Mini USB charging for devices is a great idea

One recent innovation that I recently stumbled across is the use of mini USB ports for power. I actually originally encountered a device doing this with the Morotola HT820 Bluetooth headphones I got some months ago, although at the time, I didn’t realize that the power brick that came with the device was mini USB and not yet another proprietary power cable connection.

For those unaware, mini USB is a small form factor of USB plug (otherwise essentially identical to standard USB). As with regular USB, mini USB devices can be off the bus. Now, standardizing on mini USB for power connectors has some really nice advantages:

  1. Everyone’s power bricks are now compatible. Normally, each gadget you own is going to have its own (incompatible) power transformer brick, which means that if you’re travelling, you’ll quite likely have to lug around several such power bricks (in addition to your laptop AC adapter), even if every device doesn’t really need to be plugged into “wall power” at the same time.
  2. You can charge these devices off of a laptop USB port. Of course, you’ll need a USB to mini USB cable, assuming your laptop doesn’t have any mini USB ports (I haven’t seen any that do). The really cool thing about being able to do this is that for all your mini USB, battery powered devices, you only need to bring one cable for all of them while on the move, since you can just plug the device into your laptop and charge it off of that.

Furthermore, because the connection is still USB, devices can use the same port to charge and transfer data to a computer at the same time.

Now, I didn’t really put all the pieces together about my HT820 being mini USB until I had to go and buy a replacement set of headphones (a different model this time, as Best Buy didn’t carry the HT820 anymore). The volume button on my set had died, which was rather inconvenient, to say the least.

Anyways, I noticed that the new headphones, from a different manufacturer, seemed to have a compatible power cable port from the AC adapter brick to the device’s charging port. This time, the power cable even had the ubiquitous USB logo on it (the Motorola’s charging cable didn’t, for one reason or another). Sure enough, I could use the Motorola charger with the new set of headphones, even though they weren’t of a Motorola make. Cool.

Recently, I finally ditched my old cell phone for a proper smart phone (an XV6800). This, too, is mini USB powered (and it can use the mini USB connection for data as well, at the same time). There’s a lot of other neat things about the XV6800, but the fact that I don’t need to (ever) worry about spare chargers or anything of that sort is really just the icing on the cake.

Thanks to this little advancement, I can now ditch two additional power bricks (one for the cell phone and one for the Bluetooth headset) when traveling, and just charge both of devices off of my laptop. I’m actually kind of surprised that nobody implemented this earlier, given the immediate advantages of standardizing on a uniform power source (especially one that is as easily multiplexed as USB is).

So, the next time you’re looking for a new gadget of some sort or another, look for one chargeable via mini USB and circumvent the gadget charger nightmare (or at least, begin to do so, one gadget at a time).

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7 Responses to “Mini USB charging for devices is a great idea”

  1. Zooba says:

    You won’t find any laptop with a mini USB port under the current standard, since the mini USB port is only for devices. I highly doubt USB 3.0 will allow mini USB ports on hosts, and may not even support the highest speed on mini ports, depending on whether they can fit the extra connections (optical fibre, apparently).

    One of the issues with powering devices from USB ports is that many devices simply pull current off the 5 volt pin without enumerating as a USB device. According to the standard, a USB host has no obligation to provide any current when no device is connected, though most that I’ve come across will allow at least 100mA, and a device has to go into low power mode (less than 1mA) when instructed.

    A further problem is the devices that assume they can take the maximum (according to the standard) 500mA without negotiating for it. I’ve run into a number of external hard drives that are guilty of this. A device has to request a high-powered port (500mA instead of 100mA) and if it can’t get one it has to manage without it. On a desktop PC this is less of an issue since more power can simply be taken from the grid. On a laptop, however, often the USB ports will never support 500mA, whether on battery or AC power (hence the warnings about power surges).

  2. Jeff Curless says:

    And…. now manufacturers are standardizing on Micro-usb as far as I know. So one more change in store, yay!

  3. Steve says:

    Zooba, that’s why they have dual connected USB ports for external hard drives I guess?

    On my machine at work I’ve never had to connect my external HD to anything except one port, but on my laptop, I have to connect it to two ports for it to work.

    As far as I see, that means they are basically taking the power from both ports to be able to drive enough power for the device.

    I have to say that I also have more and more devices that can be powered/charged trough mini-usb, or standard usb. I think it is a very good idea as well ;)

    It’s so much easier to plug something into your computer than to find yet another empty socket on the wall for your “nth” charger!

    The only problem I’ve had so far is that I’ve so many devices to charge that I’ll probably need to buy a powered USB hub to charge the devices when the computer is not on ;)

  4. Zooba says:

    The dual plugs are the problem. The first one is fine, since it is an actual device. The second plug, however, just steals the power without actually being a USB device. They generally get away with this because, even though a host doesn’t have to provide 100mA to a port with no device, a lot do. Some even provide 500mA to the ports, which is not required unless the device connected to that port requests it.

    Laptops tend to be more conservative with their power allocation, which is why you’ll need both ports connected. I’ve found some laptops still won’t provide enough power from two ports (keeping in mind that one of them doesn’t have a device connected to it) and the second port has to go to a powered hub or a desktop.

    Basically, as long as the device contains a USB controller and can enumerate (even if no drivers are required – both Windows and Linux ship with suitable drivers for this AFAIK) there’s no problem. It’s the devices that treat USB as a battery or a power socket that are the problem.

  5. ac says:

    I guess you could make a fuss about this and then sell some “usb power” cable that had some smartness built in to negotiate the power. Adding that logic shouldn’t really add a whole lot of size in the cable. Think of the USB two way datatransfer cables which are like this.

  6. Actually there is a USB to mini USB connector so there does not need to be a mini port on your laptop, all the external memory card readers for instance use this. The power problem is a real problem though, getting anything larger than your headphones charged in a reasonable amount of time may be pushing it. There are also battery chemistry problems with a 5V out, overcomable, but typical Li-Ion for instance is riged with 2 cells in series for 7.2-7.4V output, although a few 3.7V cells exist. What has become standard (7.2V) batteries require an inefficient voltage increase step to charge. Anyway, USB ports are great but limited.

  7. Kemp says:

    “I’m actually kind of surprised that nobody implemented this earlier, given the immediate advantages of standardizing on a uniform power source”

    Advantages for the customer, sure. But then they can’t charge you £30-£50 for a new charger.

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