A Time-to-Voltage Converter With Miller-Impedance Technique for Single-Photon Arrival Time-to-Digital Conversions

A low-power time-to-voltage converter (TVC) is composed of a reconfigurable current-mode integrator and a capacitive voltage holder specifically for random sampling-and-averaging (RSA) time-to-digital conversions (TDC) in time-correlated single-photon counting (TCSPC) systems. To accommodate the TVC circuit within each single-photon detection pixel for compact silicon-photonics integration, this paper exploits the Miller-impedance technique to demonstrate the leakage time-constant of the voltage holder being extended up to tens of milliseconds, which represents a more than 100× improvement in high-leakage 22-nm digital CMOS process technology, with only a 9-pF (36-μm × 36-μm) metal-finger hold capacitor and 120-μW power consumption.