Light emitting diode replacement lamp
View Patent ↗Thermal management and control techniques for light emitting diode and other incandescent replacement light technologies using a current controller are disclosed.
1. A lighting apparatus comprising:
a light-emitting diode (LED);
a printed circuit board (PCB) comprising circuitry (i) electrically connected to the LED and (ii) for controlling current to the LED, a first surface of the PCB being disposed in contact with the LED; and
a heat sink disposed in contact with a second surface of the PCB opposite the first surface,
wherein (i) the PCB comprises a via extending therethrough and thermally connecting the LED and the heat sink, and (ii) the circuitry controls current to the LED based on an LED temperature resulting from heat produced by the LED.
2. The lighting apparatus of claim 1 , wherein the via is plated.
3. The lighting apparatus of claim 1 , wherein the via is substantially filled with at least one of copper, aluminum, or solder.
4. The lighting apparatus of claim 1 , wherein the PCB comprises a copper sheet on at least one of the first surface or the second surface.
5. The structure of claim 1 , wherein the LED comprises a metal slug disposed in contact with the first surface of the PCB, and the via thermally connects the metal slug and the heat sink.
6. The structure of claim 1 , wherein the circuitry is configured to decrease the current to the LED as the LED temperature increases.
7. The lighting apparatus of claim 1 , further comprising a plurality of additional vias extending through the PCB and thermally connecting the LED and the heat sink.
8. The lighting apparatus of claim 7 , wherein a center-to-center distance between the vias is approximately 0.050 inches or less.
9. The structure of claim 1 , wherein the circuitry comprises:
a source voltage input for receiving a source voltage,
a voltage regulator for regulating the source voltage to generate a regulated current therefrom, the regulated current being supplied to the LED, and
a sense voltage generator for generating a sense voltage based at least in part on the regulated current and the LED temperature, whereby the sense voltage is utilized to maintain the regulated current within a non-destructive operating range of the LED.
10. The structure of claim 9 , further comprising a temperature-dependent resistance responsive to the LED temperature, wherein the sense voltage is generated based at least in part on the temperature-dependent resistance.
11. The structure of claim 10 , further comprising a resistor connected in parallel with the temperature-dependent resistance, the source voltage being generated at least in part by at least a portion of the regulated current flowing through the resistor and the temperature-dependent resistance.
12. The structure of claim 9 , wherein the sense voltage generator comprises an amplifier for amplifying the sense voltage.
13. The structure of claim 12 , wherein a gain of the amplifier depends at least in part on the LED temperature.
14. The lighting apparatus of claim 1 , further comprising a temperature-dependent resistance disposed in thermal contact with at least one of the PCB or the heat sink.
15. The structure of claim 14 , wherein the temperature-dependent resistance is disposed in contact with the LED.
16. The structure of claim 14 , wherein a thermal pathway between the temperature-dependent resistance and the LED comprises air.
17. The structure of claim 14 , wherein a thermal pathway between the temperature-dependent resistance and the LED comprises a non-air fluid medium.
18. The structure of claim 14 , wherein the temperature-dependent resistance has a negative temperature coefficient.
19. The structure of claim 14 , wherein the temperature-dependent resistance has a positive temperature coefficient.
20. The structure of claim 14 , wherein the temperature-dependent resistance comprises a thermistor.
21. A method of forming a lighting apparatus, the method comprising:
disposing a light-emitting diode over a first surface of a printed circuit board (PCB);
disposing a heat sink over a second surface of the PCB opposing the first surface, whereby a via extending through a thickness of the PCB thermally connects the LED and the heat sink; and
providing circuitry for controlling current to the LED based on an LED temperature resulting from heat produced by the LED.
22. The method of claim 21 , further comprising disposing a temperature-dependent resistance in thermal contact with at least one of the PCB or the heat sink.
23. The method of claim 21 , wherein the circuitry comprises:
a source voltage input for receiving a source voltage from a voltage source;
a voltage regulator for regulating the source voltage to generate a regulated current therefrom, the regulated current being supplied to the LED; and
a sense voltage generator for generating a sense voltage based at least in part on the regulated current and the LED temperature, whereby the sense voltage is utilized to maintain the regulated current within a non-destructive operating range of the LED.
24. The method of claim 21 , wherein the circuitry is configured to decrease the current to the LED as the LED temperature increases.