Multi-phase and multi-module power supplies with balanced current between phases and modules

• US 6,215,290 B1
• Filed: 11/15/1999
• Issued: 04/10/2001
• Est. Priority Date: 11/15/1999
• Status: Expired due to Term

• Current Assignee: Semtech Corporation
• Original Assignee: Semtech Corporation
• Inventors: Guo, Jason, Yang, Eric X.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Vu, Bao Q.
• Application Number:
  US09/440,222
• Time in Patent Office: 512 Days
• Field of Search: 323/222, 323/282, 323/284, 323/286, 323/290
• US Class Current: 323/282
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02M 3/1586 switched with a phase shift, i.e. interleaved

Abstract

A multi-phase power supply utilizes a current sensor including a sensor inductor winding connected in parallel with a filter inductor winding at the output of each phase for sensing the phase currents and balancing the current by adjusting the duty cycle of each phase through feedback control. In addition, in a multi-module power supply configuration, current between power supply modules is balanced through use of the same current sensor and current sharing technique. Each phase of the power supply includes at least one input power source and a current sensor. The sensor inductor winding and the filter inductor winding have the same number of turns and are wound about a magnetic core also present at each phase. A differential amplifier at each phase senses and amplifies any voltage difference between the outputs of the sensor inductor winding and the corresponding filter inductor winding. A current-sharing bus is formed between each of the phases, carrying the summed and averaged outputs from all the differential amplifiers. A feedback correction circuit at each phase utilizes the voltage on the current-sharing bus as a reference to control a pulse width modulator in adjusting the duty cycle of the corresponding phase, thereby balancing the load current among the phases. In a multi-module, multi-phase power supply, the current-sharing bus and a voltage-sharing bus are extended between each module and the phases of each module to achieve the same current balancing between all phases and modules.

Claims

1. A multi-phase power supply which balances current between phases, comprising:

at least one input power source for supplying current for each of said phases;

a filter capacitor at the output of each of said phases;

a sensor inductor winding at the output of each of said phases, said sensor inductor winding having an input and an output;

a filter inductor winding at the output of each of said phases, said filter inductor winding having an input and an output, wherein said sensor inductor winding and said filter inductor winding have the same number of turns and said input of said sensor inductor winding and said input of said filter inductor winding are connected together at the output of each of said phases;

a magnetic core at each of said phases, about which a corresponding sensor inductor winding and a corresponding filter inductor winding are wound;

a differential amplifier at each of said phases for sensing and amplifying a voltage difference between the outputs of said corresponding sensor inductor winding and said corresponding filter inductor winding;

circuitry to sum and average outputs from all differential amplifiers, forming a current-sharing bus between each of said phases,

a feedback correction circuit at each of said phases which utilizes the voltage on said current-sharing bus as a reference; and

a pulse width modulator at each of said phases controlled by a corresponding feedback correction circuit for adjusting the duty cycle of a corresponding phase.

2. The multi-phase power supply as recited in claim 1, wherein said differential amplifier and said feedback correction circuit are integrated as part of a multi-phase controller circuit.

3. The multi-phase power supply as recited in claim 1, wherein said differential amplifier, said feedback correction circuit and said pulse width modulator are integrated as part of a multi-phase driver circuit.

4. The multi-phase power supply as recited in claim 3, wherein said multi-phase driver circuit is combined with said multi-phase power supply as part of a power supply module.

5. The multi-phase power supply as recited in claim 4, wherein said current-sharing bus and a voltage sharing bus link said power supply module with at least one additional power supply module as a multi-module power supply system for balancing current between said power supply module and said at least one additional power supply module, said voltage-sharing bus for carrying the summed and averaged reference voltage of said power supply module and said at least one additional power supply module.

6. The multi-phase power supply as recited in claim 1, wherein said sensor inductor winding is made of conductive wire coated with insulating material.

7. The multi-phase power supply as recited in claim 1, wherein said sensor inductor winding is etched onto a printed circuit board as a printed circuit board sensor inductor winding.

8. The multi-phase power supply as recited in claim 1, wherein said filter inductor winding is etched onto a printed circuit board as a printed circuit board filter inductor winding.

9. A method of balancing current between phases in a multi-phase power supply, comprising the steps of:

supplying current for each of said phases through at least one input power source;

connecting the input of a sensor inductor winding together with the input of a filter inductor winding at each of said phases, said sensor inductor winding and said filter inductor winding having the same number of turns;

winding said sensor inductor winding and said filter inductor winding at each of said phases about a magnetic core at each of said phases;

sensing and amplifying a voltage difference between the outputs of said sensor inductor winding and said filter inductor winding at each of said phases with a differential amplifier at each of said phases;

summing and averaging the outputs from all differential amplifiers, forming a current-sharing bus between each of said phases,

referencing a feedback correction circuit at each of said phases with the voltage on said current-sharing bus; and

controlling a pulse width modulator at each of said phases with a corresponding feedback correction circuit to adjust the duty cycle of each phase of said multi-phase power supply and achieve said balancing.

