H17F - programmable driver with full thermal regulation

Wow, this seems like a great driver with an impressive set of features. I just ordered 2; one for my s2+ with single XP-L and one for a single cell 26650 triple XP-L that Iā€™m planning in a trustfire a8.

I gathered from this thread that the FET used has more on state resistance than, say, the regular FET drivers from mtn electronics? If this is the case I might not want to use this for my triple if I want the possibility of maximum current.

Iā€™m interested in the thermal control. Is it important to sink the driver with something thermally close to the emitter? The PID control sounds cool. The driver can access all 24 brightness modes to control the temperature?

Is semi turbo something like 50% PWM of the full turbo?

Thanks.

I measured my triple XP-L at 10.5A on the MTN-17DDm driver with 18awg wire, and 10.4A on the H17F driver with 22awg wire. I was a little concerned about the ā€œlossā€ of output, but for me the practicality and features of this driver heavily outweighs any losses. I donā€™t think a difference in output would be discernible outside of very controlled testing.

I just have my driver in the pill of my S2 like so:

and I ran it for over an hour one day on turbo, and the thermal regulation did its thing. There was no controlled testing, but it seemed to lose approximately half the brightness as it throttled output. I couldnā€™t ask for more.

Moonlight is super low. ā€œMoonlightā€ on the S30 (1 lumen) vs moonlight on my triple H17F:

The only thing I would change is the spacing between the lowest two modes. I would lower the output on the second level, personally (if possible). Itā€™s quite a jump in pitch darkness.

Sorry if this is a dumb question, but will this driver be suitable for this particular emitter?

http://www.mtnelectronics.com/index.php?route=product/product&product_id=572

Yes, thatā€™s whatā€™s in my light posted above.

Iā€™m glad you like it :slight_smile:

PrinceValorum: The voltage measurement depends on an internal voltage reference in the MCU, which is known to vary a bit - in uncommon cases up to 10% - you probably got one of these :frowning: Canā€™t do much about it. Calibrating each MCU would mean too much hassle (and increase the priceā€¦), and thereā€™s no space for a better external voltage reference on the board.
Lowest two modes: These two modes are the lowest possible PWM modes for the single AMC7135. The AMC7135 takes about 2Āµs to switch on, and the lowest mode sort of switches it off again right then. The second mode already gives the AMC time enough to really switch on, thatā€™s why that step is quite big.

EasyB: Yes, the FET has a higher resistance, because it had to be smaller. But the driver is good for 10+ Ampere, as several people meanwhile measured (one even 11.5A).
Thermal regulation works smoothly, i.e. does not jump in steps of those levels. The algorithm seems to work well under a wide range of thermal conditions and setups, so Iā€™d say itā€™s not important to improve thermal contact of the MCU to the LED. If the control behaves oddly, you could try that though.
Semi-turbo should be halfway between 100% and turbo - though that might vary a bit due to non-linearities in direct drive.

so, when does production start? :smiley:

Iā€™ll need a couple at least!

No worries, I was just wondering. As long as itā€™s consistent over time, I donā€™t really care what the values are, Iā€™ll learn them as I go!

Okay, I figured it must have been a limitation of something rather than a design decision, since the step between mode 1-2 is bigger than 2-3, according to this table:

Theyā€™re in stock! 17mm DrJones H17Fx Driver w/ lucidrv2 - 7135 + FET

They are available at Mountain right now! I might have to get one even though Iā€™ve way overblown the budget already.

A bit more than expected but this is a premium driver. Much cheaper than a Prometheus Icarus driver and likely better anyways. Gives me a reason to order a few more things from mtn electronics.

Cool.

Are there any estimates on how low the lowest few modes are?

Iā€™m going to guess it will depend on the emitter quite a bit. Iā€™m using it in an XP-L triple.

I posted a picture above of the lowest mode compared to 1 lumen in the S30 Baton.

It visually looks like about half the light compared to the lowest mode of my Wizard Pro (warm), which is 0.2 lumens, according to the manual.

Hope that helps!

The lowest few modes are very low. A very nice moonlight, for sure.

I am surprised you are seeing such a small difference in DD output. In my triple XP-L and Nichia 219C lights the difference in output amps is much bigger than what PrinceValorum is seeing. That said, a big jump in amps on the high-end does not equate to a big increase in visual output, so in most cases it isn't a huge deal.

The temperature sensor is very smooth, but it will let the small triples overshoot the set point by a significant margin; in cases with large temperature swings the driver is too smooth and does not ramp down fast enough. It still will not badly overheat, but it overshoots more than I'd like to see happen. An algorithm adjustment that allows for bigger steps when the temperature increases past the set point by a significant margin or at a significant rate would certainly help alleviate the problem; i.e., smoother at normal temperature increases, but bigger steps with rapid swings.

