Optimization of NFC Tag For Different Battery Levels

• US 20130084803A1
• Filed: 09/30/2011
• Published: 04/04/2013
• Est. Priority Date: 09/30/2011
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Hall, Steven, Awad, Mohamed, Trost, Theodore
• Granted Patent: US 9,119,160 B2
• Time in Patent Office: Days
• US Class Current: 455/41.1
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: H04W 52/0277 according to available power supply, e.g. switching off when a low battery condition is detected
• CPC Class Codes: H04W 52/028 switching on or off only a part of the equipment circuit blocks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A mobile communication device has a processor, a radio, a near field communication (NFC) device, a battery, and memory for storing data. The power level of the battery is measured. When the measured power level is above a first predetermined level, power is provided to the radio to allow communication. Sufficient power is provided to operate the NFC device as a reader and a tag. When the measured power level of the battery falls below the first predetermined level, battery power to the radio is shut off. Sufficient power is maintained to the NFL device to allow it to operate only as a tag. Sufficient power is maintained to the memory to retain the data stored in the memory. When the measured power level of the battery falls below a second predetermined level, the NFC device is required to harvest all of its power from the field.

Claims

1. A method of controlling the operation of a mobile communication device having a processor, a radio coupled to the processor that enables wireless communication, a near field communication (NFC) device coupled to the processor, a battery coupled to the processor and the NFC device, and memory for storing data coupled to the NFC device and the battery, comprising:

measuring the power level of the battery, wherein when the measured power level of the battery is above a first predetermined level, providing power to the radio to allow communication and providing sufficient power to the NFC device to enable the NFC device to operate as a reader and a tag;

when the measured power level of the battery falls below the first predetermined level,

shutting off battery power to the radio to disable the radio,

maintaining sufficient power to the NFC device to allow the NFC device to operate only as a tag, and

maintaining sufficient power to the memory to retain data stored in the memory; and

requiring the NFC device to operate only as a tag and to harvest all of its power from a field when the measured power level of the battery falls below a second predetermined level lower than the first predetermined level.

2. The method of claim 1, further comprising:

requiring the memory to harvest all of its power from the field when the measured power level of the battery falls below the second predetermined level.

3. The method of claim 1, further comprising:

maintaining sufficient power to the memory to retain the data stored in the memory while requiring the NFC device to harvest all of its power from the field when the measured power level of the battery falls below a third predetermined level lower than the second predetermined level.

4. The method of claim 1, further comprising:

determining the number of transactions made with the mobile communication device and transitioning from one power level to a second, lower power level as a function of the number of transactions determined.

5. The method of claim 1, further comprising:

determining the length of time that the mobile communication device has been on and transitioning from one power level to a second, lower power level as a function of the determined length of time.

6. The method of claim 1, further comprising:

determining the number of data bits that have been transferred between the NFC device and an external tag or reader during a given period of time and transitioning from one power level to a second, lower power level as a function of the determined number of bits.

7. A mobile communication device, comprising:

a central processing unit (CPU);

a battery having multiple power levels coupled to the CPU, the battery power levels being measured by the CPU;

a radio coupled to the CPU to enable the mobile communication device to conduct wireless communications and coupled to the battery to draw power from the battery when battery power is above a first predetermined level;

a near field communication (NEC) device coupled to the CPU and the battery and operable as a reader and a tag when battery power is above the first predetermined level;

wherein when the battery power falls below the first predetermined level, power to the radio is shut off and the NFC device is operable only as a tag; and

a memory coupled to the NFC device and the battery and drawing sufficient power from the battery when the battery power falls below the first predetermined level to retain data stored in the memory; and

wherein when the measured battery power falls below a second predetermined level lower than the first predetermined level, the NFC device harvests all of its power from the field.

8. The mobile communication device of claim 7, wherein:

the memory harvests all of its power from the field when the power level falls below the second predetermined level.

9. The mobile communication device of claim 7, wherein:

the memory draws power from the battery when the measured battery power falls below a third predetermined level lower than the second predetermined level to retain data stored in the memory; and

the NFC device harvests all of its power from the field when measured battery power falls below the third predetermined level.

10. The mobile communication device of claim 7, wherein:

the battery is transitioned from one power level to a second, lower power level as a function of the number of transactions made with the mobile communication device.

11. The mobile communication device of claim 7, wherein:

the battery is transitioned from one power level to a second, lower power level as a function of the length of time that the mobile communication device has been on.

12. The mobile communication device of claim 7, wherein:

the battery is transitioned from one power level to a second, lower power level as a function of the number of data bits that have been transferred between the NFC device and an external tag or reader during a given period of time.

13. An article of manufacture including a non-volatile computer readable medium having computer program logic stored thereon that, when executed by a computing device, cause the computing device to perform battery saving operations in a mobile communication device having a processor, a radio coupled to the processor that enables wireless communication, a near field communication (NFC) device coupled to the processor, a battery coupled to the processor and the NFC device, and memory for storing data coupled to the NFC device and the battery, comprising:

measuring the power level of the battery, wherein when the measured power level of the battery is above a first predetermined level, providing power to the radio to allow communication and providing sufficient power to the NFC device to enable the NFC device to operate as a reader and a tag;

when the measured power level of the battery falls below the first predetermined level,

shutting off battery power to the radio to disable the radio,

maintaining sufficient power to the NFC device to allow the NFC device to operate only as a tag, and

maintaining sufficient power to the memory to retain data stored in the memory; and

requiring the NFC device to operate only as a tag and to harvest all of its power from a field when the measured power level of the battery falls below a second predetermined level lower than the first predetermined level.

14. The article of manufacture according to claim 13, wherein the computer program logic, when executed by the computing device, cause the computing device to perform the following additional operations, including:

requiring the memory to harvest all of its power from the field when the measured power level of the battery falls below the second predetermined level.

15. The article of manufacture according to claim 13, wherein the computer program logic, when executed by the computing device, cause the computing device to perform the following additional operations, including:

maintaining sufficient power to the memory to retain the data stored in the memory while requiring the NEC device to harvest all of its power from the field when the measured power level of the battery falls below a third predetermined level lower than the second predetermined level.

16. The article of manufacture according to claim 13, wherein the computer program logic, when executed by the computing device, cause the computing device to perform the following additional operations, including:

determining the number of transactions made with the mobile communication device and transitioning from one power level to a second, lower power level as a function of the number of transactions determined.

17. The article of manufacture according to claim 13, wherein the computer program logic, when executed by the computing device, cause the computing device to perform the following additional operations, including:

determining the length of time that the mobile communication device has been on and transitioning from one power level to a secord, lower power level as a function of the determined length of time.

18. The article of manufacture according to claim 13, wherein the computer program logic, when executed by the computing device, cause the computing device to perform the following additional operations, including:

determining the number of data bits that have been transferred between the NFC device and an external tag or reader during a given period of time and transitioning from one power level to a second, lower power level as a function of the determined number of bits.