I can’t confirm this to be true but there could be something wrong with the screen. You say its charging but doesn’t turn on so I assume there must be something wrong with the screen as I’m pretty sure they are sort of connected. However, you shouldn’t jump to the conclusion that the screen is broken as it’s probably best for you to see a professional. I have a question to ask, when did the phone stop turning on? e.g, when it ran out of charge or if it randomly turned off.

I know this is a bit old but for anyone who still has this problem, there is an easy fix that will require time. If your Ipad is pretty much at 0% and every time you charge it, it attempts to turn on but uses up its power in the process, your best solution is to leave it charge for about a day or 2 (mine was a day). It will eventually gain enough battery to keep itself alive, once you see it turn on, turn it off as soon as you can so it can charge with a bit more ease. Also, please do not unplug the charger for the entire 1-2 days, not even to just move to a different socket as it would usually just restart the process.