I have a problem generate 100VDC from 24VDC

Discussion in 'General Electronics Chat' started by firend, Sep 19, 2012.

  1. firend

    Thread Starter Member

    Feb 18, 2012
    44
    0
    I was assigned a exersice. I will use DsPIC to generate 100VDC from 24VDC. because 100VDC is large, I haven't any idea to measure 100VDC to feedback DsPIC. What do anyone have idea to solve problem?
    Thanks in advance.
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,740
    759
    U are basically saying u have nothing to start with.
     
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  3. m1ch43l

    Member

    Aug 16, 2012
    62
    1
    Use a voltage multiplier. Find a way to have a sine or square wave to feed it.
    Hope these might help:
    how multiplier looks like
    http://en.wikipedia.org/wiki/File:Voltage_Multiplier_diagram.PNG
    using a timer chip to achieve this
    http://talkingelectronics.com/projects/50 - 555 Circuits/50 - 555 Circuits.html
    look for the titile 'THE SIMPLEST 555 OSCILLATOR' on the first third of the page
    using the latter schema, merge the output to the first schema with the appropriate n/o stages and you should have your 100v give or take.
    About using this chip (seems programable and I assume that you'll need a prog to do some oscillations) cant help.
     
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  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You say you're starting with 24V DC, and you need 100V DC - but you don't mention your output current requirement.

    If your current requirement is low (a few mA), you might use a boost converter. If you need more than that, you might consider a flyback converter.

    Have a look at Ronald Dekker's "Flyback Converters for Dummies" page:
    http://dos4ever.com/flyback/flyback.html
    It's really not for dummies - what it is, is an excellent introduction to a couple of types of switching power supplies that you can build with reasonably common components.

    For T1, you can substitute a 2N2222, 2N3904, 2N4401, or a variety of other small-signal NPN transistors.

    For T2, you can substitute a variety of N-channel enhancement mode MOSFETs, as long as the Vdss is 100v to ~300v. You'd have to add a regulator to step your supply voltage down to 12v from 24v, but you can use 24v to the left of C1.

    Reduce R4 to 120k. That will reduce the output voltage range considerably. When the voltage divider created by R4-R5-R6 exceeds about 0.63v, T1 turns on, which pulls pin 5 (CNTL) of the 555 timer to nearly 0v; this causes the 555 ON time to be much shorter than the OFF time along with the output frequency increasing.
     
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  5. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    Use a simple boost converter, easier than a flyback because you don't need a transformer just one inductor.

    You can use simple switcher software at National Semiconductor.
     
  6. firend

    Thread Starter Member

    Feb 18, 2012
    44
    0
    thank everyone.
     
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