controller output voltage.

[BevelTipDrip]

Maybe I'm missing something, but with 5v being input into the current mirror, only around 3v ends up coming out to the controller. Am I missing something with my implementation, or is this intended behavior? I'm using the PJS6839, and the circuit is identical to what's in the CAD files.

[ManCloud]

It's not really intended behavior but is a functional limitation.

The output voltage is about V(GS) / U(BE) lower than the input voltage.

The "solution" for this is to either use a higher input voltage or to choose parts with a low switching voltage.

In my latest attempts I used PNP-BJT Transistors as they have a pretty consistent U(BE) of about 0.7-0.8V.

[BevelTipDrip]

Thanks for the quick reply, glad I'm not missing anything. I was actually looking at dual PNP packages before I sent this. What do you think of these ICs with a shunt style setup? https://www.digikey.com/en/products/detail/texas-instruments/INA138NA-3K/765297 they're kind of pricey, but it should completely solve this problem.

[BevelTipDrip]

I ended up using the Ti INA199B3DCKR, they go for around 50¢ each. The beauty of using one of these is your voltage drop is basically nothing, as you're using resistors in the mOhm range. The sensitivity can be tuned with the resistor to ensure whatever console it's being used on will properly detect the controllers.

My schematic here says INA199B2DCKR, they're the same chip with a different gain factor, I also ended up having to use a 300 mOhm resistor to ensure the gate of the fet biases on with newer lower power draw controllers like the retro fighters.