In-situ LED junction temperature monitoring using LED as temperature sensor

A method of determining temperature of an LED device during operation of the LED device, comprising:

• generating an LED drive signal;
• operating the LED device using the LED drive signal, thereby causing the LED device to emit light;
• and
• measuring a temperature of the LED device during operation thereof, comprising:
• generating an OFF period in the LED drive signal;
• and
• during the OFF period, applying at least a first forcing current to the LED device and obtaining a first voltage measurement of the LED device while driving the LED device with the first forcing current,
• wherein a temperature of the LED device is determined based at least on the first voltage measurement.

A method of operating an LED device based on a temperature thereof, comprising:

• generating an LED drive signal for operating the LED device, the LED drive signal including at least one OFF period;
• during the OFF period in the LED drive signal while operating the LED device:
• applying a first snoop current to the LED device;
• measuring a first forward voltage of the LED device;
• applying a second snoop current to the LED device;
• and
• measuring a second forward voltage of the LED device;
• determining a first temperature of the LED device based on the first and second forward voltages;
• determining a second temperature of the LED device based on a predetermined constant and either the first or the second forward voltage;
• and
• determining an arbitrated temperature of the LED device based at least on the first and second temperatures, wherein the LED drive signal is varied based on the arbitrated temperature.