An Auto-Zero Stabilized Voltage Buffer with a Quiet Chopping Scheme and Constant Input Current

Thije Rooijers; Johan H. Huijsing; Kofi A.A. Makinwa

doi:10.1109/ISSCC.2019.8662437

An Auto-Zero Stabilized Voltage Buffer with a Quiet Chopping Scheme and Constant Input Current

Thije Rooijers, Johan H. Huijsing, Kofi A.A. Makinwa

Research output: Chapter in Book/Conference proceedings/Edited volume › Conference contribution › Scientific › peer-review

8 Citations (Scopus)

98 Downloads (Pure)

Abstract

The readout of high-impedance sensors and sampled voltage references [1] requires amplifiers that can achieve both low offset and low input current. Recently, it has been shown that this unique combination can be achieved by an auto-zero (AZ) stabilized buffer [2]. However, its low-frequency noise density is surd 5 times higher than the buffer's own white-noise voltage spectral density e _n . Furthermore, its input current is not constant, but varies significantly with the input voltage. To overcome the first issue, a chopped AZ stabilization loop with an optimized duty-cycle is proposed to bring the low-frequency noise density close to surd 2cdot {e}-{n}, the fundamental limit of an AZ stabilized amplifier. The second issue is solved by replacing the transmission-gate input switches used in [2] with NMOS switches and a constant Vgs drive. This keeps their charge injection constant over a wide input voltage range, and results in a constant input current.

Original language	English
Title of host publication	2019 IEEE International Solid-State Circuits Conference, ISSCC 2019
Editors	Jan van der Spiegel
Place of Publication	Piscataway, NJ
Publisher	IEEE
Pages	298-300
Number of pages	3
Volume	2019-February
ISBN (Electronic)	978-1-5386-8531-0
ISBN (Print)	978-1-5386-8532-7
DOIs	https://doi.org/10.1109/ISSCC.2019.8662437
Publication status	Published - 2019
Event	ISSCC 2019: IEEE International Solid-State Circuits Conference - San Francisco, CA, United States Duration: 17 Feb 2019 → 21 Feb 2019

Conference

Conference	ISSCC 2019
Country/Territory	United States
City	San Francisco, CA
Period	17/02/19 → 21/02/19

Bibliographical note

Session 18.3
Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care
Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Keywords

Low-frequency noise
Current measurement
Voltage measurement
MOS devices
Capacitors
Chopper (circuits)
Switches

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10.1109/ISSCC.2019.8662437

08662437Final published version, 360 KB

Cite this

@inproceedings{c29260496c1c45a68cc4b28ba4e6022d,

title = "An Auto-Zero Stabilized Voltage Buffer with a Quiet Chopping Scheme and Constant Input Current",

abstract = " The readout of high-impedance sensors and sampled voltage references [1] requires amplifiers that can achieve both low offset and low input current. Recently, it has been shown that this unique combination can be achieved by an auto-zero (AZ) stabilized buffer [2]. However, its low-frequency noise density is surd 5 times higher than the buffer's own white-noise voltage spectral density e n . Furthermore, its input current is not constant, but varies significantly with the input voltage. To overcome the first issue, a chopped AZ stabilization loop with an optimized duty-cycle is proposed to bring the low-frequency noise density close to surd 2cdot {e}-{n}, the fundamental limit of an AZ stabilized amplifier. The second issue is solved by replacing the transmission-gate input switches used in [2] with NMOS switches and a constant Vgs drive. This keeps their charge injection constant over a wide input voltage range, and results in a constant input current. ",

keywords = "Low-frequency noise, Current measurement, Voltage measurement, MOS devices, Capacitors, Chopper (circuits), Switches",

author = "Thije Rooijers and Huijsing, {Johan H.} and Makinwa, {Kofi A.A.}",

note = "Session 18.3 Green Open Access added to TU Delft Institutional Repository {\textquoteleft}You share, we take care!{\textquoteright} – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. ; ISSCC 2019 : IEEE International Solid-State Circuits Conference ; Conference date: 17-02-2019 Through 21-02-2019",

year = "2019",

doi = "10.1109/ISSCC.2019.8662437",

language = "English",

isbn = "978-1-5386-8532-7 ",

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editor = "{van der Spiegel}, Jan",

booktitle = "2019 IEEE International Solid-State Circuits Conference, ISSCC 2019",

