Single chip power management unit apparatus and method

• US 6,507,173 B1
• Filed: 09/13/2001
• Issued: 01/14/2003
• Est. Priority Date: 06/22/2001
• Status: Expired due to Term

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Hartular, Alexandru, Densham, William L. III, Shyr, You-Yuh, Spiridon, Constantin, Popescu-Stanesti, Vlad Mihail
• Primary Examiner(s): Tso, Edward H.
• Assistant Examiner(s): LUK, LAWRENCE W
• Application Number:
  US09/951,991
• Time in Patent Office: 488 Days
• Field of Search: 320/162, 320/137, 320/160, 320/136, 326/37, 326/38, 361/56, 361/72
• US Class Current: 320/162
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters

Abstract

A power management unit (PMU) apparatus and method may include: a bi-directional pin configured to serve as an input pin during a first condition and as an output pin during a second condition; or a battery charge controller for providing a first conditioning charge and a second full charge to a voltage source of the PMU; or an adapter detector configured to detect the presence of a continuous output adapter and a pulse output adapter; an under voltage lockout protection circuit to prevent start up of the PMU until a power source reaches a predetermined threshold lockout level and to shut down the PMU once the power source reaches a lower threshold lockout disabling level; or a plurality of internal switches for allowing an external switch to have multiple functions; or a power on reset circuit; or multi-output charge status pin.

Claims

1. A power management unit (PMU) for providing power management and supply functions to a device having a battery, comprising:

a substrate;

a bi-directional pin coupled to said substrate and configured to serve as an input pin during a first condition and as an output pin during a second condition;

a battery charge controller coupled to said substrate and said bi-directional pin, said battery charge controller having a first charge conductive path and a second charge conductive path, said first charge conductive path providing a first conditioning charge to said battery, and said second charge conductive path providing a second full charge to said battery during said first condition;

an adapter detector configured to receive a signal representative of the voltage of an external device coupled to said bi-directional pin, and to provide a detector output signal representative of the presence of an adapter, said detector output signal providing a positive indication if said adapter is a continuous output adapter or said adapter is a pulse output adapter, said adapter detector coupled to said substrate;

an under voltage lockout protection circuit configured to prevent start up of said PMU until the voltage of said battery is above a threshold lockout enabling level, and configured to shut down said PMU once the voltage of said battery falls below a threshold lockout disabling level, said threshold lockout disabling level set at a lower voltage than said lockout threshold enabling level, said under voltage lockout protection circuit further coupled to said substrate;

a plurality of internal switches coupled to a switch conductive path, said switch conductive path further coupled to an external switch, said internal switches configured to be responsive to said external switch allowing said external switch to have multiple functions, said plurality of internal switches coupled to said substrate; and

a power on reset (POR) circuit coupled to said battery, to said substrate, and to at least one low dropout voltage regulator (LDO), said POR circuit configured to provide a POR control signal to an external controller.

2. The PMU of claim 1, wherein said first condition is a battery charging condition and said second condition is a battery supply condition.

3. The PMU of claim 2, wherein said bi-directional pin is coupled to bi-directional logic, said bi-directional logic is configured to compare the voltage of said battery with the voltage of an external device coupled to said bi-directional pin and control whether said bi-directional pin functions as an input pin during said battery charging condition or as an output pin during said battery supply condition.

4. The PMU of claim 3, wherein said bi-directional pin is configured to function as an input pin if said comparison indicates the voltage of said battery is higher than the voltage of said external device, and said bi-directional pin is configured to function as an output pin if said comparison indicates the voltage of said battery is less than or equal to the voltage of said external device.

5. The PMU of claim 1, wherein said first condition is a battery charging condition, and wherein said first conditioning charge is less than said second full charge.

6. The PMU of claim 5, wherein said battery charge controller is configured to apply said first conditioning charge to said battery if the output voltage of said battery is below a predetermined full charge threshold level.

7. The PMU of claim 1, wherein said first charge conductive path comprises a first conditioning charge switch and a resistive element, and said second conductive path comprises a second full charge switch.

8. The PMU of claim 7 wherein said first conditioning charge switch is configured to close and said second full charge switch is configured to open when said first conductive path provides said first conditioning charge to said battery.

9. The PMU of claim 7, wherein said second full charge switch is configured to close and said first conditioning charge switch is configured to open when said second conductive path provides said second full charge to said battery.

10. The PMU of claim 7, wherein said second full charge switch is configured to open once the output voltage of said battery is at a maximum level and is configured to close once the voltage of said battery reaches a low limit.

