Thread: Anyone try a Forward Converter?

it seems that the link for the schematic http://albums.photopoint.com/j/AlbumList?u=1761087 is broken or server is down..can someone put it up on the mp3car.com server for backup purposes? =)

[ 08-29-2001: Message edited by: moahdib ]

Hi I put up the schematic at www.noduck.nl/namms/psu.html

PressLab: if you don't like me putting up your work, please let me know and I'll remove it.

[ 01-23-2002: Message edited by: marsjell ]

I never thought that a transformer could be used for stepping up /down DC voltage... or at least that's what I had read previously.

Anyay, someone really needs to try this. I see a future here for both newbies and people who are currently using inverters.
Let's all put our minds and resources to this and make it a group project for mp3car.com.

I will probably try and make one myself when I find some more time, even though I already have a decent dc-dc.

Originally posted by moahdib:
<STRONG>I never thought that a transformer could be used for stepping up /down DC voltage... </STRONG>

It can't directly, the primary is switched.


Rob

Originally posted by marsjell:
<STRONG>Hi presslab,

good to have you back
uhm I agree with you and wend to the local elec. shop, but some parts are hard to get, like the SMBJ28A...(28V TVS/1500W) do you have any alternetives for this diode?

tnx
marsjell</STRONG>

About the 28V TVS/1500W. You can use any TVS, and 28V is not some magical number. Try finding a 1.5KE27A. You could use anything from 20V to 35V. If you can't find a TVS, just replace it with a regular diode (like a 1N4003). It is there to limit the inductive spikes, to help reduce the audio switching noise. Also, it provides reverse input protection.

If you are in the US or Canada, go to www.digikey.com, they have lots of parts, ship overnight for $25, and sell small qty.

If you connect the supply backwards, it forward biases the diode, causing massive amounts of current to flow (protecting the circuit), and blowing the fuse farther up the power wire. Yes PUT A FUSE ON IT! I have a 25A fuse, and it hasn't blown yet. There isn't one in the schematic, but I have two fuses on mine before it hits the positive battery post. Better to blow a fuse, than to start a fire or some awful thing!


And I encourage you all to put up a web page with my schematics, construction info, whatever else. You can even say you came up with the idea and the schematic, it doesn't matter to me! I'm in this for the fun, I get enough money at my day job

Presslab

Hi guys,

sorry to do this, but I look back into this topic a lot of times while trying to build this, but lately I have a bit of a problem finding it, so I post this to get the topic back on the main page...
my humble apollogies

I'm glad you bumped this thread. It helped me find it.

Any more updates or DIY websites yet?

Thanks,
Pigseye

I'm gonna do this!

First, I'm going to try it on an old ATX supply I have laying around, then if it works, I'll do it to a small micro ATX power supply I can stuff in my mp3box.

Anyway... Quick question. I was going to order the chip and stuff from mouser, but one question...

They have a SG3525AP and a SG3525AN. Is there a difference? Which one should I get?

Oh, nevermind, I figured it out. One is surface mount, one with the normal pins.

Few more quick questions:
Resistors - Normal 1/4 watt metal film resistors good?
Capacitors - 100V, electrolytic fine?