Q: my phone screen goes blank and after a minute or so goes back to home screen. why?

Howdy mbaeguasu,

It sounds like your iPhone may be restarting unexpectedly while you’re using it. Take a look at the article linked below and, if you haven't already, try installing the latest version of iOS on your device.

If your iOS device restarts, displays the Apple logo, or powers off while you're using it - Apple Support

So long,

-Jason