TEMPLE AUDIO DESIGN USB Power Output Module

Need to charge a device? The USB Power Output Module is a solution for your modern day devices such as iPads®, iPhones® and other smart devices that are progressively replacing paper chord charts and music sheets. Utilizing a 9VDC – 24VDC power input range, you can power your USB device (up to 2.1A) with your existing pedal power supply. The charging output is relative to amount of 9V power you have available from your power supply so it only uses what it has to.

specs:

• Input Power: 9vdc-24vdc. Center Pin Negative 
• Power Output: USB Regulated 5VDC 2.1Amp 
• Dimensions: 1.02in x 1.22in x 1.92in

the "how much power do I need?" chart: