Electrical – Can you connect multiple photodiodes in parallel and treat it as one

circuit analysisinfraredphotodiodephototransistorsensor

Im working on an IR sensor based off of the Texas Instr. particle sensor (TIDA-00378). They use just one photodiode in their design. I would like to use multiple photodiodes, lined up with multiple emitters, to cover a larger area. In my current design using phototransistors, I was able to connect multiple phototransistors in parallel to achieve this, as shown in the second image. Will this work similarly with the differential amplifier if I use multiple photodiodes in parallel?

Thanks!

Block Diagram of Particle Sensor

My current design

Best Answer

Yes you may put as many PD’s which are current sources to add together like a PV panel array in series /parallel.

But will the optical sensing work? Not unless they are all blocked SNR of detection depends on this contrast ratio for all currents combined and 0.5mA/mW received typ. And SNR directly affect detection error rate.

So a good wall of laser light must be defined in terms of threshold for logic levels in current, then converted to voltage with R using a TIA with gain. Optical gain may be achieved with lenses or series strings of narrow emitters or . ??? So this must be defined in the question with the optical path spacing and length, with the size of the object anywhere typ. from 1mm to 1m in size., as well as velocity or time interval for detection.