ckt protection if voltage cross +5V

Discussion in 'General Electronics Chat' started by Vindhyachal Takniki, May 29, 2015.

  1. Vindhyachal Takniki

    Thread Starter Member

    Nov 3, 2014
    349
    6
    1. My circuit is powered by +5V. It then runs a MCU with 3.3V (LDO used) & then lcd powered by +5V.
    2. Now if any case user coonects higher voltage than +5V then it will damage the lcd.
    3. Is there any way to protect it.
    4. One way is to place a zener of 5.1V. But usually zener conducts a lower voltage than rated & second its series resistor will limit the current.
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,992
    745
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    If using a crowbar circuit, don't forget the series fuse.
     
    Hypatia's Protege likes this.
  4. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
    2,791
    1,236
    OVP is a well 'explored' area --- A basic crowbar should suffice

    My recomendation is implementation of a 1N6373 (or NTE 4900 -- http://www.ntepartsdirect.com/CGI-B...ebrtn=search&ml=LANSA:XHTML&part=CEP&lang=ENG )

    EDIT: Please be advised that the above linked page is maddeningly slow to load!:rolleyes: -- Patience though, it is a working site...:)


    Of course it goes without saying that you'll need to provide appropriate over-current protection lest the OVP device 'falls upon the proverbial sword' in vain... :(;)

    Best regards
    HP
     
    Last edited: May 29, 2015
  5. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
    2,791
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    @Dodgydave and @MikeML

    Sorry about that! It seems I spent so much time waiting on 'NTEpartsdirect" (so as to copy the link) that your responses were 'in' by the time I clicked the post button:oops:

    With abashed contrition
    HP
     
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