Singer, Julian A.Julian A.SingerGeläschus, AntonAntonGeläschusSchmidt, UteUteSchmidtBahr, AndreasAndreasBahrKuhl, MatthiasMatthiasKuhlLi, QiangQiangLi2026-06-152026-06-152026-04IEEE Custom Integrated Circuits Conference, CICC 2026https://hdl.handle.net/11420/63505Continuous monitoring of oxygen concentration in biological tissue is critical for adaptive therapies and long-term implant diagnostics. This work presents a heterogeneously integrated photoluminescent oxygen sensing system combining CMOS single-photon avalanche diodes (SPADS) with pulse- and current-controllable micrometer-sized LEDs (μLEDs) die-bonded onto the chip. A single-step encapsulation using an optically active polymer integrates both the sensing and protecting layers. The system achieves a concentration resolution of 0.03 to 0.5 % O2 with an energy consumption of 73.4 nJ per measurement at up to 6.6 ksps, outperforming state-of-the-art systems by 3x in accuracy, 20x in sampling rate, and requiring only one-third of the power.enCMOS sensor integrationLED driver circuitsphotoluminescence lifetime sensingSingle-photon avalanche diode (SPAD)Natural Sciences and Mathematics::537: Electricity and ElectronicsNatural Sciences and Mathematics::572: BiochemistryConference Paper10.1109/CICC65509.2026.11509508