Thanks for the additional info, everyone. I looked up some MOSFET resistances and it looks like the one used in this driver has 25 to 30 mOhms on-resistance. I think the dedicated FET drivers have less than 10 mOhms? An additional 20 mOhms is like having an additional tailcap in the circuit. Not too bad but enough to cause a significant drop in current, as people seem to experience. I think I will use a FET driver for my triple/quad just because I want it to be a little lumen monster. Looks like I have good excuse to build a nice C8 with the H17F :sunglasses: .

The double-tap feature is one thing I really like about the FW. How quick do the taps need to be to access this mode? Is it easy to accidentally access this mode when switching modes quickly?

On a slightly related note: I was looking at Dr. Jones different FWs and I saw that the guppydrv universal clicky I have on my QLITE 8*7135 has battery voltage indicator. This feature is not described on mountain electronicā€™s page. It seems to work like lucidrv, where 8 quick clicks brings you to the programming menu, where it will blink for each 0.1V above 3.0V.
Richard, you might want to add this to the description for this FW on your page; I think it is a pretty attractive feature and might be an important point for some people.

The MOSFET on the H17F is between 25-29 mOhms when operated between 4.5V and 2.5V gate voltages. We're never going to see 4.5V, or even 4V under load (remember the drop from the diode + battery sag under load), and that value is when the FET is cool. I suspect that in real-world use we'll typically see 29+ mOhms from this FET. Still good enough to provide a big boost in output, but not nearly as good as the big MOSFETs. The MOSFET I am using on the new MTN-17DDm is rated at 2.13 mOhms at 4.5V gate drive, and looking at the graph in the data sheet, an estimated 3.75 mOhms at 3V. In other words, an order of magnitude less resistance, but it is also much bigger, more expensive, and is harder to drive (more gate capacitance).

So, it's a tradeoff. Like I said before, the difference between an 8A and 10A triple may sound staggering, but visually the difference isn't as big as it would seem, so really it depends on what you value most.

I think the average tail cap has a bit more resistance than 20mOhms. I donā€™t think you would be disappointed if you use the H17. It is very responsive to the user input and is an advanced but practical driver. Even for use on the smaller lights. On these lights the lumens output drastically drops with high temperature. So by throttling back the current, you actually saving lumens and you will be able to sustain those lumens longer. more heat, less lumens, more battery used. I think this is the draw of a driver like this. I know its not that simple, but I think you will be pleased with the performance of this driver.

anything I say canā€™t and wonā€™t be used against me when compared to proven factā€¦

I am looking forward to using this driver in my S2+ with XP-L HI, and possibly a C8. But Iā€™m planning a triple or quad XP-L with single 26650, and I think I want to optimize this one for maximum power. Maybe there wonā€™t be a huge practical visual difference between using this driver and the 17DDm, but what can I say, sometimes Iā€™m not practical. :smiley:

I measured my S2+ tailcap by sending current through it and measuring the voltage drop, and it was 50mOhm including stock spring, and 20mOhm bypassing the spring altogether.

I just installed this driver in my S2+ with XP-L HI V2 3D. I love the extensive customizability.

Temperature setpoint is 60C. In high mode (2.9A using all the 7135 chips), the current starts to drop within 20 seconds and is down to 1.5A by around the 1 minute mark.

In turbo mode, Iā€™m getting around 4.5A with a pretty fresh LG D1 cell at around 4.26V open circuit. In turbo mode, the thermal regulation is much less active. It doesnā€™t really significantly drop the current in the first minute and the flashlight gets much hotter than high mode, of course. Is the regulation behavior different in turbo mode because it is using the FET channel?

It just occurred to me the different behavior could be a result of the heat generated by the linear regulators. In high mode, the regulators are dropping ~0.4V which means they are dissipating ~1.2W at 3A. The FET, with 30mOhms resistance, is dissipating 0.6W at 4.5A. Maybe the driver is actually getting hotter in high mode than in turbo mode because of this local heat production?

EasyB, in your case the 4.35V cell may not be the best choice for efficiency at the lower levels. It is obviously heating the driver quite a bit.

Most higher performance cells will have similar behavior at 3A. For example the LG D1 discharge curve nearly coincides with the Samsung 30Q and Sony VTC5 at 3A for the first half of the discharge.

It is a compromise between linear driver heating and being able to stay in 3A regulation for as long as possible. Ideally, there would be a cell that had a completely flat discharge curve at 3.6V at 3A, to be most efficient. I chose the LG D1 for this flashlight because it provides the longest time in 3A regulation; the discharge curve levels out near the end more than most other cells, so you get more useful power out of it.