Patent Application

App. No. 12/056,778

Abstract

Claims (25)

1 . A passive entry system for an automotive vehicle comprising:

a control unit being configured to broadcast a wake-up signal at a first frequency to prompt a token to power-up if the token is in a low-power consumption mode; and

a token, including a display, being configured to receive the wake-up signal and to deactivate the display if the display is active in response to receiving the wake-up signal.

2 . The system of claim 1 wherein the control unit is further configured to broadcast another wake-up signal at the first frequency if a reply to the wake-up signal is not received within a predetermined period of time.

3 . The system of claim 1 wherein the token is further configured to ignore the wake-up signal if the display is active.

4 . The system of claim 1 wherein the token is further configured to broadcast a retry signal after receiving the wake-up signal to prompt the control unit to broadcast another wake-up signal at the first frequency.

5 . The system of claim 4 wherein the control unit is further configured to receive the retry signal and to broadcast another wake-up signal at the first frequency in response to receiving the retry signal.

6 . The system of claim 5 wherein the token is further configured to re-activate the display after receiving the another wake-up signal.

7 . The system of claim 6 wherein the token is further configured to measure a field strength of the another wake-up signal and to generate a response signal that includes information indicative of the measured field strength.

8 . The system of claim 1 wherein the first frequency comprises a frequency in the range of 3 to 300 KHz and the second frequency comprises a frequency in the range of 300 MHZ to 3 GHz.

9 . A method of operating a token of a passive entry system, the token including a display, the method comprising:

receiving a high frequency challenge signal to validate the token;

determining if the display is on; and

turning the display off in response to receiving the high frequency challenge signal if the display is on.

10 . The method of claim 9 further comprising generating a retry signal to prompt a control unit to send a wake-up signal.

11 . The method of claim 10 further comprising receiving the another wake-up signal.

12 . The method of claim 11 further comprising turning the display on after receiving the another wake-up signal.

13 . The method of claim 11 further comprising measuring a field strength of the another wake-up signal.

14 . The method of claim 13 further comprising generating a response signal that includes information indicative of the measured field strength.

15 . The method of claim 9 further comprising receiving a low frequency wake-up signal to prompt the token to power-up if the token is in a low-power consumption mode and ignoring the low frequency wake-up signal if the display is active.

16 . A method of operating a passive entry system including a control module and token, the token including a display, the method comprising:

generating a display deactivation signal to prompt the token to deactivate the display; and

generating a wake-up signal to prompt the token to power-up if the token is in a low-power consumption mode.

17 . The method of claim 16 further comprising generating another wake-up signal if a reply to the wake-up signal is not received within a predetermined period of time.

18 . The method of claim 16 further comprising receiving a retry signal, generating another wake-up signal in response to receiving the retry signal, and receiving a response signal including information indicative of a measured field strength of the another wake-up signal.

Assignments (9)