11. The PMU of claim 1, wherein said adapter detector further comprises:

a first detector conductive path configured to receive said signal representative of the voltage of said external device and provide a first detector path output indicative of the presence of said continuous output adapter;

a second detector conductive path configured to receive said signal representative of the voltage of said external device and provide a second detector path output indicative of the presence of said pulse output adapter; and

an output decision circuit configured to receive said first detector path output and said second detector path output and output a digital one if at least one of said outputs is a digital one.

12. The PMU of claim 11, wherein said output decision circuit comprises an OR gate, and where said first detector output path and said second output detector path is coupled to an associated input of said OR gate.

13. The PMU of claim 12, wherein said first detector conductive path comprises a comparator configured to compare the voltage of said battery with the voltage of said external device coupled to said bi-directional pin.

14. The PMU of claim 13, wherein said first detector path output is configured to provide a digital one if the voltage of said battery is less than the voltage of said external device coupled to said bi-directional pin.

15. The PMU of claim 12, wherein said second detector conductive path comprises a retrigerable block, said retrigerable block is configured to output a digital one if a pulsing voltage from said external device is coupled to said bi-directional pin.

16. The PMU of claim 1, wherein said under voltage lockout protection circuit is configured to disable said PMU if the voltage of said battery is below said threshold lockout disabling level for a predetermined lockout delay time.

17. The PMU of claim 16, wherein said predetermined lockout delay time is approximately 50 ms.

18. The PMU of claim 1, wherein said plurality of internal switches comprises a first internal switch and a second internal switch, said first internal switch is configured to open and said second internal switch is configured to close in response to a power down signal from said external switch.

19. The PMU of claim 18, wherein said external switch is configured to be controlled by a controller of said battery portable device.

20. The PMU of claim 1, wherein said plurality of internal switches comprises a first internal switch and a second internal switch, said first internal switch is configured to close and said second internal switch is configured to open in response to a power up signal from said external switch.

21. The PMU of claim 19, wherein said external switch is configured to be controlled by said PMU.

22. The PMU of claim 1, wherein said POR circuit is configured to provide a POR control signal to an external controller.

23. The PMU of claim 22, wherein said POR circuit is further configured to provide a start POR control signal to said external controller once at least one LDO has a voltage level above a predetermined LDO voltage threshold level.

24. A power management unit (PMU) comprising:

a substrate; and

a bi-directional pin coupled to said substrate and configured to serve as an input pin during a first condition and as an output pin during a second condition.

25. The PMU of claim 24, wherein said first condition is a charging condition and said second condition is a supply condition.

26. The PMU of claim 25, wherein said bi-directional pin is coupled to bi-directional logic, said bi-directional logic is configured to compare the voltage of said battery with the voltage of an external device coupled to said bi-directional pin and control whether said bi-directional pin functions as an input pin during said battery charging condition or as an output pin during said battery supply condition.

27. The PMU of claim 26, wherein said bi-directional pin is configured to function as an input pin if said comparison indicates the voltage of said battery is higher than the voltage of said external device, and said bi-directional pin is configured to function as an output pin if said comparison indicates the voltage of said battery is less than or equal to the voltage of said external device.

28. A power management unit (PMU) for providing power management and supply functions to a device having a battery comprising:

a substrate; and

a battery charge controller coupled to said substrate, said battery charge controller having a first charge conductive path and a second charge conductive path, said first charge conductive path providing a first conditioning charge to said battery, and said second charge conductive path providing a second full charge to said battery during said first condition.

29. The PMU of claim 28, wherein said first condition is a battery charging condition, and wherein said first conditioning charge is less than said second full charge.

30. The PMU of claim 29, wherein said battery charge controller is configured to apply said first conditioning charge to said battery if the output voltage of said battery is below a predetermined full charge threshold level.

31. The PMU of claim 28, wherein said first charge conductive path comprises a first conditioning charge switch and a resistive element, and said second conductive path comprises a second full charge switch.

32. The PMU of claim 31 wherein said first conditioning charge switch is configured to close and said second full charge switch is configured to open when said first conductive path provides said first conditioning charge to said battery.

33. The PMU of claim 31, wherein said second full charge switch is configured to close and said first conditioning charge switch is configured to open when said second conductive path provides said second full charge to said battery.

34. The PMU of claim 31, wherein said second full charge switch is configured to open once the output voltage of said battery is at a maximum level and is configured to close once the voltage of said battery reaches a low limit.

