The goal is to design a circuit that can accurately measure light intensity with little temperature dependency.
Common application uses photodiodes to do so.
Photodiodes can be measured either in Photovoltaic mode or in photoconductive mode.
The caveat, is that photodiodes have strong temperature dependency almost 1% for 10°C, and I need to correct for it.
An idea I had going through some schematics would be to design a differential measurement between two identical photodiodes in photovoltaic mode.
The photodiodes would be on the same PCB and on top of the photodiodes a piece of translucent, diffusive material would be glued and then covered with a dark casing which is open in one side.
The light would come from one side, hit the first photodiode and then hit the second one with a lower intensity as it's being diffused through the material.
An amplification circuitry would compare the difference between the two photodiodes and the overall circuit calibrated with a known light source.
Would this principle work, or is there issue I overlooked?
Perhaps a simpler solution is possible?
There is a schematic out there that works in photoconductive mode and correct for dark current, but there is seems to be other factors that contribute to the temperature dependency, perhaps they are negligible?