Temperature-controlling system for high power LEDs based on semiconductor coolers

Semiconductor refrigeration was used for heat dissipation of high power LEDs. A practical temperature-controlling system was designed and built with a microcontroller unit (STC89C52) and a thermoelectric cooling module (TEC1-12703) as the core components. Functions including temperature measurement, display, setup, and control were realized. PWM (pulse width modulation) was applied to regulate the driving current of the thermoelectric cooler. Effective refrigeration and temperature control were thus achieved. This system was used for the temperature control of a LED module with the power of 7×3 W. When the environment temperature was 22～25 ℃, the substrate temperature of the LED module could be stabilized in the range of 40～70 ℃. If the upper and lower temperature limits of the LED substrate were set to be 64 ℃and 65 ℃, respectively, the power consumed by thermoelectric cooling was only 27% of that consumed by the LEDs. The temperature-controlling system had a high cooling speed (up to 14 ℃/min) and small temperature fluctuation (only ±0.5 ℃). It fulfilled the requirements for LED temperature control and could be used for many other applications