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Low‐power class‐AB 4 th ‐order low‐pass filter based on current conveyors with dynamic mismatch compensation of biasing errors
Author(s) -
Centurelli Francesco,
Monsurrò Pietro,
Stornelli Vincenzo,
Barile Gianluca,
Trifiletti Alessandro
Publication year - 2020
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.2762
Subject(s) - biasing , topology (electrical circuits) , filter (signal processing) , amplifier , electronic engineering , control theory (sociology) , active filter , cmos , power (physics) , resistor , compensation (psychology) , total harmonic distortion , computer science , voltage , physics , engineering , electrical engineering , psychology , control (management) , quantum mechanics , artificial intelligence , psychoanalysis
Summary A 4 th ‐order Butterworth class‐AB current‐mode low‐pass filter is proposed, based on second‐generation Current Conveyors (CCII). Class‐AB operation allows high‐power efficiency and driving large loads with small quiescent currents. The CCII topology uses the class‐AB output buffer with error amplifiers: this topology is known to be sensitive to mismatch errors, which cause offsets in the error amplifiers, affecting the biasing current of the stage. This problem is solved via a control loop, which compensates the effect of mismatches. The technique is shown to be effective in Monte Carlo simulations with process variations and mismatches. Simulations have been carried out in 40 nm CMOS technology. The proposed filter achieves good power efficiency, thanks to the class‐AB architecture, and good dynamic range, thanks to the closed‐loop output buffer. A cut‐off frequency of 6 MHz, with 184 μW of total quiescent power consumption, is achieved, with a THD of ‐55 dB and a SNR of 49 dB.