Nonlinear Applications of CCs - Current Conveyors: Variants, Applications and Hardware Implementations - page 219

Y

I 1

CCII 1

V 0

R 1

Z

V CC

X

R L

I 3

D 1

+

I 2

R 2

V in

V EE

− X

CCII 2

Z

D 2

Y

Fig. 8.7 Low output impedance dual-CCII full wave rectifier proposed by Monpapassorn [ 21 ]

CCII+, the gain of the circuit becomes unity. The AD844 was biased with 12 V DC

supply and DC bias currents were taken as I 1 ¼ 9.71 mA. With

these values, for an input sine wave of 1 V p-p, 1 MHz, the circuit functioned as a full
wave rectifier quite well with the output offset voltage reduced to as low as

I 2 ¼ 5mAandI 3 ¼

132 μ V

while the output impedance was found to be as low as 99.9 ʩ .

8.3 Frequency Doubler and Full Wave Rectifier

A number of authors have reported full wave rectifiers and frequency doublers
made from CCs such as [ 12 , 34 , 36 , 38 , 41 ]. We present here some exemplary
circuits out of these.
The frequency doubler and full wave rectifier circuit devised by Surakampontorn
et al. in [ 12 ] is shown here in Fig. 8.8 .
From the analysis of the translinear loop consisting of the transistors Q 1 -Q 2 -Q 3 -
Q 4 , it can be deduced that

h i

1 = 2

I in þ 4 I 0 I 1 ¼ I in = 2 ð 8 : 5 Þ

h i

1 = 2

I in þ 4 I 0

I 2 ¼ þ I in = 2 ð 8 : 6 Þ

Also, by noting that I A ¼ (2I 0 +2I 1 ) and I B ¼ (3I 0 +2I 2 ), the output current of the

circuit can be written as:

I out ¼ ð I A þ I B Þ I C ¼ 5 I 0 þ 2 I 1 þ ð I 2 Þ I C ð 8 : 7 Þ

If we choose I C ¼ 5I 0 , we get

1 = 2

2 I in þ 4 I 0

I out ¼ ð 8 : 8 Þ