A low-voltage regulator circuit with self-bias to improve accuracy

Balan, Vishnu

doi:10.1109/jssc.2002.807396

Cited by 24 publications

(7 citation statements)

References 3 publications

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“…That way, the input impedance of the diode connected transistor tracks the load impedance to facilitate the frequency compensation over a large dynamic range [3]. When an adaptive biasing scheme [5], [14], [15] is applied, it helps to achieve a better trade-off between the quiescent current and the dynamic response of the regulator. Fig.…”

Section: Introductionmentioning

confidence: 99%

A Hybrid-Mode Operational Transconductance Amplifier for an Adaptively Biased Low Dropout Regulator

Maity

Patra

2017

IEEE Trans. Power Electron.

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This paper presents a hybrid mode, operational trans-conductance amplifier (HM-OTA) to improve the dynamic response of an adaptively biased low dropout regulator (AB-LDR) while maintaining a low quiescent current. Using the proposed HM-OTA in the AB-LDR, we can achieve higher dc-gain and wider loop bandwidth compared to a conventional current mode OTA (CM-OTA). Additionally, the proposed HM-OTA provides a high discharging slew-rate at the gate of the PMOS power transistor during a low-to-high load step. So, the proposed HM-OTA helps to achieve a good dc load regulation as well as a reduced undershoot during load transient. At the same time, the regulator requires a small value of the output capacitor for achieving the loop stability compared to the conventional differential mode OTA (DM-OTA). The conventional CM-OTA and the DM-OTA turn out to be special cases of the proposed HM-OTA which does not occupy extra space in silicon or consume additional power to realize. The AB-LDR using the proposed HM-OTA has been implemented in 0.18-µm CMOS technology. The regulator consumes a quiescent current of 1.6-µA at the no load condition with a transient variation of 24 mV at V o =1.2 V for 0-50 mA of load step with a 1-µF output capacitor.Index Terms-Low dropout regulator, operational transconductance amplifier (OTA), current mirror, adaptive biasing. Ashis Maity (S'15) received his BE degree from

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Section: Introductionmentioning

confidence: 99%

A Hybrid-Mode Operational Transconductance Amplifier for an Adaptively Biased Low Dropout Regulator

Maity

Patra

2017

IEEE Trans. Power Electron.

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“…Therefore, it is a major challenge to achieve the transient specifications with a low quiescent current [19]. Different biasing philosophies like constant biasing [20], [21], dynamic biasing [22], [23] and adaptive biasing [24]- [27] are adopted in various regulator topologies. In constant biasing, Ashis the bias current of the regulator is fixed and independent of the load current.…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of an Adaptively Biased Low-Dropout Regulator Using Enhanced Current Mirror Buffer

Maity

Patra

2016

IEEE Trans. Power Electron.

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This paper presents an adaptively biased, low dropout regulator (AB-LDR) using an enhanced current mirror (ECM) buffer for effectively driving the gate of the PMOS power transistor. The proposed ECM buffer offers very low output impedance which pushes out the pole at the gate of the PMOS power transistor to improve the stability. At the same time, it offers a symmetric pull-up/down slew rate to enhance the speed of the buffer, whenever the regulator is under large signal operation during the load transient. Moreover, the ECM buffer is modified to develop the regulator topology without introducing an error amplifier as a separate independent stage. It helps to minimize the overall quiescent current consumption at low load condition and makes frequency compensation easier. Finally, the speed of the adaptive bias loop (ABL) is increased by avoiding the highly capacitive gate node of the PMOS power transistor. A comprehensive small signal analysis of the proposed regulator is also carried out for a clear understanding of the stability of each loop considering the interaction of the other loop. The regulator is implemented in a 0.18 µm CMOS technology with a quiescent current of 900 nA. A maximum transient output voltage variation of 2.1% is observed with C o =470 nF. Index Terms-Low dropout regulator, current mirror, voltage buffer, main feedback loop, adaptive bias loop. 0885-8993 (c)

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“…The adaptively biased LDR (AB LDR) topology in [15], [16] adopts both the techniques of Q-reduction compensation [5] and adaptive biasing (AB) [1], [13], [14] and achieves the desirable features of low-voltage high-precision regulation with extended loop bandwidth and without significant degradation of the current efficiency . The biasing current of the error amplifier (EA) is high at heavy load.…”

Section: Introductionmentioning

confidence: 99%

An Output-Capacitor-Free Adaptively Biased Low-Dropout Regulator With Subthreshold Undershoot-Reduction for SoC

Zhan

2012

IEEE Trans. Circuits Syst. I

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This paper presents an output-capacitor-free adaptively biased low-dropout regulator with subthreshold undershootreduction (ABSTUR LDR) for SoC power management applications. Techniques of adaptive biasing (AB) and Miller compensation with Q-reduction are employed to achieve low-voltage highprecision regulation with extended loop bandwidth while maintaining low quiescent current and high current efficiency. The pass transistor is designed to work in the linear region at heavy load to save silicon area, and a symmetrically matched current-voltage mirror is used to implement the AB scheme with accurate current sensing for the full load range. The dedicated STUR circuit, which is low-voltage compatible and consumes very low current in the steady state, is inserted to momentarily but exponentially increase the gate discharging current of the pass transistor when the LDR output has a large undershoot due to a large step up of the load current. Undershoot voltage is hence dramatically reduced. Stability of the ABSTUR LDR is thoroughly analyzed and tradeoffs between the undershoot-reduction strength and the light load stability are discussed. Features of the proposed ABSTUR LDR are experimentally verified by a prototype fabricated in a standard 0.35-m CMOS process.

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A low-voltage regulator circuit with self-bias to improve accuracy

Cited by 24 publications

References 3 publications

A Hybrid-Mode Operational Transconductance Amplifier for an Adaptively Biased Low Dropout Regulator

A Hybrid-Mode Operational Transconductance Amplifier for an Adaptively Biased Low Dropout Regulator

Design and Analysis of an Adaptively Biased Low-Dropout Regulator Using Enhanced Current Mirror Buffer

An Output-Capacitor-Free Adaptively Biased Low-Dropout Regulator With Subthreshold Undershoot-Reduction for SoC

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