Self Destroying Mosfet with PIC


Closed Thread
Results 1 to 10 of 10

Hybrid View

  1. #1

    Red face Self Destroying Mosfet with PIC

    Just that, i am using a IRF530 with a circuit as boost converter. Seems to work fine But
    from time to time i receive complains and the MOSFET is destroyed.

    How do you interface MOSFET to PIC to avoid destruction?

    I am posting my circuit, in case there is any flaw on it.

    Thanks FOr all your POSTs


    <img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=2114;stc=1&amp;d=11938 56902" width="400" height="350" />
    Attached Images Attached Images  

  2. #2


    Did you find this post helpful? Yes | No

    Default Irf 530

    A couple of thoughts.

    a. Try a small series resistor in the gate drive. I have read this somehow helps with the large input capacitance (1300 pF). I guess it reduces gate current.

    b. If the gate drive is held on too long, the inductor will saturate and the drain current will be enormous. Max allowable is 16 amps continuous or 64 amps pulsed.

    c. If the PIC driving the gate has other tasks to do, can you be certain that you are not leaving the gate high long enough to saturate the inductor?

    HTH

    Brian

  3. #3


    Did you find this post helpful? Yes | No

    Default But i am using HPWM

    i will try with the resistor at gate.

    I am using HPWM that is supposed to be on all the time the device is on... it is like the first part of my code.

    Appart from that i never use HPWM off or something like that, but it is true that a cide BUG could be guilt for this behaviour..... As i said i am usin HPWM switching at 4000 with dutty 20.

    Would there be any other idea? Would a NPN transistor like tip31 work better?

    thanks

    DJC

  4. #4
    Join Date
    Nov 2003
    Location
    Wellton, U.S.A.
    Posts
    5,924


    Did you find this post helpful? Yes | No

    Default

    I will echo what Brian said with the added thought about amps.

    You will need a good heat sink and if the amps are near tolerance run two or more MOSFETS in parallel.

    Another high current/voltage solution would be an IGBT.
    Dave
    Always wear safety glasses while programming.

  5. #5
    Join Date
    May 2004
    Location
    NW France
    Posts
    3,651


    Did you find this post helpful? Yes | No

    Wink

    Hi,

    Would certainly be interesting to scope the Mosfet Drain voltage ... I would not be surprised it goes much over the 100 v rating of the '530.

    1mH is a BIG inductor...

    You did not tell about your diode ... very fast recovery, I hope !

    a series resistor in the gate will lengthen the switching time, and may be hide the problem.
    but also increase losses ...

    some simulation could help to choose the best components match ...


    May be also too close OFF/ON "togglings" of your device ( mains failure i.e. ) can generate some Mosfets destroyed ... my computer inverter supply did it to me once my finger slipped on the ON switch ...

    Alain
    ************************************************** ***********************
    Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
    ************************************************** ***********************
    IF there is the word "Problem" in your question ...
    certainly the answer is " RTFM " or " RTFDataSheet " !!!
    *****************************************

  6. #6
    Join Date
    Nov 2003
    Location
    Greece
    Posts
    4,121


    Did you find this post helpful? Yes | No

    Default

    I will double what Alain stated about MOSFET protection from the coil. Use a diode anti-parallel to the D-S of the MOSFET. If you have a scope, check the spikes on th D pin, but anyway, put that fast diode there.

    Ioannis

Similar Threads

  1. SMS via pic
    By kenandere in forum GSM
    Replies: 15
    Last Post: - 10th March 2010, 10:00
  2. pic to pic ir link versus wired link : help please anyone
    By xnihilo in forum mel PIC BASIC Pro
    Replies: 13
    Last Post: - 30th May 2008, 21:01
  3. destroying my last pic? driving a miniature motor
    By Michael Wakileh in forum Schematics
    Replies: 20
    Last Post: - 28th August 2007, 09:38
  4. Waking a sleeping PIC
    By anj in forum mel PIC BASIC Pro
    Replies: 3
    Last Post: - 19th May 2005, 01:51
  5. Serial Pic to Pic using HSER
    By Chadhammer in forum mel PIC BASIC Pro
    Replies: 5
    Last Post: - 11th March 2005, 23:14

Members who have read this thread : 0

You do not have permission to view the list of names.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts