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Question about using Diodes as protection on inputs — Parallax Forums

Question about using Diodes as protection on inputs

T ChapT Chap Posts: 4,223
edited 2008-11-03 04:21 in General Discussion
If you are designing a product consisting of a controller board(Prop) and motor driver board(motor/mosfet driver IC's), and you are supplying the wiring harness as well for single application, how much protection do you build into the boards to safeguard against shorts, etc? If so, what is the standard practice for inputs/outputs, as well as mosfet gate drive clamps? I always use 200 ohms going off the controller, but have yet to start a practice of using clamps and am looking for a good solution.

Thanks

Comments

  • LeonLeon Posts: 7,620
    edited 2008-11-02 04:55
    TVSs are often used on inputs.

    Leon

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  • metron9metron9 Posts: 1,100
    edited 2008-11-03 04:21
    One way to protect against a reverse connection is an inline PTC fuse and a diode across the terminals.

    A diode in series if you have enough voltage and you are not dealing with high currents. I used 5 shottky doides in parallel connected in series for a very low voltage drop with the positive side of a connector wire harness to protect against a reverse connection to a 6V battery by the user for a 5V 1 amp device. A standard fuse would not work as any reverse connection would blow one of the components before the fuse would blow.


    TVS and zeners for surges and static electricity if you have long wires. I remember using long wires in the winter with some 555 timers and blew them up when I walked across the carpet and touched something made of metal.

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