10. The method as recited in claim 9, further comprising the step of integrating said differential amplifier and said feedback correction circuit as a multi-phase controller circuit.

11. The method as recited in claim 9, further comprising the step of integrating said differential amplifier, said feedback correction circuit and said pulse width modulator as a multi-phase driver circuit.

12. The method as recited in claim 11, further comprising the step of combining said multi-phase driver circuit with said multi-phase power supply as part of a power supply module.

13. The method as recited in claim 12, further comprising the step of linking said power supply module with at least one additional power supply module as a multi-module power supply system for balancing current between said power supply module and said at least one additional power supply module through said current-sharing bus and a voltage sharing bus, said voltage-sharing bus for carrying the summed and averaged reference voltage of said power supply module and said at least one additional power supply module.

14. The method as recited in claim 9, wherein said sensor inductor winding is made of conductive wire coated with insulating material.

15. The method as recited in claim 9, wherein said sensor inductor winding is etched onto a printed circuit board as a printed circuit board sensor inductor winding.

16. The method as recited in claim 9, wherein said filter inductor winding is etched onto a printed circuit board as a printed circuit board filter inductor winding.

17. A single-phase power supply which adjusts duty cycle according to sensed changes in load current, comprising:

at least one input power source for supplying current;

a filter capacitor at the output of said power supply;

at most one sensor inductor winding having an input and an output;

a filter inductor winding having an input and an output, wherein said sensor inductor winding and said filter inductor winding have the same number of turns and have their inputs connected together at the output of said power supply;

a magnetic core about which said sensor inductor winding and said filter inductor winding are wound;

a differential amplifier for sensing and amplifying a voltage difference between the outputs of said sensor inductor winding and said filter inductor winding;

a feedback correction circuit which utilizes the voltage at the output of said differential amplifier as a reference; and

a pulse width modulator controlled by said feedback correction circuit for adjusting said duty cycle.

18. The single-phase power supply as recited in claim 17, wherein said differential amplifier and said feedback correction circuit are integrated as part of a controller circuit.

19. The single-phase power supply as recited in claim 17, wherein said differential amplifier, said feedback correction circuit and said pulse width modulator are integrated as part of a driver circuit.

20. The single-phase power supply as recited in claim 19, wherein said driver circuit is combined with said single-phase power supply as part of a power supply module.

21. The single-phase power supply as recited in claim 20, further comprising;

at least one additional power supply module linked by a current-sharing bus to said power supply module;

circuitry to sum and average outputs from all differential amplifiers from said power supply module and said at least one additional power supply module, forming said current-sharing bus; and

wherein said feedback correction circuit utilizes the voltage on said current-sharing bus as a reference.

22. The single-phase power supply as recited in claim 17, wherein said sensor inductor winding is made of conductive wire coated with insulating material.

23. The single-phase power supply as recited in claim 17, wherein said sensor inductor winding is etched onto a printed circuit board as a printed circuit board sensor inductor winding.

24. The single-phase power supply as recited in claim 17, wherein said filter inductor winding is etched onto a printed circuit board as a printed circuit board filter inductor winding.

25. A circuit for sensing current changes through a filter inductor winding in a power supply system, said filter inductor winding having an input and an output, the circuit comprising:

at most one sensor inductor winding having an input and an output, wherein said sensor inductor winding has the same number of turns as said filter inductor winding and the input of said sensor inductor winding is connected to the input of said filter inductor winding; and

a differential amplifier for sensing and amplifying a voltage difference between the outputs of said filter inductor winding and said sensor inductor winding.

26. The circuit as recited in claim 25, wherein said sensor inductor winding is made of conductive wire coated with insulating material.

27. The circuit as recited in claim 25, wherein said sensor inductor winding is etched onto a printed circuit board as a printed circuit board sensor inductor winding.

28. The circuit as recited in claim 25, wherein said filter inductor winding is etched onto a printed circuit board as a printed circuit board filter inductor winding.

29. A method of sensing current changes through a filter inductor winding in a power supply system, comprising the steps of:

connecting the input of at most one sensor inductor winding together with the input of said filter inductor winding, said sensor inductor winding and said filter inductor winding having the same number of turns; and

sensing and amplifying a voltage difference between the outputs of said filter inductor winding and said sensor inductor winding with a differential amplifier.

30. The method as recited in claim 29, wherein said sensor inductor winding is made of conductive wire coated with insulating material.

31. The method as recited in claim 29, wherein said sensor inductor winding is etched onto a printed circuit board as a printed circuit board sensor inductor winding.

32. The method as recited in claim 29, wherein said filter inductor winding is etched onto a printed circuit board as a printed circuit board filter inductor winding.