Phototransitors power supply

[exapod]

I have a doubt about the phototransitors power supply. In my mouse i have a very small regulator max 30 mA powering the analog part of the mouse (Gyro and phototransitors) but my doubt is if 30 mA is enough or the phototransitors consume more power.

[Green]

it is sufficient if it only supplies the IR receiver.
Just assume the resistance of photo-transistor becomes zero when max IR is received. It will draw about 2mA current when serial with 1.8K ohm resistor. 30mA might not be enough if it also supplies the gyro.