Power supply with a magnetically uncoupled phase and an odd number of magnetically coupled phases, and control for a power supply with magnetically coupled and magnetically uncoupled phases

• US 8,570,009 B2
• Filed: 06/09/2008
• Issued: 10/29/2013
• Est. Priority Date: 06/08/2007
• Status: Expired due to Fees

• Current Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Original Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Inventors: Wei, Jia, Houston, Michael Jason
• Primary Examiner(s): Laxton, Gary L
• Application Number:
  US12/136,014
• Publication Number:
  US 20080303495A1
• Time in Patent Office: 1,968 Days
• Field of Search: 323/225, 323/237, 323/244, 323/271, 323/272, 323/284, 323/320, 323/350
• US Class Current: 323/272
• CPC Class Codes: G05F 3/04 wherein the variable is ac
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H02M 1/0064 Magnetic structures combining different functions, e.g. storage, filtering or transformation
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections

Abstract

An embodiment of a power supply includes an input node that receives an input voltage, an output node on which a regulated output voltage is provided, an odd number of magnetically coupled phase paths each coupled between the input and output nodes, and a first magnetically uncoupled phase path coupled between the input and output nodes. Such a power supply can improve its efficiency by activating different combinations of the coupled and uncoupled phase paths depending on the load conditions. For example, the power supply may activate only an uncoupled phase path during light-load conditions, may activate only coupled phase paths during moderate-load conditions, and may activate both coupled and uncoupled phase paths during heavy-load conditions and during a step-up load transient.

Claims

1. A power supply, comprising:

an input node operable to receive an input voltage;

an output node operable to provide a regulated output voltage;

an odd number of magnetically coupled phase paths each coupled between the input and output nodes;

a first magnetically uncoupled phase path coupled between the input and output nodes; and

a power-supply controller coupled to the phase paths and operable;

to activate each of the magnetically coupled phase paths at a first frequency; and

to activate the magnetically uncoupled phase path at a second frequency that is substantially equal to a product of the first frequency and the odd number.

2. The power supply of claim 1, further comprising:

an inductor assembly comprising a core having members; and

wherein each of the magnetically coupled and uncoupled phase paths includes a single winding disposed about a respective one of the members.

3. A power supply, comprising:

an input node operable to receive an input voltage;

an output node operable to provide a regulated output voltage;

an odd number of magnetically coupled phase paths each coupled between the input and output nodes;

a first magnetically uncoupled phase path coupled between the input and output nodes; and

an inductor assembly including a core having

a group of first members that are magnetically coupled to one another, and

a second member that is magnetically isolated from the first members;

wherein each of the magnetically coupled phase paths includes a winding disposed about a respective one of the first members; and

wherein the magnetically uncoupled phase path includes a winding disposed about the second member.

4. The power supply of claim 3, further comprising a second magnetically uncoupled phase path coupled between the input and output nodes.

5. A system, comprising:

a power supply, comprising,

an input node operable to receive an input voltage,

an output node operable to provide a regulated output voltage,

an odd number of magnetically coupled phase paths each coupled between the input and output nodes, the odd number of magnetically coupled phase paths being magnetically to each other,

a magnetically uncoupled phase path coupled between the input and output nodes, and

a power-supply controller coupled to and operable to activate each of the magnetically coupled phase paths at a first frequency and to activate the magnetically uncoupled phase path at a second frequency that is approximately equal to a product of the first frequency and the odd number; and

a load coupled to the output node of the power supply.

6. The system of claim 5, further comprising:

an integrated-circuit die; and

wherein the controller and the load are disposed on the die.

7. The system of claim 5, further comprising:

first and second integrated-circuit dies;

wherein the controller is disposed on the first die; and

wherein the load is disposed on the second die.

8. The system of claim 5 wherein the load comprises an integrated circuit.

9. A method, comprising:

activating each of an odd number of magnetically coupled phase paths at respective first frequencies, the odd number of magnetically coupled phase paths being magnetically coupled to one another; and

activating a first magnetically uncoupled phase path at a second frequency that is substantially equal to a product of the first frequency and the odd number.

10. The method of claim 9 wherein activating the magnetically coupled phase paths comprises activating each one of the magnetically coupled phase paths at a phase offset from a respective other one of the magnetically coupled phase paths, the phase offset substantially equal to a quotient of a total number of the magnetically coupled phase paths and 360 degrees.

11. A method, comprising:

activating each of an odd number of magnetically coupled phase paths at respective first frequencies; and

activating a first magnetically uncoupled phase path a second frequency;

wherein the second frequency is substantially equal to a product of the first frequency and the odd number;

wherein activating the magnetically coupled phase paths comprises activating each one of the magnetically coupled phase paths at a first phase offset from a respective other one of the magnetically coupled phase paths, the phase offset substantially equal to a quotient of a total number of the magnetically coupled phase paths and 360 degrees; and

wherein activating the magnetically uncoupled phase path comprises activating the magnetically uncoupled phase path at a second phase offset from each of the magnetically coupled phase paths, the second phase offset substantially equal to one half of the first phase offset relative to the first frequency.

