Saturday, January 21, 2012

Micro USB for Power Everywhere

One of the reasons I'm very excited for  Rasberry Pi is that it uses micro USB for power. This is also the standard may cell phone manufacturers are settling on for charging. I would love to see more every day devices use micro USB for charging and for power. Granted, not all devices can run off the 100mA from USB 2.0 (or charge at a reasonable rate), but I can eliminate just one more of those odd coaxial chargers, I'd be a happy fellow.


  1. What would be nice is if a power standard was created for these applications, much like the 12V add-on to USB that was created to power add on to POS devices, like scales, scanners, cash drawers, etc...

    Except this would be an up to 1500 may micro USB form factor that defaults to 100mA on devices that cannot negotiate up, as opposed to an add-on like the 12V.

  2. The usb2 standard actually states that a device can draw 500ma. usb2 states you can draw power in units of a 100ma up to a maximum 5 units

  3. There is a standard for it. It is called the USB Battery Charging specification, and it allows up to 5 A and requires 1.5 A. The European Union has pushed this standard for cell phone charging, and all the major manufacturers have signed up.

    So it's not just a de facto standard, and it is not just limited to 500 mA.

    The spec is available at


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