Transponder for remote keyless entry systems

• US 6,323,566 B1
• Filed: 10/10/1996
• Issued: 11/27/2001
• Est. Priority Date: 10/10/1996
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Meier, Herbert
• Primary Examiner(s): PALADINI, ALBERT WILLIAM
• Application Number:
  US08/728,844
• Time in Patent Office: 1,874 Days
• Field of Search: 307/10.1, 307/10.2, 340/825.69, 340/825.72, 340/539, 340/426, 340/825.31, 180/287
• US Class Current: 307/10.2
• CPC Class Codes: G07C 2009/00357 and the lock having more than one limited data transmission ranges
• CPC Class Codes: G07C 2009/00396 starting with prompting the keyless data carrier
• CPC Class Codes: G07C 2009/00412 the transmitted data signal being encrypted
• CPC Class Codes: G07C 2009/00492 whereby the code is a rolling code
• CPC Class Codes: G07C 2009/00507 keyless data carrier having more than one function
• CPC Class Codes: G07C 2009/00777 by induction
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

A road vehicle keyless entry system (10) having an in-vehicle communication processor (11) and a remote transponder (15) is provided. The communication processor (10) has a radio frequency receiver (12), a low frequency transmitter/receiver (13) and a controller (14) capable of encrypting and reading the signals sent and received by the low frequency transmitter/receiver (13). The transponder (15) has a radio frequency transmitter (16) that transmits a signal to the communication processor (11) upon receipt of a manual stimulus and a low frequency transmitter/receiver (17) capable of reading and responding to encrypted signals received from the communication processor (11).

Claims

1. A road vehicle keyless entry system comprising an in-vehicle communication processor and a remote, miniaturized transponder;

the communication processor having a radio frequency receiver, a low frequency transmitter/receiver for transmitting low frequency signals and a controller for reading the signals sent and received by the low frequency transmitter/receiver; and

the transponder having a radio frequency transmitter that transmits a signal to the radio frequency receiver of said communication processor upon receipt of a manual stimulus thereat and a low frequency transmitter/receiver for reading low frequency signals received from the communication processor and transmitting an encrypted response to the communication processor.

2. The road vehicle keyless entry system of claim 1 wherein the radio frequency transmitter of the transponder and the radio frequency receiver of the communication processor send and receive a signal having a frequency of 433 megahertz.

3. The road vehicle keyless entry system of claim 1 wherein the low frequency transmitter/receivers of the transponder and the communication processor send and receive a signal having a frequency of 134.2 kilohertz.

4. The road vehicle keyless entry system of claim 3 wherein the low frequency transmitter/receiver of the transponder operates in a passive mode.

5. The road vehicle keyless entry system of claim 1 wherein the transponder supplements or replaces the vehicle door and ignition keys, signals from the transponder being received by the communication processor that, after reception and verification of access codes, authorizes unlocking the vehicle and performance of vehicle related initialization functions such as seat, seat belt and vehicle mirror adjustments.

6. The road vehicle keyless entry system of claim 1 wherein the transponder further includes an interface circuit and a coupling coil to provide contactless transfer of data between the radio frequency transmitter and the low frequency transmitter/receiver.

7. The road vehicle keyless entry system of claim 6 wherein the transponder radio frequency transmitter and low frequency transmitter/receiver are in separate cases.

8. The road vehicle keyless entry system of claim 1 wherein the communication processor radio frequency receiver and the transponder radio frequency transmitter are radio frequency transmitter/receivers capable of two way transmissions between the communication processor and the transponder.

9. A road vehicle keyless entry system comprising an in-vehicle communication processor and a remote transponder;

the communication processor having a radio frequency receiver, a low frequency transmitter/receiver and a controller capable of reading the signals sent and received by the low frequency transmitter/receiver; and

the transponder having a radio frequency transmitter that transmits a signal to the radio frequency receiver of said communication processor upon receipt of a manual stimulus, a low frequency transmitter/receiver capable of reading signals received from the communication processor and transmitting an encrypted response to the communication processor and an interface circuit and coupling coil to provide contactless transfer of data between the radio frequency transmitter and the low frequency transmitter/receiver.

10. The road vehicle keyless entry system of claim 9 wherein the radio frequency transmitter of the transponder and the radio frequency receiver of the communication processor send and receive a signal having a frequency of 433 megahertz.

11. The road vehicle keyless entry system of claim 9 wherein the low frequency transmitter/receivers of the transponder and the communication processor send and receive a signal having a frequency of 134.2 kilohertz.

12. The road vehicle keyless entry system of claim 9 wherein the manual stimulus is the manual actuation of one of a plurality of push buttons.

13. The road vehicle keyless entry system of claim 9 wherein the communication processor radio frequency receiver and the transponder radio frequency transmitter are radio frequency transmitter/receivers capable of two way transmissions between the communication processor and the transponder.

14. A secure road vehicle keyless entry system comprising an in-vehicle communication processor and a remote transponder, the communication processor and transponder communicating in parallel paths, a first path being a radio frequency transmission from the transponder to the communication processor and a second path being a low frequency, encrypted two way transmission between the transponder and the communication processor.

15. The secure road vehicle keyless entry system of claim 14 wherein the radio frequency transmission and the low frequency transmission are compared for authentication of the transmitted data.

16. The secure road vehicle keyless entry system of claim 14 wherein the radio frequency transmission is a two way transmission between the transponder and the communication processor.

17. A method of vehicle keyless entry comprising the steps of:

providing an in-vehicle communication processor and a remote, miniaturized transponder, the communication processor having a radio frequency receiver, a low frequency transmitter/receiver for transmitting low frequency signals and a controller for reading the signals sent and received by the low frequency transmitter/receiver and the transponder having a radio frequency transmitter that transmits a signal to the communication processor upon receipt of a manual stimulus thereat and a low frequency transmitter/receiver for reading low frequency signals received from the communication processor and transmitting an encrypted response to the communication processor;

providing said manual stimulus to cause said transponder to send an RF signal to said communication processor and sending a low frequency signal to said low frequency transmitter/receiver at said communication processor in response to said manual stimulus;

then sending a low frequency signal from said low frequency transmitter/receiver at said communication processor to said transmitter/receiver at said transponder in response to at least one of said signals from said transponder to said communication processor; and

then sending a signal from said transponder to said communication processor in response to said signal from said communication processor to said transponder.

18. The method of claim 17 wherein said signal from said low frequency transmitter/receiver at said communication processor to said low frequency transmitter/receiver at said transponder is an encoded signal.

19. The method of claim 18 wherein said encoded signal is a rolling coded signal.

20. The method of claim 17 wherein said signal from said low frequency transmitter/receiver at said transponder to said low frequency transmitter/receiver at said communication processor is an encoded signal.

21. The method of claim 18 wherein said signal from said low frequency transmitter/receiver at said transponder to said low frequency transmitter/receiver at said communication processor is an encoded signal.

22. The method of claim 20 wherein said encoded signal is a rolling coded signal.

23. The method of claim 21 wherein said encoded signal is a rolling coded signal.