12. A method, comprising:

activating each of an odd number of magnetically coupled phase paths at respective first frequencies; and

activating a first magnetically uncoupled phase path a second frequency;

wherein the second frequency is substantially equal to a product of the first frequency and the odd number;

wherein activating the magnetically coupled phase paths comprises activating each one of the magnetically coupled phase paths at a first phase offset from a respective other one of the magnetically coupled phase paths, the phase offset substantially equal to a quotient of a total number of the magnetically coupled phase paths and 360 degrees; and

wherein activating the magnetically uncoupled phase path comprises activating the magnetically uncoupled phase path at a second phase offset from each of the magnetically coupled phase paths, the second phase offset substantially equal to 180 degrees relative to the second frequency.

13. The method of claim 12, further comprising activating a second magnetically uncoupled phase path at the second frequency.

14. A power-supply controller, comprising:

a phase controller operable,

to enable a first number of magnetically uncoupled phase paths in response to a load current having a first relationship to a first threshold level, and

to enable a second number of magnetically coupled phase paths in response to the load current having a second relationship to the first threshold level; and

a load-current monitor coupled to the phase controller, operable to be coupled to the magnetically uncoupled and coupled phase paths, and operable to determine the load current; and

wherein the phase controller is further operable;

to activate each of the enabled first number of the magnetically uncoupled phase paths at a first frequency; and

to activate each of the enabled second number of the magnetically coupled phase paths at a second frequency that is substantially equal to a quotient of the first frequency divided by the second number.

15. The power-supply controller of claim 14 wherein:

the first number equals one; and

the second number is greater than one.

16. The power-supply controller of claim 14 wherein the phase controller is operable:

to enable the first number of magnetically uncoupled phase paths in response to a magnitude of the load current being smaller than the first threshold level; and

to enable the second number of magnetically coupled phase paths in response to the magnitude of the load current being greater than the first threshold level.

17. The power-supply controller of claim 14 wherein the phase controller is operable to enable at least one magnetically uncoupled phase path in response to a magnitude of the load current being greater than the first threshold level.

18. The power-supply controller of claim 14 wherein the phase controller is operable to disable the second number of magnetically coupled phase paths in response to a magnitude of the load current being smaller than the first threshold level.

19. The power-supply controller of claim 14, further comprising:

an inductor assembly comprising a core having members; and

wherein each of the magnetically coupled and uncoupled phase paths includes a winding disposed about a respective one of the members.

20. A power-supply controller, comprising:

a phase controller operable

to enable a first number of magnetically uncoupled phase paths in response to a load current having a first relationship to a first threshold level, and

to enable a second number of magnetically coupled phase paths in response to the load current having a second relationship to the first threshold level; and

a load-current monitor coupled to the phase controller, operable to be coupled to the magnetically uncoupled and coupled phase paths, and operable to determine the load current;

an inductor assembly including a core having

a group of first members that are magnetically coupled to one another, and

a group of second members that are each magnetically isolated from the first members and from the other second members;

wherein each of the magnetically coupled phase paths includes a winding disposed about a respective one of the first members; and

wherein each of the magnetically uncoupled phase paths includes a winding disposed about a respective one of the second members.

21. The power-supply controller of claim 20 wherein the load-current monitor is operable to determine a magnitude of the output current.

22. A power supply, comprising:

an input node operable to receive an input voltage;

an output node operable to provide a regulated output voltage and a load current;

a first number of magnetically uncoupled phase paths coupled between the input and output nodes, each of the first number of phase paths operable, when active, to provide a respective portion of the load current;

a second number of magnetically coupled phase paths coupled between the input and output nodes, each of the second number of the phase paths operable, when active, to provide a respective portion of the load current; and

a power-supply controller coupled to the first number of the magnetically uncoupled phase paths and to the second number of the magnetically uncoupled phase paths, the power-supply controller comprising

a phase controller operable

to enable the first number of magnetically uncoupled phase paths in response to the load current having a first relationship to a first threshold level,

to activate the enabled first number of magnetically uncoupled phase paths at a first frequency,

to enable the second number of magnetically coupled phase paths in response to the load current having a second relationship to the first threshold level, and

to activate the enabled second number of magnetically coupled phase paths at a second frequency that is approximately equal to quotient of the first frequency divided by the second number, and

a output-current monitor coupled to the phase controller and to the magnetically uncoupled and coupled phase paths, and operable to determine the output current.

