A 1.2 V–20 V Closed-Loop Charge Pump for High Dynamic Range Photodetector Array Biasing

Abstract

Ultra-high dynamic range optical sensing is achieved by operating a CMOS photodiode or imager alternately in linear and single-photon avalanche modes, which requires reverse bias from low voltage to above junction breakdown voltage for the process. To address this need, this brief presents a reconfigurable, closed-loop charge pump generating regulated output voltage from 1.2 to 20 V fabricated in a standard 0.18- ${\mu }\text{m}$ CMOS process. The dual-mode dc–dc converter architecture demonstrates maximum efficiency of 34% in high-voltage mode (>10 V) and 56% in low-voltage mode (<5 V) to provide efficient detector bias for both linear and single-photon operation. The charge pump demonstrates 960 ns recovery of 60 mV voltage droop at 11.9 V when biasing a CMOS-integrated single-photon avalanche diode device with an emulated array capacitance equivalent of 68 pF.