Temperature-Aware Adaptive Control for Automotive Front-Lighting System

• Published in: IEEE access 2022, Vol.10, p.73269-73277
• Main Authors: Lee, Jiseong, Kwak, Seung Soo, Kim, Yong Sin
• Format: Article
• Language: English
• Subjects: active-matrix; Adaptive control; Adaptive front-lighting systems; Adaptive systems; Arrays; Calibration; Control systems; Integrated circuits; Light emitting diodes; Light sources; Lighting; Maximum power; over temperature protection; Power efficiency; Power management; Pulse duration modulation; Pulse width modulation; smart headlamp; Temperature sensors; Vehicles
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2022.3189176

Adaptive front-lighting systems (AFSs) have been widely adopted to automotive industries for providing higher driver's safety. As their light sources, multi-string light-emitting diodes (LED) arrays have been widely adopted because of their simpler driver controls. Recently, micro-structured AFSs ( \mu AFSs) with a micro-LED ( \mu LED) array are highly demanded for their controllability of individual LEDs. However, the integration of a \mu LED array and its high-power active-matrix driver are not available on the market. Moreover, a high-power driver causes not only a significant variation in driving current, but also a higher power density requiring over-temperature protection (OTP). In this paper, the average current through each \mu LED is adaptively controlled with pulse width modulation (PWM) in conjunction with an additional PWM control for temperature calibration. Experimental results with a 16 \times 16\,\,\mu LED array placed on top of the proposed driver show that a 5-bit PWM signal controls the average current through each \mu LED cell up to 11 mA. The maximum current error of 4.11% at 100 °C is reduced to 0.23%. When OTP is enabled, the amount of average pixel current reduction depends on the given temperature. The maximum power efficiency of the proposed \mu AFSs driver is as high as 92.3%.