12V fan from USB port (5v) Charge Pump (?) 0,06A (only 60mA)

Discussion in 'General Electronics Chat' started by alan1975, Jan 15, 2012.

  1. alan1975

    Thread Starter Member

    Jan 1, 2012
    42
    0
    Hello,

    //For people who remember me from previous question about Bar Led driver, with 10.5V relay disable circuit. I don't forget about this project. I don't forget about You guys who spend time to help me!. I just have spending some time to learn many things. I decide to use IC, called Atmega. I finished writing application (firmware), i tested it using Atmega8, but it's to big (it's overkill), and i'm waiting for shipping atmega tiny, in dip 8 package. When i will be done, i will answer in that thread and show working project on my breadboard. I appreciated Your help, and i promise when i will have something to show i will!.


    Today's question:
    I would like power my 12V fan, from USB.
    Please don't tell me i should buy 5V, because i was unable to find perfect size. It's slim fan, quiet...

    I't take only 0,06A with 12V.

    Any of step-up converters are not possible, because of problem in getting IC for it.

    I found this project:
    http://www.eleccircuit.com/voltage-doubler-with-ic-555/

    It's voltage doubler, if i understand corect it will get me about 10V from 5V usb.
    Question is, is this charge pump, can provide 0,06A ?
    It's very little 60mA, just like 3 LED.

    If anyone was trying that device, please tell me the current at output.

    Regards
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    USB should only allow 100mA without negotiation, which wouldn't be enough to run 12V@60mA, around 170mA would be needed.

    I'd suggest using a 12V tap from the computer power supply, or getting a 5V fan.
     
  3. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,887
    1,012
    He told you not to tell him that. :)
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    Well, if he doesn't need to move a lot of air, the fan will probably turn at 1/2 speed when run directly off the USB port.

    If he has a cheap USB adapter card or motherboard, it might give him 500mA (or more) without negotiation, but then if his charge pump components or wiring fail, he'll blow the port, potentially more than that port.

    It's similar to using super-conducting wire for your interconnects. Very low loss on the wires, but keeping it all near absolute zero is a big hassle.
     
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