A Review on Frequency Compensation and Transient Enhancement Schemes of Flipped Voltage Follower LDO Regulators for SoC Applications

The low dropout (LDO) regulator is an essential circuit in the wireless power module of any portable device. The power management integrated circuits demand low power, high performance LDO regulator. Designing the LDO regulators for the desired performance parameters is challenging since it has desi...

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Main Authors: P. Manikandan, B. Bindu
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Access
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Online Access:https://ieeexplore.ieee.org/document/10849570/
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author P. Manikandan
B. Bindu
author_facet P. Manikandan
B. Bindu
author_sort P. Manikandan
collection DOAJ
description The low dropout (LDO) regulator is an essential circuit in the wireless power module of any portable device. The power management integrated circuits demand low power, high performance LDO regulator. Designing the LDO regulators for the desired performance parameters is challenging since it has design trade-offs. The power reduction is one main design challenge in the LDO to make it suitable for low-power, high-performance applications. The output capacitor-less LDOs are attractive for system-on-chip (SoC) applications, however the removal of the external capacitor degrades its stability and transient responses. The flipped voltage follower (FVF) output capacitor-less LDO regulators gained attention due to its superior transient performance with less power, as this structure demands lesser quiescent current to achieve the same transient response compared to the conventional LDOs. To our knowledge, the FVF LDOs in terms of transient enhancement schemes and stability techniques are not yet reviewed to understand the challenges in these LDO designs to suit for SoC applications. This paper provides a comprehensive study of different types of FVF low dropout regulators, the compensation circuits used in these LDOs for the stability of feedback loop and different transient enhancement schemes to improve the settling time and to reduce the output voltage spikes. A capacitor-less FVF LDO regulator with improved settling time and PSR is proposed in this paper. The transient performance of the FVF LDOs are measured based on the figure of merits and stability in terms of the phase margin. The proposed FVF LDO achieves a settling time of <inline-formula> <tex-math notation="LaTeX">$100 \ ns$ </tex-math></inline-formula> and PSR of <inline-formula> <tex-math notation="LaTeX">$-31\ dB\text{@}1\ MHz$ </tex-math></inline-formula>. The design challenges of FVF LDOs to achieve the required specifications to use for wireless power module of battery-operated devices are also discussed.
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spelling doaj-art-0170d3ac241a45d1904b68c11bf9eab32025-01-29T00:00:53ZengIEEEIEEE Access2169-35362025-01-0113161501617010.1109/ACCESS.2025.353276110849570A Review on Frequency Compensation and Transient Enhancement Schemes of Flipped Voltage Follower LDO Regulators for SoC ApplicationsP. Manikandan0https://orcid.org/0000-0002-7583-4742B. Bindu1https://orcid.org/0000-0002-9274-6883School of Electronics Engineering, Vellore Institute of Technology, Chennai, Tamil Nadu, IndiaCentre for Nanoelectronics and VLSI Design, Vellore Institute of Technology, Chennai, Tamil Nadu, IndiaThe low dropout (LDO) regulator is an essential circuit in the wireless power module of any portable device. The power management integrated circuits demand low power, high performance LDO regulator. Designing the LDO regulators for the desired performance parameters is challenging since it has design trade-offs. The power reduction is one main design challenge in the LDO to make it suitable for low-power, high-performance applications. The output capacitor-less LDOs are attractive for system-on-chip (SoC) applications, however the removal of the external capacitor degrades its stability and transient responses. The flipped voltage follower (FVF) output capacitor-less LDO regulators gained attention due to its superior transient performance with less power, as this structure demands lesser quiescent current to achieve the same transient response compared to the conventional LDOs. To our knowledge, the FVF LDOs in terms of transient enhancement schemes and stability techniques are not yet reviewed to understand the challenges in these LDO designs to suit for SoC applications. This paper provides a comprehensive study of different types of FVF low dropout regulators, the compensation circuits used in these LDOs for the stability of feedback loop and different transient enhancement schemes to improve the settling time and to reduce the output voltage spikes. A capacitor-less FVF LDO regulator with improved settling time and PSR is proposed in this paper. The transient performance of the FVF LDOs are measured based on the figure of merits and stability in terms of the phase margin. The proposed FVF LDO achieves a settling time of <inline-formula> <tex-math notation="LaTeX">$100 \ ns$ </tex-math></inline-formula> and PSR of <inline-formula> <tex-math notation="LaTeX">$-31\ dB\text{@}1\ MHz$ </tex-math></inline-formula>. The design challenges of FVF LDOs to achieve the required specifications to use for wireless power module of battery-operated devices are also discussed.https://ieeexplore.ieee.org/document/10849570/Capacitorless LDOpower managementregulationstabilitySoCtransient response
spellingShingle P. Manikandan
B. Bindu
A Review on Frequency Compensation and Transient Enhancement Schemes of Flipped Voltage Follower LDO Regulators for SoC Applications
IEEE Access
Capacitorless LDO
power management
regulation
stability
SoC
transient response
title A Review on Frequency Compensation and Transient Enhancement Schemes of Flipped Voltage Follower LDO Regulators for SoC Applications
title_full A Review on Frequency Compensation and Transient Enhancement Schemes of Flipped Voltage Follower LDO Regulators for SoC Applications
title_fullStr A Review on Frequency Compensation and Transient Enhancement Schemes of Flipped Voltage Follower LDO Regulators for SoC Applications
title_full_unstemmed A Review on Frequency Compensation and Transient Enhancement Schemes of Flipped Voltage Follower LDO Regulators for SoC Applications
title_short A Review on Frequency Compensation and Transient Enhancement Schemes of Flipped Voltage Follower LDO Regulators for SoC Applications
title_sort review on frequency compensation and transient enhancement schemes of flipped voltage follower ldo regulators for soc applications
topic Capacitorless LDO
power management
regulation
stability
SoC
transient response
url https://ieeexplore.ieee.org/document/10849570/
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