A Galvanic Isolated Amplifier Based on CMOS Integrated Hall-Effect Sensors

A novel galvanic isolated amplifier based on CMOS integrated Hall sensors is presented in this paper. Two serially connected Hall-effect sensors are integrated along with their instrumentation amplifiers using the TSMC 65nm process. A printed-circuit board is employed to validate the proposed isolation amplifier by assembling the chip with chopper modulator, coil driver, miniature coil, variable gain amplifier, and anti-aliasing filter. Because of the miniaturized size of isolation components, this approach can be packaged in chip for industrial applications. This solution replaces the need of bulky/frequency dependent current transformers, complex isolation amplifiers with embedded analog to digital converters, and allows proposed sensors to be used in voltage and current sensing applications. The introduced prototype achieves an input referred offset of 1 mV, 50 dB full-scale signal-to-noise ratio in a 10 kHz bandwidth, and spurious-free dynamic range of 53 dB, while satisfying continuous isolation working voltage of 550 V.