[Prototype stage]17mm Buck driver (enhanced MTN MAX)

Designed similar to the discontinued MTN MAX driver

completely went from scratch just taking the same Max16820 chip as starting point

Differences to the original MTN Max:

- a lot wider ground ring and part clearance from edge on top side so it fits better with smaller pill cavity

- 6mm spring pad to fit common BLF springs, where the MTN had 5mm

- many cases the 16819 is far better to get a relative low switching frequency (the 16820 is designed for 2Mhz the 16819 has with same values only 666kHz)

- 2 1206 Resistors so its relatively easy to modify the output current, while the original resistor was not stackable at all

- design with optional double amount of Input Caps,

- up to 2 3A fly back diodes depending on the output current (same type but lower forward voltage bin)

- QFN25 Attiny25/85 replaces the MLF10 Attiny 13A

- programming port for my Pogo pin flash key

- switch and indicator Pads for Anduril

  • added a low pass filter to protect MCU from any voltage spikes

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Using the formulas from the data sheet to optimize part values on 3 examples

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It is an interest list to see how much parts I order from mouser beside from prototype ones

Prices:

18.5€ driver (first 20 drivers then reduced to 16€ to cover development and stock up parts)
+0.8€ double diode and input caps
+3.25€ Coilcraft XEL6060 inductor (for high output currents)
+0.5€ BLF Copper alloy spring

Shipping:
Worldwide
2€ <10mm 50g envelope priority air mail shipping worldwide
4€ for optional tracking insurance up to 25€
Soldered long phosphor bronze springs are possible, but it adds about 2.5€ shipping costs (EU more than world because of tax)

+2€ insurance per full 100€ insurance

Germany
1.3€ <10mm 50g
2.4€ thick
add 2.8€ for signed tracking + insurance up to 25€

reserved 2

Lexel, thanks for working on this. I hope a lot of people are interested. Richard, I believe, had an option for 3s input for 6v LEDs. Would that be doable here as well? I’d like to run an sst-70 at 6a with this and have 3 cells in series.

thanks Lexel !

Any chance for a migration to 1634?

“+0.8€ double diode and input caps”
Why?

In for 1. Need to run Rgwn GT-FC40 @12V more than 2A...

Can we order now or need to wait for confirmation?

In for one. Thank you.

Because XHP35 build does not stress like a high current XHP50.2
so no need to put unnecessary parts on it that add costs
I have looked for a cheap coil for lower currents like XHP35 because 2.75€ plus tax vs 0.45€ plus tax makes a lot of difference
And stocking up Coilcraft inductors is quite expensive and may create overstock in the end

Sure the Input of 3S is possible, but the more voltage gap the higher are the losses on the schottki diode reducing the efficiency and create heat

If someone can hand me a proper Atmel Studio Project with firmware migrated possibly,
it makes no sense putting an MCU on it as I have no firmware for it
Would be nice to have also more PWM resolution as the buck chip has only one input to control it programmed for moonlight

I think the design is pretty much final
Next step order prototype boards and solder paste stencil
Then validating at least 2 prototypes with XHP35 setup and one that stresses the buck a lot like 3S to XHP50.2

Tom E has integrated it with AS7 recently:
https://drive.google.com/open?id=1jdx8U3LruVaAzHQi7MOk2UqsE5VW7wKK

But it’s out of tree and may not be maintained. :frowning:
I’ll see, maybe it would be possible to merge that into master?…

I mean taking real advantage of the MCU features with code enhancing for example the PWM above the stupid low 8 bit
not just have 2 more output pins for 3 colors use in the D4V2
that 17mm build has one unused MCU pin anyway

IMHO 3 colors is the killer feature that 1634 brings. :wink:
Anyway, I know that Noctigon K1 has 10 bit PWM. And TK worked with loneoceans to enable that in his buck-boost driver.
I don’t think the code has been published yet though, at least a quick glance tells me that there’s no compile target for K1.

Thank you Lexel. I’m interested in one.

Your link in the other thread does not lead to this one. FYI.

No 1S 3v?

Will this be duplicated in either a 20 or 22mm package? I have an XHP50 light that I dearly love, but have been looking for a buck driver that will supply more than the 2.5-2.7 amps that the driver installed can deliver.

for 20, 21 and 22mm I have already Buck drivers on LM3409 on sale, PM me for order
more details here

Is this still available?

I have done a 3-week holiday and have only my phone with me to check mail or skype

So the board order with these prototypes on it is still not done