This article presents a cost-effective, fully integrated shunt-resistor-based in-line current sensor that delivers high linearity and strong PWM rejection, enabling precise current measurement and control in dynamic driving systems like robotics, imaging, and audio. To mitigate the self-heating of the on-chip shunt resistor, which degrades linearity, a location-based thermal compensation technique is proposed. This technique reduces self-heating-induced distortion, improving THD+N by up to 23.6 dB over the full operating range without calibration. In addition, a floating transconductance (FG_m) stage is introduced to reject the high dv/dt, high-voltage PWM components at the switching node of the power stage, enabling robust current sensing with this PWM common mode voltage. The prototype is implemented in a 180 nm BCD process and demonstrates a peak THD+N of–87.2 dB and a dynamic range (DR) of 89.1 dB. It achieves up to 2 MHz, 14.4 V PWM rejection with 2 V/ns dv/dt, and supports a ±6 A bidirectional current range.

Floating-G_m-based current sensors are effective in rejecting PWM common-mode voltage. But their linearity drops at high voltages due to substrate-current-induced body effect in LDMOS devices. To address this issue, this work introduces a DLL-assisted dynamic body biasing sensor in 0.18μm BCD, improving HD2 by 31dB and THD+N by 14dB. And a peak THD+N of -82.3dB is achieved in the meanwhile. It supports 60V common-mode, rejects PWM up to 2MHz, and enables high-linearity sensing for high power audio and motor-driver systems.