An Incremental Zoom ADC Readout IC and FPGA-Based Digital Calibration System for High-Precision Capacitive Pressure Sensors

Abstract

This work presents an incremental zoom analog-to-digital converter (ADC) readout integrated circuit (IC) and field-programmable gate array (FPGA)-based digital calibration system for high-precision capacitive micro electro-mechanical system (MEMS) pressure sensors, aimed at enhancing pressure readout resolution, pressure measurement accuracy, and long-term output stability. In the readout IC, the zoom ADC employs coarse-fine quantization, achieving high readout accuracy while relaxing requirements on integrator output swing and front-end linearity. On the digital side, a sparrow-search-algorithm-optimized Gaussian process regression (SSA-GPR) model constructs a nonlinear pressure–temperature mapping with limited calibration samples, while a segmented aging-compensation scheme based on dual-channel periodic self-test dynamically corrects aging-induced offset and sensitivity drifts. Together, these three techniques form a complete signal-conditioning chain addressing weak capacitance variation readout, pressure–temperature coupling, and long-term drift. Measured results show 0.11 PaRMS output root mean square (RMS) noise under a 205.2 ms conversion time, 37.44 Pa mean absolute error over −40 °C to 85 °C and 30 kPa to 120 kPa, and ±30 Pa residual error after 85 °C/1000 h aging, confirming the effectiveness of the proposed readout IC and digital calibration system.