OPTIMIZING POWER CONSUMPTION IN A NEAR FIELD COMMUNICATIONS (NFC) ENVIRONMENT

• US 20130005248A1
• Filed: 06/29/2011
• Published: 01/03/2013
• Est. Priority Date: 06/29/2011
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: WILSON, Robin Wyndham John, Royston, Philip Stewart
• Granted Patent: US 9,054,749 B2
• Time in Patent Office: Days
• US Class Current: 455/41.1
• CPC Class Codes: G06K 7/10217 parameter settings controlling the transmission power of the interrogator
• CPC Class Codes: G06K 7/10237 the reader and the record carrier being capable of selectively switching between reader and record carrier appearance, e.g. in near field communication [NFC] devices where the NFC device may function as an RFID reader or as an RFID tag
• CPC Class Codes: H04B 5/77 for interrogation
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An apparatus and method is disclosed to optimize power consumption in a NFC environment. A first NFC capable device provides a polling command to a second NFC capable device. The second NFC capable device provides a response to the polling command. The first NFC capable device provides a read command to the second NFC capable device. The second NFC capable device provides a response to the read command that indicates an overvoltage condition is present. The first NFC capable device adjusts a power level that is to be used to transmit further commands when the overvoltage condition is present.

Claims

1. A method for optimizing power consumption in a near field communication (NFC) environment, comprising:

(a) providing, by a first NFC device, a first communications signal including a read command at a first power to a second NFC device to recover a unique identifier (UID) of the second NFC device;

(b) receiving, by the first NFC device, a second communications signal including a response to the read command from the second NFC device;

(c) determining, by the first NFC device, whether a complete UID of the second NFC device has been received; and

(d) determining, by the first NFC device, whether the response indicates an overvoltage condition is present in the second NFC device when the complete UID of the second NFC device has not been received.

2. The method of claim 1, further comprising:

(e) adjusting, by the first NFC device, the first power to a second power when the overvoltage condition is present.

3. The method of claim 2, further comprising:

(f) repeating steps (a) through (e) until the complete UID of the second NFC device has been received.

4. The method of claim 2, further comprising:

(f) providing, by the first NFC device, the first communications signal at the second power to recover the UID of the second NFC device;

(g) activating, by the first NFC device, a timing mechanism; and

(h) providing, by the first NFC device, the first communications signal at the first power to recover the UID of the second NFC device upon expiration of the timing mechanism.

5. The method of claim 1, wherein the response includes a plurality of bits, at least a first bit from among the plurality of bits indicating whether a complete UID of the second NFC device has been provided, and at least one second bit from among the plurality of bits indicating whether overvoltage condition is present in the second NFC device.

6. The method of claim 1, further comprising:

(f) providing, by the first NFC device, a third communications signal including a polling command to a second NFC device; and

(g) receiving, by the first NFC device, a fourth communications signal including a response to the polling command from the second NFC device.

7. The method of claim 1, further comprising:

(e) storing, by the first NFC device, an overvoltage indictor to indicate the presence of the overvoltage condition in a memory module.

8. The method of claim 7, wherein step (e) comprises:

(e) storing the overvoltage indictor in one or more bits of the memory module that are unused or reserved for future use.

9. A method for optimizing power consumption in a near field communication (NFC) environment, comprising:

(a) receiving, by a first NFC device, a first communications signal including a read command at a first power from a second NFC device to recover a unique identifier (UID) of the first NFC device;

(b) monitoring, by the first NFC device, the first power to determine whether an overvoltage condition is present; and

(c) providing, by the first NFC device, a second communications signal including a response to the read command to the second NFC device, the response including one or more bits of the UID and an indication of whether the overvoltage condition is present.

10. The method of claim 9, wherein step (b) comprises:

(b) comparing, by the first NFC device, the first power with an overvoltage threshold, the overvoltage condition being present when the first power is greater than the overvoltage threshold.

11. The method of claim 9, wherein step (c) comprises:

(c)(i) encoding, by the first NFC device, a first group of one or more bits of the response to indicate that the overvoltage condition is present.

12. The method of claim 11, wherein step (c) further comprises:

(c)(ii) encoding, by the first NFC device, a second group of one or more bits of the response to indicate a complete UID has been provided to the second NFC device.

13. The method of claim 9, wherein step (b) comprises:

(b)(i) converting, by the first NFC device, the first communications signal from alternating current (AC) to direct current (DC) to provide to provide a rectified power; and

(b)(ii) comparing the rectified power with the an overvoltage threshold, the overvoltage condition being present when the rectified power is greater than the overvoltage threshold.

14. The method of claim 13, wherein step (b) further comprises:

b(iii) comparing the rectified power with a reference power; and

b(iv) regulating the first communications signal when the rectified power is greater than the reference power.

15. The method of claim 9, further comprising:

(d) receiving, by the first NFC device, a third communications signal including a polling command from the second NFC device; and

(e) providing, by the first NFC device, a fourth communications signal including a response to the polling command to the second NFC device.

16. An apparatus for optimizing power consumption in a near field communication (NFC) environment, comprising:

an antenna module configured to inductively receive a first communications signal including a read command to recover one or more bits of a unique identifier (UID) via a magnetic field;

a power harvesting module configured to rectify the first communications signal to provide a rectified power and to compare the rectified power with an overvoltage threshold to determine whether an overvoltage condition is present; and

controller module configured to provide a response to the read command to indicate whether the overvoltage condition is present,

wherein the antenna module is configured to provide a second communication including the response using the magnetic field.

17. The apparatus of claim 16, wherein the response comprises:

a first group of one or more bits to indicate that the overvoltage condition is present; and

a second group of one or more bits of the response to indicate a complete UID has been provided.

18. The apparatus of claim 17, wherein the power harvesting module comprises:

a rectifier module configured to convert the first communications signal from alternating current (AC) to direct current (DC) to provide to provide the rectified power; and

a regulator controller configured to compare the rectified power with the overvoltage threshold to determine whether the overvoltage condition is present, the overvoltage being present when the rectified power is greater than the overvoltage threshold.

19. The apparatus of claim 18, wherein the regulator controller is further configured to compare the rectified power with a power threshold to provide a regulation control signal, and wherein the power harvesting module comprises:

a regulator module configured to adjust a power level of first communications signal in response to the regulation control signal.

20. The apparatus of claim 16, wherein the antenna module is further configured to inductively receive a third communications signal including a polling command via the magnetic field and to provide a fourth communications signal including a response to the polling command via the magnetic field.