FREE DIY open source BOOST driver!!! Tested & working!!

@rhd

sorry for my small englisch!

i edit my post in a new version with a better englisch.

benmwv said:

How would you like free boost driver designs?! :drool:

So this is a boost driver based on the lm3410. Single li-ion or 2x/3x alkaline/nimh ONLY. It is meant to drive diodes with a Vf greater than the input voltage, like 445 and 405 diodes. It has been tested at a little under 1.2A on a 445nm diode and worked great, it may go a bit higher but I wouldn't expect anything over 1.3A. These drivers can also be paralleled to get higher currents like 1.8A. Rhd currently has a build using two of these drivers in parallel and is going to make a thread about it, I'll pop in the link when he does.

Here is the parts list:

Q1:
P-channel mosfet - $0.79: Digi-Key - SI3473CDV-T1-GE3CT-ND (Manufacturer - SI3473CDV-T1-GE3)

R1, R2:
Set Resistors (0805) - VARIES

C1, C2, C3:
3x 10uF Caps - $0.54: Digi-Key - 490-3347-1-ND (Manufacturer - GRM21BF51C106ZE15L)

D1:
Shottky - $0.47: Digi-Key - 568-4105-1-ND (Manufacturer - PMEG1020EH,115)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Changelog
R6 R9: Original posted design. Has reverse polarity protection, 0805 caps, No OVP.

R6 R9 Round v6: Originally posted design (0805 caps, no OVP) on a 16.5mm board to go right into most flashlight pills, with battery contacts on the bottom.

R6 R10: Replaced 0805 caps with 1206 caps (not as tall).
C1, C2, C3:
3x 10uf caps - $0.60 Digi-Key - 490-3383-1-ND (Manufacturer - GRM31MF51C106ZA12L)

Click to expand...

I have a few compatibility questions.

First, will the 1206 caps work on any of the boards? They are just shorter, right? I guess specifically, will the 1206's work with the PCB's that moh was unloading by the 100's?

Second, assuming the 1206 caps are ok, would these GCM31CR71C106KA64L Murata Multilayer Ceramic Capacitors (MLCC) - SMD/SMT work on this driver, or am I missing something important that would keep them from working?



I know RHD doesn't like me trying to spend/waste more money on components, but I like adding a higher operating temp where I can on parts. I think we run our drivers in very tight compartments next to a heat sink that is dumping extremely high temps from a laser diode and if I can buy a little insurance on my driver by getting a 125C rated part instead of an 85C rated part for a small amount more, then I would like to do that.

Tseele those caps would work fine assuming they fit. But they are a huge ripoff

AnthoT said:

Tseele those caps would work fine assuming they fit. But they are a huge ripoff

Click to expand...

Is there any advantage to the 1206 package vs the 0805 package for the regular (not round) benboost?

tsteele93 said:

Is there any advantage to the 1206 package vs the 0805 package for the regular (not round) benboost?

Click to expand...

No, plain and simple, just a different size, of course if one fits better take that one :beer:

Ok, this has me confused...

Newark Caps comparison

Looking at that, I can have my cake and eat it too with the TDK versions.

CAPACITOR CERAMIC, 10UF, 16V, X7R, 1206 at @ $0.17

Is there something wrong with that?

I get the 125C operating temp, but at a low price. Would this be a good compo of price and improved high temp performance?

Thanks for being patient with me AnthoT!

tsteele93 said:

Ok, this has me confused...

Newark Caps comparison

Looking at that, I can have my cake and eat it too with the TDK versions.

CAPACITOR CERAMIC, 10UF, 16V, X7R, 1206 at @ $0.17

Is there something wrong with that?

I get the 125C operating temp, but at a low price. Would this be a good compo of price and improved high temp performance?

Thanks for being patient with me AnthoT!

Click to expand...

Yup those will work fine :beer: tseele if you like I can revise the original BenBoost to fit 1206 for ya it would work the same and be the same size, that way you won't have a problem fitting them, Ill do it when I get home

AnthoT said:

Yup those will work fine :beer: tseele if you like I can revise the original BenBoost to fit 1206 for ya it would work the same and be the same size, that way you won't have a problem fitting them, Ill do it when I get home

Click to expand...

Hold on,

I'm confused here. Let me make sure I am communicating my side well.

I bought a hundred of Moh's Benboost PCB's.

They are R6 (fork again) R9

He lists the 0805 in the parts list, but I couldn't tell from the first post if the 1206 would fit also and just be shorter. Maybe I should stick with the 0805 package to be sure?

Typically, it will be much harder to solder a 1206 capacitor to the pads of an 0805 capacitor. However, it should fit, as long as there isn't anything in relatively close proximity.

Wolfman29 said:

Typically, it will be much harder to solder a 1206 capacitor to the pads of an 0805 capacitor. However, it should fit, as long as there isn't anything in relatively close proximity.

Click to expand...

