SEATBELT LATCH CIRCUIT

• US 20140266663A1
• Filed: 01/28/2014
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Schlaps, Edgar H.
• Granted Patent: US 9,434,348 B2
• Time in Patent Office: Days
• US Class Current: 340/457.1
• CPC Class Codes: A44B 11/2565 Illuminated buckles
• CPC Class Codes: B60R 2022/4816 for sensing locking of buckle
• CPC Class Codes: B60R 22/48 Control systems, alarms, or interlock systems, for the correct application of the belt or harness
• CPC Class Codes: G08G 1/00 Traffic control systems for road vehicles arrangement of road signs or traffic signals E01F9/00 ; automatic vehicle control B62D

Abstract

A seatbelt latch circuit can include an illumination source configured to illuminate a seatbelt latch in response to a signal. The seatbelt latch circuit can also include a status sensor configured to output a first current if the seatbelt latch is in a removed state, output a second current if the seatbelt latch is in an inserted state and output a third current if the seatbelt latch has a fault. The seatbelt latch circuit communicates with a vehicle electrical system through only two conductors.

Claims

1. A seatbelt latch circuit comprising:

an illumination source configured to illuminate a seatbelt latch in response to a signal; and

a status sensor configured to;

output a first current if the seatbelt latch is in a removed state;

output a second current if the seatbelt latch is in an inserted state; and

output a third current if the seatbelt latch has a fault, the third current being different than the first and second currents;

wherein the seatbelt latch circuit communicates with a vehicle electrical system through only two conductors.

2. The seatbelt latch circuit of claim 1, wherein the seatbelt latch circuit is housed in the seatbelt latch.

3. The seatbelt latch circuit of claim 2, wherein the illumination source is connected in series with the status sensor.

4. The seatbelt latch circuit of claim 3, wherein the illumination source comprises a light emitting diode (LED) connected in series with a resistor.

5. The seatbelt latch circuit of claim 3, wherein the status sensor comprises a Hall effect sensor configured to output a current that varies based on a presence or absence of a tongue inserted into the seatbelt latch.

6. The seatbelt latch circuit of claim 3, wherein the status sensor comprises one of a normally open and normally closed switch connected in parallel with a resistor, the switch being configured to change state based on a state of the seatbelt latch.

7. The seatbelt latch circuit of claim 2, wherein the illumination source is connected in parallel with the status sensor.

8. The seatbelt latch circuit of claim 7, wherein the illumination source comprises a light emitting diode (LED) connected in series with a resistor.

9. The seatbelt latch circuit of claim 7, wherein the status sensor comprises a hall effect sensor configured to output a current that varies based on a presence or absence of a tongue inserted into the seatbelt latch.

10. The seatbelt latch circuit of claim 7, wherein the status sensor comprises one of a normally open and normally closed switch connected in series with a resistor, the one of the normally open and normally closed switch being configured to change state based on a state of the seatbelt latch.

11. The seatbelt latch circuit of claim 2, wherein the illumination source comprises:

a first light emitting diode (LED) of a first color; and

a second LED of a second color, the second color being different that the first color.

12. The seatbelt latch circuit of claim 2, wherein the status sensor comprises:

a Hall effect sensor configured to provide an output current that varies based on a presence or absence of a tongue being inserted in the seatbelt latch; and

first and second diodes configured to receive the output current provided by the Hall effect sensor.

13. A vehicle electrical system comprising:

an illumination source configured to illuminate an associated seatbelt latch in response to a signal;

a signal measurement system configured to provide a measured signal that varies based on a status of the associated seatbelt latch; and

a comparator configured to provide a status signal that indicates whether the seatbelt latch is in a removed or an inserted state or if a circuit housed in the seatbelt latch and including the illumination source has a fault;

wherein the vehicle electrical system and the circuit housed in the seatbelt latch communicate over exactly two conductors.

14. The vehicle electrical system of claim 13, further comprising a pulse width modulator (PWM) configured to provide a pulse width modulated signal that varies as a function of an intensity control.

15. The vehicle electrical system of claim 14, further comprising a driver configured to provide an amplified version of the pulse width modulated signal to the illumination source of the seatbelt latch circuit via a first of the exactly two conductors.

16. The vehicle electrical system of claim 15, further comprising a current sensor configured to receive an output signal from a status sensor via a second of the exactly two conductors.

17. The vehicle electrical system of claim 13, further comprising a pulse width modulator (PWM) configured to provide a pulse width modulated signal that varies as a function of an intensity and color control.

18. The vehicle electrical system of claim 17, further comprising an H-bridge configured to provide a first driving signal to the illumination source of the seatbelt latch circuit via a first of the exactly two conductors and a second driving signal to the illumination source of the seatbelt latch circuit via a second of the exactly two conductors.

19. A system comprising:

a seatbelt latch circuit comprising;

an illumination source configured to illuminate a seatbelt latch in response to a signal; and

a status sensor configured to;

output a first current if the seatbelt latch is in a removed state;

output a second current if the seatbelt latch is in an inserted state; and

output a third current if the seatbelt latch circuit has a fault, the third current being different than the first and second currents; and

a vehicle electrical system comprising;

a signal measurement system configured to provide a measured signal that varies based on a current output by the status sensor; and

a comparator configured to provide a status signal that indicates whether the seatbelt latch is in the removed or inserted state or if the seatbelt latch circuit has a fault;

wherein the seatbelt latch circuit communicates with a vehicle electrical system with no more than two conductors.

20. The system of claim 19, wherein the illumination source is connected in series with the status sensor, the illumination source comprising a light emitting diode (LED) connected in series with a resistor;

and

the status sensor comprising a Hall effect sensor configured to provide the first or second current based on a presence or absence of a tongue inserted into the seatbelt latch.