17mm/22mm MTN-MAXlp - Low-Profile 1A-4A Programmable Buck Driver + 22mm MTN-MAX

5A 17mm board ? Yes please ! how do i order one of these ? I was going to make an adapter for the 22mm board for my 1405 but this will save me the trouble.
Thanks

I still can’t get a working example. I’m tried 3 times and no success.

17mm? I have built about 50 of them so far and they've all worked. 20mm--well, you read my post earlier (no go for most setups). 22mm I've built and have been using about 6 of them in lights and they've all worked so far.

A lot of the issues you'll run into is that reflowing these boards properly is much more difficult than anything else we usually do because of the tiny pin pitch and non-existant leads. A stencil may help a little bit (although I don't use one for these), but really it comes down to some practice and then following up with a manual reflow of the leads with your iron on the sides of the flat packages after the initial reflow, if needed.

Soon! I have been testing them and I have a few test samples going out to other members and flashlight guys as well to make sure they're 100% before the "official" release.

Richard, can you please post pictures of a 17mm completed driver?

I'll take some later this week when I build another one.

I finally got my last set if parts to work! About time.

Great! Did you figure out what made the others not work?

The first two I have no clue. The second one I made wouldn’t work so I put it away to take a break. I got back to playing with it a couple of days ago and absent minded me fried it. I forgot to change my test bench setup back to 2S. I inserted the batteries like it was 2S in my side by side battery holder. Well, it was 1S and the way I have it set up also means it was reversed polarity to the driver. It smoked. I dunno what fried but something did. It also blew the LED too. I’m just gonna take all the components off my first one and reflow them to see if I can get it to work.

So for future reference to others, 1S reversed polarity doesn’t get along with this driver :wink:

Good to know! :stuck_out_tongue:

I haven't tried to reverse one, but I think that cerealkiller said that he had reversed polarity to this same IC before and nothing happened. He said he had even measured the LDO output and it also didn't reverse.

As far as the non-working drivers go: I can almost guarantee you that it's your reflow of the MCU, Buck IC, or both. The MCU is usually the culprit.

Hi Richard. Have you done any specific efficiency testing of this driver with an MG-G2 in high, medium and low modes? Alternatively, have you sent any to HJK for testing? Thanks :slight_smile:

Nope, haven't sent any, but you can do a rough efficiency calculation based on the information posted up above.

I built a 17mm MTN-MAX at 2A with the standard inductor [not Coilcraft] and compared it to two zener modded 7135 drivers.

LED: 6V MT-G2
MTN-MAX 2A: 8.4V=1.6A; 6V= 1.2A --- Continuous output. Driver produces far less heat with full cells
QLITE 2.2A: 8.4V=2.5A; 6V=1.5A --- Thermally derates within around 30 seconds w/ full cells
QLITE 1.9A: 8.4V=2.0A ;6V=1.5A --- Thermally derates within around 20 seconds w/ full cells

Thanks. I saw the post and thought I misunderstood something. Would the calculation be (6x1.2)/(8.4x1.6)=0.536 or 53.6%?

The way I understand it, those are two different data points. The driver is outputting 2amps at the emitter. When the input is 8.4v, the input current is 1.6amps. When the input is 6v, the inp[ut current is 1.2amps. You can’t really do the calculation correctly without knowing the forward voltage during his testing, but I guesstimate by just saying Vf is 6v.

So the equation would be (6v*2A)/(8.4v*1.6A) = 89%

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I think.
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I would be more confident, but I feel when input and output voltage are the same (6v) the input current should be much higher than 1.2amps, so I’m probably reading it wrong.

Ahhhhh! This is more what I expected! Thank you. :smiley:

That's correct. Convert to watts, then compare watts in to watts out.

I saw a Cray II running once. There is one at the computer museum in Mountain View, but it doesn’t look so impressive turned off. When it was running, there were streams of tiny bubbles rising from the components. It ran in an aquarium full of freon.
A cooling liquid should be low viscosity and preferably have its boiling point below the highest component temperature. The main practical requirement, though, is that it not affect the components. Water probably won’t do, because it holds ions that make it conduct and it hydrolyzes. The ideal fluid would also have a high heat conductivity, high heat capacity, low surface tension and large thermal expansion.

Can the 22mm version of this driver be used with an electronic switch?

Yes, if it is programmed to use one. The quiescent current drain isn't super high (lower than zener mod), but it still isn't ideal for use as a momentary driver without a lockout of some sort.