JSC „Ledigma“ is working with the stability of the lighting output parameters. LEDs output parameters measurements and assessments are our daily work.
We create a high quality thermal feedback systems for multicolour solid-state lighting devices. Thermal stability and performance of the LEDs are measured using illumia®pro system (Labsphere Inc.).
We are using a Peltier cooler/heater to stabilize the pad temperature of the LED(s). Average LED current can be set in two ways: Constant current regulation (CCR) or Pulse-width modulation (PWM). Pulse-frequency modulation (PFM) is not used due to the lack of practical implementation.
Spectral power distributions dependence on the average currents and pad temperatures allows us to model a thermal feedback systems for stabilizing light source output parameters (such as white point colour coordinate, radiant or luminous flux, etc.).