OPEN SOURCE: "CC-Boost" - 2.4 Amp boost driver - RC1

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

I'm doing a digikey order this week, so I can test out some other inductors with the driver Let me know which ones you have in mind (already added the 587-2956-1-ND to cart) and I'll test it out.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

ARG said:

I'm doing a digikey order this week, so I can test out some other inductors with the driver Let me know which ones you have in mind (already added the 587-2956-1-ND to cart) and I'll test it out.

Click to expand...

It would be worth testing the following inductors on the 850mA V14:

587-2956-1-ND (which you've already added)
and
ASPI-6045S-470M-TCT-ND

What would also be hugely valuable would be if you could take the V15 and swap the RSET to lower its current to 850mA. V15 already used a higher inductance inductor, so testing it at 850mA and 6.5V (or something close to that) will give us useful information. If it scopes well, then we could consider not forking the driver at all (though we'd want to have a discussion in the thread about whether 2 forks of a small driver are preferable to 1 universal driver that needed to be larger - but we'll cross that bridge if we come to it).

One challenge is that I can't remember the scaling resistances I used, so I can't tell you exactly what RSET to purchase. Any chance you could measure the resistance on this?

I'm thinking it's around 500 ohms. I may have paralleled a couple resistors vertically. I can't remember. If you can test that resistance, I can find a part number for a set resistor that will switch this driver to 850mA.

EDIT: There was a question earlier about whether a zip file is out for the driver V14. In short, no, not yet. I know it's really tempting to want to use this driver since it's now scoping really cleanly for 445s, but there is some housekeeping / general tidy-up required. V14 had a few awkward component placements that, while not a show stopper, were annoying, and should be fixed. There was also a problem with the wire-holes not really being convenient. It also wasn't tailored to the exact dimensions of the inductor (because we were testing a couple different ones), so it's worth getting that right, now that we know what components we're landing on. Finally, in all likelihood, we should make it adjustable. So while it's exciting that we're at or near the end of the road here, there still a little bit more revision required to get this perfect. ARG's testing (above) may give us some ideas too.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

Yup, you remember correctly Measured at 500ohms on my Fluke, and the numbers on the resistor are 4990.

Here's a picture if it helps.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

ARG said:

Yup, you remember correctly Measured at 500ohms on my Fluke, and the numbers on the resistor are 4990.

Click to expand...

Awesome - that was easy

Unfortunately, setting the V15 board I sent you down to 850mA isn't as easy as a single resistor swap, because the sense resistor on that one is only 0.05 ohms, which means the Vdrop across it will be under 50mV @ 850mA if we only swap the RSET (the minimum Vdrop our current monitor needs to see is 50mV). On the V14 driver I gave you to test at 850mA, I compensated for this by increasing the resistance of the sense resistor to create more of a drop.

Anyway, why don't you try swapping the SET resistor with this 1200 Ohm part:
1276-5275-1-ND

That will actually set it to 1A, but I think you'll still be able to test it at 6.6V of output. Although the move from 850 mA to 1000 mA is now an additional variable that has changed, I don't think it will skew the data we're hoping to glean from the test in any significant way.

Subjectively, any thoughts on the sizes of V14 vs V15 in terms of their practicality for builds? In particular, do you think V15 is too large? (for everyone's reference, V15 is 13x13 for 169 sq mm, and V14 was 12x12 for 144 sq mm)

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

4990 is 499Ω high precision, >1%, so 500Ω is within 0.2% well within
tolerance (unless it was 0.1%).

13mm is a bit large for pen builds. It may squeeze into a Survival host,
but it would be a tight fight. Even 12mm is cutting it close. 10.0mm
fits inside an AixiZ module with enough clearance to thread the back
on. (Freshly verified with both DTR and genuine Aixiz)

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

The Lightning Stalker said:

4990 is 499Ω high precision, >1%, so 500Ω is within 0.2% well within
tolerance (unless it was 0.1%).

13mm is a bit large for pen builds. It may squeeze into a Survival host,
but it would be a tight fight. Even 12mm is cutting it close. 10.0mm
fits inside an AixiZ module with enough clearance to thread the back
on. (Freshly verified with both DTR and genuine Aixiz)

Click to expand...

