BATTERY MONITOR

• US 20070118309A1
• Filed: 01/11/2007
• Published: 05/24/2007
• Est. Priority Date: 05/06/2005
• Status: Active Grant

• Current Assignee: Stragent, LLC (Oso IP, LLC)
• Original Assignee: Intelleflex Corporation
• Inventors: Stewart, Roger
• Granted Patent: US 7,593,822 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/36 Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
• CPC Class Codes: G06K 19/0707 the arrangement being capable of collecting energy from external energy sources, e.g. thermocouples, vibration, electromagnetic radiation G06K19/0702 takes precedence
• CPC Class Codes: G06K 19/0712 the arrangement being capable of triggering distinct operating modes or functions dependent on the strength of an energy or interrogation field in the proximity of the record carrier active means for hindering electromagnetic reading or writing G06K19/07336
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer

Abstract

Circuit and methods for tracking the total amount of time that a host device has spent in its high power “activated” state (and optionally idle and hibernate states) and thereby can estimate the total power consumed by the host device. A value representing this time may be send to a remote device to, for example, accurately determine how much of the energy has been consumed by the host device and how much time is left and/or how many operations can be performed before the host device'"'"'s battery is exhausted.

Claims

1. A host Radio Frequency Identification (RFID) device, comprising:

a subsystem for estimating power consumption thereof, the subsystem comprising;

a mechanism for tracking at least an amount of time the RFID device is in an active state; and

a mechanism for generating a value representing at least the amount of time the RFID device is in the active state based on the tracking; and

a mechanism for sending the value or derivative thereof to a remote device.

2. The host RFID device of claim 1, wherein the mechanism for tracking an amount of time the host RFID device is in the active state is a first oscillator.

3. The host RFID device of claim 2, wherein the first oscillator operates at a fraction of a rate of a primary oscillator of the host RFID device.

4. The host RFID device of claim 3, wherein the first oscillator operates at no greater than one sixteenth the rate of the primary oscillator of the host RFID device.

5. The host RFID device of claim 2, wherein the first oscillator is idle when the host RFID device is in an inactive state.

6. The host RFID device of claim 2, wherein the first oscillator operates at a first frequency when the host RFID device is in the active state, wherein the first oscillator operates at a second frequency when the host RFID device is in a state other than the active state.

7. The host RFID device of claim 2, wherein the first oscillator is a voltage controlled oscillator, a frequency of the first oscillator varying depending on a power dissipation of the host RFID device.

8. The host RFID device of claim 2, wherein a frequency of the first oscillator is calibrated.

9. The host RFID device of claim 1, wherein a reference current source is calibrated.

10. The host RFID device of claim 1, wherein a rate that the value increases varies independently of a data transmission rate of the host RFID device, wherein the mechanism for tracking the amount of time is dependent upon a rate of a primary oscillator of the host RFID device.

11. The host RFID device of claim 1, wherein a rate that the value increases varies depending on a power dissipation rate of the host RFID device.

12. The host RFID device of claim 1, wherein the mechanism for generating the value representing the amount of time the host RFID device is in the active state is a counter, the value being a cumulative count stored in the counter.

13. The host RFID device of claim 12, wherein the speed of the counter is digitally controlled.

14. The host RFID device of claim 1, wherein the mechanism for tracking an amount of time the host RFID device is in the active state is a first oscillator, the first oscillator operating at at least two frequencies, wherein the first oscillator operates at a first frequency for tracking the amount of time the host RFID device is in the active state, wherein the first oscillator operates at a second frequency for tracking an amount of time the host RFID device is in a state other than the active state.

15. The host RFID device of claim 14, wherein the frequency of the first oscillator is controlled by an analog control signal.

16. The host RFID device of claim 14, wherein the oscillator operates continuously.

17. The host RFID device of claim 1, wherein the mechanism for tracking an amount of time the host RFID device is in the active state is an oscillator, the oscillator operating at about a constant frequency, wherein at least one frequency divider operates between the oscillator and the mechanism for generating the value.

18. The host RFID device of claim 17, further comprising a calibration matrix of digitally controlled diodes for calibrating a bias current of the oscillator.

19. The host RFID device of claim 18, wherein the calibration matrix is automatically calibrated upon detection of an event.

