Light emitting diode thermal foldback control device and method

Patent metadata

Field	Value
Publication number	US-2020008279-A1
Application number	US-201916565750-A
Country	US
Kind code	A1
Filing date	Sep 10, 2019
Priority date	Feb 20, 2015
Publication date	Jan 2, 2020
Grant date	—

Abstract

A thermal foldback control system electrically connected to a light emitting diode (LED) driver, the thermal foldback control system including a temperature sensitive circuit and a regulator. The temperature sensitive circuit is configured to output a reference voltage based on a first resistance and a second resistance. The regulator is configured to control a driver output of the LED driver based on the reference voltage.

First claim

What is claimed is:

1 . A thermal foldback control system electrically connected to a light emitting diode (LED) driver, the thermal foldback control system comprising:
a temperature sensitive circuit configured to output a reference voltage based on a first resistance and a second resistance; and a regulator configured to control a driver output of the LED driver based on the reference voltage.

2 . The thermal foldback control circuit of claim 1 , wherein the driver output powers one or more light emitting diodes (LEDs).

3 . The thermal foldback control circuit of claim 1 , wherein the first resistance is from a first resistance component and the second resistance is from a second resistance component.

4 . The thermal foldback control circuit of claim 3 , wherein the first resistance component is at least one selected from the group consisting of a negative temperature coefficient (NTC) type thermistor and a positive temperature coefficient (PTC) type thermistor.

5 . The thermal foldback control circuit of claim 3 , wherein the second resistance component is at least one selected from the group consisting of a negative temperature coefficient (NTC) type thermistor and a positive temperature coefficient (PTC) type thermistor.

6 . The thermal foldback control circuit of claim 1 , wherein the regulator is a shunt regulator.

7 . The thermal foldback control circuit of claim 1 , wherein the regulator includes at least one selected from the group consisting of a Zener diode, an avalanche breakdown diode, and a voltage regulator tube.

8 . The thermal foldback control circuit of claim 1 , wherein the regulator decreases a drive current in response to the reference voltage crossing a predetermined threshold.

9 . The thermal foldback control circuit of claim 8 , wherein the predetermined threshold is related to a predetermined temperature at the reference point.

10 . The thermal foldback control circuit of claim 1 , wherein the reference point is located at at least one selected from the group consisting of the LED driver and an LED engine.

11 . The thermal foldback control circuit of claim 1 , further comprising a capacitor in a parallel-type configuration with a second resistance component providing the second resistance.

12 . A method of controlling power to one or more light emitting diodes (LEDs), the method comprising:
outputting, via a temperature-sensitive circuit, a control signal based on a first and second resistance; and controlling one or more LEDs based on the control signal; wherein the first and second resistances vary in response to the temperature.

13 . The method of claim 12 , wherein the temperature sensitive circuit includes
a voltage divider including
a first resistor component having the first resistance that varies in response to the temperature at the reference point,
a second resistor component having the second resistance that varies in response to the temperature at the reference point, and
a regulator in a parallel-type configuration with the voltage divider, the regulator configured to
receive a reference voltage from the voltage divider, and
output the control signal based on the reference voltage.

14 . The method of claim 12 , wherein the step of controlling the one or more LEDs includes
reducing power to the one or more LEDs when the temperature at the reference point crosses a predetermined threshold.

15 . The method of claim 14 , wherein the step of controlling the one or more LEDs includes
returning power to the one or more LEDs to a normal level when the temperature at the reference point is below the predetermined temperature threshold.

16 . The method of claim 12 , wherein the reference point is located at at least one selected from the group consisting of an LED driver and an LED engine.

Assignees

• Hubbell Inc

Inventors

• Bandel Michael W
• Lazalier Ray M

Classifications

• H05B33/0851 Primary

  Electricity · mapped topic

• H05B33/0809

  Electricity · mapped topic

• H05B33/0854

  Electricity · mapped topic

• H05B45/56

  involving measures to prevent abnormal temperature of the LEDs · CPC title

• H05B45/30

  Driver circuits · CPC title