35. A power management unit (PMU) for providing power management and supply functions to a device having a battery comprising:

a substrate;

a bi-directional pin coupled to said substrate; and

an adapter detector configured to receive a signal representative of the voltage of an external device coupled to said bi-directional pin, and to provide a detector output signal representative of the presence of an adapter, said detector output signal providing a positive indication if said adapter is a continuous output adapter or said adapter is a pulse output adapter, said adapter detector coupled to said substrate.

36. The PMU of claim 35, wherein said adapter detector further comprises:

a first detector conductive path configured to receive said signal representative of the voltage of said external device and provide a first detector path output indicative of the presence of said continuous output adapter;

a second detector conductive path configured to receive said signal representative of the voltage of said external device and provide a second detector path output indicative of the presence of said pulse output adapter; and

an output decision circuit configured to receive said first detector path output and said second detector path output and output a digital one if at least one of said outputs is a digital one.

37. The PMU of claim 36, wherein said output decision circuit comprises an OR gate, and where said first detector output path and said second output detector path is coupled to an associated input of said OR gate.

38. The PMU of claim 37, wherein said first detector conductive path comprises a comparator configured to compare the voltage of said battery with the voltage of said external device coupled to said bi-directional pin.

39. The PMU of claim 38, wherein said first detector path output is configured to provide a digital one if the voltage of said battery is less than the voltage of said external device coupled to said bi-directional pin.

40. The PMU of claim 38, wherein said second detector conductive path comprises a retrigerable block, said retrigerable block is configured to output a digital one if a pulsing voltage from said external device is coupled to said bi-directional pin.

41. A power management unit (PMU) for providing power management and supply functions to a device having a battery comprising:

a substrate; and

an under voltage lockout protection circuit configured to prevent start up of said PMU until the voltage of said battery is above a threshold lockout enabling level, and configured to shut down said PMU once the voltage of said battery falls below a threshold lockout disabling level, said threshold lockout disabling level set at a lower voltage than said lockout threshold enabling level, said under voltage lockout protection circuit further coupled to said substrate.

42. The PMU of claim 41, wherein said under voltage lockout protection circuit is configured to disable said PMU after the voltage of said battery falls below said threshold lockout disabling level for a predetermined lockout delay time.

43. The PMU of claim 42, wherein said predetermined lockout delay time is approximately 50 ms.

44. A power management unit (PMU) comprising:

a substrate; and

a plurality of internal switches coupled to a switch conductive path, said switch conductive path further coupled to an external switch, said internal switches configured to be responsive to said external switch allowing said external switch to have multiple functions, said plurality of internal switches coupled to said substrate.

45. The PMU of claim 44, wherein said plurality of internal switches comprises a first internal switch and a second internal switch, said first internal switch is configured to open and said second internal switch is configured to close in response to a power down signal from said external switch.

46. The PMU of claim 45, wherein said external switch is configured to be controlled by an external controller.

47. The PMU of claim 44, wherein said plurality of internal switches comprises a first internal switch and a second internal switch, said first internal switch is configured to close and said internal switch is configured to open in response to a power up signal from said external switch.

48. The PMU of claim 46, wherein said external switch is configured to be controlled by said PMU.

49. A power management unit (PMU) comprising:

a substrate; and

a power on reset (POR) circuit coupled to said substrate, and to at least one low dropout voltage regulator (LDO).

50. The PMU of claim 49, wherein said POR circuit is configured to provide a POR control signal to an external controller.

51. The PMU of claim 50, wherein said POR circuit is further configured to provide a start POR control signal to said external controller once at least one LDO has a voltage level above a predetermined LDO voltage lockout threshold level.

52. A power management unit (PMU) comprising:

a substrate; and

an adapter detector configured to receive a signal representative of the voltage of an external device and to provide a detector output signal representative of the presence of an adapter, said detector output signal providing a positive indication if said adapter is a continuous output adapter or said adapter is a pulse output adapter, said adapter detector coupled to said substrate; and

a multi-function output charge status pin.

53. The PMU of claim 52, wherein said multi-function output charge status pin is configured to display the presence of an adapter when said adapter detector provides said positive indication.

54. The PMU of claim 52, wherein said multi-function output charge status pin is configured to display the absence of an adapter when said adapter detector does not provide said positive indication.

55. The PMU of claim 52, wherein said multi-function output charge status pin is configured to provide an end-of-charge signal when the voltage of said battery reaches a maximum voltage level.

