High ambient temperature LED luminaire with thermal compensation circuitry
The present disclosure provides a method for powering a light fixture to provide a constant light output. In one embodiment, the method includes providing a current to one or more light emitting diodes (LEDs), monitoring an external ambient temperature and increasing the current to the one or more LEDs as the external ambient temperature rises to maintain the constant light output.
1. A light emitting diode (LED) luminaire, comprising:
one or more LEDs having a maximum light output that is higher than a required light output for a particular application;
a housing enclosing the one or more LEDs;
a plurality of heat sink fins coupled to the housing to dissipate heat away from the housing in a vertical direction in a shape of a plume;
a temperature sensor located on an exterior side of the housing along a perimeter of the housing via a spacer;
an LED driver with a current control coupled to each one of the one or more LEDs and in communication with the temperature sensor, wherein the current control:
provides a current to the one or more LEDs that is less than a maximum current such that the current powers the one or more LEDs at a light output less than the maximum light output;
calculates an amount of makeup current based upon a linear relationship between the current and an external ambient temperature that is stored in a computer readable storage medium; and
increases the current to the one or more LEDs by the amount of makeup current that is calculated as the external ambient temperature rises to maintain a constant light output; and
an adapter to communicatively couple the temperature sensor to the LED driver, wherein the adapter comprises a threaded portion and a locking nut to couple an end of the adapter to an opening in the housing.
2. The LED luminaire of claim 1 , wherein the each one of the one or more LEDs is driven at a current less than a maximum current to power the each one of the one or more LEDs at a light output less than the maximum light output.
3. The LED luminaire of claim 1 , wherein the spacer comprises a non-conductive material.
4. The LED luminaire of claim 1 , further comprising:
a positive temperature coefficient thermistor coupled to the LED driver and the each one of the one or more LEDs.
5. A circuit for maintaining a constant light output of a light emitting diode (LED) having a maximum light output that is higher than a required light output for a particular application, the circuit comprising:
an LED driver with a current control coupled to the LED, wherein the current control provides a current to the LED that is less than a maximum current such that the current powers the LED at a light output less than the maximum light output, calculates an amount of makeup current based upon a linear relationship between the current and an external ambient temperature that is stored in a computer readable storage medium, and increases the current to the LED by the amount of makeup current that is calculated as the external ambient temperature rises to maintain a constant light output; and
a temperature sensing device coupled to the LED driver and the LED, wherein the temperature sensing device is located on an exterior side of a housing of the LED and along a perimeter of the housing via a spacer, wherein the housing comprises a plurality of heat skink fins that are shaped to dissipate heat away from the housing in a vertical direction in a shape of a plume.