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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

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 c...

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Detalles Bibliográficos
Autores principales: Li, Fanyang, Yin, Tao, Yang, Haigang
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8309490/
https://www.ncbi.nlm.nih.gov/pubmed/34300367
http://dx.doi.org/10.3390/s21144627
Descripción
Sumario: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.