[retired] [WIP] 20mm single sided & 17mm double-sided ?-amp linear driver - surprisingly good!

Argh too bad…and yes of course bigger is only sorta better for my particular scenerio where it’s easier for me to mount onto a heatsink and airwire to the rest of the driver.
Those tiny little LFPAK fets are quite remarkable and will work also, as long as I don’t drop them and lose them while installing that is… :wink:

Don’t forget that there’s no reason not to use led4power’s expander PCB w/ this driver: OSH Park ~ Shared Projects by led4power

Of course that big copper pour must be electrically isolated from your heatsink!

So am I the first non-Wight person to fully assemble it? It was a piece of cake to assemble, but I must not have the FW right, because it only lights up on turbo. Here is my source file.

sorry for the blurry cell-phone pic

mine is all in the mail should be here any time soon

You didn’t share that file properly, I get the “You need permission” message.

Just keep dropping the freq until it works.

EDIT: Build looks good BTW.

Thanks for posting your code. I think there is what I would consider a minor regression redundancy of stuff in this version. I’ll take a closer look when I’m more on point.

Please comment out “#define FAST_PWM_START” and then change this line:

“TCCR0A = 0x23; // phase corrected PWM is 0x21 for PB1, fast-PWM is 0x23”

to read like this:

“TCCR0A = 0x21; // phase corrected PWM is 0x21 for PB1, fast-PWM is 0x23”

I fixed my link… I think… and fixed an obvious error in the FW, but now it appears as if moon is missing. The FW has Moon>L>M>T, but it I am only seeing three modes. It is lighting up on Medium and Turbo, but nothing on low.
So you’re saying to take it from :8 to :64?
………….
Oops, missed your last post

I tried the “TCCR0A = 0x21” and I upped moon from 3 to 5 pwm, and there appear to be no changes since my last post. 3 modes, one of them doesn’t light.
Rev 3 code

Update: I also just tried setting “TCCR0B = 0x03” and moon PWM to 8. Again, no changes.

Up the PWM levels a bit. The response curve isn't the same as 7135s or normal FETs.

Ah, sorry. I didn’t think about / notice the low moon mode you were using. That won’t work! :wink:

… Crap, that took forever. I couldn’t find where I posted on the subject! (Post #45.)

I’d start with around 10 to 15 and work from there.

Ok I tried it with this code.
Modes L>M>H>T with PWM levels at 20, 50, 100, 255
Still acts like there are three modes, but only two of them light up. very strange.

Well, just keep going upwards until you get something.

EDIT: I see now that you are saying that you’ve added a mode. Hmm.

My eyes need a break. I’ll take another stab at it tomorrow afternoon.

Good luck. Programming 4 modes and only getting 3 does not sound like a hardware problem. In fact, it kind of sounds like it didn’t flash at all…

Well, it has always had 4 modes, I just replaced moon with high. There has been no change in results from the last 3 fw revisions, so I thought maybe it wasn’t actually flashing it. This last time I erased it completely, then took the clip off and made sure the chip was actually clear before flashing rev5. Didn’t make any noticeable difference.

Maybe you are flashing the same hex file over and over?

I’m rebuilding it with each iteration, but if you don’t see something wrong with my code, that is still my best guess. Maybe there’s something weird going on with the avr tools cache. We’ll find out tomorrow.

I don’t see anything that would make either 4 mode config appear as 3 modes.

What procedure are you following? I do this:

  • build in AVR STudio
  • expand “output files”, double click on the hex -> save the hex file with a unique name
  • switch to the CLI (command prompt)
  • flash that particular hex file using a command formatted like this:
    avrdude -p t13 -c usbasp -u -Uflash:w:xxxxxxxxxxxxxx.hex:a -Ulfuse:w:0x75:m -Uhfuse:w:0xff:m

That’s exactly what I’ve been doing, except for the unique name. I have been overwriting “FW.hex” with each build so I can just copy/paste the same command line. I’ll try closing studio between builds to make sure it’s actually rebuilding it, then try unique names if that doesn’t work.

I don’t see why you should need to do the unique names part, I was just telling you exactly what I was doing. If you are actually opening the “save” or “save as” dialog box and overwriting the file each time I think we can be confident that you do not need to do anything different there.