A Direct Current-Sensing VCO-Based 2nd-Order Continuous-Time Sigma-Delta Modulator for Biosensor Readout Applications.
In: IEEE transactions on biomedical circuits and systems, Jg. 18 (2024-04-01), Heft 2, S. 288-298
Online
academicJournal
Zugriff:
A second-order voltage-controlled oscillator (VCO)-based continuous-time sigma-delta modulator (CTSDM) for current-sensing readout applications is proposed. Current signals from the sensor can directly be quantized by the proposed VCO-based CTSDM, which does not require any extra trans-impedance amplifiers. With the proportional-integral (PI) structure and a VCO phase integrator, the capability of second-order noise shaping is available to reduce the in-band quantization noise. The PI structure can be simply realized by a resistor in series with the integrating capacitor, which can reduce the architecture complexity and maintain the stability of the system. The current-steering digital-to-analog converter with tail and sink current sources is used on the feedback path for the subtraction of the current-type input signal. All the components of the circuit are scaling friendly and applicable to current-sensing readout applications in the Internet of Things (IoT). The proposed VCO-based CTSDM implemented in a 0.18-μm standard CMOS process has a measured signal-to-noise and distortion ratio (SNDR) of 74.6 dB at 10 kHz bandwidth and consumes 44.8 μw only under a supply voltage of 1.2 V, which can achieve a Figure-of-Merit (FoM) of 160.76 dB.
Titel: |
A Direct Current-Sensing VCO-Based 2nd-Order Continuous-Time Sigma-Delta Modulator for Biosensor Readout Applications.
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Autor/in / Beteiligte Person: | Lee, SY ; Hsieh, YT ; Lee, HY ; Chang, SS ; Chen, JY |
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Zeitschrift: | IEEE transactions on biomedical circuits and systems, Jg. 18 (2024-04-01), Heft 2, S. 288-298 |
Veröffentlichung: | New York, NY : IEEE, c2007-, 2024 |
Medientyp: | academicJournal |
ISSN: | 1940-9990 (electronic) |
DOI: | 10.1109/TBCAS.2023.3322901 |
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