The Optimization of Current Mirror Topologies in Low-Dropout Regulators

Shiyu Huang

doi:10.54097/tg68hh27

Authors

Shiyu Huang Department of Automation and Electrical Engineering, Lanzhou University of technology, Lanzhou, China

DOI:

https://doi.org/10.54097/tg68hh27

Keywords:

Current mirror, low-noise design, cascode amplifier, flicker noise, transistor, mismatch mitigation.

Abstract

This review examines practical methods for reducing noise in current mirrors, which are essential building blocks in precision analog circuits like low-dropout regulators (LDOs). Three main noise control approaches are discussed: improvements to cascode current mirror structures, optimization of transistor parameters, and specialized biasing techniques. Cascode-based designs—such as stacked nonlinear mirrors, regulated folded cascode (RFC) amplifiers, and nonlinear nested current mirrors (NL-NCM) help lower mismatch and low-frequency noise while strengthening power supply rejection. Transistor-level methods incorporate dynamic threshold MOSFETs (DTMOS) and regenerative current mirrors to improve linearity and support low-power operation. Biasing strategies, including back-gate biasing in FDSOI processes and PTAT resistor feedback, further suppress noise by adjusting threshold voltages and limiting noise propagation. Each technique involves trade-offs between noise, power, area, and linearity. Looking ahead, combining architectural, process, and biasing improvements is a promising path for developing efficient, low-noise current mirrors suitable for sensor interfaces and other noise-sensitive systems.

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