Programmable Selective Wake-Up for Radio Frequency Transponder

• US 20090256674A1
• Filed: 06/24/2009
• Published: 10/15/2009
• Est. Priority Date: 04/23/2004
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Microchip Technology Incorporated
• Inventors: Yach, Randy, Nolan, James B., Lee, Thomas Youbok, Vernier, Steve, Lamphier, Alan
• Granted Patent: US 8,164,416 B2
• Time in Patent Office: Days
• US Class Current: 340/5.600
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: G06K 19/07 with integrated circuit chips
• CPC Class Codes: G07C 2009/00333 and the lock having more than one limited data transmission ranges
• CPC Class Codes: G07C 2009/00373 whereby the wake-up circuit is situated in the lock
• CPC Class Codes: G07C 2009/00769 with data transmission performed by wireless means
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: H04B 1/1615 Switching on; Switching off, e.g. remotely battery saving circuits associated with selective call operation H04W52/00; details of power consumption reduction in a PLL, H03L7/0802, H03L7/14, H03L2207/08, H03L2207/18; muting amplifiers by gain control see H03G3/34
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A remote keyless entry (RKE) transponder has a programmable selective wake-up filter for determining whether the RKE transponder should wake-up to process a received signal. The wake-up filter correlates the timing of an input signal'"'"'s carrier amplitude on and off time periods to a predefined programmable time period profile for a desired signal which has a certain carrier on time (time period on) and a certain carrier off time (time period off) arranged into a coded “header.” When a received signal matches the predefined time period profile, then the RKE transponder will wake-up to process the incoming signal data. The predefined time period profile may be programmable and may be stored in a header configuration register. Each RKE transponder has unique predefined time period on and time period off profiles.

Claims

1. A method for waking up a remote keyless entry (RKE) transponder for further processing of incoming data using temporal time pattern detection of a received low frequency signal, said method comprising the steps of:

a) detecting a low frequency signal with an analog front-end (AFE) of a remote keyless entry (RKE) transponder;

b) determining if the low frequency signal is being detected for at least a stabilization time period (TSTAB), if not, then inhibiting detection of the low frequency signal for a lock-out time period and going to step h);

c) determining if the low frequency signal is not being detected for a gap time period (TGAP), if not, then inhibiting detection of the low frequency signal for the lock-out time period and going to step h);

d) determining if the low frequency signal is being detected for at least a high time period (TWAKH), if not, then inhibiting detection of the low frequency signal for the lock-out time period and going to step h);

e) determining if the low frequency signal is not being detected for at least a low time period (TWAKL), if not, then inhibiting detection of the low frequency signal for the lock-out time period and going to step h);

f) determining if the detection of the low frequency signal in step d) and no detection of the low frequency signal in step e) occur within a total time period (TWAKT), if not, then inhibiting detection of the low frequency signal for the lock-out time period and going to step h);

g) waking up logic circuits of the RKE transponder for processing of data from the low frequency signal and after processing of the data then returning to step a);

h) waiting for the lock-out time period to expire and then returning to step a).

3. The method according to claim 1, wherein the total time period (TWAKT) is programmable.

4. The method according to claim 1, wherein the high time period (TWAKH) is programmable.

5. The method according to claim 1, wherein the low time period (TWAKL) is programmable.

6. The method according to claim 1, wherein the step of waking up the logic circuits of the RKE transponder further comprises the step of waking-up an external control device for accepting data from the received low frequency signal.

7. The method according to claim 6, wherein the external control device is selected from the group consisting of digital processor, microcontroller, microprocessor, digital signal processor, application specific integrated circuit (ASIC) and programmable logic array (PLA).

8. The method according to claim 1, further comprising the steps of storing the high time period (TWAKH), the low time period (TWAKL) and the total time period (TWAKT) in at least one configuration register.

9. The method according to claim 8, wherein the steps of storing the high time period (TWAKH), the low time period (TWAKL) and the total time period (TWAKT) in the at least one configuration register are done with an external control device.

10. The method according to claim 1, wherein the step of detecting the low frequency signal further comprises the steps of detecting the low frequency signal with a plurality of remote keyless entry (RKE) transponders, each of the plurality of RKE transponders having an analog front-end (AFE) and a wake-up filter, wherein each of the wake-up filters uses a different high time period (TWAKH) so that only one of the plurality of RKE transponders will wake-up during reception of the low frequency signal.

