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a
+V
M 1
M 3
y
x
z
M 4
M 2
−V
+V
+V
M 9
M 5
M 6
M 10
M 7
M 8
−V
−V
Fig. 4.4 Class AB first generation current conveyors proposed by Bruun (a) without bias
stabilization (b) with bias stabilization [ 10 ]
I QY ¼
I D1 ¼
I Qx ¼
I D3 ¼
I SS =
ð
1
λ FB
Þ
ð
4
:
1
Þ
If (1-
ʻ FB ) is reasonably large as compared to expected mismatch in the devices, a
well-controlled quiescent current mechanism is, thus, available. Now, in order that
as required for a CCI, i y can be made equal to i x , a fraction (1-
ʻ FB ) of the X- branch
current must be feedback directly to the Y-input. This function is performed by the
MOSFETs M 5b and M 7b .
Subject to the assumption of matched transistors having same g m and neglecting
the bulk effect, the input resistance looking into the port-X is given by:
1
2 gm 1
R x ¼
ð
λ FB
Þ
ð
4
:
2
Þ
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