Power-Efficient Recycling Folded Cascode Operational Transconductance Amplifier Based on Nested Local Feedback and Adaptive Biasing

In this paper, we present a novel enhanced recycling folded cascode (ERFC) operational transconductance amplifier (OTA), which exhibits high efficiency and a fast transient response under weak inversion. Our innovative combination of adaptive biasing with nested local feedback (ABNLF) effectively en...

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Main Authors: Chunkai Wu, Peng Cai, Jinghu Li, Jin Xie, Zhicong Luo
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/25/8/2523
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author Chunkai Wu
Peng Cai
Jinghu Li
Jin Xie
Zhicong Luo
author_facet Chunkai Wu
Peng Cai
Jinghu Li
Jin Xie
Zhicong Luo
author_sort Chunkai Wu
collection DOAJ
description In this paper, we present a novel enhanced recycling folded cascode (ERFC) operational transconductance amplifier (OTA), which exhibits high efficiency and a fast transient response under weak inversion. Our innovative combination of adaptive biasing with nested local feedback (ABNLF) effectively enhances the input transconductance and slew rate (SR), thus improving the transient response. By incorporating coupling capacitors at the output stage, we achieve a stable operating region with large signal responses. Both the traditional RFC OTA and the proposed ERFC OTA were designed in a 0.18 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>m CMOS process, operating at a power supply of 1.8 V, with quiescent currents of 8 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>A and 10.4 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>A, respectively. Post-layout simulations reveal a remarkable enhancement in the proposed ERFC OTA over the traditional RFC OTA, with the SR and gain–bandwidth (GBW) surging by 120- and 5.95-fold, respectively. This advancement boosts the efficiency of the traditional RFC OTA and provides an impressive figure of merit (FoM) of 130.04 (V/<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>s)·pF/<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>A.
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publishDate 2025-04-01
publisher MDPI AG
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spelling doaj-art-8f43d09672ea4f659e9b98a09eb0a44b2025-08-20T02:18:10ZengMDPI AGSensors1424-82202025-04-01258252310.3390/s25082523Power-Efficient Recycling Folded Cascode Operational Transconductance Amplifier Based on Nested Local Feedback and Adaptive BiasingChunkai Wu0Peng Cai1Jinghu Li2Jin Xie3Zhicong Luo4School of Computer and Information Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, ChinaDepartment of Information and Electromechanical Engineering, Jinshan College, Fujian Agriculture and Forestry University, Fuzhou 350002, ChinaSchool of Computer and Information Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, ChinaSchool of Mechanical and Electrical Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, ChinaSchool of Mechanical and Electrical Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, ChinaIn this paper, we present a novel enhanced recycling folded cascode (ERFC) operational transconductance amplifier (OTA), which exhibits high efficiency and a fast transient response under weak inversion. Our innovative combination of adaptive biasing with nested local feedback (ABNLF) effectively enhances the input transconductance and slew rate (SR), thus improving the transient response. By incorporating coupling capacitors at the output stage, we achieve a stable operating region with large signal responses. Both the traditional RFC OTA and the proposed ERFC OTA were designed in a 0.18 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>m CMOS process, operating at a power supply of 1.8 V, with quiescent currents of 8 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>A and 10.4 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>A, respectively. Post-layout simulations reveal a remarkable enhancement in the proposed ERFC OTA over the traditional RFC OTA, with the SR and gain–bandwidth (GBW) surging by 120- and 5.95-fold, respectively. This advancement boosts the efficiency of the traditional RFC OTA and provides an impressive figure of merit (FoM) of 130.04 (V/<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>s)·pF/<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>A.https://www.mdpi.com/1424-8220/25/8/2523enhanced recycling folded cascode (ERFC)high efficiencytransient responseadaptive biasingnested local feedback technique
spellingShingle Chunkai Wu
Peng Cai
Jinghu Li
Jin Xie
Zhicong Luo
Power-Efficient Recycling Folded Cascode Operational Transconductance Amplifier Based on Nested Local Feedback and Adaptive Biasing
Sensors
enhanced recycling folded cascode (ERFC)
high efficiency
transient response
adaptive biasing
nested local feedback technique
title Power-Efficient Recycling Folded Cascode Operational Transconductance Amplifier Based on Nested Local Feedback and Adaptive Biasing
title_full Power-Efficient Recycling Folded Cascode Operational Transconductance Amplifier Based on Nested Local Feedback and Adaptive Biasing
title_fullStr Power-Efficient Recycling Folded Cascode Operational Transconductance Amplifier Based on Nested Local Feedback and Adaptive Biasing
title_full_unstemmed Power-Efficient Recycling Folded Cascode Operational Transconductance Amplifier Based on Nested Local Feedback and Adaptive Biasing
title_short Power-Efficient Recycling Folded Cascode Operational Transconductance Amplifier Based on Nested Local Feedback and Adaptive Biasing
title_sort power efficient recycling folded cascode operational transconductance amplifier based on nested local feedback and adaptive biasing
topic enhanced recycling folded cascode (ERFC)
high efficiency
transient response
adaptive biasing
nested local feedback technique
url https://www.mdpi.com/1424-8220/25/8/2523
work_keys_str_mv AT chunkaiwu powerefficientrecyclingfoldedcascodeoperationaltransconductanceamplifierbasedonnestedlocalfeedbackandadaptivebiasing
AT pengcai powerefficientrecyclingfoldedcascodeoperationaltransconductanceamplifierbasedonnestedlocalfeedbackandadaptivebiasing
AT jinghuli powerefficientrecyclingfoldedcascodeoperationaltransconductanceamplifierbasedonnestedlocalfeedbackandadaptivebiasing
AT jinxie powerefficientrecyclingfoldedcascodeoperationaltransconductanceamplifierbasedonnestedlocalfeedbackandadaptivebiasing
AT zhicongluo powerefficientrecyclingfoldedcascodeoperationaltransconductanceamplifierbasedonnestedlocalfeedbackandadaptivebiasing