Buck driver design - component selection example

Tiny10’s can have issues being programmed in C. Like very easy to run out of RAM and stack space.

Yeah, just outside Raleigh; I’d love to

Looks good to me. The links didn’t work, so just be sure the Maxim part is correct since it looks like there’s a typo in the part number

Awesome man… So after this is out we should have a go to buck and direct drive in the blfdd?

Allright guys, after a little bit of a headache here’s the .sch. Now I need to find the dimensions of a Courui driver, anyone got one to measure?

Double check the direction that diode is facing

5-8 amps with constant current? If this driver turns out well, then ill just say...

Good catch, fixed. And while I’m waiting for either one of my Courui’s to get here or for someone to hook me up with measurements, just for S&G’s I thought I’d see if it’d fit in 26mm, definitely not even close!

Try using a smaller footprint FET like the LFPAK56, about half the size and very low Rds-on.

Very first draft of the very first board, AVR based for you guys (cause if it was for me I’d make everything in PIC). Wish I cold be working on the Courui driver but no one’s yet came threw with measurements or a driver I can borrow…

Notice there is only one remaining air wire (which I cant find, even when I turn off all layers) and it almost passes DRC (only has a couple of clearance errors)!

NICE)!! smash compments, fix silk scrern,but daggum most AWESOME what size driver and what will it go in when you are done?

42mm for TK61. I have some more components to add to the other side including a smart latching FET based switch to kill the buck chip (since it doesn’t have a low power standby mode), that’s what the 2nd e-switch will do, one for power and one as the normal AVR momentary FW input. That will all require major changes, I just needed something to show for what I’ve got in this already so I threw this together.

Sorry C_K, I loaned my Courui to a mate for the night. I should be getting it back tomorrow, so I can give you dimensions in about 24hrs from now if need be.

…So he ‘forgot’ to bring it back in to work today….

If you need other measurements, like shelf width, etc., let me know.

Yes I need everything, I also need the spacing of the cells so I can get that figured out.

Question, will it be possible to drill and tap mounting / ground holes (2 or 3) in the ledge the driver sits on to be able to screw it down? With the series conversion driver orientation will be critical.

This is what I’m working on in the mean time, there are several components missing for a smart latching switch (that will run off a coin cell) that uses a FET to kill power to the MAXUM chip, this will allow both buttons on the TK61 to work as normal, one as power (turn the FET on/off) and the other as the one mode change switch everyone uses for the different AVR momentary FW’s. The ATTiny13A wont control the FET at all, the Li coin cell will power a small iC to handle that part.

As you can see this is version 0.1, there are several issues I see right off the bat so still very far from having anything to order.

Nice job CK!

The inside diameter of the driver tube on my Courui is 34.1mm and the cells are in a 22.2mm circle.

Hope this helps, keep up the good work :slight_smile:

The driver for the Courui has two locating tabs, with corresponding cut-outs in the shelf, which would be the perfect place to drill & tap. ~12 o'clock & 6 o'clock in picture below;

In fact, I will do this to mine when I get it back instead of having the solder blobs there for grounding purposes.

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Hm, I hadent paid attention to the ears, one thing I’ll need to verify is that the cut’s for the tabs are at the same location in every different variation of host. I may have to end up not doing them, since again there’s only gonna be one way the driver can be orientated cause of the cell conversion.

I’ll be getting a couple more Courui’s from the GB deal, so will be able to compare the cut out location. Unfortunately, they probably are a few weeks off yet.

Even with the driver in a fixed position, won’t we have to make sure the battery tube will end up in the same position when screwed on?

edited- changed ‘BG’ to ‘GB’…