Light emitting diode replacement lamp

• US 7,777,430 B2
• Filed: 10/30/2007
• Issued: 08/17/2010
• Est. Priority Date: 09/12/2003
• Status: Active Grant

• Current Assignee: LEDVANCE LLC (MLS Co. Ltd.)
• Original Assignee: TerraLUX Incorporated
• Inventors: Hall, John, Catalano, Anthony, Harrison, Daniel
• Primary Examiner(s): VO, TUYET THI
• Application Number:
  US11/928,752
• Publication Number:
  US 20080130288A1
• Time in Patent Office: 1,022 Days
• Field of Search: 315/247, 315/246, 315/224, 315/291, 315/297, 315307-311, 315/312, 315/324, 315/326, 315/185.S
• US Class Current: 315/309
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• CPC Class Codes: F21K 9/233 specially adapted for generating a spot light distribution, e.g. for substitution of reflector lamps
• CPC Class Codes: F21K 9/238 Arrangement or mounting of circuit elements integrated in the light source
• CPC Class Codes: F21V 23/003 the elements being electronics drivers or controllers for operating the light source, e.g. for a LED array
• CPC Class Codes: F21V 23/005 the substrate is supporting also the light source
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48464 the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/18 using temperature feedback
• CPC Class Codes: H05B 45/3574 Emulating the electrical or functional characteristics of incandescent lamps
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/40 Details of LED load circuits
• CPC Class Codes: H05B 45/56 : involving measures to prevent abnormal temperature of the LEDs
• CPC Class Codes: Y02B 20/30 : Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

Thermal management and control techniques for light emitting diode and other incandescent replacement light technologies using a current controller are disclosed.

Claims

1. A method for regulating current drive through at least one light emitting diode to compensate for temperature induced resistance changes in the light emitting diode, comprising:

supplying a source voltage;

using the source voltage to create a regulated current that is usable by the light emitting diode;

applying the regulated current to the light emitting diode to cause the regulated current to flow through the light emitting diode;

generating a sense voltage that is related to the regulated current and to a temperature at a position in a thermal pathway of heat emanating from the light emitting diode which heat is produced by the light emitting diode responsive to the regulated current; and

using the sense voltage as a feedback to modify the regulated current to be maintained within a non-destructive operating range of the light emitting diode when the regulated current would otherwise be outside of the non-destructive range due to a decreased resistance of the light emitting diode caused by an increased temperature of the light emitting diode.

2. A method as defined in claim 1 wherein the sense voltage is generated by at least a portion of the regulated current flowing through a temperature dependent resistance located in said thermal pathway.

3. A method as defined in claim 2 wherein generating the sense voltage includes selecting the temperature dependent resistance as having a positive temperature coefficient that causes the resistance of the temperature dependent resistance to increase with increases in temperature.

4. A method as defined in claim 2 wherein generating the sense voltage includes selecting the temperature dependent resistance as having a negative temperature coefficient that causes the resistance of the temperature dependent resistance to decrease with increases in temperature.

5. A method as defined in claim 2 wherein generating the sense voltage includes arranging the temperature dependent resistance in parallel with a parallel resistor and wherein the sense voltage is generated at least partially by the regulated current flowing through the temperature dependent resistance and the parallel resistor.

6. A method as defined in claim 5 wherein arranging includes configuring the temperature dependent resistance and parallel resistor in series with a series resistor and wherein the sense voltage is generated by the regulated current flowing through the temperature dependent resistance, the parallel resistor and series resistor.

7. A method as defined in claim 1 wherein the sense voltage is generated based on the regulated current flowing through a non-temperature dependent resistance.

8. A method as defined in claim 7 wherein generating the sense voltage includes amplifying the regulated current flowing through the non-temperature dependent resistance to produce the sense voltage and where an amplitude of the amplification is dependent at least partially on a temperature dependent resistance.

9. A method as defined in claim 8 wherein amplifying includes applying a negative feedback loop in the amplification based on the temperature dependent resistance.

10. A method as defined in claim 9 including arranging the temperature dependent resistance in the negative feedback loop with a negative temperature coefficient that causes the resistance of the temperature dependent resistance to decrease with increased temperature.

11. A method as defined in claim 9 further comprising:

arranging the temperature dependent resistance in the negative feedback with a positive temperature coefficient that causes the resistance of the temperature dependent resistance to increase with increased temperature.

12. A current regulator for regulating current drive through at least one light emitting diode to compensate for temperature induced resistance changes in the light emitting diode, the current regulator comprising:

a source voltage input for receiving a source voltage from a voltage source;

a voltage regulator connected to the source voltage input for regulating the source voltage to create the regulated current and for connection to the light emitting diode to cause the regulated current to flow through the light emitting diode; and

a sense voltage generator for generating a sense voltage that is related to the regulated current and to a temperature at a position in a thermal pathway of heat emanating from the light emitting diode, which heat is produced by the light emitting diode responsive to the regulated current, where the sense voltage is used as a feedback to modify the regulated current to be maintained within a non-destructive operating range of the light emitting diode when the regulated current would otherwise be outside of the non-destructive range due to a decreased resistance of the light emitting diode caused by an increased temperature of the light emitting diode.

13. A current regulator as defined in claim 12, further comprising:

a temperature dependent resistor positioned in said thermal pathway and wherein the sense voltage generator generates the sense voltage based on at least a portion of the regulated current flowing through the temperature dependent resistor.

14. A current regulator as defined in claim 13 wherein the temperature dependent resistor has a positive temperature coefficient.

15. A current regulator as defined in claim 13 wherein the temperature dependent resistor has a negative temperature coefficient.

16. A current regulator as defined in claim 13, further comprising:

a parallel resistor and wherein the temperature dependent resistor is arranged in parallel with the parallel resistor and the sense voltage is generated by at least a portion of the regulated current flowing through the temperature dependent resistor and the parallel resistor.

17. A current regulator as defined in claim 12,

wherein the sense voltage generator includes an amplifier for generating the sense voltage based at least in part on the regulated current flowing through a non-temperature dependent resistor.

18. A current regulator as defined in claim 17 wherein the gain of the amplifier is dependent on a temperature dependent resistor positioned in said thermal pathway.

19. A current regulator as defined in claim 18 wherein the temperature dependent resistor has a positive temperature coefficient that causes the resistance of the temperature dependent resistor to increase with increases in temperature.

20. A current regulator as defined in claim 18 wherein the temperature dependent resistor has a negative temperature coefficient that causes the resistance of the temperature dependent resistor to decrease with increases in temperature.