The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: email@example.com (Nico Coesel)
Subject: Re: My flyback experiment is on the web
Date: Mon, 14 Oct 2002 09:58:53 GMT
NNTP-Posting-Date: Mon, 14 Oct 2002 10:00:33 +0000 (UTC)
X-Newsreader: Forte Free Agent 1.21/32.243
Chris Carlen wrote:
>Here is the URL to my web page showing the results of my most recent
>experiments with a flyback converter. I still haven't gotten a PWM chip
>hooked up yet, as my first goal was to buy some inductors that look like
>they are designed for switching supplies, and see if they'd work better
>than the hand wound transformer I made from a PC power supply core.
>Actually, the inductor seems a bit worse :-(
>All the details are on the web page.
>My main question is why does the inductor get so warm? I figured I
>wasn't really pushing it too hard, so it shouldn't loose much power.
>but it seems most of my losses are occurring in the inductor. I was
>hoping to avoid complex topologies such as a two transistor flyback,
>which requires a transformer, but lends itself to easily shunting the
>remaining core energy back to the input rail. Can that be done with the
>simple flyback that I am working with? I figured I could get 75% or
>better, so I'm not really far off. But I don't like heating the
>inductor, and I want to push up the power another 25% from what I'm
>testing at before I finish.
>I have a smaller inductor, and a larger one too, but all of the toroidal
>type, designed for 150kHz switchers.
>Comments appreciated on what steps I might take to make this simple
>circuit move in the direction of something worth committing to FR-4.
Strange; I've designed a similar converter (48V in, 168V / 100mA
@100kHz) but didn't have problems with the inductors. I've used 2
newport power filtering 100uH inductors in series (didn't have 200uH
I see there is also some ringing in your circuit. Did you try to put a
small snubber accross the drain and ground? Did you also consider
simulating the circuit?
Reply to nico@nctdevpuntnl (punt=.)
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup