How does a photodiode behave in saturation?

In my design, a photo diode is connected in reverse bias with 12V. The LDO (low-dropout) voltage regulator which is used for biasing can deliver a maximum current of 500mA

My configuration:

^{simulate this circuit – Schematic created using CircuitLab}

What I want to know is: If my photo diode gets saturated, how would it behave? Will it behave like a current source generating maximum rated current? or a short circuit allowing 500mA of supply current directly to the TIA (transimpedance amplifier)?

I'm asking because I want to put a protection diode before the TIA, which has maximum rated input current of 100mA.

I want to know the equivalent circuit of a saturated photo diode - is it a closed switch or a regulated current source?