LIGHTING APPARATUS USING A NON-LINEAR CURRENT SENSOR AND METHODS OF OPERATION THEREOF

• US 20120153844A1
• Filed: 12/15/2010
• Published: 06/21/2012
• Est. Priority Date: 12/15/2010
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Chobot, Joseph Paul
• Granted Patent: US 10,057,952 B2
• Time in Patent Office: Days
• US Class Current: 315/185.R
• CPC Class Codes: H05B 45/44 with an active control inside an LED matrix
• CPC Class Codes: H05B 45/48 having LEDs organised in strings and incorporating parallel shunting devices

Abstract

A lighting apparatus includes a lighting circuit including at least one light-emitting device, e.g., a string of LEDs, and at least one current sense diode configured to generate a forward voltage responsive to a current passing through the at least one light-emitting device. The apparatus further includes a control circuit configured to control the lighting circuit responsive to the generated forward voltage. In some embodiments, the least one light-emitting device includes the at least one current sense diode. In some embodiments, the at least one current sense diode is connected in series with the at least one light-emitting device.

Claims

1. A lighting apparatus comprising:

a lighting circuit comprising at least one light-emitting device;

at least one current sense diode configured to generate a forward voltage responsive to a current passing through the at least one light-emitting device; and

a control circuit configured to control the lighting circuit responsive to the generated forward voltage.

2. The apparatus of claim 1, wherein the least one light-emitting device comprises the at least one current sense diode.

3. The apparatus of claim 1, wherein the at least one current sense diode is connected in series with the at least one light-emitting device.

4. The apparatus of claim 1, wherein the lighting circuit comprises a string of serially connected light emitting devices and wherein the at least one current sense diode is connected in series with serially connected light emitting devices.

5. The apparatus of claim 4, wherein the control circuit is configured to control a current passing through the string of serially connected light emitting devices responsive to the sensed forward voltage.

6. The apparatus of claim 4, wherein the control circuit is configured to control a bypass current around at least one light emitting device of the string of serially connected light emitting devices responsive to the sensed forward voltage.

7. The apparatus of claim 4, wherein the lighting circuit comprises a first string of serially connected light emitting devices and a second string of serially connected light emitting devices, wherein the current sense diode is connected in series with the first string of serially connected light emitting devices and wherein the control circuit is configured to control a current through the second string of serially connected light emitting devices responsive to the sensed forward voltage.

8. The apparatus of claim 1, further comprising a temperature sensor configured to generate a temperature sense signal, and wherein the control circuit is configured to control the lighting apparatus responsive to the forward voltage and the temperature sense signal.

9. The apparatus of claim 1, wherein the at least one current sense diode comprises at least one LED.

10. The apparatus of claim 1, wherein the lighting circuit comprises a string of serially connected LEDs and wherein the at least one current sense diode is connected in series with the string of serially connected LEDs.

11. The apparatus of claim 10, wherein the at least one current sense diode comprises an LED of the string of serially connected LEDs.

12. The apparatus of claim 11, wherein the control circuit is configured to control a current passing through the string of serially connected LEDs responsive to the sensed forward voltage.

13. The apparatus of claim 11, wherein the control circuit is configured to control a bypass current around at least one LED of the string of serially connected LEDs responsive to the sensed forward voltage.

14. The apparatus of claim 11, wherein the lighting circuit comprises a first string of serially connected LEDs and a second string of serially connected LEDs, wherein the current sense diode comprises at least one LED of the first string of serially connected LEDs and wherein the control circuit is configured to control a current through the second string of serially connected LEDs responsive to the sensed forward voltage.

15. The apparatus of claim 14, wherein the first and second strings of serially connected LEDS comprise LEDs of different colors.

16. A lighting apparatus comprising:

at least one string of serially connected LEDs;

at least one current sense diode configured to generate a forward voltage responsive to a current passing through the at least one string of serially connected LEDs; and

a control circuit configured to sense the forward voltage and to control the at least one string of LEDs responsive to the sensed forward voltage.

17. The apparatus of claim 16, wherein the at least one current sense diode comprises at least one LED of the string of serially connected LEDs.

18. The apparatus of claim 16, wherein the control circuit is configured to control a current passing through the string of serially connected LEDs responsive to the sensed forward voltage.

19. The apparatus of claim 16, wherein the control circuit is configured to control a bypass current around at least one LED of the string of serially connected LEDs responsive to the sensed forward voltage.

20. The apparatus of claim 16, wherein the at least one string of serially connected LEDs comprises a first string of serially connected LEDs and a second string of serially connected LEDs, wherein the current sense diode is connected in series with the first string of serially connected LEDs and wherein the control circuit is configured to control a current through the second string of serially connected LEDs responsive to the sensed forward voltage.

21. The apparatus of claim 20, wherein the first and second strings of serially connected LEDS comprise LEDs of different colors.

22. A lighting apparatus comprising:

a lighting circuit comprising at least one light-emitting device;

a non-linear current sensor configured to generate a voltage representative of a current passing through the at least one light-emitting device; and

a control circuit configured to control the lighting circuit responsive to the generated voltage.

23. The apparatus of claim 22, wherein the current has a substantially exponential relationship the generated voltage.

24. The apparatus of claim 22, wherein the non-linear current sensor comprises a diode and wherein the voltage comprises a forward voltage across the diode.

25. A method of controlling a lighting circuit comprising at least one light-emitting device, the method comprising:

generating a forward voltage across at least one current sense diode responsive to a current passing through the at least one light-emitting device;

sensing the forward voltage; and

controlling the lighting circuit responsive to the sensed forward voltage.

26. The method of claim 25, wherein the least one light-emitting device comprises the at least one current sense diode.

27. The method of claim 25, wherein the at least one current sense diode comprises at least one LED.

28. The method of claim 25, wherein the lighting circuit comprises a string of serially connected LEDs and wherein the at least one current sense diode is connected in series with the string of serially connected LEDs.

29. The method of claim 28, wherein the at least one current sense diode comprises an LED of the string of serially connected LEDs.

30. The method of claim 28, wherein controlling the lighting circuit responsive to the sensed forward voltage comprises controlling a current passing through the string of serially connected LEDs responsive to the sensed forward voltage.

31. The method of claim 28, wherein controlling the lighting circuit responsive to the sensed forward voltage comprises controlling a bypass current around at least one LED of the string of serially connected LEDs responsive to the sensed forward voltage.

32. The method of claim 28, wherein the lighting circuit comprises a first string of serially connected LEDs and a second string of serially connected LEDs, wherein the current sense diode comprises at least one LED of the first string of serially connected LEDs and wherein controlling the lighting circuit responsive to the sensed forward voltage comprises controlling a current through the second string of serially connected LEDs responsive to the sensed forward voltage.