Second Generation Applications of Other Types of Current Conveyors in Realizing Synthetic Impedances - Current Conveyors: Variants, Applications and Hardware Implementations - page 473

Fig. 14.15 Electronically
controllable FI simulator
proposed by Sagbas
et al. (Adapted from [ 32 ]
© 2009 Elsevier)

I 0

I 1

V 1 z − x

+

DO-CCCII

I 2

y

V 2 z+

+

I B

−

C

g m OTA

+

14.14 Resistor-Less Simulated FI Using DXCCII

Figure 14.16 shows a resistor-less simulated FI using three dual -X CCIIs
(DXCCII), three NMOS transistors (operating in triode region) and a grounded
capacitor propose by Saad and Soliman in [ 37 ]. Since drain and source terminals of
all the three MOSFETs have complementary signals this enables cancellation of the
square non-linearity in the expression for drain current in all the three cases and
each MOSFET, therefore, realizes a linear voltage-controlled-resistor whose value
is given by

1

μ n C ox L i V Gi

R i ¼ ð 14 : 26 Þ

2 ð V th Þ

Furthermore, since M 2 and M 3 have a common gate voltage V G2 , it therefore
follows that R 2 ¼ R 3 .

With the above in mind, the equations for the 2-port can be written as:

μ n C ox W
L

I 1 ¼ I Z 2 A ¼ I X 2 A ¼ I D 1 A ¼ 2 ð V G 1 V th Þ V 3 ð 14 : 27 Þ

1

Similarly

I 2 ¼ I Z 1 A ¼ I X 1 A ¼ I D 1 A ¼ I 1 ð 14 : 28 Þ

The current in the capacitance (I C ) is given by:

I C ¼ ð I Z 1 C þ I Z 2 B Þ ¼ ð I X 1 C þ I X 2 B Þ ¼ ð I D 2 C þ I D 3 B Þ

V G 2

2 ¼

μ n C ox W

for W
L

W
L

¼ ð V th Þ ð V 1 V 2 Þ ð : Þ

2 14 29

L

3

Therefore, the voltage across the capacitor (V 3 ) will be obtained as