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  1. #1
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    How to generate 15V from 5V USB port?

    Hi All!

    I have a +5V and I need a +15V generated from that +5V. This power supply is the USB port.

    The currency is very low(Maximun 50mA).

    It will be in 15V for 3 or 4 sec.

    So, I need to generate 15V from 5V USB port.

    Is that possible?

    Thanks all!!!

  2. #2
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    mc34063 calc

    Yes it is posible. and I made it for my pic programmer. Mc34063 used. Here is the calculator:
    http://www.nomad.ee/micros/mc34063a/index.shtml



    •   Alt29th December 2005, 15:26

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  3. #3
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    Davood Amerion's Avatar
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    mc34063a calculator

    yes it is possible:
    you can use MC34063 switching voltage regulator
    try download it's datasheet from:
    http://katalog.elektroda.net/index.php?d_start=0

    Regards
    Davood



    •   Alt29th December 2005, 15:26

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  4. #4
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    usb 15v

    Could you post you programmer schematic?

    So I can how to do this boost converter.

    Thanks you guys!

    Tercio



    •   Alt29th December 2005, 15:33

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  5. #5
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    mc34063 calculation

    what about clamping the 5v.. not sure if its possible to draw 50 mA from the circuit, what do people think ?



  6. #6
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    15v from usb

    Quote Originally Posted by terciof
    Could you post you programmer schematic?

    So I can how to do this boost converter.

    Thanks you guys!

    Tercio
    http://www.kitsrus.com/
    k149bc



  7. #7
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    ramy gad's Avatar
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    mc34063 5v circuit

    there is a chip and easy 555 timer circuit can do this job search google for it



  8. #8
    VVV
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    usb to 15v

    You can use a boost converter, such as the LT1615 from Linear Tech: http://www.linear.com/pc/productDeta...31,C1061,P1775

    or MAX8575 from Maxim www.maxim-ic.com/quick_view2.cfm/qv_pk/4369/ln/

    The USB port can source up to 100mA, as per the USB specification.
    Since the available input power is Pin=5V*100mA=500mW, your output current can only be Iout=Pout/Vout=Pin*η/Vout. Typically, η=0.9 for a boost (though it can be lower), so your maximum output current can only be Iout=500mW*0.9/15V=30mA. This is a best-case scenario. In reality, the input voltage will be lower than 5V, due to voltage drops in the USB cable and connectors. Therefore, an output current of about 25mA is a more realistic expectation.

    Does that work for you?



  9. #9
    v_c
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    calculate mc34063 .xls

    You could use a switching regulator -- check out

    http://www.national.com/appinfo/power/

    for more information. You can enter in the details of your specifications and
    it will suggest a part for you. You can use this as your starting point.

    Best of luck,
    v_c



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