Broken screen, powers up but current flow fell after few seconds

Hello guys!

I have a Samsung S3 with a Broken LCD.

My device isn't charging.

When i use a power supply on my phone, first (before pressing on power button) it shows no current flow ( 0 Amp as it should), after i press on the power button it shows, for few seconds, some values of current flow but after 5-10 seconds the current flow falls down back to 0 Amp.

Can someone please guide me to the right solution?

Thank You.