A Bond-Wire Drift Offset Minimized Capacitance-to-Digital Interface for MEMS Accelerometer with Gain-Enhanced VCO-Based Quantization and Nested Digital Chopping Feedback Loops

Sensors

Fanyang Li¹  Tao Yin²  Haigang Yang³ 

[1] Fujian Province Integrated Circuit Design Center, Fuzhou University, Fuzhou 350108, China;Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;School of Microelectronics, University of Chinese Academy of Sciences, Beijing 100049, China;

关键词: MEMS;    accelerometer;    VCO;    digital chopping;    offset;    bond-wire;   

DOI  :  10.3390/s21144627

来源: DOAJ

【 摘 要 】

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 μm 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.

【 授权许可】

Unknown