POWER FACTOR CONTROL SYSTEMS AND METHODS

• US 20080205103A1
• Filed: 05/05/2008
• Published: 08/28/2008
• Est. Priority Date: 09/24/2004
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Sutardja, Sehat, Lin, Jianqing
• Granted Patent: US 7,812,576 B2
• Time in Patent Office: Days
• US Class Current: 363/84
• CPC Class Codes: G05F 1/70 Regulating power factor; Regulating reactive current or power
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A boost converter comprises an inductance that receives an input signal. A switch controls current supplied via the inductance to a load. A power factor control module comprises a mode control module that selects an operating mode of the boost converter and a switch control module that switches the switch at a frequency. The frequency is equal to a first frequency when the mode control module selects a continuous mode and equal to a second frequency when the mode control module selects a discontinuous mode. The first frequency is greater than the second frequency.

Claims

1. A boost converter, comprising:

an inductance that receives an input signal;

a switch that controls current supplied via said inductance to a load; and

a power factor control module comprising;

a mode control module that selects an operating mode of said boost converter; and

a switch control module that switches said switch at a switching frequency, that sets said switching frequency equal to a first frequency when said mode control module selects a continuous mode and that sets said switching frequency equal to a second frequency when said mode control module selects a discontinuous mode,

wherein said first frequency is different from said second frequency.

2. The boost converter of claim 1 wherein said first frequency is greater than said second frequency.

3. The boost converter of claim 1 wherein said switch control module determines said switching frequency independently of measurement of current through said inductance.

4. The boost converter of claim 1 wherein the power factor control module further includes:

a phase detecting module that determines a period of said input signal;

a peak voltage determining module that senses a peak voltage of said input signal; and

an on-time module that provides an on-time of said switch.

5. The boost converter of claim 3 wherein the power factor control module further comprises an off-time module that calculates an off-time of said switch based on said period, said on-time and said peak voltage.

6. The boost converter of claim 4 wherein said off-time module calculates said off-time independently of measurement of current flowing through said inductance.

7. The boost converter of claim 4 wherein the phase detecting module comprises a zero-crossing module that detects zero-crossing of a voltage of said input signal.

8. The boost converter of claim 7 wherein said mode control module controls transitions between said discontinuous mode and said continuous mode based on said zero-crossing.

9. The boost converter of claim 4 wherein said phase detecting module further determines a phase of said input signal.

10. The boost converter of claim 9 wherein said first frequency is greater than a boundary frequency and said second frequency is less than said boundary frequency, and wherein said boundary frequency is based on said phase of said input signal.

11. The boost converter of claim 10 wherein said boundary frequency is based on:

f_c=0.25*(V_p²)*(1−

V_p*sin(θ

)/V_o)/(P_o*L)

where f_c is said boundary frequency, θ

is said phase, V_p is a peak voltage of said input signal, V_o is an output voltage of said boost converter, P_o is an output power of said boost converter, and L is a value of said inductance.

12. The boost converter of claim 10 wherein said boundary frequency is based on a peak value of said input signal, an output power of said boost converter, and a value of said inductance.

13. The boost converter of claim 10 wherein said boundary frequency is a product of a maximum boundary frequency and a first value, wherein said maximum boundary frequency is based on said peak voltage of said input signal, an output power of said boost converter, and a first inductance value of said inductance and wherein said first value is based on said peak voltage of said input signal and said output power of said boost converter.

14. A power factor controller, comprising:

a mode control module that selects an operating mode of a power converter; and

a switch control module that switches a switch at a switching frequency to control a current, that sets said switching frequency equal to a first frequency when said mode control module selects a continuous mode and that sets said switching frequency equal to a second frequency when said mode control module selects a discontinuous mode,

wherein said first frequency is different from said second frequency, and

wherein said switch control module determines said switching frequency independent of measurement of current through an inductance.

15. The power factor controller of claim 14 wherein said first frequency is greater than said second frequency.

16. The power factor controller of claim 14, wherein the current is supplied via the inductance to a load, the power factor controller further comprising:

a phase detecting module that determines a period of an input signal received by said inductance;

a peak voltage determining module that senses a peak voltage of said input signal; and

an on-time module that provides an on-time of said switch.

17. The power factor controller of claim 16 further comprising an off-time calculating module that calculates off-time of said switch based on said period, said on-time and said peak voltage.

18. The power factor controller of claim 16 wherein the phase detecting module comprises a zero-crossing module that detects zero-crossing of a voltage of said input signal.

19. The power factor controller of claim 18 wherein said mode control module controls transitions between said discontinuous mode and said continuous mode based on said zero-crossing.

20. The power factor controller of claim 16 wherein said phase detecting module determines a phase of said input signal.

21. The power factor controller of claim 20 wherein said first frequency is greater than a boundary frequency and said second frequency is less than said boundary frequency, and wherein said boundary frequency is based on said phase of said input signal.

