Transimpedance Amplifier with voltage feedback amplifier

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powersys

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Hi,

Is it necessary to use the inverting input of the voltage feedback amplifier (VFA) to amplify the photocurrent signal from a photodiode? Can we use the noninverting input configuration of the VFA?

Thank you.
 

The only configuration I know of connects the output to the inverting input with a resistor, with the photodiode connection being the inverting input.

You need the negative feedback to create a low impedance node for the photodiode. You cannot do that at the non-inverting input.

Keith
 



Dear Keith,

Thanks for your help.
But could we connect the photodiode to the noninverting input but using a negative feedback?

Thanks
 

powersys said:
Dear Keith,
Thanks for your help.
But could we connect the photodiode to the noninverting input but using a negative feedback?
Thanks
Click to expand...

May I try an answer instead of keith?

Of course, you can. As you said: ...but using a negative feedback.
This means: negative feedback to the non-inv. input by using an additional inverter (sign change) within this feedback loop. But I don`t know if this was your idea behind the question.
LvW
 

powersys said:
Dear Keith,

Thanks for your help.
But could we connect the photodiode to the noninverting input but using a negative feedback?

Thanks
Click to expand...

You could, but then it wouldn't be a transimpedance amplifier - it would be a voltage amplifier. Maybe if you showed what you had in mind I could explain better.

Keith
 

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