Low-cost metal (e.g., PCB trace) shunts can be used to make accurate current sensors (< 1 % gain error) [1-3]. However, their reported maximum operating temperature (85 circC) is not high enough for automotive applications, and at higher temperatures, shunt resistance may exhibit increased drift, especially at high current levels. This paper presents a metal-shunt-based current sensor with a wide temperature range and a stable on-chip reference current (I textREF) source for shunt self-calibration. By employing a continuous-time (CT) front-end, it achieves an input noise density of 14textnV/sqrttextHz while consuming only 280mu A, making it > 10times more energy efficient than prior art [1], [2], with comparable gain error (pm0.2%) over a wider current (pm 40A) and temperature (-40 circC to 125 circC) range.

This article presents a hybrid magnetic current sensor for galvanically isolated measurements. It consists of a CMOS chip that senses the magnetic field generated by current flowing through a lead-frame-based current rail. Hall plates and coils are used to sense low-frequency (dc to 10 kHz) and high-frequency (10 kHz to 5 MHz) magnetic fields, respectively. With the help of on- chip calibration coils, the biasing current of the Hall plates is trimmed to match the sensitivity of the Hall and coil signal paths. The sensitivity drift of the coil path with temperature is compensated by using temperature-dependent gain-setting resistors, while the drift of the Hall path is compensated by biasing the Hall plates with a proportional- to-absolute-temperature (PTAT) current. The resulting sensitivity drift is less than 9% from-40 °C to 80 °C. The offset of the Hall plates is reduced by the current spinning technique, and the resulting ripple is suppressed by a multiplexed ripple-reduction loop (MMRL). Fabricated in a standard 0.18-μm CMOS process, the current sensor occupies 4.6 mm2 and draws 7.8 mA from a 1.8-V supply. It achieves a gain variation of only ±2% in a 5-MHz BW. It also achieves high energy efficiency, with an figure of merit (FoM) of 1.6 fW/Hz.

This paper presents a nano-power high-side shunt-based current sensor (CS) that digitizes the voltage drop across an on-chip (±1A) or a lead-frame (±30A) shunt. A TC-tunable ADC reference compensates for the shunts' large temperature coefficient (TC), resulting in ±0.5% gain error from -40 to 85°C. The CS employs a capacitively coupled gm-boosted front-end followed by a CCO-based Δ Σ ADC. Together with a floating input chopper, this results in an input common-mode range (ICMR) of 0-to-15V, the largest reported for a CS implemented in a standard CMOS process. It achieves high energy efficiency (164dB FoM) while consuming only 720nW, representing a 4 × improvement on the state-of-the-art and making this the first ever reported sub-μ W smart current sensor.

This letter presents a low-power, fully integrated current sensor for Coulomb-counting. It employs a hybrid delta–sigma modulator ( ΔΣM ) with an FIR-DAC to digitize the voltage drop across a shunt. The modulator’s first stage consists of a capacitively coupled chopper amplifier, which enables a beyond-the-rails (−0.3 to 5 V) input common-mode voltage range from a 1.8-V supply. A tunable voltage reference is used to accurately compensate for the large temperature coefficient ( ∼3500 ppm/°C) of low-cost metal shunts. With a 20- mΩ on-chip shunt, ±2 A currents can be digitized with 0.35% gain error from −40°C to 85°C, after a 1-point trim. With a 3- mΩ PCB trace, currents up to ±15 A can be digitized with 0.6% gain error over the same temperature range. Fabricated in a standard 0.18- μm CMOS process, the sensor occupies 1.6 mm2 and consumes 2.5 μW , which is 3× less than the state of the art. It also achieves competitive energy efficiency, with a figure of merit (FoM) of 149 dB.

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.