Title
A Novel Automatic Quality Factor Tuning Scheme For A Low-Power Wideband Active-Rc Filter
Abstract
A novel automatic quality factor (Q) tuning scheme for an low-power and wideband active-RC filter is presented. Although Q-tuning is effective to reduce the power consumption of wideband active-RC filters, there are several problems since the Q-tuning normally relies on a magnitude locked loop (MLL). MLL is not accurate due to the amplitude detection circuits, and occupied area and power consumption tends to be large due to its complexity. In addition, flexibility to the reference signal may be the problem, since the reference signal which has a fixed accurate frequency is required. In order to solve these problems, we propose a Q-tuning scheme, which does not require a MLL. Therefore, proposed Q-tuning scheme has good accuracy, small die area, low power consumption and flexibility to the reference signal. In our proposed scheme, Q is tuned by adjusting the phase of an integrator to 90 degrees. The phase of an integrator is adjusted by detecting and controlling the oscillation frequency of a two-stage ring-integrator to the cutoff frequency of a filter, since the phase shift of an integrator is exactly 90 degrees at the oscillation frequency. The frequency is easily detected and controlled by counters and variable resistors, respectively. The Q-tuning circuit with a 5th-order Chebyshev LPF is implemented in a 0.13 mu m CMOS technology. The tuning circuit occupies 0.12 mm(2) and consumes 2.6 mW from 1.2 V supply.
Year
DOI
Venue
2009
10.1587/transfun.E92.A.411
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES
Keywords
Field
DocType
active-RC, LPF, quality factor tuning
Wideband,Control theory,Integrator,CMOS,Resistor,Low-pass filter,Chebyshev filter,Electronic circuit,Cutoff frequency,Mathematics
Journal
Volume
Issue
ISSN
E92A
2
0916-8508
Citations 
PageRank 
References 
0
0.34
8
Authors
4
Name
Order
Citations
PageRank
Shouhei Kousai112718.37
Mototsugu Hamada213022.06
Rui Ito3427.53
Tetsuro Itakura418733.44