USB to DC Booster Cable - 9V Output (5.5mm*2.5mm Connector) - (AD57591)

Description:

This cable is a bit fascinating: it has a built-in boost converter, so you can plug it into any USB port (on a computer, battery pack, etc.) and it will give you a higher DC voltage. It's a handy way to power 9V devices with a center-positive DC barrel connector from a USB port. The DC barrel plug has a large 2.5mm opening and springs for the center terminal, so it can also be used with 2.1mm connectors.

These have a 500mA output, but you can go a little higher. We drew 700mA and got a small voltage drop, but it worked fine. It's probably best not to go to 700mA continuously!

So, overall, there's an 85% efficiency at low current draw, which drops to around 80% at high current draw. There's also a quiescent current of 3 mA. Keep in mind that the USB port voltage can often drop, and you may also experience power losses with thin or low-quality cables with high resistivity.