Don’t forget that you’ll need to significantly drop the PWM freq for this thing to work correctly. The last test I did was at ~1khz I think. I switched the firmware to Phase Correct PWM and used the :8 divider as per post #51 in this thread.
With the PWM frequency at 1 Khz, what do you see on the output? Is it still pretty smooth? I still find it intersting that the 9.4 kHz runs so well in the M6, but it's got to have something to do with the component network that feeds the 7136 its PWM signal.
I also have not found the parasitic drain to be objectionable.
Here is what I recall from my last testing with the scope (I’ve never placed one of these in an actual flashlight). The waveform is stretched out a lot of course. Output is still pretty smooth, especially at low levels where (as I’ve mentioned) PWM appears to bring arbitrary output levels rather than ones which are really based on the set current + PWM duty cycles. At the higher PWM levels it’s easier to see what’s going on (eg the waveform isn’t actually stretched out, but rather less chopped off than at lower freq. I did not see anything which seemed like it would definitely be a problem.
I am confident that it is not “something to do with the component network that feeds the 7136”.
A. Your normal M6 mod bypasses that entire network: the “P” pad is attached directly to the 7136’s.
B. The driver in this thread works fine at 9.6Khz with the DTU30N02 pulled from the M6 driver.
Therefore the issue is entirely with FET selection…
Ah that’s cool to hear I was a bit worried about the 1khz only part of this driver. This fet looks like a good option for my particular usage since when it comes to fet size, the bigger the better.
Is there a known source for this mosfet that isn’t from an m6 driver? I can’t seem to find it available at the usual places, ie farnell, mouser or digikey.
No known source. I see the smiley, but just to be clear: bigger is not better. Bigger is because it’s an older, less advanced, higher thermal resistance package.
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…
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.