1 research outputs found
Delta-Sigma Modulator based Compact Sensor Signal Acquisition Front-end System
The proposed delta-sigma modulator (M) based signal acquisition
architecture uses a differential difference amplifier (DDA) customized for dual
purpose roles, namely as instrumentation amplifier and as integrator of
M. The DDA also provides balanced high input impedance for signal
from sensors. Further, programmable input amplification is obtained by
adjustment of M feedback voltage. Implementation of other
functionalities, such as filtering and digitization have also been
incorporated. At circuit level, a difference of transconductance of DDA input
pairs has been proposed to reduce the effect of input resistor thermal noise of
front-end R-C integrator of the M. Besides, chopping has been
used for minimizing effect of Flicker noise. The resulting architecture is an
aggregation of functions of entire signal acquisition system within the single
block of M, and is useful for a multitude of dc-to-medium
frequency sensing and similar applications that require high precision at
reduced size and power. An implementation of this in 0.18-m CMOS process
has been presented, yielding a simulated peak signal-to-noise ratio of 80 dB
and dynamic range of 109dBFS in an input signal band of 1 kHz while consuming
100 W of power; with the measured signal-to-noise ratio being lower by
about 9 dB.Comment: 13 pages, 16 figure