A 140 dB equivalent dynamic range receiver interface for an infrared rain-sensing IC

A receiver interface for automotive infrared rain-sensing application is described which uses multi-scale ΔΣ A/D conversion and digital closed-loop compensation to achieve a dynamic range from 1.5nA to 14mA. It compensates ambient current from 14mA down to 1μA within 56μsec and accommodates an infrared pulse within 32μsec. The receiver is designed to operate synchronized with a transmitter to build an infrared light measurement system. The active area of the receiver is 2.75mm
²
including 1mm
²
of digital circuitry in 0.35μm CMOS.