Wireless access system and method

• US 7,683,756 B2
• Filed: 03/30/2007
• Issued: 03/23/2010
• Est. Priority Date: 03/30/2007
• Status: Active Grant

• Current Assignee: Lear Corporation
• Original Assignee: Lear Corporation
• Inventors: Enderich, Mark A., Ghabra, Riad
• Primary Examiner(s): Mullen; Thomas J
• Application Number:
  US11/694,147
• Publication Number:
  US 20080238637A1
• Time in Patent Office: 1,089 Days
• Field of Search: 340/825.69, 340/825.72, 340/5.2, 340/5.6, 340/5.61, 340/5.62, 340/5.64, 340/5.8, 340/10.1, 340/10.3, 340/10.4, 340/426.36, 455/522
• US Class Current: 340/5.61
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: B60R 25/406 Power supply in the remote key

Abstract

The disclosed embodiments include a wireless access system and method that enable the transmission of wireless access signals having a desired power level. In some embodiments, the wireless access system determines the amount of supply current drawn by certain devices and causes adjustment of the wireless access signal power level based on an assessment of the supply current.

Claims

1. A wireless access system comprising:

a power source; and

an electronic device coupled to the power source, the device having;

a driver for drawing a supply current from the power source and generating a driver current,

an antenna for receiving the driver current and wirelessly transmitting a wireless access signal having a power level in response to the driver current, wherein the power level of the wireless access signal corresponds to the driver current, and

a controller being in communication with the driver and having a predetermined current range within a memory;

wherein the controller determines whether the supply current is within the predetermined current range, the controller causing an adjustment of the power level when the supply current is outside of the predetermined current range.

2. The system of claim 1, further comprising:

a portable device configured to receive the wireless access signal and transmit an entry signal to a receiver.

3. The system of claim 2, wherein the portable device includes a keyless entry device.

4. The system of claim 3, wherein the keyless entry device includes a passive entry fob.

5. The system of claim 4, wherein the passive entry fob is configured to transmit a response signal to the receiver.

6. The system of claim 1, wherein adjusting the power level includes adjusting a duty cycle of control signals transmitted to the driver.

7. The system of claim 1, wherein adjusting the power level includes the controller adjusting a supply voltage supplied to the driver by the power source.

8. The system of claim 1, further comprising:

a current detection device for detecting the supply current being supplied by the power source, the current detection device transmitting to the controller signals indicative of the supply current.

9. A method of transmitting a wireless access signal through the use of a wireless access system coupled to a power source and having a controller, wherein the controller has predetermined current range within a memory, the method comprising:

drawing a supply current from the power source through the use of a driver;

generating a driver current;

receiving the driver current at an antenna;

wirelessly transmitting the wireless access signal having a first power level in response to the driver current, wherein the first power level of the wireless access signal corresponds to the driver current;

determining whether the supply current is within the predetermined current range;

generating a control signal to adjust the first power level when the supply current is not within the predetermined current range thereby causing the wireless access signal to have a second power level that is equal to or greater than a predetermined power level; and

transmitting the wireless access signal having the second power level.

10. The method of claim 9 further comprising:

receiving the wireless access signal at a portable device; and

transmitting an entry signal to an electronic device.

11. The method of claim 10, wherein the portable device includes a keyless entry device.

12. The method of claim 11, wherein the keyless entry device includes a passive entry fob.

13. The method of claim 12, wherein the passive entry fob is configured to transmit a response signal to the electronic device in response to the wireless access signal.

14. The method of claim 9, wherein adjusting a first power level includes adjusting a duty cycle of control signals transmitted to the driver.

15. The method of claim 9, wherein adjusting the power level includes adjusting a supply voltage supplied to the driver by the power source.

16. The method of claim 9, further comprising:

detecting the supply current being supplied by the power source through the use of a current detection device; and

transmitting, to the controller, a signal indicative of the supply current.

17. A passive entry system configured to generate a low-frequency signal having a predetermined power level comprising:

a power source;

a module coupled to the power source, the module having;

a driver for drawing a supply current from the power source and generating a driver current,

an antenna for receiving the driver current and wirelessly transmitting a low-frequency signal having a first power level in response to the driver current, wherein the first power level corresponds with the driver current,

a current detection device for detecting the supply current being supplied by the power source, the current detection device transmitting a signal indicative of the supply current, and

a controller being in communication with the driver and receiving the signal indicative of the supply current, the controller having a predetermined current range within a memory wherein the controller determines whether the supply current is within the predetermined current range, the controller causing an adjustment of the first power level to a second power level when the supply current is outside of the predetermined current range, wherein the second power level is equal to or greater than the predetermined power level;

wherein the module transmits the low-frequency signal having the second power level; and

a portable device configured to receive the low-frequency signal, the portable device transmitting an entry signal to the module.

18. The system of claim 17, wherein adjusting the first power level to the second power level includes the controller adjusting a duty cycle of a control signal transmitted to the driver.

19. The system of claim 17, wherein adjusting the first power level to the second power level includes the controller adjusting a supply voltage supplied to the driver by the power source.

20. The system of claim 17, wherein the low-frequency signal has a frequency in the range of 19 kilohertz to 140 kilohertz.