A ±4-A High-Side Current Sensor With 0.9% Gain Error From −40 °C to 85 °C Using an Analog Temperature Compensation Technique

Abstract

This paper presents a fully integrated shunt-based current sensor that supports a 25-V input common-mode range while operating from a single 1.5-V supply. It uses a high-voltage beyond-the-rails ADC to directly digitize the voltage across an on-chip shunt resistor. To compensate for the shunt's large temperature coefficient of resistance (~0.335%/°C), the ADC employs a proportional-to-absolute-temperature voltage reference. This analog compensation scheme obviates the need for the explicit temperature sensor and calibration logic required by digital compensation schemes. The sensor achieves 1.5-V noise over a 2-ms conversion time while drawing only 10.9 μA from a 1.5-V supply. Over a ±4-A range, and after a one-point trim, the sensor exhibits a 0.9% (maximum) gain error from -40 °C to 85 °C and a 0.05% gain error at room temperature.