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What is difference between "transconductance" opamp and "normal" (or "voltage") opamp

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grizedale

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What is difference between "transconductance" opamp and "normal" (or "voltage") opamp

What is difference between "transconductance" opamp and "normal" (or "voltage") opamp?

Is there actually no difference at all.......and its just in how they are connected up?
 

Re: What is difference between "transconductance" opamp and "normal" (or "voltage") o

grizedale said:
What is difference between "transconductance" opamp and "normal" (or "voltage") opamp?
Is there actually no difference at all.......and its just in how they are connected up?
Click to expand...

The "normal" voltage opamp (voltage in and voltage out) has a specified gain value (unitless).
In contrast, the transconductance amp (current out and voltage in) has a "gain", which has the dimension "transconductance".
 

Re: What is difference between "transconductance" opamp and "normal" (or "voltage") o

See this material
Click to expand...
I fear, the presentation misses the concept of a transconductance amplifier. At least it's not related to OTAs as amplifier building block.

I guess, the original question refers to an OTA often used as error amplifier in switch-mode supply controllers? In this designs, the OTA property to expose a current as output quantity is essential. This shows, when the error amplifier is compensated by a RC circuit connected in parallel to the output. Or when the error amplifier output is limited to a certain level by a clamp circuit. Or the simple way to implement a soft start function.
 

Re: What is difference between "transconductance" opamp and "normal" (or "voltage") o

Thanks FvM

I guess, the original question refers to an OTA often used as error amplifier in switch-mode supply controllers?
Click to expand...

Yes thats right.

I think the feedback transfer function for either Transconductance error amp or voltage error amp with feedback, is basically -RF/RI

as shown by equation 6 here............

**broken link removed**
 

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