0
\$\begingroup\$

I'm in need of a different perspective here on how to approach the circuit I'm designing. Currently I have a PD that I want to reverse bias with 2V and measure the current from the PD. This is easy enough to do using a TIA IC like OPA380. I can even easily apply voltage to the INPUT+ to reverse bias the PD.

enter image description here

Unfortunately, this would only work for measuring the current in this condition. I don't think I can forward bias the PD and measure the current using this. One thought I had is to use 2 analog MUX ICs to just swap the PD polarity around. I think that will work since the current direction is still the same and I don't have to worry about voltage being negative.

Why am I measuring PD in a forward voltage mode? Well, I'm actually doing an IV characterization of the PD and trying to plot a current vs. voltage curve going from -1 Bias to +1 Bias on the PD. The design I have now would require having to measure from 0 to +1 twice to get my data (switching the polarity at 0V).

Are there other more elegant ways to measure the PD reverse and forward biased using the same TIA?

\$\endgroup\$

1 Answer 1

1
\$\begingroup\$

Bias Anode to 2.5V and sweep V+in from 1.5 to 3.5V.

\$\endgroup\$
1
  • \$\begingroup\$ Ah, why didn't I think of that! That's brilliant. Basically I just raise the DC offset by 2.5V and now I have 1.5V against it which makes +1 on cathode and then +3.5V against it which makes it -1V!!! I'll give that a shot! \$\endgroup\$
    – Patratacus
    Commented Mar 14, 2018 at 0:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.