1 2 3 Previous Next 30 Replies Latest reply: Jan 6, 2014 12:30 PM by brianx87
Roger Barre Level 2 Level 2 (225 points)

I have a SuperDrive that does not draw enough power froma  pwered USB hub or from the USB port on my 30" Cinema Display or from the USB port on the back of my Time Capsule.  The ONLY thing I have that's powerful enough to power the SuperDrive is my MacBook Pro.  The problem with that for me is that my MBP has only two USB ports - one is taken up by my Cinema Display, and the other by the powered USB hub that connects (among other things) my speakers.  So if I want to watch a movie, I have to disconnect either the Cinema Display or the speakers.  Bummer.

 

So here's my question ...

 

Exactly how much power does the SuperDrive require, and is there any other hub or device that will supply that much power so I can have the SuperDrive plugged in without disconnecting either the monitor or speakers?


MacBook Pro with Retina display, iOS 6.0.2
  • 1. Re: How much power is required for a SuperDrive?
    davidsignal Level 3 Level 3 (525 points)

    I would get a usb hub that can supply 2 amps at 5 volt.

  • 2. Re: How much power is required for a SuperDrive?
    Csound1 Level 8 Level 8 (35,280 points)

    A Superdrive requires 0.45a at 5vdc, well within USB range.

  • 3. Re: How much power is required for a SuperDrive?
    Roger Barre Level 2 Level 2 (225 points)

    Thanks for that - and do you know of a powered USB hub that delivers that?

  • 4. Re: How much power is required for a SuperDrive?
    Csound1 Level 8 Level 8 (35,280 points)

    They all do, 0.5a is the minimum for a hub but practically they all deliver more if needed.

  • 5. Re: How much power is required for a SuperDrive?
    davidsignal Level 3 Level 3 (525 points)

    I think it requires significantly more than that, which is why his current hub and monitor usb ports are not working.

  • 6. Re: How much power is required for a SuperDrive?
    Roger Barre Level 2 Level 2 (225 points)

    Alas, NONE of my powered USB hubs will power the SuperDrive.  Every one of them results in this error message:

     

    "A USB device can't draw enough power to operate properly.  If the device came with a power cord, plug it into an electrical outlet.  Otherwise, connect the device to a USB port on your computer."

     

    Again, the SuperDrive doesn't draw enough pwoer from any USB hub I own, OR the Apple Cinema Display OR the Time Capsule.  I went to the Apple Store today, and was able to get a SuperDrive to work when plugged into the newer Thunderbolt Display ... but until I buy one of those, I'm trying to figure out if there's ANY way I can power the SuperDrive from anything other than my MBP.

  • 7. Re: How much power is required for a SuperDrive?
    davidsignal Level 3 Level 3 (525 points)
  • 8. Re: How much power is required for a SuperDrive?
    Csound1 Level 8 Level 8 (35,280 points)

    djcastaldo wrote:

     

    I think it requires significantly more than that, which is why his current hub and monitor usb ports are not working.

    Please read the USB power spec, the Superdrive conforms to it and if you are going to discuss it you should be aware of it as well.

     

    To Whit:

     

    Power

    The USB 1.x and 2.0 specifications provide a 5 V supply on a single wire from which connected USB devices may draw power. The specification provides for no more than 5.25 V and no less than 4.75 V (5 V±5%) between the positive and negative bus power lines. For USB 3.0, the voltage supplied by low-powered hub ports is 4.45–5.25 V.[47]

    A unit load is defined as 100 mA in USB 2.0, and 150 mA in USB 3.0. A device may draw a maximum of 5 unit loads (500 mA) from a port in USB 2.0; 6 (900 mA) in USB 3.0. There are two types of devices: low-power and high-power. A low-power device draws at most 1 unit load, with minimum operating voltage of 4.4 V in USB 2.0, and 4 V in USB 3.0. A high-power device draws at most the maximum number of unit loads permitted by the standard. Every device functions initially as low-power but the device may request high-power and will get it if the power is available on the providing bus.[48]

    Some devices, such as high-speed external disk drives, require more than 500 mA of current[49] and therefore may have power issues if powered from just one USB 2.0 port: erratic function, failure to function, or overloading/damaging the port. Such devices may come with an external power source or a Y-shaped cable that has two USB connectors (one for power+data, the other for power only) to be plugged into a computer. With such a cable, a device can draw power from two USB ports simultaneously.[50]

    A bus-powered hub initializes itself at 1 unit load and transitions to maximum unit loads after it completes hub configuration. Any device connected to the hub will draw 1 unit load regardless of the current draw of devices connected to other ports of the hub (i.e. one device connected on a four-port hub will draw only 1 unit load despite the fact that more unit loads are being supplied to the hub).[48]

    A self-powered hub will supply maximum supported unit loads to any device connected to it. In addition, the VBUS will present 1 unit load upstream for communication if parts of the Hub are powered down.

     

    It is not guesswork, there are rules.

  • 9. Re: How much power is required for a SuperDrive?
    Csound1 Level 8 Level 8 (35,280 points)

    Take your Superdrive back to the store, it is not working to specification

  • 10. Re: How much power is required for a SuperDrive?
    davidsignal Level 3 Level 3 (525 points)

    The superdrive is not designed to fall within the usb power spec.  Apple made it so that you could only attach it directly to certain Apple computers or certain displays that provide more power than the USB specification.

     

    EDIT:  and I am sure that Apple did this because the drive looks "pretier" without an external power supply that needs to be plugged into it (and should be if the device were to fall within standard usb specification).

  • 11. Re: How much power is required for a SuperDrive?
    Csound1 Level 8 Level 8 (35,280 points)

    djcastaldo wrote:

     

    The superdrive is not designed to fall within the usb power spec.  Apple made it so that you could only attach it directly to certain Apple computers or certain displays that provide more power than the USB specification.

     

    EDIT:  and I am sure that Apple did this because the drive looks "pretier" without an external power supply that needs to be plugged into it (and should be if the device were to fall within standard usb specification).

    Sorry, if you use USB connectors you are bound by the USB spec, instaed of posting nonsense post the links containing some attribution for what you are posting.

  • 13. Re: How much power is required for a SuperDrive?
    Csound1 Level 8 Level 8 (35,280 points)

    I don't mean from rumor sites, actual figures please, either from Apple or a representative testing agency (such UL) or some other. MacRumors is called that for a reason.

  • 14. Re: How much power is required for a SuperDrive?
    davidsignal Level 3 Level 3 (525 points)

    Ok, well it seems you think that if the OP goes out and exchanges his superdrive for a different one that his current hubs will suddenly start working.  I am simply stating that I don't think so, I think that Apple designed the drive outside of USB spec. 

     

    Here is a link from Apple stating that Apple designs some USB devices that require more power than the USB spec: http://support.apple.com/kb/HT4049

1 2 3 Previous Next