A Microcontroller-based Compensation of High-power LED Controller in Active Infrared Thermography

Abstract

The main goal of the study is to apply frequency compensation on a voltage-controlled current source LED driver and to correct the control voltage to achieve faster impulse response and more linear control of the power LED. The output current is precisely measured using accurate resistive shunt and RMS-to-DC converter. Using the converter eliminates the measurement error even in the scenario of high output current ripple. The compensation delivers higher bandwidth and more linear phase response. This increases possibilities for using of power LED as an excitation source for active thermography in case of higher modulation frequency and non-sinusoidal waveform of modulating signal.