23. A system, comprising:

a power supply, comprising

an input node operable to receive an input voltage,

an output node operable to provide a regulated output voltage and a load current,

a first number of magnetically uncoupled phase paths coupled between the input and output nodes, each of the first number of phase paths operable, when active, to provide a respective portion of the load current,

a second number of magnetically coupled phase paths coupled between the input and output nodes, each of the second number of the phase paths operable, when active, to provide a respective portion of the load current, and

a power-supply controller coupled to the first number of the magnetically uncoupled phase paths and to the second number of the magnetically uncoupled phase paths, the power-supply controller comprising

a phase controller operable

to enable the first number of magnetically uncoupled phase paths in response to the load current having a first relationship to a first threshold level, and

to enable the second number of magnetically coupled phase paths in response to the load current having a second relationship to the first threshold level, and

a load-current monitor coupled to the phase controller and to the magnetically uncoupled and coupled phase paths, and operable to determine the load current; and

wherein the phase controller is further operable;

to activate each of the enabled first number of the magnetically uncoupled phase paths at a first frequency; and

to activate each of the enabled second number of the magnetically coupled phase paths at a second frequency that is substantially equal to a quotient of the first frequency divided by the second number; and

a load coupled to the output node.

24. The system of claim 23, further comprising:

an integrated-circuit die; and

wherein the power-supply controller and the load are disposed on the die.

25. The system of claim 23, further comprising:

first and second integrated-circuit dies;

wherein the controller is disposed on the first die; and

wherein the load is disposed on the second die.

26. The system of claim 23 wherein the load comprises an integrated circuit.

27. A method comprising:

enabling a magnetically uncoupled phase path in response to a load current having a first relationship to a first threshold level; and

enabling a number of magnetically coupled phase paths in response to the load current having a second relationship to the first threshold level;

wherein enabling the uncoupled phase path in response to the load current having a first relationship to the first threshold level comprises enabling the uncoupled phase path in response to a magnitude of the load current being less than the first threshold level;

disabling the coupled phase paths in response to the magnitude of the output current being less than the first threshold level;

wherein enabling the coupled phase paths in response to the load current having a second relationship to the first threshold level comprises enabling the coupled phase paths in response to the magnitude of the load current being greater than the first threshold level; and

enabling the uncoupled phase path in response to the magnitude of the load current being greater than the first threshold level.

28. A method comprising:

enabling a magnetically uncoupled phase path in response to a load current having a first relationship to a first threshold level; and

enabling a number of magnetically coupled phase paths in response to the load current having a second relationship to the first threshold level;

wherein enabling the uncoupled phase path in response to the load current having a first relationship to the first threshold level comprises enabling the uncoupled phase path in response to a magnitude of the load current being less than the first threshold level;

disabling the coupled phase paths in response to the magnitude of the load current being less than the first threshold level;

wherein enabling the coupled phase paths in response to the load current having the first relationship to the first threshold level comprises enabling the coupled phase paths in response to the magnitude of the load current being greater than the first threshold level;

disabling the uncoupled phase path in response to the magnitude of the load current being greater than the first threshold level and less than a second threshold level; and

enabling the uncoupled phase path in response to the magnitude of the load current being greater than the second threshold level.

29. A method comprising:

enabling a magnetically uncoupled phase path in response to a load current having a first relationship to a first threshold level; and

enabling a number of magnetically coupled phase paths in response to the load current having a second relationship to the first threshold level;

while the magnetically coupled phase paths are enabled, activating each of the magnetically coupled phase paths at a first frequency; and

while the magnetically uncoupled phase path is enabled, activating the uncoupled phase path at a second frequency that is substantially equal to a product of the first frequency and the number of magnetically coupled phases.

30. A method comprising:

enabling a magnetically uncoupled phase path in response to a load current having a first relationship to a first threshold level; and

enabling a number of magnetically coupled phase paths in response to the load current having a second relationship to the first threshold level;

while the magnetically coupled phase paths are enabled, activating each of the magnetically coupled phase paths at a first frequency and at a first time offset relative to one of the other coupled phase paths; and

while the magnetically uncoupled phase path is enabled, activating the uncoupled phase path at a second frequency that is substantially equal to a product of the first frequency and the number of magnetically coupled phases and at a second time offset relative to each of the coupled phase paths.

31. A method comprising:

enabling a magnetically uncoupled phase path in response to a load current having a first relationship to a first threshold level; and

enabling a number of magnetically coupled phase paths in response to the load current having a second relationship to the first threshold level;

while the magnetically coupled phase paths are enabled, activating each of the magnetically coupled phase paths at a first frequency and at a first time offset relative to one of the other coupled phase paths; and

while the magnetically uncoupled phase path is enabled, activating the uncoupled phase path at the first frequency and at the first time offset relative to one of the coupled phase paths.

32. A method comprising:

enabling a magnetically uncoupled phase path in response to a load current having a first relationship to a first threshold level; and

enabling a number of magnetically coupled phase paths in response to the load current having a second relationship to the first threshold level;

while the magnetically coupled phase paths are enabled, activating each of the magnetically coupled phase paths at a first frequency and at a first time offset relative to one of the other coupled phase paths; and

while the magnetically uncoupled phase path is enabled, activating the uncoupled phase path at the first frequency and substantially in phase with one of the coupled phase paths.