My phone goes into sleep mode every ten seconds. How do I turn off the sleep mode?

Go to Settings. Tap on Display, then tap on Sleep. Select a screen timeout duration.

Hi, this sounds like it's not as much of a charging problem as it is a software problem.
This sort of situation can happen when the software on your phone becomes corrupted. The phone will try to reboot over and over like what you're describing.
The only way to fix this problem is to do a complete restore from Apple. First, connect your phone via USB to the computer you regularly sync it with and then start iTunes. Next, place your phone in front of you. You'll need to put your phone in safe mode (also called DFU mode) to do a successful restore.
To do this: 1.] Hold down the sleep button for exactly five seconds. 2.] While continuing to hold the sleep button, take another finger and hold down the home button (the one below your screen) for ten seconds. 3.] While continuing to hold the home button, let go of the sleep button and continue holding the home button for another ten seconds.
iTunes should automatically detect that your phone has gone into DFU mode and will then request to do a full restore.
Good luck!

Are you using a legitimate ATT sim card or are you jailbroken using Tmobile or some other GSM provider? you can try putting the phone into DFU mode. Have it plugged into the computer. and turn it off. Then hold both the upper sleep/wake button and the bottom Home button for 10 seconds. Then when you get to ten release the top sleep/wake button and continue holding the bottom home button until itunes gives you a message about it recognizing a phone in recovery mode. This should allow you to restore the phone.

Normally, there is a solution for such of these strange problems. Reset iPhone. Press and hold both the Sleep/Wake button and the Home button for at least ten seconds, until the Apple logo appears and restarts.

Did you try resetting the iPhone. Press and hold both the Sleep/Wake button and
the Home button for at least ten seconds, until the Apple logo appears and restarts.

If something isn't working right, restarting, force quitting an application, or resetting
iPhone will likely solve the problem.
Restart iPhone: Press and hold the Sleep/Wake button until the red slider appears.
Slide your finger across the slider to turn off iPhone. To turn iPhone back on, press and
hold the Sleep/Wake until the Apple logo appears.
If you can't turn off iPhone or if the problem continues, you may need to reset. A reset
should be done only if turning iPhone off and on doesn't resolve the problem.
Force quit an application: Press and hold the Sleep/Wake button on top of iPhone
for a few seconds until a red slider appears, and then press and hold the Home button
until the application quits.
Reset iPhone: Press and hold the Sleep/Wake button and the Home button at the
same time for at least ten seconds, until the Apple logo appears.

go to control panel > power options. Turn off hibernate and sleep mode, change all settings to never sleep and change the setting for "when closing the lid" to "do nothing" sleep mode, hibernation can destroy the registry on these laptops, you are better off turning that garbage off and just letting it run.

Hello there...
Check its sleep settings. Someone may have hit the sleep timer and have set it to about 10 seconds. If that still doesn't help, please post a reply here.

Mine does that sometimes too. If you just press and hold the button for about 3 seconds, it will turn on within 15 seconds.

I had the same problem with my iPhone the only way I was able to fix it was to re-flashed the latest 2.2 firmware. Power phone off, power on by holding power and home at same time, hold power for ten seconds and then release still holding home key for another 30 seconds to put phone in DFU mode. Then plug into iTunes it will detect phone in recovery mode and allow you to re-image