Nonlinear Applications of CCs - Current Conveyors: Variants, Applications and Hardware Implementations - page 230

Fig. 8.21 An analog switch
employing CCII- proposed
by Monpapassorn [ 15 ]

+V

I bias

Z

CCII−

YX

i B

V A

R L

V B

A C

B

i A

i RL

R L

A B C

current to the CCII , when it is proposed to be turned ON and by not supplying I bias
current when one wants to turn the switch OFF.
A SPICE simulation check [ 15 ] for the workability of this switch using a CMOS
CCII

m CMOS technology has demonstrated that this
analog switch can operate satisfactorily with DC bias voltage of

implementation in 0.5 μ

1.2 V and

exhibits an operational range from 300 to +300 mV up to a frequency of

1 MHz. This simple switch appears to be a suitable choice for mixed analog and
digital signal processing applications.

8.7 Pseudo-Exponential Circuit Realization

Pseudo-exponential function circuits are useful in a number of communication and
signal processing systems. Such circuits have an important role in applications
which require allowing wide gain control changes with a control parameter. In
principle, the exponential v-i characteristics of a BJT or a MOSFET operating in
week inversion mode can be exploited to design exponential circuits.
A pseudo-exponential function can alternatively be realized by analog circuits
using its rational function approximation such as:

1 þ ʲ x

e 2 ʲx ð 8 : 30 Þ

ʲ x

1

Two circuits to realize the above functions were proposed by Maundy and Gift [ 16 ]
and are shown in Fig. 8.22 .