Best Quality DC to AC Converter for Multiple Applications. It can be used for mobile charging, laptop charging, led bulb and other applications Converts a standard USB Type A (5v) and boosts the power output to 12V DC. The booster delivers up to 500mA (0.5A) of current in a convenient 5x3. 5x1. 5cm module.USB is limited (with exceptions) to 0.5A at 5V. That's 2.5W. If you boost the 5V to 12, the available current goes down. The power stays the same, but the voltage goes up.