LED module for sign channel letters and driving circuit

• US 20100061025A1
• Filed: 09/09/2008
• Published: 03/11/2010
• Est. Priority Date: 09/09/2008
• Status: Active Grant

• Current Assignee: Principal Lighting Group LLC
• Original Assignee: Inshore Holdings, LLC
• Inventors: Parker, Francis J., Crawbuck, Robert, Padurariu, Emilian
• Granted Patent: US 8,611,057 B2
• Time in Patent Office: Days
• US Class Current: 361/42
• CPC Class Codes: G09F 13/22 electroluminescent electroluminescent light sources per se H05B33/00
• CPC Class Codes: G09F 9/33 being semiconductor devices, e.g. diodes

Abstract

An LED module for use in sign letter channel lights comprises a substrate, a reflector mounted on the substrate, an LED mounted within the reflector on the substrate and a Zener diode shunt element connected in parallel across the LED, a printed circuit board on the substrate, wherein the LED is mounted on the printed circuit board, and an insulating cover. The module may be entirely encapsulated. An LED driving protection circuit provides ground fault protection for a plurality of series connected LED modules.

Claims

1. An LED module for use in a lighting circuit for illumination of channel letters in a sign and having LED modules connected in series to a source of constant current, comprising:

a substrate; and

an electrical circuit mounted on the substrate, said electrical circuit consisting essentially of an LED and a shunt element connected in parallel with the LED, the electrical circuit having two electrical connection points for connecting the LED module to other modules in a series circuit.

2. The module according to claim 1, wherein the substrate is mounted in a housing, and further comprising a clip on the exterior of the housing for accepting and mounting a return power wire.

3. The module according to claim 1, wherein the shunt element is a Zener diode.

4. The module according to claim 1, wherein the substrate includes a heat sink for dissipating heat.

5. The module according to claim 1, wherein the substrate includes at least one mounting region at an edge for mounting the module.

6. The module according to claim 5, wherein the mounting region comprises at least one of a notch and a hole.

7. The module according to claim 1, wherein the module includes an insulating cover.

8. The module according to claim 1, wherein the insulating cover is molded onto the module.

9. The module according to claim 1, wherein the module includes a heat sink, a printed circuit board on the insulator, and wherein the LED is mounted on the printed circuit board.

10. The module according to claim 1, including a reflector in which the LED is mounted.

11. An LED lighting system for illumination of channel letters in a sign, comprising a circuit having a plurality of LED modules connected in series to a source of constant current, each LED module being removable and replaceable within the circuit, each LED module comprising an LED connected in parallel with a shunt element.

12. The module according to claim 11, wherein the substrate is mounted in a housing, and further comprising a clip on the exterior of the housing for accepting and mounting a return power wire.

13. The module according to claim 11, wherein the LED modules are connected using double insulated wire.

14. The module according to claim 11, wherein the shunt element is a Zener diode.

15. The module according to claim 11, wherein the substrate includes a heat sink for dissipating heat.

16. The module according to claim 11, wherein the substrate includes at least one mounting region at an edge for mounting the module.

17. The module according to claim 16, wherein the mounting region comprises at least one of a notch and a hole.

18. The module according to claim 11, wherein the module includes an insulating cover.

19. The module according to claim 11, wherein the insulating cover is molded onto the module.

20. The module according to claim 11, wherein the module includes a heat sink, a printed circuit board on the insulator, and wherein the LED is mounted on the printed circuit board.

21. An LED lighting system comprising a plurality of LED modules connected in series to a source of constant current, comprising:

a substrate;

a reflector mounted on the substrate; and

an electrical circuit mounted on the substrate, said electrical circuit consisting essentially of an LED mounted within the reflector on the substrate and a Zener diode shunt element connected in parallel across the LED.

22. An LED lighting system, comprising:

a LED circuit having a plurality of LEDs connected in series and connectable to a source of constant current; and

a ground fault detecting circuit for detecting the presence of a ground fault condition in the LED circuit, and in response to a ground fault condition being detected, for disconnecting the LED circuit from the source of constant current.

23. The LED lighting system according to claim 22, wherein the LEDs are connected with double insulated wire.

24. An LED driving protection circuit for providing ground fault protection for a series LED circuit, comprising:

an output circuit for outputting power to drive an LED circuit of series connected LEDs, and for outputting a output voltage signal at a reference voltage potential, said voltage potential remaining substantially constant in the absence of a ground fault in the LED circuit, but which changes from the reference voltage potential if a ground fault exists in the LED circuit; and

a comparator circuit for detecting when the output voltage signal changes from the reference voltage potential, and in response produces an inhibit signal which disables the output circuit from outputting power to drive the LED circuit.

25. The circuit according to claim 24, wherein the output circuit comprises a first transformer having a primary terminal connected to receive an AC current source, secondary terminals, and a rectifier bridge connected to the secondary terminals for outputting DC power to drive the LED circuit, said first transformer having an output center tap for providing the reference voltage potential.

26. The circuit according to claim 25, wherein the comparator circuit comprises:

a bridge rectifier for producing rectified current;

an opto isolator to receive the rectified current;

a comparator connected to an output of the opto isolator and the reference voltage potential, and for outputting the inhibit signal when the voltage from the secondary terminals exceeds the reference voltage potential.