being electrically connected to a corresponding one of said plurality of current feedback paths;
• an error amplifier having a reference input, an error input, and an error output, said reference input being electrically connected to a reference voltage;
• a voltage feedback path connecting said converter output to said error input of said error amplifier;
• a plurality of second subtraction circuits each having a first input, a second input and a second subtraction circuit output, each said first input being electrically connected to said error output, each said second input being electrically connected to a corresponding said first subtraction circuit output;
• and
• a plurality of pulse width modulators each having a ramp input, a control input, and a pulse width modulator output, each said control input being electrically connected to a corresponding said second subtraction circuit output, each said ramp input being connected to a ramp voltage source, each said pulse width modulator output being electrically connected to a corresponding said converter channel input.

A control circuit for a multi-phase DC/DC converter having an output voltage, the control circuit comprising:

• an averaging circuit, responsive to a plurality of channel current signals representative of channel currents for a plurality of channels, that averages the values of the plurality of channel current signals to produce one or more signals representative of the average channel current;
• an error amplifier, responsive to the output voltage and a reference signal, the error amplifier providing a common error signal;
• and
• a plurality of pulse width modulator circuits, each responsive to the common error signal, the one or more signals representative of the average channel current, one of the plurality of channel current signals, and a second reference signal to produce a plurality of pulse width modulated signals to control the plurality of channels of the multi-phase DC/DC converter.

A multi-phase DC/DC converter having an output voltage comprising:

• a plurality of converter channels to supply a plurality of channel currents, each converter channel having a control input and an output;
• and
• a control circuit coupled to the control input of each converter channel to provide each converter channel with an associated pulse width modulated signal to regulate the channel current flowing through each converter channel, the control circuit is further coupled to receive channel current signals representative of the plurality of channel currents, the control circuit comprising,
• a scaling circuit, responsive to the plurality of channel current signals, that produces one or more scaled values based on the plurality of channel current signals,
• an error amplifier, responsive to the output voltage and a first reference signal, the error amplifier providing a common error signal, and
• a plurality of pulse width modulator circuits, each pulse width modulator circuit responsive to the common error signal, the one or more scaled values, one of the plurality of channel current signals, and a second reference signal to produce a plurality of pulse width modulated signals to control the plurality of channels of the multi-phase DC/DC converter.

A multi-phase DC/DC converter having an output voltage, the converter comprising:

• a plurality of converter channels, each converter channel having a control input to receive a control signal and an output, wherein each converter channel is adapted to output a converter channel current based at least on the control signal received at the control input of the converter channel;
• and
• a control circuit comprising,
• an error amplifier to output a common error signal, the error amplifier coupled to a first reference signal and the output voltage, a summing circuit coupled to receive channel current signals representative of the converter channel currents, the summing circuit outputting a cumulative current signal representative of the summation of the channel current signals,
• a scaling circuit coupled to the summing circuit and producing one or more scaled signals based on the cumulative current signal, and
• a pulse width modulator for each converter channel, each pulse width modulator responsive to a combination of the one or more scaled signals, an associated channel current signal, a second reference signal, and the common error signal.

A control circuit for a multi-phase DC/DC converter having an output voltage, the control circuit comprising:

• a scaling circuit, responsive to a plurality of channel current signals representative of channel currents for a plurality of channels, that scales the values of the plurality of channel current signals to produce one or more scaled signals;
• an error amplifier, responsive to the output voltage and a reference signal, the error amplifier providing a common error signal;
• and
• a plurality of pulse width modulator circuits, each responsive to the common error signal, the one or more scaled signals, one of the plurality of channel current signals, and a second reference signal to produce a plurality of pulse width modulated signals to control the plurality of channels of the multi-phase DC/DC converter.

A control circuit for a multi-phase DC/DC converter having an output voltage, the control circuit comprising:

• a scaling circuit, responsive to a plurality of channel current signals representative of channel currents for a plurality of channels, that scales the values of the plurality of channel current signals to produce one or more scaled signals;
• an error amplifier, responsive to the output voltage and a reference signal, the error amplifier providing a common error signal;
• and
• a plurality of pulse width modulator circuits, each responsive to the common error signal, the one or more scaled signals, and one of the plurality of channel current signals to produce a plurality of pulse width modulated signals to control the plurality of channels of the multi-phase DC/DC converter.