24V 200mA to 12V 3Amps

Discussion in 'General Electronics Chat' started by rmrps, Jul 14, 2015.

  1. rmrps

    Thread Starter New Member

    Feb 24, 2012
    17
    0
    Hi friends
    I am having 24v 200ma power supply i have to convert it into 12v 3amps supply how can i convert it if i am giving input of 24v 200ma to lm350 regulator it will convert 12v 3amps is this correct or what will be the best method to decrease the volt into 12v and increase current into 3amps please give me your guidance
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    You will NEVER get more power out of a circuit than you put in.
    Your input is 24 Volts X 0.2 A = 4.8 Watts.
    Even when you use a good quality switching regulator (95 % efficiency), you will get a max of about 380 mA at 12 Volts.

    Bertus
     
  3. rmrps

    Thread Starter New Member

    Feb 24, 2012
    17
    0
    thanks for the reply
     
  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,534
    1,251
    Your idea has two problems.

    First, your source power is 24 V at 200 mA, or 4.8 W, while your load power is 12 V at 3 A, or 36 W. The only way to deliver 36 W to the load is to have more than 36 W available at the source.

    Second, and LM350 is a linear regulator, not a switching power converter. A linear regulator can regulate a 24 V source down to 12 V, but the output current will still be only 200 mA. A switching power converter can regulate the input down to 24 V *and* deliver a corresponding increase in output current (minus circuit inefficiencies). So with your source the output current might be 320 mA. Better than 200 mA, but still not anywhere near 3 A.

    ak
     
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
    Time to buy a different power supply..
     
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