Need help with a max1771 design

Discussion in 'The Projects Forum' started by illayaraja, Oct 10, 2015.

  1. illayaraja

    Thread Starter New Member

    Oct 6, 2015
    12
    0
    Hi...
    I need to generate 100V @20mA using max1771 and i want connect 1k to 10k load it's ?..... plz give me any ideas?


    Moderator note: The first three posts of this thread were moved here from a highjacked thread.
     
    Last edited: Oct 10, 2015
  2. illayaraja

    Thread Starter New Member

    Oct 6, 2015
    12
    0
    Hi fnds........
    I need to generate 100v @ 20mA it's possible to do ?...i'm using max1771 in my circuit i got 100v but while i'm connecting load it i'll goes 50v @54mA ....i want connect 1k to 10k load
     
  3. bumba000

    Member

    Oct 7, 2015
    72
    2
    I do have three of these tantalum caps available (https://www.digikey.com/product-detail/en/TAP336K020SCS/478-1895-ND/563998). Put them in parallel and it didn't help. So, I pulled a couple of aluminum polymer caps (these ones http://nichicon-us.com/english/products/pdfs/e-l8.pdf) from a good video card and it doesn't seem to have helped. =0(
    The caps are the 6.3v 560uF version.

    Also, I'm not sure what it means just yet but I've found out that the PWM speed is actually 500Hz. I see that you've mentioned the inductor's resonance should be 5x greater than the switching frequency. I don't know what switching frequency means but I'm assuming it's the PWM speed. Which would mean that the inductor resonance should be about 2500? I feel so lost. I am finding resonance is when inductive and capactive reactive are the same?? Oh my goodness.

    Help please. Unplugging solder iron, multi meter off, lcr meter off, head on pillow...
     
    Last edited: Oct 10, 2015
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,780
    1,103
    First, you need to post a schematic of your circuit.
    :confused: A 1k load on a 100V supply will draw 100mA; not the 20mA you specified.
    Google will help you regarding PWM.
     
  5. illayaraja

    Thread Starter New Member

    Oct 6, 2015
    12
    0
    View attachment 92826
     
  6. illayaraja

    Thread Starter New Member

    Oct 6, 2015
    12
    0
    Untitled.png
    I'm using same circuit .....switching frequency 60khz
    while input 12v E=80%
    while input 9v E=40%
    my inductance 100uH
     
  7. illayaraja

    Thread Starter New Member

    Oct 6, 2015
    12
    0
    thank you
     
  8. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,780
    1,103
    The link in post #4 is broken and the image in post #6 is too small and too faint to read :(.
     
  9. illayaraja

    Thread Starter New Member

    Oct 6, 2015
    12
    0
    View attachment 92877 max117.png
     
    Last edited: Oct 13, 2015
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