Claims
- 1. 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 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 a respective input voltage, and being coupled to receive a ramp voltage and said differential error signal and to pulse width modulate said input voltage to produce said output voltage in accordance with a comparison of said ramp input 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
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.
- 2. The multi-phase DC-DC converter according to claim 1, wherein said plurality of control circuit channels have the same gains.
- 3. The multi-phase DC-DC converter according to claim 2, wherein said pulse width modulators have the same modulator gains.
- 4. The multi-phase DC-DC converter according to claim 3, wherein a respective pulse width modulator is coupled to receive a ramp voltage having an amplitude proportional to said input voltage.
- 5. The multi-phase DC-DC converter according to claim 3, wherein a respective converter channel is configured to scale said differential error signal inversely proportional to the gain of said pulse width modulator.
- 6. In a multi-phase DC-DC converter producing an output voltage at an output node and including 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, said control circuit having 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, and wherein each of said plurality of control circuit channels includes:
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 a respective input voltage, and being coupled to receive a ramp voltage and said differential error signal and to pulse width modulate said input voltage to produce said output voltage in accordance with a comparison of said ramp input with said differential error signal, and wherein pulse width modulators of said plurality of control circuit channels have different input voltages; the improvement wherein said plurality of control circuit channels are configured to balance said converter channel currents.
- 7. The improvement according to claim 6, wherein said plurality of control circuit channels have the same gains.
- 8. The improvement according to claim 6, wherein said pulse width modulators have the same modulator gains.
- 9. The improvement according to claim 8, wherein a respective pulse width modulator is coupled to receive a ramp voltage having an amplitude proportional to said input voltage.
- 10. The improvement according to claim 9, wherein a respective converter channel is configured to scale said differential error signal inversely proportional to the gain of said pulse width modulator.
- 11. A method of operating a multi-phase DC-DC converter, that generates an output voltage at an output node and contains 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, said control circuit having 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, and wherein each of said plurality of control circuit channels includes:
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 a respective input voltage, and being coupled to receive a ramp voltage and said differential error signal and to pulse width modulate said input voltage to produce said output voltage in accordance with a comparison of said ramp input with said differential error signal; said method comprising the step of:
(a) supplying different input voltages to selected ones of said pulse width modulators of said plurality of control circuit channels; and (b) causing said plurality of control circuit channels to balance said converter channel currents.
- 12. The method according to claim 11, wherein step (b) includes configuring said plurality of control circuit channels to have the same gains.
- 13. The method according to claim 12, wherein step (b) comprises configuring said pulse width modulators to have the same modulator gains.
- 14. The method according to claim 13, wherein step (b) comprises supplying to a respective pulse width modulator a ramp voltage having an amplitude proportional to said input voltage.
- 15. The method according to claim 13, wherein step (b) includes scaling said differential error signal in inverse proportion to the gain of said pulse width modulator.
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims the benefit of U.S. Application Serial No. 60/368,894, filed Mar. 29, 2002, by M. Harris, entitled: “Method and Circuit for Scaling and Balancing Input and Output Currents in a Multi-Phase DC-DC Converter Using Different Input Voltages,” assigned to the assignee of the present application and the disclosure of which is incorporated herein.
Provisional Applications (1)
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Number |
Date |
Country |
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60368894 |
Mar 2002 |
US |