Hardware Reference
In-Depth Information
a
b
i
x
Y
y
z
2
+
y
z
1
+
i
x
i
x
x
z
1
+
X
Z
x
z
2
+
i
x
c
d
y
z
A
+
Y
Y
X
y
x
z
A
+
z
A
+
x
z
A
+
x
z
B
+
Z
x
y
X
z
B
+
Z
Z
y
z
B
+
Fig. 3.2 Realization of various CCs from dual output CCII+ s (a) dual output CCII+ (b) CCI+ (c)
CCI
(d) CCII
3.2.2 Normand
s Translinear CCs
'
Normand [
2
] presented two types of translinear CCs working either in class A mode
or Class AB mode. In both the cases, a wide input range has been claimed. These
architectures are based upon two types of basic cells both of which can be made
either from NPN transistors or PNP transistors. The so-called type one cell is based
upon Wilson current mirror and is shown in Fig.
3.3a
. On the other hand, type two
cell is based upon Pookaiyaudom-Quartet [
2
] as shown in Fig.
3.3b
. Corresponding
to these two basic cells, the two realizations of translinear CCs proposed by
Normand [
2
] are as shown in Fig.
3.4a and b
respectively.
A straight forward analysis of type- one cell with common-emitter current gain
β
reveals that it can be characterized by the following hybrid matrix in terms of
dynamic currents and voltages.
2
4
3
5
1
β
0
0
2
4
3
5
¼
2
4
3
5
with
r
e
¼
2
i
y
v
x
i
z
v
y
i
x
v
z
β
β þ
1
1
r
e
0
kT
=
qI
¼
V
T
=
I
ð
3
:
1
Þ
1
β
0
1
þ
0
2
It may be seen that for large
and very small r
e
, the above matrix approximates to that
applicable to a Current Conveyor. Similarly, the type two-cell is characterized by
β
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