Since the driver should be heatsinked, I don't see a need for it to fit inside an aixiz. But we should figure out some target dimensions. This is a point that everyone can weigh in on. I'm sure there won't be agreement, but it would be helpful to gather as much input on shape as possible.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

I actually don't mind the size of the V15 driver, for a high current driver I don't think it's too big at all, same with the V14.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

Length isn't nearly as critical, but for width, either 10 or 12mm
would be ideal. Even though it will be removed and heatsinked,
when I send out a presoldered diode, I like to have the back of
the module threaded on for extra protection.

Also on Mouser and Digikey, there is a feature where you can
go back and view past orders. I have used it many times when
I can't remember a part number.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

The Lightning Stalker said:

Length isn't nearly as critical, but for width, either 10 or 12mm
would be ideal. Even though it will be removed and heatsinked,
when I send out a presoldered diode, I like to have the back of
the module threaded on for extra protection.

Click to expand...

I don't really catch your drift. But in any event, I need some convincing that 10 or 12mm is a target worth shooting for. It may / may not be doable. More to the point though, I'm not sure I understand why those numbers are magic.

Remember that to drive at 2.3A out, you need up to 4A of input. I just don't see this being used in a lot of "pen" style situations. Certainly this isn't going to be soldered directly to diode leads and used as a "hanging" driver, with a battery spring (or at least I would hope not).

Given the need for heatsinking, I don't see why the internal diameter of an Aixiz module, or the internal diameter of most heatsinks, are numbers of relevance.

Thoughts?

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

I occasionally get a request to solder a driver directly to diode
pins, even with 9mm diodes, then ship it off somewhere.
Shipping is rough and all kinds of things can happen and bend
things like diode pins, so it is just more convenient to be able
to thread on the back of the module over everything to protect
it. If that can't be done, then 12mm is the next sweet spot
because it allows clearance for such a pre-soldered module to
be slid completely through a heatsink in either direction.

There will be other cases where a small heatsink would work
or possibly even none at all, for instance in the case of an
A140 running @ 1A. It makes just that much easier to
assemble when a module can be slid out from the front Or the
back. That is my reasoning behind the 10 and 12mm figures.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

The Lightning Stalker said:

I occasionally get a request to solder a driver directly to diode
pins, even with 9mm diodes, then ship it off somewhere.
Shipping is rough and all kinds of things can happen and bend
things like diode pins, so it is just more convenient to be able
to thread on the back of the module over everything to protect
it. If that can't be done, then 12mm is the next sweet spot
because it allows clearance for such a pre-soldered module to
be slid completely through a heatsink in either direction.

There will be other cases where a small heatsink would work
or possibly even none at all, for instance in the case of an
A140 running @ 1A. It makes just that much easier to
assemble when a module can be slid out from the front Or the
back. That is my reasoning behind the 10 and 12mm figures.

Click to expand...

Cool.

Though I don't think any of that (shipping convenience, etc) is a reason to go with a particular size TBH. But appreciate the input.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

rhd said:

Cool.

Though I don't think any of that (shipping convenience, etc) is a reason to go with a particular size TBH. But appreciate the input.

Click to expand...

I see where he is coming from. And agree with him that it would be convenient. However I don't consider it being that size to be more important than say adding adjustable current to the driver.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

Got around to putting the digikey order in today. Will likely have results posted on this weekend

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

ARG said:

Got around to putting the digikey order in today. Will likely have results posted on this weekend

Click to expand...

Exciting news

The nice thing about digikey is that they're fast - even to Canada (which is rare). They've got their system down.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

rhd said:

Exciting news

The nice thing about digikey is that they're fast - even to Canada (which is rare). They've got their system down.

Click to expand...

Yeah no kidding I placed an order Tuesday night and its in my hands right now. Doest get faster than that for $8 shipping charge that's for sure.

Re: OPEN SOURCE: New Boost Drive, 2.4A capable from one cell, tested and working

V14 - 587-2956-1-ND




V14 - ASPI-6045S-470M-TCT-ND




V15 - 1276-5275-1-ND
Test 1:

Test 2: