An active feedback coefficient tuning technique for compensating time-constant variations in continuous-time delta-sigma modulators
- We propose a novel technique to compensate the effects of R-C / gm-C time-constant (TC) errors due to process variation in continuous-time delta-sigma modulators. Local TC error compensation factors are shifted around in the modulator loop to positions where they can be implemented efficiently with tunable circuit structures, such as current-steering digital-to-analog converters (DAC). This approach constitutes an alternative or supplement to existing compensation techniques, including capacitor or gm tuning. We apply the proposed technique to a third-order, single-bit, low-pass continuous-time delta-sigma modulator in cascaded integrator feedback structure. A feedback path tuning scheme is derived analytically and confirmed numerically using behavioral simulations. The modulator circuit was implemented in a 0.35-μm CMOS process using an active feedback coefficient tuning structure based on current-steering DACs. Post-layout simulations show that with this tuning structure, constant performance and stable operation can be obtained over a wide range of TC variation.
Author of HS Reutlingen | Wolfer, Tobias; Hennig, Eckhard |
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DOI: | https://doi.org/10.1109/APCCAS51387.2021.9687676 |
ISBN: | 978-1-6654-3916-9 |
Erschienen in: | 2021 IEEE Asia Pacific Conference on Circuit and Systems (APCCAS), 22-26 November 2021, Pulau Pinang, Malaysia, proceedings |
Publisher: | IEEE |
Place of publication: | Piscataway, NJ |
Document Type: | Conference proceeding |
Language: | English |
Publication year: | 2022 |
Tag: | RLC circuits; delta-sigma modulation; digital-analog conversion; error compensation; modulation; numerical models; semiconductor device modeling |
Page Number: | 4 |
DDC classes: | 600 Technik |
Open access?: | Nein |
Licence (German): | In Copyright - Urheberrechtlich geschützt |