Can't find the right device to use.. please help?!

Discussion in 'General Electronics Chat' started by MichaelR, Mar 5, 2008.

  1. MichaelR

    Thread Starter New Member

    Mar 5, 2008
    1
    0
    Hi folks. I am new to the group and I am very happy to have found it. Someone might be able to help me and make a reccomendadtion on what type of device I should use for the following:

    I am trying to find a transistor to use as a switch to handle some pretty hefty current and can’t seem to find one. I need to find a way to switch +200VDC at around 3 Amperes, (possibly 5 Amperes surge). I can only drive it with a + 5V TTL 24 mA source or 64 mA ground sink max. I haven’t had any luck finding a PNP transistor that will let me do that. Is there something better then a transistor to use? I don't really want to use a relay because of the reliability of the mechanical contacts at that voltage, and it would be cost prohibitive since I need to build many of these for my project. This is a personal project and is not for profit. If you have any suggestions, I would really appreciate the help. Thanks so much!
     
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    There are oodles of MOSFET switches able to handle the voltage and current, but the requirement of being driven by TTL is a big challenge. Would you consider driving a transistor or MOSFET driver with the TTL, and in turn driving the MOSFET with the driver or transistor?
     
  3. S_lannan

    Active Member

    Jun 20, 2007
    247
    2
    you'd definately have to have a driver in between the ttl and the high voltage/current switching device.

    maybe you could drive a darlington from ttl but in essence a darlington is a monolithic device of the above i'd say.
     
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