24V, 5A Dual regulated power supply using any voltage regulator?

Discussion in 'General Electronics Chat' started by prashant_007, Apr 14, 2016.

  1. prashant_007

    Thread Starter New Member

    Apr 14, 2016
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    0
    Hello,
    I am trying to build 24V, 5A DUAL regulated power supply.For my application it is necessary to use any on these pair of regulators :- 7824,7924 or LM317 and LM337. But current limit of all these vtg regulators is only 1.5A
    So, can any one suggest me any way to build such regulated power supply with current limit 5 amp.


    Thanks
    Prashant
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
    3,246
    622
    Welcome to AAC!

    Add an external pass transistor. Datasheets should have an example.
     
  3. prashant_007

    Thread Starter New Member

    Apr 14, 2016
    2
    0
    Thanks for your rply.
    I have checked this possibility, but getting problem with negative side. transistor getting heated too much(after adding heat sink also).

    Is there any other possibility?


    Thanks
    Prashant
     
  4. dl324

    Distinguished Member

    Mar 30, 2015
    3,246
    622
    What are the test conditions?

    What are you using for a pass transistor and what type of heat sink?
    You could parallel regulators, but the typical solution is one or more external pass transistors mounted on the same heat sink as the regulator so the regulator will provide safe area protection for the power transistors.
     
  5. crutschow

    Expert

    Mar 14, 2008
    13,016
    3,235
    You can't do anything about the heat. It's an intrinsic function of a linear regulator.
    The dissipation will be the voltage drop across the pass element times current.
    For your circuit that would be (24-5)V * 5A = 95W which requires a substantial heat-sink, likely with a fan such as those used to cool PC processors, to minimize its size.

    If you want to dissipate less power, you could go to a switching regulator, which typically dissipates only about 10% of the load power in heat or 2.5W for a 5A load @ 5V.
     
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