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 highvoltage 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-μV rms 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.

A Current Monitoring and Over-Current Detection Circuit for Safe Electrical Stimulation

“…Depending on the placement of R S , there are two possible topologies: low-side current sensing [11] (Fig. 4a) and highside current sensing [12] (Fig. 4b).…”

Integrated Transceivers for Emerging Medical Ultrasound Imaging Devices: A Review

“…This requires an extra level-translator to drive the high-side PMOS relative to the HV supply (HVDD). It can be implemented using either a low-power capacitively-coupled latch, similar to [28], or a pull-up resistor in parallel with voltage-clamping diodes [8], [26]. Adding extra digital buffers between the level-translators and the gates of HV transistors helps to speed up switching [26], but requires a floating ground at the voltage of HVDD-V GS , where V GS is the gate-source voltage of the HV transistor.…”

A 2.5-µW Beyond-the-Rails Current Sensor With a Tunable Voltage Reference and ±0.6% Gain Error From −40 °C to +85 °C

“…It involves measuring and integrating battery current to determine the net influx of charge. Shunt-based current sensors are often used to achieve the required accuracy and dynamic range [1], [3], [5]. These should be configured for highside sensing to avoid adding extra resistance between the battery and the system ground.…”

“…Accurate current sensors often employ precision off-chip shunts. To reduce cost, metal shunts made from CMOS interconnect [3], lead-frame metal [4], or PCB traces [5] can also be used. However, they have two main disadvantages.…”

“…Although it achieves a gain error of 0.3% over the industrial temperature range (−40 • C to +85 • C), it requires a complex trimming scheme and consumes 20 μW. In [3], rather than directly measuring the shunt temperature, the TC of a metal shunt is compensated by applying a proportional-to-absolute-temperature (PTAT) voltage reference to the current sensor's ADC. However, it consumes 25 μW and only achieves a gain error of 0.9% with an on-chip metal shunt.…”