Current regulated LED driver with fast switch-off behavior for integrated optoelectronic implants

Citation
IEEE International Symposium on Circuits and Systems, ISCAS 2025
Contribution to Conference
IEEE International Symposium on Circuits and Systems, ISCAS 2025  
Publisher DOI
10.1109/ISCAS56072.2025.11043414
Scopus ID
2-s2.0-105010576714
Publisher
IEEE
ISBN
979-8-3503-5684-7
979-8-3503-5683-0
This paper presents a power, speed and area optimized mini-LED driver integrated in 180 nm CMOS HV process and capable of sinking up to 4mA current. It aims to cover various applications of optoelectronic implants with a single design. The current driver consists of a drain-regulated self-cascode current mirror. An additional carrier sweep-out circuit reduces the mini-LED voltage fall time down to 4.7 ns. The current can be digitally adjusted from 0.5 mA to 4 mA, depending on its use-case. The temperature-compensated current reference provides 0.01 mA with a temperature coefficient (TC) of 210 ppm/°C between -10 °C and 110 °C leading to a TC of 357 ppm/°C for the output current. The successfully performed measurements for circuit under pad constructs revealed a possible size reduction only limited by the dimensions of the on-die processed mini-LEDs of 0.1 mm x 0.2 mm.
Subjects
CMOS | current reference | integrated LED driver | level shifter | medical implant | mini-LED | optoelectronic
DDC Class
600: Technology