Detecting outages in a LED lamp assembly

Patent metadata

Field	Value
Publication number	US-9942971-B2
Application number	US-201615236915-A
Country	US
Kind code	B2
Filing date	Aug 15, 2016
Priority date	Aug 15, 2016
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

Apparatus and systems are disclosed for detecting outages in an LED lamp assembly. An example disclosed lamp assembly includes a plurality of LED circuits serially connected together. The LED circuits include an LED, a first resistor and an optocouper. The example disclosed lamp assembly also includes a sense line electrically coupled to one of the LED circuits. The sense line has a first voltage value when all of LEDs in that plurality of LED circuits are operational and a second voltage value when at least one of the LEDs has failed.

First claim

What is claimed is:

1. A lamp assembly for a vehicle comprising:
a plurality of LED circuits serially connected together, the LED circuits including an LED, a first resistor and an optocoupler, a first terminal of the first resistor being electrically coupled to an anode terminal of the LED, a second terminal of the first resistor being connected to an anode terminal of the optocoupler, and a cathode terminal of the LED being electrically connected to a cathode terminal of the optocoupler; and
a sense line electrically coupled to one of the LED circuits, the sense line having a first voltage value when all of LEDs in that plurality of LED circuits are operational and a second voltage value when at least one of the LEDs has failed.

2. The lamp assembly of claim 1 , including:
a second resistor electrically coupled to a first one of the plurality of LED circuits; and
a third resistor electrically coupled to a second one of the plurality of LED circuits and the sense line.

3. The lamp assembly of claim 2 , wherein the optocouplers of the plurality of LED circuits form a conductive path between the second and third resistors.

4. The lamp assembly of claim 3 , wherein, when the LEDs are operating, the corresponding optocouplers conduct current, and wherein when one of the LEDs fails, the corresponding optocoupler does not conduct current.

5. The lamp assembly of claim 1 , wherein a value of the first resistor is determined by an first activation voltage of the corresponding LED and a second activation voltage of the corresponding optocoupler.

6. The lamp assembly of claim 5 , wherein the first activation voltage is greater than the second activation voltage.

7. A vehicle including:
a headlamp power driver;
a body control module; and
a lamp assembly including:
a plurality of LED circuits serially connected together, the LED circuits including one of a plurality of LEDs, a first resistor and an optocoupler, a first terminal of the first resistor being electrically coupled to an anode terminal of the LED, a second terminal of the first resistor being connected to an anode terminal of the optocoupler, and a cathode terminal of the LED being electrically connected to a cathode terminal of the optocoupler; and
a sense line that has a first voltage value when all of the plurality of LEDs in the lamp assembly are operational and a second voltage value when at least one of the plurality of LEDs has failed.

8. The vehicle of claim 7 , including:
a second resistor electrically coupled to a first one of the plurality of LED circuits; and
a third resistor electrically coupled to a second one of the plurality of LED circuits and the sense line.

9. The vehicle of claim 7 , wherein the optocouplers of the plurality of LED circuits are electrically coupled between the second and third resistors.

10. The vehicle of claim 9 , wherein, when the LEDs are operating, the corresponding optocouplers conduct current, and wherein when one of the LEDs fails, the corresponding optocoupler does not conduct current.

11. The vehicle of claim 7 , wherein a value of the first resistor is determined by an first activation voltage of the corresponding LED and a second activation voltage of the corresponding optocoupler.

12. The vehicle of claim 7 , wherein a first activation voltage is greater than a second activation voltage.

13. The vehicle of claim 7 , wherein the body control module is to, in response to the sense line having the second voltage value, instruct a human machine interface to display an indicator that signifies that at least one of the LEDs has failed.

14. A vehicle comprising:
a headlamp power driver;
a lamp assembly with LEDS coupled to a single fault sense line via corresponding optocouplers that cause the sense line to have a first voltage when all the LEDs are operational and a second voltage when one of the LEDs has failed; and
a body control module to, upon detecting the second voltage, instruct a display to activate an indicator signifying that one of the LEDs has failed.

Assignees

• Ford Global Tech Llc

Inventors

• Brombach Ronald Patrick
• Barrs John

Classifications

• H05B45/48

  having LEDs organised in strings and incorporating parallel shunting devices · CPC title

• B60Q11/005 Primary

  for lighting devices, e.g. indicating if lamps are burning or not · CPC title

• B60Q1/0088

  Details of electrical connections (B60Q1/305 takes precedence; electrical connection of the light source itself F21S41/192, F21S43/195) · CPC title

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title

• H05B45/50 Primary

  responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits · CPC title