Author Topic: I need help with with buck/flyback converther that does not use any controllers  (Read 872 times)

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Offline NikKotTopic starter

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I want to make a 32V to 16V converter but I do not have access to microcontrollers and other specialized components. I'm looking for for a circuit that only requires base components like pnp/npn transistors and etc. It doesn't have to be "beefy", I only need 100-200mA from it and I don't really care about efficiency. Any help and ideas or circuits will be appreciated. I'm using LTSpice so the ideal option would be some kind for circuit for that.
I'm sorry if this kind of topic isn't accepthed here, but it seems to me like a good place to post this.

upd. Forgot to mention that I have ferrite cores and I can wind them with the amount for turns needed.
« Last Edit: August 23, 2020, 06:37:40 pm by NikKot »
 

Offline Buriedcode

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The MC34063A is pretty widely available - even if you can't order form any distributor, they are so ubiquitous you can find them in almost any USB car cigarette power adapter.  It's old, less than stellar efficiency, low frequency, but it does the job, and will work fine for your application.

It's Vmax is 40V so should be fine for 32V in, and should just about handle the output current.
 

Offline T3sl4co1l

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This is a pretty reasonable approach, having current-mode behavior similar to UC3842, but with variable frequency as well.  Multiple outputs are shown, you may not need those.



Tim
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The following users thanked this post: NikKot

Online langwadt

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why a switcher if you don't care about efficiency ?
 

Offline nigelwright7557

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my last smps was llc and used a pic micro.
was easy to develop and worked well.
even had oc detect.

 

Offline NikKotTopic starter

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This is a pretty reasonable approach, having current-mode behavior similar to UC3842, but with variable frequency as well.  Multiple outputs are shown, you may not need those.
Thank you very much! I'll look into it and modify to my needs when I'll have time and update on how it turned out. Sorry for not replying quickly i was too busy too check this thread.
 


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