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a
+V
+V
+V
Q
5
I
0
Q
6
Q
1
Q
2
I
x
I
z+
I
z−
Y
X
I
y
z+
z−
Q4
Q
8
Q
3
Q
7
−V
−V
−V
b
I
0
I
x
I
x
Z+
B
Y
I
x
A
X
Z−
Fig. 9.54 (a) Implementation of the CCCII
with negative intrinsic resistance (b) circuit
connections for realizing a floating negative controlled resistance [
52
]
Whereas most common CCCIIs are built around the four transistors mixed
translinear cell, a number of authors also attempted alternative architectures
based upon differential pair with biasing circuitry and mechanism of duplicating
the X- port current through CMOS transistors. Two such architectures proposed by
Erkan and Alci for realizing a CCCII with positive R
x
and CCCII with negative R
x
[
55
] are shown in Figs.
9.56
and
9.57
respectively.
In the first circuit, by a straight forward analysis, it can be easily verified that
relationship between current I
x
and the differential input voltage (V
x
-V
y
) is given by:
V
x
V
y
2
V
T
I
x
¼
I
B
tanh
ð
9
:
78
Þ
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