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Rooijers, T , Huijsing, JH & Makinwa, KAA 2019, An Auto-Zero Stabilized Voltage Buffer with a Quiet Chopping Scheme and Constant Input Current. in J van der Spiegel (ed.), 2019 IEEE International Solid-State Circuits Conference, ISSCC 2019. vol. 2019-February, 8662437, IEEE, Piscataway, NJ, pp. 298-300, ISSCC 2019, San Francisco, CA, United States, 17/02/19. https://doi.org/10.1109/ISSCC.2019.8662437

An Auto-Zero Stabilized Voltage Buffer with a Quiet Chopping Scheme and Constant Input Current. / Rooijers, Thije ; Huijsing, Johan H.; Makinwa, Kofi A.A.
2019 IEEE International Solid-State Circuits Conference, ISSCC 2019. ed. / Jan van der Spiegel. Vol. 2019-February Piscataway, NJ: IEEE, 2019. p. 298-300 8662437.

Research output: Chapter in Book/Conference proceedings/Edited volume › Conference contribution › Scientific › peer-review

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AU - Rooijers, Thije

AU - Huijsing, Johan H.

AU - Makinwa, Kofi A.A.

N1 - Session 18.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

PY - 2019

Y1 - 2019

N2 - The readout of high-impedance sensors and sampled voltage references [1] requires amplifiers that can achieve both low offset and low input current. Recently, it has been shown that this unique combination can be achieved by an auto-zero (AZ) stabilized buffer [2]. However, its low-frequency noise density is surd 5 times higher than the buffer's own white-noise voltage spectral density e n . Furthermore, its input current is not constant, but varies significantly with the input voltage. To overcome the first issue, a chopped AZ stabilization loop with an optimized duty-cycle is proposed to bring the low-frequency noise density close to surd 2cdot {e}-{n}, the fundamental limit of an AZ stabilized amplifier. The second issue is solved by replacing the transmission-gate input switches used in [2] with NMOS switches and a constant Vgs drive. This keeps their charge injection constant over a wide input voltage range, and results in a constant input current.

AB - The readout of high-impedance sensors and sampled voltage references [1] requires amplifiers that can achieve both low offset and low input current. Recently, it has been shown that this unique combination can be achieved by an auto-zero (AZ) stabilized buffer [2]. However, its low-frequency noise density is surd 5 times higher than the buffer's own white-noise voltage spectral density e n . Furthermore, its input current is not constant, but varies significantly with the input voltage. To overcome the first issue, a chopped AZ stabilization loop with an optimized duty-cycle is proposed to bring the low-frequency noise density close to surd 2cdot {e}-{n}, the fundamental limit of an AZ stabilized amplifier. The second issue is solved by replacing the transmission-gate input switches used in [2] with NMOS switches and a constant Vgs drive. This keeps their charge injection constant over a wide input voltage range, and results in a constant input current.

KW - Low-frequency noise

KW - Current measurement

KW - Voltage measurement

KW - MOS devices

KW - Capacitors

KW - Chopper (circuits)

KW - Switches

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DO - 10.1109/ISSCC.2019.8662437

M3 - Conference contribution

AN - SCOPUS:85063488523

SN - 978-1-5386-8532-7

VL - 2019-February

SP - 298

EP - 300

BT - 2019 IEEE International Solid-State Circuits Conference, ISSCC 2019

A2 - van der Spiegel, Jan

PB - IEEE

CY - Piscataway, NJ

T2 - ISSCC 2019

Y2 - 17 February 2019 through 21 February 2019

ER -

An Auto-Zero Stabilized Voltage Buffer with a Quiet Chopping Scheme and Constant Input Current

Abstract

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Keywords

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