Determining the LEDs junction temperature as a function of forward voltage in given operating conditions

Abstract

High-power LEDs have many advantages for use in lighting systems. To benefit from these advantages we need to ensure proper heat management. In this paper forward voltage variation is studied as a function of ambient temperature variation at the same supply current. The aim of the study is to estimate the junction temperature as a function of ambient temperature and forward voltage. Two types of LEDs are analyzed (18W COB (chip on board) type and 1W) at different operating temperatures. The concept is not new but the temperature range for which measurements were performed includes temperatures lower than 25 ° C and even temperatures below zero; also one of the LEDs is COB. The results are presented and analyzed.