20. The host RFID device of claim 18, wherein the subsystem self-calibrates from a single reference frequency.

21. The host RFID device of claim 20, wherein the reference frequency is derived from a signal from the remote device.

22. The host RFID device of claim 17, wherein the oscillator operates continuously.

23. The host RFID device of claim 17, wherein the oscillator operates on a current of less than about one microampere (μ

A).

24. The host RFID device of claim 17, wherein the oscillator operates on a current of less than about 5 nanoamperes (nA).

25. The host RFID device of claim 1, further comprising a switched capacitor precision resistor for controlling a bias current to the mechanism for tracking the amount of time the host RFID device is in the active state.

26. The host RFID device of claim 1, wherein the mechanism for tracking an amount of time the host RFID device is in the active state is a first oscillator, and further comprising a second oscillator, the second oscillator tracking an amount of time the host RFID device is in a state other than the active state.

27. The host RFID device of claim 1, wherein the remote device uses the value to estimate usage of power in the host RFID device.

28. A host Radio Frequency Identification (RFID) device having a subsystem for estimating power consumption thereof, the subsystem comprising:

a mechanism for tracking at least an amount of time the RFID device is in an active state; and

a mechanism for generating a value representing at least the amount of time the RFID device is in the active state based on the tracking.

29. A method for estimating power consumption, comprising:

tracking an amount of time a host Radio Frequent Identification (RFID) device is in an active state;

generating a value representing the amount of time the host RFID device is in the active state; and

sending the value to a remote device.

30. The methof of claim 29, wherein the remote device uses the value to apporpriate power consumption in the hole.

31. A system for estimating power consumption(a) of a host device, comprising:

an oscillator for tracking at least an amount of time a host device is in a first state;

a counter receiving output from the oscillator for generating a value representing a power consumption of the host device based on output from the oscillator, wherein the counter operates at different speeds, denpending on the state of the host drive.

32. The system of claim 31, wherein the frequency of the oscillator is controlled by an analog control signal.

33. The system of claim 31, wherein the frequency of the oscillator is digitally controlled.

34. The system of claim 31, further comprising a calibration matrix of digitally controlled diodes for calibrating a bias current of the oscillator.

35. The system of claim 34, wherein the calibration matrix is automatically calibrated upon detection of an event.

36. The system of claim 34, wherein the system self-calibrates from a single reference frequency.

37. The system of claim 36, wherein the reference frequency is derived from a signal from a remote device.

38. The system of claim 31, further comprising a switched capacitor precision resistor for controlling a bias current to the oscillator.

39. The ssytem of claim 31, wherein the oscillator operates continuously.

40. The system of claim 31, wherein the oscillator operates on a current of less than about one microampere (β

A).

41. The system of claim 31, wherein the oscillator operates on a current of less than about 5 nanoamperes (nA).

42. The system of claim 31, wherein a frequency of the oscillator is about constant, wherein at least one frequency divider operates between the oscillator and the mechanism for generating the value.

43. The system of claim 31, wherein a frequency of the oscillator varies depending on the state of the host device.

44. The system of claim 31, wherein the system is embodied on a Radio Frequency Identification (RFID) tag, the RFID tag being the host device.

45. The system of claim 31, wherein a visual indication of the estimation of a remaining battery life of the host device is output to a user.

46. An RFID system, comprising:

an RFID tag implementing the system of claim 31;

and

an RFID reader in communication with the RFID tag.

47. A method for estimating power consumption of a host Radio Frequency Identification (RFID) device, comprising:

generating a first tracking signal at a first frequency when a host RFID device is in a first state;

generating a second tracking signal at a second frequency when the host RFID device is in a good second state different from the first state;

processing the tracking signals for generating a value representing a power consumption of the host RFID device,

wherein a derivative of the value is generated for output to a user.

48. A method for estimating power consumption of a host Radio Frequency Identification (RFID) device, comprising:

generating a tracking signal at a constant frequency when a host RFID device is in a first or second state;

dividing the frequency of the tracking signal when the host RFID device is in the second state; and

storing a count of the frequency,

wherein a derivative of the value is generated for output to a user.

49. A system for estimating power consumption of a host device, comprising:

a mechanism for tracking at least an amount of time a host device is in an active state;

a mechanism for generating a value representing at least the amount of time the host device is in the active state based on the tracking; and

a mechanism for sending the value or derivative thereof to a remote device.

50. A method for estimating power consumption, comprising:

tracking an amount of time a host device is in an active state;

generating a value representing the amount of time the host device is in the active state;

sending the value to a remote device.