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.

@en

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.

@en

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.

@en

This article presents a versatile shunt-based current sensor for battery management applications. It digitizes the current-induced voltage drop across an external shunt resistor with the help of a 2 nd -order delta-sigma ( ΔΣ ) ADC, whose summing node is implemented as a low-noise capacitively coupled amplifier. To compensate for the shunt’s finite temperature coefficient (TC), the TC of the ADC on-chip voltage reference can be tuned. As a result, the sensor maintains high accuracy when used with low-cost high TC shunts, such as PCB traces, as well as with more expensive low TC shunts, such as metal-alloy resistors. Optimal gain flatness over temperature is achieved by a two-current room-temperature TC tuning scheme, which exploits the shunt’s self-heating at high current levels. Fabricated in a standard 0.18- μ m CMOS process, the current sensor occupies 0.36 mm 2 and draws 265 μ A from a 1.8-V supply. Over the industrial temperature range ( − 40 ∘ C to 85 ∘ C) and a ± 25-A current range, it achieves the state-of-the-art gain error ( ± 0.25%) with both PCB (1.6 m Ω ) and metal-alloy (2 m Ω ) shunts. With these shunts, it achieves 5.3-mA/4.3-mA (rms) resolution in a 10-kHz bandwidth.@en

Accurate current sensing is critical in many industrial applications, such as battery management and motor control. Precise shunt-based current sensors have been reported with gain errors of less than 1% over the industrial temperature range (-40°C to 85°C) [1]–[4]. However, since they are intended for coulomb counting, their bandwidth is limited to a few tens of Hz, making them unsuitable for battery impedance or motor-current sensing. This paper presents a current sensor with a wide (10kHz) bandwidth and a tunable temperature compensation scheme (TCS), which allows it to be flexibly used with different types of shunts while maintaining high accuracy. A low-cost room-temperature calibration scheme is proposed to optimize gain flatness over temperature by exploiting the shunt's self-heating at large currents. Over the industrial temperature range and a ±25A current range, it achieves state-of-the-art gain error (±0.25^%) with both low-cost PCB and stable metal-alloy shunts.@en

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.

@en

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.

@en