9 Volts to 12 Volts DC to DC converter

Discussion in 'General Electronics Chat' started by haran, Apr 12, 2008.

  1. haran

    Thread Starter Active Member

    Apr 6, 2008
    42
    0
    i would like to know how to build a 9V to 12V dc to dc converter. I want to use a 9Volt battery as the voltage source(input).
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
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    What is the power consumed by the 12V load?

    hgmjr
     
  3. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    http://www.national.com/appinfo/power/

    Plug in the values and it will spit out the part you need. I came up with the LM25575 but I can't find the specs on the power output of a 9v battery so don't know how much power it can produce.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    9v PP3 "transistor" batteries are pretty low-power devices, perhaps 150mAh

    If the load was more than a few mA, the battery would get sucked flat pretty quick.
     
  5. haran

    Thread Starter Active Member

    Apr 6, 2008
    42
    0
    how do i calculate the power load for a circuit?
     
  6. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    A X Hours = AH

    What you need is a measurement of current your circuit requires from the 12V source, and we'll work from there.
     
  7. haran

    Thread Starter Active Member

    Apr 6, 2008
    42
    0
    my circuit is using a 12 Volt input and the amp is below then 500mA
     
  8. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    If you make a voltage converter circuit that is 85% efficient and need 400mA at 12V then then 9V battery must supply 640mA.

    A 9V alkaline battery's voltage drops quickly with such a heavy load. I have graphs from energizer.com and the highest current calculated is "only" 400mA.
     
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