A Hybrid Magnetic Current Sensor With a Multiplexed Ripple-Reduction Loop

Journal article (2023)

Authors

A. Jouyaeian Electronic Instrumentation - EEMCS
Q. Fan Microelectronics
R.L. Brito Zamparette Electronic Instrumentation - EEMCS
Udo Ausserlechner Infineon Technologies AG
Mario Motz Infineon Technologies AG
K.A.A. Makinwa Microelectronics
Research Group
Electronic Instrumentation (EEMCS) (TU Delft)
Copyright: © 2023 A. Jouyaeian, Q. Fan, R.L. Brito Zamparette, Udo Ausserlechner, Mario Motz, K.A.A. Makinwa
DOI: https://doi.org/10.1109/JSSC.2023.3273389
Temperature compensation Wide bandwidth Galvanic isolation Hybrid current sensors Magnetic current sensing Ripple-reduction loop (RRL)
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Published Date

2023

Language

English

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Electronic Instrumentation

Abstract

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.