This brief presents a current to digital convertor (CDC) with low power, wide dynamic range and fast conversion speed. Proposed coarse converter extends the maximum input current range, and achieves fast conversion speed with the input adaptive control scheme. Capacitive transimpedance amplifier (CTIA) based fine converter digitizes the residue current and achieves fine resolution. Proposed mixed-signal coarse-fine subrange normalization technique enables seamless processing of the final converter output. The proposed CDC implemented in 0.18μm CMOS process converts input current up to 512μA with 7.8125nA resolution and 400μs conversion time. Power consumption is 79.4 μW.
This work was supported by the National Research Foundation (NRF) of Korea under Grant 2022M3H4A1A03067131, Grant 2021R1A2C4002496, Grant 2020M3F3A2A01082593, and Grant 2019R1A5A1027055. This brief was recommended by Associate Editor S.-W. Sin. The EDA tools were supported by IDEC.
