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Thread: Powered USB hubs

  1. #31
    FLAC W3bMa5t3r's Avatar
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    Quote Originally Posted by RawsonDR
    I'm not sure what "standard package" refers to but I don't think it's the min order.... they list prices for quantities of 1 ($1.80) and let you add one to your cart. If you do a general search for LD1585 you'll see that the Min Qty is 1.
    Yes, you can add just one to the cart, but it won't let you check out until you meet the minimum order / standard pack. makes no sense... but yeah... just tried it at Mouser.

  2. #32
    Raw Wave shotgunefx's Avatar
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    Quote Originally Posted by RawsonDR
    If you use a 5V line as the ground on the USB hub, it's possible that the 5V would be shorted to your car's ground through the USB cable. If not that, then say perhaps you have a USB touchscreen plugged into the hub, which would short the 5V to your car's ground through your touchscreen monitor which is properly grounded..... both examples are only theoreticals, but the point is that there are a lot of ways the 12-7V trick can fail. It works on fans and such because they are simple, isolated devices which don't share any other connections.

    UPDATE

    Must not seen the second page of this thread before replying, my bad



    As far as getting 8v....
    Hubs are expected to be able to source a decent bit of power correct?

    Pretty sure you wouldn't want to use a resistor. You'd need a huge power rating on it. A voltage divider won't work well either with any signifigant current.

    You could use a 8v zener plus transistor to brute force it, but probably the easiest is to get a LM317T adjustable voltage regulator and use that. I think you'd need a decent bit of heatsinking though.

    It might need 8v as it may have a 5v regulator inside (usually need a few volts above the output to regulate well). If your feeling adventurous, maybe worth cracking it open to see. If so, you could remove the internal regulator and put the 5v and ground to the appropiate locations on the board.

  3. #33
    FLAC W3bMa5t3r's Avatar
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    Quote Originally Posted by shotgunefx



    As far as getting 8v....
    Hubs are expected to be able to source a decent bit of power correct?
    specs for usb are up to 500mA for each port/line


    as far as using the adjustable/variable power regulator, that's what I'm looking at using, since my application isn't a hub, but an external capture device (6vdc) and getting a fixed power regulator is requiring the masive 1k parts power purchase

    But Yeah... as you said, he might be able to hack into the hub and wire directly in for the 8v hub... ah... but what about his 3v hub??

  4. #34
    Raw Wave shotgunefx's Avatar
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    Quote Originally Posted by W3bMa5t3r
    specs for usb are up to 500mA for each port/line


    as far as using the adjustable/variable power regulator, that's what I'm looking at using, since my application isn't a hub, but an external capture device (6vdc) and getting a fixed power regulator is requiring the masive 1k parts power purchase

    But Yeah... as you said, he might be able to hack into the hub and wire directly in for the 8v hub... ah... but what about his 3v hub??
    Mouser has some other ldo 8v regulators.

    Here's one NTE1952

    The LM317T could do both, it has an output range of 1.25 to 37 volts. Though for the 3v, I'd power it off the 5v line so it doesn't have to dissipate so much current.

    Might also want to look at National's WEBENCH power supply tool.

  5. #35
    Low Bitrate 2000Jeep's Avatar
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    Ok. i got my power usb hub working. the only thing is that im still not getting enough power to my slim cd slot drive. How can i get little more power for the cd/dvd drive.
    this is what i have.

    http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN%3AIT&rd=1

  6. #36
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    Quote Originally Posted by 2000Jeep
    Ok. i got my power usb hub working. the only thing is that im still not getting enough power to my slim cd slot drive. How can i get little more power for the cd/dvd drive.
    this is what i have.

    http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN%3AIT&rd=1
    are you supplying power with the included external usb/ps2 power cable for the cd drive? if not and you're just running it off the usb hub, you'll need the external power as well.

  7. #37
    Low Bitrate 2000Jeep's Avatar
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    OK. i still have the adaptor that it came with. Do i have to use the 2nd usb for power or can i cut it and use another power source. The reason im asking is my usb hub is full.

  8. #38
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    Quote Originally Posted by 2000Jeep
    OK. i still have the adaptor that it came with. Do i have to use the 2nd usb for power or can i cut it and use another power source. The reason im asking is my usb hub is full.
    you could do like before, cutting the end off the usb plug on the adaptor and hooking that up to a +5vdc power source and a GND. I don't know where your external cd is in relation to where you tapped the external power for you hub, but if it's close enough, you could tap into the same area.

    the usb cable will (should) have a red and a black wire. Just go to +5vdc on the red and GND for the black.

  9. #39
    Constant Bitrate RawsonDR's Avatar
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    Quote Originally Posted by W3bMa5t3r
    Yes, you can add just one to the cart, but it won't let you check out until you meet the minimum order / standard pack. makes no sense... but yeah... just tried it at Mouser.
    Code:
    Judy ext. 1264: Welcome to Digi-Key Live-Help. How may I assist you?
    David: Hi. Simple question: what does the "Standard Package" mean on the product description page?
    David: If it matters, I am viewing part number 497-3466-5-ND
    Judy ext. 1264: Standard package is the packaging that the manufactures sends us the parts in. We usually break them down to smaller quantities.
    David: So even though it says 1000, I can order 1 or 2 of the item?
    David: There is a price for quantity: 1 in the price menu
    Judy ext. 1264: That is correct.

  10. #40
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    Quote Originally Posted by RawsonDR
    Code:
    Judy ext. 1264: Welcome to Digi-Key Live-Help. How may I assist you?
    David: Hi. Simple question: what does the "Standard Package" mean on the product description page?
    David: If it matters, I am viewing part number 497-3466-5-ND
    Judy ext. 1264: Standard package is the packaging that the manufactures sends us the parts in. We usually break them down to smaller quantities.
    David: So even though it says 1000, I can order 1 or 2 of the item?
    David: There is a price for quantity: 1 in the price menu
    Judy ext. 1264: That is correct.
    guess they have a different setup than Mouser... good stuff. lol I added one on mouser and it wouldn't let me check out until I meet the standard packing / mininum quantity... guess I'll be heading to Digi-Key...

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