Difference between Differential difference current conveyor and OTA

Hi all,

I want to know the difference between

Differential difference Current conveyor(DDCC) and Operational Tranconductance amplifier(OTA).

Since both is used to convert Voltage to current(V to I).

What is the use of both the types.

Can anyone explain me in detail.

Thanks in advance.

They are different from each other.

OTA, means operational transconductance amplifier as you explain. For example, let's think an opamp. It has 2 input nodes as positive and negative. It senses voltage and gives output node as a voltage by amplifying. OTA input is the same with opamp. However, the output of the circuit gives current. Hence, OTA has the Gm. Of course, due to current output, OTA has high impedance at the output node different from OPAMP.

DDCC, is not amplifier like opamp or OTA. It is a current conveyor and it has a two input TYPE different from OTA. First, it has voltage mode input ports like Y1, Y2 and Y3. Second, it has a current mode input port as X. And there is two output TYPE different form OTA. First, current output at Z port. Second, voltage mode output at X port. There is two operation in there:

First, Y to X: In ideal CCII if you give a voltage Y port, X should be equal to this. Hence, Y to X can be considered like voltage buffer. It's gain is equal to 1 different from OTA or OPAMP.

Second, X to Z: In ideal CCII, the current flowing through both ports must be equal (but the sign can change). Hence, X to Z can be considered like current buffer. It's gain is equal to 1 different from OTA or OPAMP.

As you see, in current conveyor there is no voltage to current transformation. It can be considered as voltage and current buffer. DDCC of course has the same principle like CCII.