LED with integrated constant current driver

• US 8,810,151 B2
• Filed: 11/15/2012
• Issued: 08/19/2014
• Est. Priority Date: 07/17/2007
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Underwood, Robert, Wu, Yifeng
• Primary Examiner(s): PHILOGENE, HAISSA
• Application Number:
  US13/677,709
• Publication Number:
  US 20130069527A1
• Time in Patent Office: 642 Days
• Field of Search: 315/312, 315/291, 315/294, 315/307, 315/219, 315224-226, 315/247, 315/276, 362/227, 362/240, 362/800, 257/84, 257/79, 257/13, 438/238, 438/328
• US Class Current: 315/291
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/13062 Junction field-effect transistor [JFET]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/395 Linear regulators
• CPC Class Codes: H05B 45/40 Details of LED load circuits
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

An LED package containing integrated circuitry for matching a power source voltage to the LED operating voltage, LEDs containing such integrated circuitry, systems containing such packages, and methods for matching the source and operating voltages are described. The integrated circuitry typically contains a power converter and a constant current circuit. The LED package may also contain other active or passive components such as pin-outs for integrated or external components, a transformer and rectifier, or a rectifier circuit. External components can include control systems for regulating the LED current level or the properties of light emitted by the LED. Integrating the power supply and current control components into the LED can provide for fabrication of relatively small LEDs using fewer and less device-specific components.

Claims

1. A light emitting device package comprising:

at least one LED in said package; and

circuitry comprising control circuits integrated into said package, said control circuits comprising at least one oscillator and at least one transistor and arranged such that said oscillator controls when at least one of said transistors is in an on-state.

2. The package of claim 1, wherein said control circuits comprise logic circuits.

3. The package of claim 1, wherein said circuitry is organized into a separate power substrate within said LED package.

4. The package of claim 1, further comprising at least one mount surface.

5. The package of claim 4, wherein said circuitry is within said at least one mount surface.

6. The package of claim 4, wherein said circuitry is on an opposite side of said mount surface than said LED.

7. The package of claim 1 further comprising external components in electrical communication with said circuitry.

8. The package of claim 7, wherein said external components comprise passive electrical components.

9. The package of claim 8, wherein said passive components comprise at least one inductor.

10. The package of claim 8, wherein said passive components comprise at least one capacitor.

11. The package of claim 7, wherein said external components comprise at least one control system.

12. The package of claim 1, wherein said control circuits regulate voltage.

13. The package of claim 1, wherein said control circuits regulate current.

14. A light emitting device package comprising:

at least one LED in said package; and

circuitry comprising control circuits integrated into said package, said control circuits comprising at least one oscillator having a duty cycle and at least one detection and feedback circuit, said at least one detection and feedback circuit configured to control the duty cycle of the oscillator.

15. The package of claim 14, wherein said control circuits comprise logic circuits.

16. The package of claim 14, wherein said circuitry is organized into a separate power substrate within said LED package.

17. The package of claim 14, further comprising at least one mount surface.

18. The package of claim 17, wherein said circuitry is within said at least one mount surface.

19. The package of claim 17, wherein said circuitry is on an opposite side of said mount surface than said LED.

20. The package of claim 14 further comprising external components in electrical communication with said circuitry.

21. The package of claim 20, wherein said external components comprise passive electrical components.

22. The package of claim 21, wherein said passive components comprise at least one inductor.

23. The package of claim 21, wherein said passive components comprise at least one capacitor.

24. A light emitting package, comprising:

at least one on board LED; and

on board voltage converter components and interconnects arranged to compensate for an input voltage different from the operating voltage of said LED.

25. The package of claim 24, wherein said input voltage is greater than said LED operating voltage, and wherein said voltage converter components and interconnects comprise a step-down converter.

26. The package of claim 25, wherein said voltage converter components and interconnects comprise a buck converter.

27. The package of claim 24, wherein said input voltage is less than said LED operating voltage, and wherein said voltage converter components and interconnects comprise a step-up converter.

28. The package of claim 27, wherein said voltage converter components and interconnects comprise a boost converter.

29. The package of claim 24, wherein said voltage converter components and interconnects comprise a buck-boost converter.

30. The package of claim 24, wherein said voltage converter component comprise a flying capacitor.

31. The package of claim 24, wherein said voltage converter components comprise a charge-pump, linear voltage regulator.

32. A light emitting package, comprising:

at least one on board LED;

on board circuitry, wherein at least a portion of said on board circuitry matches a power source voltage to the operating voltage of said LED; and

pin outs for connecting to power matching circuitry which is external to said light emitting package.

33. The package of claim 32, wherein said on-board circuitry comprises integrated circuitry.

34. The package of claim 33, wherein said integrated circuitry comprises a power converter.

35. The package of claim 33, wherein said integrated circuitry comprises a constant current circuit.

36. The package of claim 35, wherein said constant current circuit comprises a current-limiting resistor.

37. The package of claim 36, wherein said current-limiting resistor is connected in series to said LED.

38. The package of claim 35, wherein said constant current circuit comprises a junction field-effect transistor (JFET).

39. The package of claim 35, wherein said constant current circuit comprises linear regulators.

40. The package of claim 39, wherein said linear regulators comprise operational amplifiers with current sensing and feedback components.

41. The package of claim 32, wherein said power matching circuitry external to said light emitting package comprises a transformer circuit.

42. The package of claim 32, wherein said power matching circuitry external to said light emitting package comprises a rectifier circuit.

43. The package of claim 42, wherein said rectifier circuit comprises a transformer and a capacitor.

44. The package of claim 32, wherein said power matching circuitry external to said light emitting package comprises an inductor circuit.

45. The package of claim 32, wherein said pin outs further allow for setting of LED current or dimming.