11. The method according to claim 1, wherein the step of detecting the low frequency signal further comprises the steps of detecting the low frequency signal with a plurality of remote keyless entry (RKE) transponders, each of the plurality of RKE transponders having an analog front-end (AFE) and a wake-up filter, wherein each of the wake-up filters uses a different low time period (TWAKL) so that only one of the plurality of RKE transponders will wake-up during reception of the low frequency signal.

12. The method according to claim 1, wherein the RKE transponder further comprises a plurality of analog front-ends (AFEs) for receiving the signal.

13. The method according to claim 12, wherein the plurality of AFEs comprise three low frequency signal input channels.

14. The method according to claim 1, wherein the received low frequency signal is at a frequency from about 100 kHz to about 400 kHz.

15. The method according to claim 1, wherein the received low frequency signal is at a frequency of about 125 kHz.

2. (canceled)

16. A remote keyless entry (RKE) transponder having selective wake-up by using temporal time pattern detection of a received low frequency signal, said RKE transponder comprising:

an analog front-end (AFE) for receiving a low frequency signal;

logic circuits coupled to the AFE and adapted for processing data from the received low frequency signal, the logic circuits having a low power mode and an operational mode; and

a wake-up filter coupled to the AFE and the logic circuits, wherein the wake-up filter determines from the received low frequency signal whether to cause the logic circuits to go from the low power mode to the operational mode, whereby when the logic circuits are in the operational mode the data from the received low frequency signal is processed;

the wake-up filter in determining whether to cause the logic circuits to change from the low power mode to the operational mode comprises the steps of;

a) determining if the low frequency signal is being detected for at least a stabilization time period (TSTAB), if not, then inhibiting detection of the low frequency signal for a lock-out time period and going to step g);

b) determining if the low frequency signal is not being detected for a gap time period (TGAP), if not, then inhibiting detection of the low frequency signal for the lock-out time period and going to step g);

c) determining if the low frequency signal is being detected for at least a high time period (TWAKH), if not, then inhibiting detection of the low frequency signal for the lock-out time period and going to step g);

d) determining if the low frequency signal is not being detected for at least a low time period (TWAKL), if not, then inhibiting detection of the low frequency signal for the lock-out time period and going to step g);

e) determining if the detection of the low frequency signal in step c) and no detection of the low frequency signal in step d) occur within a total time period (TWAKT), if not, then inhibiting detection of the low frequency signal for the lock-out time period and going to step g);

f) causing the logic circuits to change from the low power mode to the operational mode so as to process the data from the low frequency signal, after processing of the data the logic circuits return to the low power mode and then returning to step a);

g) retaining the logic circuits in the low power mode while waiting for the lock-out time period to expire and then returning to step a).

17. The RKE transponder according to claim 16, wherein the AFE comprises a low frequency signal amplifier and an amplitude modulation signal detector.

18. The RKE transponder according to claim 16, wherein the high time period (TWAKH) and the low time period (TWAKL) are programmable.

19. The RKE transponder according to claim 16, wherein the RKE transponder further comprises at least one configuration register for storing the high time period (TWAKH), the low time period (TWAKL) and the total time period (TWAKT).

20. The RKE transponder according to claim 19, wherein the RKE transponder further comprises an external control device for programming the high time period (TWAKH), the low time period (TWAKL) and the total time period (TWAKT) into the at least one configuration register.

21. The RKE transponder according to claim 19, wherein the external control device is selected from the group consisting of digital processor, microcontroller, microprocessor, digital signal processor, application specific integrated circuit (ASIC) and programmable logic array (PLA).

22. The RKE transponder according to claim 16, wherein the RKE transponder has at least one AFE for receiving the low frequency signal.

23. The RKE transponder according to claim 22, wherein the at least one AFE comprises three low frequency signal input channels.

24. The RKE transponder according to claim 22, wherein the AFE receives low frequency signals at about 125 kHz.

25. The RKE transponder according to claim 22, wherein the AFE is adapted to receive low frequency signals from about 100 kHz to about 400 kHz.