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  1. #1
    Join Date
    Feb 2006
    Posts
    77

    Short circuit protection

    Hey all,
    Have been on the lookout for a schematic kinda like a crowbar circuit but instead of using an SCR and blowing a fuse I want it to pull a relay and disconnect the load.
    My fancy lab PSU has this feature and I want to use the circuit in a high current PSU .
    Have looked all over the net.
    Have had an idea with a shunt resistor and even an opamp but not really sure which way to go.
    Anyone got any good tips, ideas or a circuit.
    Cheers

  2. #2
    Join Date
    Mar 2008
    Posts
    267
    Hello Beaker,

    do a bit of searching on "fold back current limit"

    I know this is not the nature of answer You want and if i were in Your shoes i might get agranoyed with this kind of response.

    This is the best i can do with the information You have supplied ( load voltage and current would be a nice start).

  3. #3
    Join Date
    Feb 2006
    Posts
    77
    Hey Zig,

    All info is good info, will be sure to check it out. Thanks

    What I would like the circuit to do is:
    When the power supply's output is shorted a relay disconnects the output and stays that way until the short is removed then reconnects the output.

    Cheers

  4. #4
    Join Date
    Jan 2006
    Posts
    738
    Sounds interesting.... One problem I see is that using a relay to disconnect the load would not allow the circuit to sense the load current while disconnected. The bench supply I use has adjustable current limit and it's circuit is probably similar to the one here....
    http://freecircuitdiagram.com/2008/0...miter-circuit/
    It won't shut off the current entirely, but will limit to a set value.

    Steve

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