I'm using a level shifter (https://cdn-shop.adafruit.com/datasheets/txb0104.pdf) to interface with an LCD display (https://www.sparkfun.com/products/16398) that runs on 3.3V.
When connected to a DC power supply, everything works as expected (the screen turns on, the voltage coming from the level shifter to the screen is ~3.3V and the logic signal is ~2V.)
When I plug it in using an AC power supply, the output voltage to the screen drops from ~3.3V to ~2.8V, which is not enough to power the screen. I checked the level shifter's input voltage in both cases and it was the exact same (5.02V pwr 4.98V logic.)
I have included the relevant parts of my schematic below. (The input voltage for the entire circuit is 12V and I have a DC-DC converter that goes from 12V to 5V and the logic signal is coming from pin 7 on a 5V Arduino pro mini).
Why is the output voltage different and how can I get the screen to turn on using my AC power supply?