Current Limiting circuit with regulator adjustment pin disconnected

Discussion in 'Power Electronics' started by maw455, Jul 29, 2016.

  1. maw455

    Thread Starter Member

    Jul 20, 2016
    30
    1
    I'd like to use this current limiting circuit to have current limit in a series of steps.

    LM338 Current Limited Supply.PNG.pdf

    It would be connected in series with another LM338 which would be used to control the voltage.

    I think I understand how this circuit works except for one thing. Note that in position 1 on the current limit selector switch, the adjustment pin is left disconnected from the rest of the circuit. My understanding of how the LM338 works is limited, but I'm guessing that what will happen is that the regulator will be expecting 10mA from ADJ, and it will keep raising Vout until it is there. Since the ADJ is disconnected, effectively the regulator will turn on full, dropping the full output voltage across R1, rather than Vref? Is this correct?

    If so, I'm guessing that output current will also rise as the voltage rises, until the regulator's internal current limit circuit is activated. Correct?

    Thanks
     
  2. maw455

    Thread Starter Member

    Jul 20, 2016
    30
    1
    Moderator: I thought I had posted this in the General Electronics section. Is it possible to move it there?
     
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