USB On-The-Go is probably one of the greatest tools for Android that not a lot of people know about. With it you can connect virtually anything that requires USB into your Android device, including external hard drives, flash drives, keyboards, mice, and pretty much whatever else you can think of—even your DSLR. As OTG technology gets more popular, the features that come with it will evolve as well. For many Xperia devices, including the Xperia S, P, U, Sola, and Acro S, you can now simultaneously use OTG and charge your device.
The method was written out by XDA Senior Member sonic_boom and it does require some hardware modification. Initially, the hardware mod gave users a choice to switch a cable from OTG mode to Charge mode and thus not have to use multiple cables. However, after some more tinkering, sonic_boom managed to get simultaneous OTG and charging using a 4-way USB hub. What’s the only other way to get this? By purchasing a special dock.
As expected with hardware modifications, your mileage may vary. This involves tinkering with pieces of hardware and may damage your device or your accessories. Aside from the standard boilerplate warning, the mod is actually pretty simple. As stated by sonic_boom, this should work on any OTG-enabled Xperia device.
To learn more, visit the original thread._________