Verification of an active time constant tuning technique for continuous-time delta-sigma modulators
- In this work we present a technique to compensate the effects of R-C / g m -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 finely tunable circuit structures, such as current-steering digital-to-analog converters (DAC). We apply our technique to a third-order, single-bit, low-pass continuous-time delta-sigma modulator in cascaded integrator feedback structure, implemented in a 0.35-μm CMOS process. A tuning scheme for the reference currents of the feedback DACs is derived as a function of the individual TC errors and verified by circuit simulations. We confirm the tuning technique experimentally on the fabricated circuit over a TC parameter variation range of ±20%. Stable modulator operation is achieved for all parameter sets. The measured performances satisfy the expectations from our theoretical calculations and circuit-level simulations.
Author of HS Reutlingen | Hennig, Eckhard; Wolfer, Tobias |
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DOI: | https://doi.org/10.1109/SMACD55068.2022.9816223 |
ISBN: | 978-1-6654-6703-2 |
Erschienen in: | 2022 18th International Conference on Synthesis, Modeling, Analysis and Simulation Methods and Applications to Circuit Design (SMACD), 12-15 June 2022, Villasimius, Italy, proceedings |
Publisher: | IEEE |
Place of publication: | Piscataway, NJ |
Document Type: | Conference proceeding |
Language: | English |
Publication year: | 2022 |
Tag: | CMOS process; DAC; active time constant tuning technique; cascaded integrator feedback structure; continuous-time delta-sigma modulator; current-steering digital-to-analog converters; individual TC errors; local TC error compensation factors; modulator loop; process variation; reference currents; time-constant errors |
Page Number: | 4 |
DDC classes: | 600 Technik |
Open access?: | Nein |
Licence (German): | In Copyright - Urheberrechtlich geschützt |