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  1. #1
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    555 power supply

    a 150W switchmode power supply with 555 timer:
    it cheapest method to design such switch mode power supply.

  2. #2
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    555 smps

    March 1977, you must be kidding. I it 2004 now, get real!

    Ante



  3. #3
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    ka3525 circuit

    in 2004,we can advanced chip(like 3842,....),but 555 chip is cheapest!


    1 members found this post helpful.

    •   Alt29th May 2004, 15:53

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  4. #4
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    homemade switching power supply

    the fundamental behind the most of SMPSes are the same but the advances in technology provide lower cost, efficient and feature rich chips which integrate all of the power electronincs circuits in a single die or package (hybrids).
    currently several manufacturers provide integrated switchers/regulators with this range of power or upper; BTW the circuit is useful as a home made DC to DC convertor.

    BEST!



  5. #5
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    ka3525 application

    This 'simple' step down converter is one of the most expensive I ever seen. (1977 it's ok, but today too expensive)
    This regulator has a poor efficiency. I think the losses in the switching Darlington transistor are > 10W. So you are in need to cool it well with a very expensive and BIG heat sink !!! A mechanical disaster.

    Modern concepts are much cheaper. They work with MOSFETs and do not need heatsinks to be cooled.

    felix1200


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  6. #6
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    smps 555

    8) i have used 555 timer in low power DC DC converter application, works fine but has many limitations. 1; have to add external referances 2: add external drive elements 3: limited sypply voltage range. 4:external components required for current limiting .

    way back in 77 the price of SMPS controllers where high and people where experimenting using other available IC s.
    but now the price of 555 , SG3524, TL494 or UC 3842 are almost equal. there is no point in designing using Timer IC.



  7. #7
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    555 switching power supply

    The 555 is cool but not for this application! And look 8O at some of the other stuff, transistors, diodes, PUT and more. They are gonners in an app like this, maybe not even possible to get hold of.

    Ante



    •   Alt30th May 2004, 21:11

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  8. #8
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    555 timer power supply

    It sounds to me like "Rocket-engine powered dragster using cart wheels".
    Call me ultramodern but I prefer KA3525 ;)
    If everything looks fine,there must be something very wrong here.



  9. #9
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    lm555 with smps

    Ka3525 for halfbridge,
    I think Uc3843 for forward topology power supply is better.



  10. #10
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    power supply 555

    Hello Everybody

    I don't know why people think its shame to use old or cheap stuff to acomplish a job, the guy just wanted to share a nice circuit, in deed, the UC3843 is not available in my country, so Such people like me will consider such circuit of great help.

    Anyway,ITS UP TO THE CONSTRUCTOR whether to use new, old or even discontinued products. My self, I have used the µPC1225H to build an audio power amplifier of 60 watts output. Its performance was great, although its a continued one and really old one.

    No hard feelings
    Regards


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  11. #11
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    uc3843 power supply

    Good one!!
    We should think about improving this circuit by replacing switching transiotor
    by power MOSFET!



  12. #12
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    ka3525 schematic

    i think we should improve effcient.



  13. #13
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    uc3843 power supply schematic

    Hello

    Concerning the MOSFET, I think there is no need to use it, as long as the switching frequency is not too high. So as not to raise the cost, for being cost effective.

    Regards



  14. #14
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    homemade switch mode power supply

    Hi, friends
    Anyone can please send me some SMPS schemmatic, I´m working in a project like these. Thanks!



  15. #15
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    ka3525 application note

    I made an alternative link on my server.

    Hope that helps!

    150_Watt smps.pdf



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