A ±2A/15A Current Sensor with 1.4 μA Supply Current and ±0.35%/0.6% Gain Error From −40 to 85°C using an Analog Temperature-Compensation Scheme

Abstract

This paper presents a ±2A fully-integrated current sensor with a 20 mΩ on-chip shunt (resistor). It employs an energy-efficient hybrid sigma-delta ADC with an FIR-DAC and consumes only 1.4 μA, a 3× improvement on the state-of-the-art. A tunable analog non-linear temperature-compensation scheme (TCS) allows ±2A currents to be digitized with 0.35% gain error from −40 to 85°C. With a 3 mΩ PCB shunt, ±15A currents can be digitized with slightly more (0.6%) gain error. In a 0.18 μm CMOS process, the sensor occupies 1.6 mm2.