Led with integrated constant current driver

• US 20090021180A1
• Filed: 07/17/2007
• Published: 01/22/2009
• Est. Priority Date: 07/17/2007
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Underwood, Robert, Wu, Yifeng
• Granted Patent: US 8,111,001 B2
• Time in Patent Office: Days
• 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 having at least one operating voltage; and

circuitry comprising at least one voltage level converter and at least one constant current circuit, wherein the at least one converter and the at least one circuit are integrated into the package and electrically connected to the LED.

2. The package of claim 1, wherein the circuitry is drive circuitry.

3. The package of claim 1, wherein the circuitry provides the at least one operating voltage to the LED.

4. The package of claim 1, wherein the at least one voltage converter is selected from the group consisting of a DC voltage converter, a charge pump, a switched-mode power supply, and combinations thereof.

5. The package of claim 1, further comprising at least one transformer and at least one rectifier.

6. The package of claim 1, further comprising at least one first electrical connector.

7. The package of claim 6, wherein the at least one first connector provides an electrical connection to at least one power source.

8. The package of claim 6, wherein the at least one first connector provides an electrical connection to at least one control system.

9. The package of claim 8, wherein the at least one control system provides control over at least one LED current.

10. The package of claim 8, wherein the at least one control system provides control over at least one property of light emitted by the LED.

11. The package of claim 8, wherein the at least one control system is connected to the package though at least one of a serial bus, a parallel bus, and combinations thereof.

12. A packaged LED comprising the device package of claim 1.

13. A light emitting system comprising the package of claim 1.

14. The system of claim 13, further comprising at least one power source.

15. The system of claim 13, further comprising at least one control system.

16. The system of claim 15, wherein the control system is connected to the package and provides control over at least one property of light emitted by the LED.

17. The system of claim 15, wherein the at least one control system is connected to the package though at least one of at least of a serial bus, a parallel bus, and combinations thereof.

18. An LED comprising at least one voltage level converter and at least one constant current circuit, wherein the converter and the circuit are integrated into the LED and electrically connected to the LED.

19. A method for matching a power source voltage to an LED operating voltage, the method comprising providing a first voltage level from a power source to a drive circuitry, wherein

the circuitry is integrated into the LED;

and

the circuitry is electrically connected to the LED and provides a second voltage level to the LED.

20. The method of claim 19, wherein the second voltage level is less than about the first voltage level.

21. The method of claim 19, wherein the second voltage level matches the operating voltage of the LED.