Second Generation Miscellaneous Linear/Nonlinear Applications of Various Types of Current Conveyors - Current Conveyors: Variants, Applications and Hardware Implementations - page 490

Fig. 15.2 Current-mode
PID controller and
instrumentation amplifier
(Adapted from [ 2 ] © 2010
Elsevier Ltd.)

I 1

I 01

z+

y

I 2

DOCCII+

I 02

y 1

z−

x

y 2

R 3
R 7 þ α 2 ʲ 1 ʲ 2 ʳ 1

C 1 R 3
C 2 R 2

K p ¼ α 1 ʲ 1 ð : Þ

15 3

C 2 R 1 R 2
α 2 ʲ 1 ʲ 2 ʳ 1 R 3

T i ¼ ð 15 : 4 Þ

T d ¼ α 1 ʲ 1 C 1 R 3 ð 15 : 5 Þ

It is interesting to note that all the three relevant parameters can be tuned or adjusted
arbitrarily or independently by various resistance values or alternatively by gain
variable current conveyors through the parameters

ʳ 1 . A novel
feature of both the current mode and voltage mode PID controllers is that they
employ five passive elements only all of which are grounded and do not require any
kind of component matching. These properties make these circuits good candidates
for realizing PID controllers in integrated circuit form.
Using DO-CCII, a very versatile configuration was reported by Yuce and Minaei
in [ 2 ] which employs only one active element and only two admittances and can
realize not only a PID controller but also an instrumentation amplifier in current
mode depending upon appropriate choice of the two admittances.
If admittance Y 1 is selected as a parallel combination of a resistor R 1 and a
capacitor C 1 with admittance Y 2 has chosen as a series combination of a resistor R 2
and capacitor C 2 , the circuit realizes PID controller with the following transfer
function:

α 1 , α 2 , ʲ 1 , ʲ 2 and

1
sT ik þ

H k s ðÞ ¼ K pk þ sT dk ð 15 : 6 Þ

In equation ( 15.6 ), the proportional gain (K p ), the integral time constant (T i ) and the
derivative time constant (T d ) parameters are given by:

R 1
R 2 þ

C 2
C 1

K p 1 ¼ αʲ a ð 15 : 7 Þ

R 1
R 2 þ

C 2
C 1

K p 2 ¼ ʲʳ þ a ð 15 : 8 Þ