Prevent iOS device from sleeping if plugged to charger This is available in Developer options in Android's system Settings. I'm trying to look for an equivalent in iOS. This is great if I want the screen to be always visible for screen updates/notifications. No problem with battery since it is plugged in anyway.

Is there a Jailbreak tweak for this?

This setting applies for both plugged and unplugged. I'm looking for something specific to a plugged device.
In the past there was an Cydia App called ScreenDimmer.

I hope you can find this application via your iPhone and fix your problem.

One of its features: 


  
  Doesn't dim the screen if the battery is being charged.