56. A power management unit (PMU) for providing power management and supply functions to a device having a battery, comprising:

a substrate;

a bi-directional pin coupled to said substrate and configured to serve as an input pin during a first condition and as an output pin during a second condition;

a means for providing a first conditioning charge to said battery and second full charge to said battery, said means coupled to said substrate and said bi-directional pin;

a means for detecting the presence of an adapter and providing a positive indication if said adapter is a continuous output adapter or a pulse output adapter, said means for detecting coupled to said substrate;

a means for protecting the PMU from starting up if the voltage of said battery is below a threshold lockout enabling voltage level and from shutting down until the voltage of said battery is below a threshold disabling voltage level, said threshold lockout disabling voltage level set lower than said threshold lockout enabling voltage level;

a means for switching so that an external switch coupled to said switching means may have multiple functions; and

a means for enabling at least one LDO to provide power to an external controller if said at least on LDO has an output voltage greater than a predetermined LDO threshold voltage level.

57. A method of inputting and outputting power to and from a power management unit (PMU) having a voltage source comprising:

connecting an external device to a bi-directional pin of said PMU;

triggering a first condition or a second condition;

inputting power through said bi-directional pin from said external device during said first condition; and

outputting power through said bi-directional pin to said external device from said voltage source of said PMU during said second condition.

58. The method of claim 57, wherein said first condition is a charging condition and said second condition is a supply condition.

59. The method of claim 58, wherein said triggering step is determined by comparing the voltage of said voltage source to the voltage of said external device.

60. The method of claim 59, wherein said inputting step is performed if the voltage of said voltage source is higher than the voltage of said external device.

61. The method of claim 59, wherein said outputting step is performed if the voltage of said voltage source is less than or equal to the voltage of said external device.

62. A method of detecting an adapter coupled to a power management unit (PMU) comprising:

receiving a signal representative of the voltage of said adapter;

providing a positive indication if said adapter is a continuous output adapter; and

providing a positive indication if said adapter is a pulse output adapter.

63. A method of protecting a power management unit (PMU) from entering a start up mode comprising:

detecting the voltage of a power source for said PMU;

preventing start up of said PMU if the voltage of said power source is below a predetermined threshold lockout enabling voltage level; and

shutting down said PMU if the voltage of said power source is below a predetermined threshold lockout disabling voltage level set lower than said threshold lockout enabling voltage level.

64. The method of claim 63, wherein said shutting down step does not occur until the voltage of said power source is below said predetermined threshold lockout disabling voltage level for a predetermined lockout time.

65. The method of claim 64, wherein said predetermined lockout time is approximately 50 ms.

66. A method of protecting an external controller of a portable device, powered by a power management unit (PMU), from starting up until proper supply voltage is present comprising:

detecting the voltage of at least one LDO of said PMU; and

preventing said at least one LDO from providing voltage to said controller until the voltage of said at least one LDO is greater than a predetermined LDO voltage threshold level for a predetermined reset time.

67. A power management unit (PMU) for providing power management and supply functions to a device having a battery, comprising:

a substrate;

a bi-directional pin coupled to said substrate and configured to serve as an input pin during a first condition and as an output pin during a second condition; and

a battery charge controller coupled to said substrate and said bi-directional pin, said battery charge controller having a first charge conductive path and a second charge conductive path, said first charge conductive path providing a first conditioning charge to said battery, and said second charge conductive path providing a second full charge to said battery during said first condition.

68. The PMU of claim 67, further comprising:

an adapter detector configured to receive a signal representative of the voltage of an external device coupled to said bi-directional pin, and to provide a detector output signal representative of the presence of an adapter, said detector output signal providing a positive indication if said adapter is a continuous output adapter or said adapter is a pulse output adapter, said adapter detector coupled to said substrate.

69. The PMU of claim 68 further comprising:

an under voltage lockout protection circuit configured to prevent start up of said PMU until the voltage of said battery is above a threshold lockout enabling level, and configured to shut down said PMU once the voltage of said battery falls below a threshold lockout disabling level, said threshold lockout disabling level set at a lower voltage than said lockout threshold enabling level, said under voltage lockout protection circuit further coupled to said substrate.

70. The PMU of claim 69, further comprising:

a plurality of internal switches coupled to a switch conductive path, said switch conductive path further coupled to an external switch, said internal switches configured to be responsive to said external switch allowing said external switch to have multiple functions, said plurality of internal switches coupled to said substrate.

71. The PMU of claim 67, further comprising:

a disable pin coupled to said substrate, said disable pin configured to be responsive to an external signal for disabling said first conditioning charge or said second full charge.