22. The power factor controller of claim 21 wherein said boundary frequency f_c is based on:

f_c=0.25*(V_p²)*(1−

V_p*sin(θ

)/V_o)/(P_o*L)

where f_c is said boundary frequency, θ

is said phase, V_p is a peak voltage of said input signal, V_o is an output voltage of said power converter, P_o is an output power of said power converter, and L is a value of said inductance.

23. The power factor controller of claim 21 wherein said boundary frequency is based on a peak value of said input signal, an output power of said power converter, and a value of said inductance.

24. The power factor controller of claim 21 wherein said boundary frequency is based on a maximum boundary frequency and a first value, wherein said maximum boundary frequency is based on said peak voltage of said input signal, an output power of said power converter, and a first inductance value of said inductance, and wherein said first value is based on said peak voltage of said input signal and said output power of said power converter.

25. A method for operating a boost converter, comprising:

controlling current supplied via an inductance to a load with a switch;

selecting an operating mode of said boost converter;

switching said switch at a switching frequency;

setting said switching frequency equal to a first frequency when operating in a continuous mode; and

setting said switching frequency equal to a second frequency when operating in a discontinuous mode, wherein said first frequency is different from said second frequency.

26. The method of claim 25 wherein said first frequency is greater than said second frequency.

27. The method of claim 25 further comprising determining said switching frequency independently of measurement of current through said inductance.

28. The method of claim 25 further comprising:

determining a period of an input signal;

sensing a peak voltage of said input signal; and

providing an on-time of said switch.

29. The method of claim 28 further comprising calculating an off-time of said switch based on said period, said on-time and said peak voltage.

30. The method of claim 29 wherein said off-time is calculated independently of measurement of current flowing through said inductance.

31. The method of claim 28 further comprising detecting zero-crossing of a voltage of said input signal.

32. The method of claim 31 further comprising:

controlling transitions between said discontinuous mode and said continuous mode based on said zero-crossing.

33. The method of claim 28 further comprising detecting a phase of said input signal.

34. The method of claim 33 wherein said first frequency is greater than a boundary frequency and said second frequency is less than said boundary frequency, and wherein said boundary frequency is based on said phase of said input signal.

35. The method of claim 34 wherein said boundary frequency is based on:

f_c=0.25*(V_p²)*(1−

V_p*sin(θ

)/V_o)/(P_o*L)

where f_c is said boundary frequency, θ

is said phase, V_p is a peak voltage of said input signal, V_o is an output voltage of said boost converter, P_o is an output power of said boost converter, and L is a value of said inductance.

36. The method of claim 34 wherein said boundary frequency is based on a peak value of said input signal, an output power of said boost converter, and a value of said inductance.

37. The method of claim 34 wherein said boundary frequency is a product of a maximum boundary frequency and a first value, wherein said maximum boundary frequency is based on said peak voltage of said input signal, an output power of said boost converter, and a first inductance value of said inductance and wherein said first value is based on said peak voltage of said input signal and said output power of said boost converter.

38. A method for operating a power factor controller, comprising:

selecting an operating mode of a power converter; and

switching a switch at a frequency to control current supplied via an inductance to a load;

setting said switching frequency equal to a first frequency when a continuous mode is selected as the operating mode; and

setting said switching frequency equal to a second frequency when a discontinuous mode is selected as the operating mode,

wherein said first frequency is greater than said second frequency, and

wherein said switching frequency is determined independent of measurement of current through said inductance.

39. The method of claim 38 further comprising:

determining a period of an input signal received by said inductance;

sensing a peak voltage of said input signal; and

providing an on-time of said switch.

40. The method of claim 39 further comprising calculating off-time of said switch based on said period, said on-time and said peak voltage.

41. The method of claim 39 further comprising detecting zero-crossing of a voltage of said input signal.

42. The method of claim 41 further comprising:

controlling transitions between said discontinuous mode and said continuous mode based on said zero-crossing.

43. The method of claim 39 further comprising detecting a phase of said input signal.

44. The method of claim 43 wherein said first frequency is greater than a boundary frequency and said second frequency is less than said boundary frequency, and wherein said boundary frequency is based on said phase of said input signal.

45. The method of claim 44 wherein said boundary frequency f_c is based on:

f_c=0.25*(V_p²)*(1−

V_p*sin(θ

)/V_o)/(P_o*L)

where f_c is said boundary frequency, θ

is said phase, V_p is a peak voltage of said input signal, V_o is an output voltage of said power converter, P_o is an output power of said power converter, and L is a value of said inductance.

46. The method of claim 44 wherein said boundary frequency is based on a peak value of said input signal, an output power of said power converter, and a value of said inductance.

47. The method of claim 44 wherein said boundary frequency is based on a maximum boundary frequency and a first value, wherein said maximum boundary frequency is based on said peak voltage of said input signal, an output power of said power converter, and a first inductance value of said inductance, and wherein said first value is based on said peak voltage of said input signal and said output power of said power converter.