Abstract
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.
Original language | English |
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Pages (from-to) | 264 - 267 |
Number of pages | 4 |
Journal | IEEE Solid-State Circuits Letters |
Volume | 5 |
DOIs | |
Publication status | Published - 2022 |
Bibliographical note
Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-careOtherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Keywords
- coulombcounting
- current sensor
- FIR-DAC
- Fully-integrated
- high-side
- hybrid delta-sigma modulator
- on-chip shunt resistor
- PCB trace shunt resistor