Author(s): Li, Fanyang; Yin, Tao; Yang, Haigang

Source: SENSORS Volume: 21 Issue: 14 Article Number: 4627 DOI: 10.3390/s21144627 Published: JUL 2021

Abstract: This paper presents an output offset minimized capacitance-to-digital interface for a MEMS accelerometer. With a gain-enhanced voltage-controlled oscillator (VCO)-based quantization loop, the interface is able to output a digital signal with improved dynamic range. For optimizing the output offset caused by nonideal factors (e.g., the bond-wire drift), a nested digital chopping feedback loop is embedded in the VCO-based quantization loop. It enables the interface to minimize the output offset without digital filtering and digital-to-analog conversion. The proposed architecture is well suited for dynamic range and offset improvements with low cost. Fabricated with a 0.18 mu m Global Foundry (GF) CMOS process, the interface offers a 78 dB dynamic range with 0.4% nonlinearity from a single 2 V supply. With the input referred offset up to 1.3 pF, the offset cancellation loop keeps the DC output offset within 40 mV. The power dissipation is 6.5 mW with a bandwidth of 4 kHz.

Accession Number: WOS:000676936000001

eISSN: 1424-8220

Full Text: https://www.mdpi.com/1424-8220/21/14/4627