Ok, I went back and re-read the first post and saw that the 1206's didn't come into play until R10 version, and I have the R9 version so I need to be looking at 0805's, which severely limits me in finding X7R versions.



Looks like I PROBABLY ought to go with the 0805's, although there are some very inexpensive 1206's on Ebay that might be worth trying to see if I can solder them or not.

:thanks:

Ceramic SMD capacitors
The ceramic SMD capacitors form the majority of SMD capacitors that are used and manufactured. They are normally contained in the same type of packages used for resistors.
1812 - 4.6 mm x 3.0 mm (0.18" x 0.12")
1206 - 3.0 mm x 1.5 mm (0.12" x 0.06")
0805 - 2.0 mm x 1.3 mm (0.08" x 0.05")
0603 - 1.5 mm x 0.8 mm (0.06" x 0.03")
0402 - 1.0 mm x 0.5 mm (0.04" x 0.02")
0201 - 0.6 mm x 0.3 mm (0.02" x 0.01")

You are a great help to me Wolfman! You've really come through a couple of times for me now. +1 (When I can!)

Hey - no problem. You're an asset to the community! :beer:

tsteele93 said:

Hold on,

I'm confused here. Let me make sure I am communicating my side well.

I bought a hundred of Moh's Benboost PCB's.

They are R6 (fork again) R9

He lists the 0805 in the parts list, but I couldn't tell from the first post if the 1206 would fit also and just be shorter. Maybe I should stick with the 0805 package to be sure?

Click to expand...

Then stick with the 0805, I wouldn't try squeezing 1206. That's based on personal experiences though. :beer:

I hate to rain on everyone's parade -
But the 1206 vs 805 debate is totally misguided.

If you're choosing between one and the other, you should be asking yourself which form factor will fit the board better. That's your consideration. Period.

You'll run into a lot more trouble if you foolishly try to strive for some meaningless additional "temperature rating" at the expense of using the part shape that your PCB was designed for.

It's silly. This is a silly silly silly debate. You're not talking about a current set resistor that actually generates some heat. You're talking about caps. Those caps are never going to get near 120 degrees, unless you're doing something majorly wrong.

Sorry for being critical

I have some schematics that I would like being put into "board" form. Would anybody be so kind to help me with that?

rhd said:

I hate to rain on everyone's parade -
But the 1206 vs 805 debate is totally misguided.

If you're choosing between one and the other, you should be asking yourself which form factor will fit the board better. That's your consideration. Period.

You'll run into a lot more trouble if you foolishly try to strive for some meaningless additional "temperature rating" at the expense of using the part shape that your PCB was designed for.

Click to expand...

Just saw that, please read carefully - that was never my intention. I was looking at the R10 version which uses 1206 caps, I wasn't trying to cram 1206's on an 0805 board. That was a misunderstanding that was corrected.

rhd said:

It's silly. This is a silly silly silly debate. You're not talking about a current set resistor that actually generates some heat. You're talking about caps. Those caps are never going to get near 120 degrees, unless you're doing something majorly wrong.

Sorry for being critical

Click to expand...

I don't mind, my feelings aren't fragile.

I still feel like that if you can find a good 125C component for not TOO MUCH more than an 85C component, then it is worth doing.

And please also note, I am not suggesting the caps are creating 125C, I'm suggesting that they may be living in a >85C environment.

No one has a good number on what is going on inside a case, but when you are moving an amp around on a small board that is connected to a (often far too small) heat sink that is sucking heat from a high powered laser diode, in a small enclosed space then who knows what it is doing in there?

Furthermore, even if it isn't exceeding 85C, a part rated for 125C is going to last a lot longer at 70-80C than a part rated for 85C.

If you can fit it on the board (which may turn out not to be the case here) then the only real consideration is price. If it is affordable, then there is no downside that I can see to over-engineering the components on the driver.

Also, please note - I am NOT preaching to anyone or trying to get them to convert to my religion of over-engineering. I'm just asking for my personal building purposes. I respectfully don't see anything wrong with that.

Next you'll be telling me that my tantalum capacitor idea is a bad one!

You're not talking about a current set resistor that actually generates some heat.

Click to expand...

Oh, I haven't gotten to those yet...

tsteele93 said:

Furthermore, even if it isn't exceeding 85C, a part rated for 125C is going to last a lot longer at 70-80C than a part rated for 85C.

Click to expand...

Can you support that claim?

I don't know that that is true.

I get that you want "quality". At the same time, I think it's important to understand what is really contributing to quality, as opposed to what is just snake oil in the context of your application.

If you really wanted to improve the "quality" of your driver, you'd take the design, fork it, double the width of each important trace, swap in the TSSOP version of the IC, use a larger package Shottky, a larger package set resistor, and get new PCBs make.

While only incurring perhaps a 25% additional size penalty, that might actually improve the quality of your driver.

But this business of wasting time micromanaging capacitor "temperature ratings" is not.

I'm busting your balls, because I know you can handle it