A -87.2 dB THD+N 89.1 dB DR Fully-Integrated Shunt-Resistor-Based In-Line Current Sensor with up to 2 MHz 14.4 V PWM Rejection

This paper presents a cost-effective, fully-integrated shunt-resistor-based in-line current sensor offering high linearity and effective PWM rejection for audio applications. To mitigate the on-chip shunt resistor self-heating, which could severely compromise the linearity of the current sensor, a thermal compensation method is proposed and improves the THD+N by up to 23.6 dB. A floating Gm stage is proposed to reject highfrequency high-voltage (HV) PWM signals at the audio amplifier switching node. Implemented in a 180 nm BCD process, the prototype achieves a peak THD + N of −87.2 dB and a DR of 89.1 dB with up to 2 MHz, 14.4 V PWM rejection,