My TO-3 switcher (buck converter)

[Alex Eisenhut]

That new switcher looks nice, you probably could also add extra pads for the feedback side to make a drop in replacement for a 5V, 8V and 12V regulator, or just put the bottom resistor of the divider near the side so it is easy to change out to adjust. Bottom resistor so it defaults to 0.8V if it goes open circuit.

Yes, the pads for L1 are oversized for other output inductors, and changing the voltage is just a question of changing feedback resistors.

But the 12V has transient loads; the floppy motor and head stepper. That's where the compensation loop will probably need to be tweaked too.

I'd buy one just to sit on the shelf!

A 1541 or a Ton3y? I have two other boards!  And it looks like KS has a Canadian section now. I don't know if there's this enormous TO-3 market though. Jewellery, eh?

[BravoV]

I don't know if there's this enormous TO-3 market though. Jewellery, eh?

The audiophools herd, once they're picking up, you could be ended with filthy rich. 

[emc-problem.net]

Well work.     This is awesome!!!

[Alex Eisenhut]

Well work.     This is awesome!!!

?  O0

[T3sl4co1l]

"Good work"?

[Alex Eisenhut]

Well work.     This is awesome!!!

?  O0

Oh, weird, the Cyrillic characters just get zapped? Oh well. Spasibo, I guess?

[babysitter]

You have beean HackADayed!

[Alex Eisenhut]

You have beean HackADayed!

Ah, that explains the explosion of views. I also see that there is a previous to-3 switcher out there. Great minds, I guess...

[TiN]

Great idea, thumbs up :-)

[AccountRemovedPerUsersRequest]

...Anyway, congrats on a fine looking project, and on reviving that 1541. Please let us know if you make the project available, even if it's as an OSHPark file and a BOM.

Second that. Even if you're not publishing the project the schematic and/or BOM would be interesting to see. Just built a small size dc/dc converter myself...

Axel.

[Alex Eisenhut]

Well the schematic is just the TI circuit from the datasheet. I ain't no EE genius over here. I just calculated the coil value, added some filtering, a fuse, and the layout. Oooh and I picked those Mill-Max pins.  O0

The regulator is working in a 1541, and there are no problems.

I'll take some waveforms and post them, as soon as the weather sucks.

[AccountRemovedPerUsersRequest]

Well the schematic is just the TI circuit from the datasheet. I ain't no EE genius over here. I just calculated the coil value, added some filtering, a fuse, and the layout. Oooh and I picked those Mill-Max pins.  O0

The regulator is working in a 1541, and there are no problems.

I'll take some waveforms and post them, as soon as the weather sucks.

Could you tell which chip you used? (I think I didn't catch the information)

Axel.

[Alex Eisenhut]

It's the TPS54232.

[Kjelt]

Very nice project, well done. Now a nice looking cap on top and heat conducting potting material and finished 
I thought there was a TO3 7805 that was rated for 5 Amps or am I mistaken?

[rdl]

I thought there was a TO3 7805 that was rated for 5 Amps or am I mistaken?

I'm pretty sure there was. I also seem to remember there was one company that made a TO-3 5 volt regulator that went to 10 amps, it had a different number from 7805 though. I have an LM338K in a TO-3 rated for 5 amps in my parts collection.

[Monkeh]

I thought there was a TO3 7805 that was rated for 5 Amps or am I mistaken?

I'm pretty sure there was. I also seem to remember there was one company that made a TO-3 5 volt regulator that went to 10 amps, it had a different number from 7805 though. I have an LM338K in a TO-3 rated for 5 amps in my parts collection.

LT1038 comes to mind.

[Alex Eisenhut]

Very nice project, well done. Now a nice looking cap on top and heat conducting potting material and finished 
I thought there was a TO3 7805 that was rated for 5 Amps or am I mistaken?

78H05

[Alex Eisenhut]

I thought there was a TO3 7805 that was rated for 5 Amps or am I mistaken?

I'm pretty sure there was. I also seem to remember there was one company that made a TO-3 5 volt regulator that went to 10 amps, it had a different number from 7805 though. I have an LM338K in a TO-3 rated for 5 amps in my parts collection.

He is only after 0.5A so a regulator with a higher CL is pointless. The object was to minimize heat within the enclosure because he says the regulator is fed with a high voltage. Even at 12V in you would be looking at about 3.5W at 5V @0.5A output.

For that T03 package to deliver that 10A across a wide input range would mean a large expensive heatsink plus a fan. A bjt pass device would likely need at least 3V headroom @ 10A so you would be burning 30W minimum, probably why you don’t see too many of those types of regulators anymore. Basically the 10A rating is pretty well meaningless.

Ton3y can safely source 1A with 9V DC in. The TPS chip is rated to 2A, and I think it can do it if I review the inductor selection. The weak point is the thermal design, I should have put more thermal vias around the diode too.

I will likely re-spin with a higher-rated part and put more thermal vias.

[technix]

You can put a bit of solder on the component side to old the pins down firmly.

[LabSpokane]

So, OSHPark doesn't have a design rule issue with copper extending all the way to the board edge?

Nope. And you could just download Laen's design rules. I have run copper to the edge on a couple boards and it's been fine.

[tree]

Neat project. I sure do love the TPS54xxx datasheets. They are very well written with tons of design equations that result in good enough starting values for designers.

[Alex Eisenhut]

If anyone is still reading, I'm building up the 12V version and will try a Commodore 1541 with two Ton3ys in it.
Soon.

[Alex Eisenhut]

Wow, time flies. Well, it is just a regulator, and they work pretty well so far.

The rightmost one is the 5V version with extra output capacitance, and the 12V one is for driving the motors, the output can be noisier.

The 1541 runs quite cool.

[AF6LJ]

This is one fo the best things I have seen come along in a long time.
I am also following. Great

[Alex Eisenhut]

This is one fo the best things I have seen come along in a long time.
I am also following. Great

Thanks, it looks good but the fatal flaw is that now that the input side needs less current, the voltage on the smoothing capacitors rises and they are running close to their rated voltage. Don't know how great that is for 30 year old electrolytics. So the lifetime I might gain by running cooler I'll lose by running those capacitors too close to their rated voltage.