Keyless entry system, and system transmitter having optimized signal transmission power level

• US 6,292,107 B1
• Filed: 08/27/1998
• Issued: 09/18/2001
• Est. Priority Date: 08/27/1997
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Yamaura, Masafumi, Harada, Takashi, Miyagawa, Tomoyuki
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): Shimizu, M
• Application Number:
  US09/141,732
• Time in Patent Office: 1,118 Days
• Field of Search: 340/825.31, 340/825.69, 340/825.72, 340/825.49, 340/825.36, 340/5.7, 340/5.71, 340/5.72
• US Class Current: 340/12.22
• CPC Class Codes: B60R 25/104 characterised by the type of theft warning signal, e.g. visual or audible signals with special characteristics
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: B60R 25/245 where the antenna reception area plays a role
• CPC Class Codes: G07C 2009/00198 the keyless data carrier having more than one limited data transmission ranges
• CPC Class Codes: G07C 2009/00261 the keyless data carrier having more than one function
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: G08C 17/00 Arrangements for transmitting signals characterised by the use of a wireless electrical link

Abstract

A keyless entry system transmitter that achieves both a reduction in power consumption when transmitting radio signals, and enhances system convenience by boosting transmission power in cases where required. A set-voltage value corresponding to a function specified by operation of an operation switch is read from a corresponding-voltage memory portion, and this read set-voltage value is output to a DAC. Accordingly, when operation specifying the same function is again performed with the operation switch before a predetermined timeout time clocked by a timer has elapsed, a counter is incremented, and a voltage-setting output to the DAC increases in accordance with a count value thereof. As a result, voltage supplied to a transmitter unit through a regulator increases as well. Consequently, transmission power of a remote-control signal sent via a transmission antenna is also increased.

Claims

1. A keyless entry system transmitter configured for remotely operating a vehicle-mounted apparatus, the apparatus including a plurality of functions, the transmitter comprising:

a switch configured for selecting a desired function from the plurality of functions;

means for transmitting configured for (i) providing a control signal for transmission to the apparatus, (ii) encoding the control signal with information representative of the selected function and with an identification code, and (iii) transmitting the encoded signal;

means for regulating an operating voltage of the transmitting means, the encoded signal being responsive to the operating voltage; and

means for controlling the regulating means, the means for controlling the regulating means automatically varying the operating voltage in accordance with the information representative of the selected function.

2. The transmitter of claim 1, wherein the information representative of the selected function includes a number of repetitions of the selected function and data corresponding to the desired function.

3. The transmitter of claim 1, wherein the selected function is a door lock/unlock function, a trunk-open function, a car-finder function, or a panic function;

the controlling means causes the regulating means to output the operating voltage at a door lock/unlock level when a door lock/unlock function has been specified;

the controlling means causes the adjusting means to reduce the operating voltage from the door lock/unlock level when the trunk-open function has been specified; and

the controlling means causes the adjusting means to increase the operating voltage from the door lock/unlock level when the car-finder function or panic function has been specified.

4. The transmitter of claim 1, wherein the operation switch correlates the vehicle-mounted apparatus and the information representative of the selected function and the identification code.

5. The transmitter of claim 1, further comprising:

a vehicle-mounted receiver that receives the transmitted encoded signal; and

means for controlling operation of the receiver in correspondence with the information representative of the selected function and the identification code in the transmitted encoded signal.

6. The transmitter of claim 5, wherein a transmitter-specific code is also converted and transmitted in the encoded signal from the transmitter;

the receiver receives and analyzes the encoded signal, and determines whether the transmitter-specific code contained in the signal coincides with a code for determination use stored in the receiver; and

the receiver operation controlling means operates only when both the transmitter-specific code and the code for determination use coincide.

7. A keyless entry system transmitter configured for remotely operating one of a plurality of vehicle-mounted devices, each device having a number of associated functions, the transmitter comprising:

a switch configured for selecting a desired function;

a transmitting unit configured for (i) providing a control signal for transmission to the apparatus, (ii) encoding the control signal with an information code representative of the selected function and representative of a switch operating state;

a voltage regulator configured for receiving a power source voltage and providing a regulated power source voltage to the transmitting unit, the encoded signal being responsive to the regulated power source voltage; and

a controller configured for controlling the voltage regulator, the controller automatically varying the power source voltage according to the information code in the encoded signal.

8. The transmitter of claim 7, wherein at least one among a door-lock/unlock function, a trunk-open function, a car-finder function, and a panic function is established as a function which can be specified by the operation switch;

and

the controller sets the power source voltage at a level associated with the door lock/unlock function when the door lock/unlock function has been specified, the controller reduces the power source voltage from the level associated with the door lock/unlock function when the trunk-open function has been specified, and increases supply voltage from a level associated with the door lock/unlock function when the car-finder function or the panic function has been specified.

9. The transmitter of claim 7, further comprising:

a vehicle-mounted receiver that receives the encoded signal from the transmitter; and

a vehicle-mounted controller that causes the vehicle-mounted receiver to operated in correspondence with the information in the received encoded signal.

10. The transmitter of claim 9, wherein a transmitter-specific code is also provided and encoded in the control signal transmitted from the transmitter;

wherein the receiver is configured for (i) receiving and analyzing the encoded signal from the transmitter and (ii) determining whether the selected transmitter-specific code coincides with an identification code for determination use stored in the receiver; and

wherein the vehicle-mounted controller causes the receiver to operate in correspondence with the information code in the encoded signal when the identification codes coincide.

11. A transmitter for a keyless entry system, comprising:

a controller configured for storing identification information and operating state information for remotely operating at least one vehicle-mounted apparatus;

a transmitter unit configured for selective operation by the controller in order to transmit the stored identification and operating state information;

a switch configured for communication with the controller to identify the vehicle-mounted apparatus, and to cause the controller to provide the stored identification and operating state information to the transmitter;

a voltage regulator configured for regulating a voltage supplied to the transmitter unit;

wherein the controller is operative to automatically adjust the supplied voltage in accordance with switch operating parameters; and

wherein the controller increases the supply voltage in accordance with a count of repeated operations of the switch.

12. The transmitter of claim 11, wherein the controller resets the count when a predetermined time elapses for operation of the switch.

14. The transmitter of claim 11, wherein the controller inhibits an increase in the supply voltage when the supply voltage from the voltage regulator has reached a predetermined upper-limit value.

13. A transmitter for a keyless entry system, comprising:

a controller including stored identification and operating state information associated with remote operation of at least one vehicle-mounted apparatus;

a transmitter unit configured for being selectively instructed by the controller to transmit the stored information;

a switch electrically coupled to controller and configured to (i) identify the vehicle-mounted apparatus and (ii) cause the controller to provide the stored information to the transmitter;

a voltage regulator configured for regulating a voltage supplied to the transmitting unit;

wherein the controller is operative to automatically adjust the supplied voltage in accordance with switch operating parameters; and

wherein the controller increases a level of the supplied voltage to rise in accordance with a continuous time period of operation for the switch, the level of supplied voltage increasing in a stepwise manner at predetermined time intervals during the continuous time period of operation.