Active pulse shaping circuit for bandwidth enhancement of high-brightness LEDs using GaN devices

摘要

HB-LED sources which generates high speed optical pulses are desired in applications such as Light Detection and Ranging (LiDAR) for Time-of-Flight (ToF) measurements and Visible Light Communications (VLC). Inherent optical bandwidth of HB-LEDs plays a major role in generating high speed optical pulse outputs. Pulse shaping the current flowing through HB-LEDs, is a technique used for their bandwidth enhancement. In this paper, a new active pulse shaping circuit that enhances the bandwidth of HB-LEDs by 3× is presented. In addition, this pulse shaping circuit employed with constant current output LED drivers provides illumination control of HB-LEDs. Further, realization of the proposed pulse shaping circuit with GaN-based HEMTs resulted in performance improvement.