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

[rhd]

I bought three Ben boost driver from Mohrenberg. Two of them are build in the dual driver setup. I have a problem with the third driver.
When I turn up the input voltage the current increases and if the voltage is dropped then the current decreases. It is basically a resistor. I think the driver is defect. What component can I change to repair it ?

You should put comments like this ^ in Moh's thread, because they deal with (potentially) a defect in the assembly of one of his drivers, not a problem with the design itself (what this thread is about).

Though I would add, that this is probably exactly what you would expect as behavior from a boost driver.... what's weird about that?!?!?

If the voltage is low, then the BOOST driver is going to struggle (and not be able) to provide the full output current at the voltage it needs to boost too. As you start to increase voltage of your input, then the driver has to do less boosting, so it can start providing more current up to the point of reaching it's intended output current. Once you provide adequate input voltage, and enough current, for the driver to hit its current output target, then your output current will stay constant. If you start decreasing voltage, then the driver just backs down into the same scenario, where you're no long supplying a sufficient input for it to boost up to the required output voltage at the set output current.

At least based on the behavior you've described, this just sounds to me exactly how a boost driver would normally behave when you're stingy on the voltage.

 

[benmwv]

What are your input and output voltages (measure the voltage across your entire test load instead of just the resistor)? What is the driver set to?

If your input went above the output you could have fried it. If the difference between the input and output is too large it may not be able to achieve the set current. If it allows the current to rise above the set current it must be defective or fried.

 

[Blord]

I wasn't sure to put it in this thread or Moh thread. Anyway I have the measurements :

The driver was set at 372mA by a R510 resistor.
Testload with four diodes
Vin...Vout...C-in...C-out
2.8 3.0 0.92 0.192
3.2 3.2 0.99 0.278
3.6 3.5 0.73 0.342
3.9 3.5 0.37 0.362
4.1 3.7 0.45 0.452

 

[rhd]

I wasn't sure to put it in this thread or Moh thread. Anyway I have the measurements :

The driver was set at 372mA by a R510 resistor.
Testload with four diodes
Vin...Vout...C-in...C-out
2.8 3.0 0.92 0.192
3.2 3.2 0.99 0.278
3.6 3.5 0.73 0.342
3.9 3.5 0.37 0.362
4.1 3.7 0.45 0.452

Four diodes will probably drop 0.6 or 0.7V at that low current. So:

4x 0.7V = 2.8V
+ 1x 0.37V (1ohm resistor) = 3.17V
+ 0.19 V (set resistor) = 3.36V load

So your test load had a lower voltage drop than you fed as input voltage into the boost driver. At some point around 3.36V of input, you probably fried the driver.

 

[benmwv]

I wasn't sure to put it in this thread or Moh thread. Anyway I have the measurements :

The driver was set at 372mA by a R510 resistor.
Testload with four diodes
Vin...Vout...C-in...C-out
2.8 3.0 0.92 0.192
3.2 3.2 0.99 0.278
3.6 3.5 0.73 0.342
3.9 3.5 0.37 0.362
4.1 3.7 0.45 0.452

Looks like it stopped boosting (well stopped attempting to and went into direct drive) between 3.6 and 3.9, but it seems like something weird was happening before that too. Is this the original data or had it been run with a Vin > Vout before those readings? It acts like it was already damaged.

 

[Blord]

No need for troubleshooting it further. It can't stay regulated at 372mA. The driver is damaged. The design of the driver is sound. For a boost driver it is important that the V-in must be lower than V-out and that there is always a load connected to the output.

As I recall I did once connect the wire of the testload wrong on the Ben driver. Because of the testload only let the current thru in one direction, the driver has to boost the voltage to met the current setting. I think the driver has fried itself and now it is non-functional.

I only want to know which ic must be change in order to be functional again. I am going to order more from Moh and he has also the parts. Thank you guys for helping me out.

 

[rhd]

Blord:

I simulated the damage on similarly configured Ben Boost here (it was set to 230mA for a single mode blue).

Anyway, like yours, it fells out of regulation (read: went high on currect) when VOut was lower than VIn. However, when I actually reconfigured the driver properly (with a test load that used ~7 diodes for a roughly 5.1V simulated Vf, the driver was just fine again.

Now, I only very briefly had run it at the wrong output voltage, so maybe there wasn't as much time for damage to occur. But maybe, damage DOESN'T occur, and yours will be fine too, if you run it now on an appropriate test load.

I tossed the driver just to be safe, but I'm pretty sure it was A-OK after the incorrect usage. So maybe don't give up on yours - give it a shot?

 

[rhd]

I did some further testing last night with the same build setup I had used in that second post.

I paralleled 864mA Ben Boost drivers on SAIK heatsinks. I used H-series diodes that had binned relatively similarly. I used identical (seperate) fully charged 26650 cells in each build, and moved the same G lens from one to the next when LPMing time came. Each build LPM'd within 5% of the mean output power (pretty amazing diode binning job eh?) and the wavelengths were also within a +/- of 1nm from center (save for the original build which doesn't count because I wasn't wavelength binning back then, and it was probably an M-series diode anyway)

SAIK 1 - 2260mW, 448.5nm
SAIK 2 - 2420mw, 447.5nm
SAIK 3 - 2360mW, 447.7nm
SAIK 4 - 2237mW, 449.0nm
SAIK 5 - 2318mW, 442.9nm (the original build)

Bottom line is that the parallel-ability of these drivers is pretty consistent. They handle it well, without complaint.

 

[tsteele93]

I did some further testing last night with the same build setup I had used in that second post.

I paralleled 864mA Ben Boost drivers on SAIK heatsinks. I used H-series diodes that had binned relatively similarly. I used identical (seperate) fully charged 26650 cells in each build, and moved the same G lens from one to the next when LPMing time came. Each build LPM'd within 5% of the mean output power (pretty amazing diode binning job eh?) and the wavelengths were also within a +/- of 1nm from center (save for the original build which doesn't count because I wasn't wavelength binning back then, and it was probably an M-series diode anyway)

Is it safe to assume the H series are generally more efficient than the M series?

Also, any info on the new 4,000 lumen ex-jay H-seventeen-hunert?

 

[Kizdawg]

The thing I see Is that I'm going to have to check each diode I buy or salvage and test it on the desktop psu then decide what to do with them... What are you measuring nm with?

 

[Kizdawg]

Hey is there enough interest in this to get a COMPONENT GROUP BUY GOIN?

 

[Mohrenberg]

I probably would of gone in with you but I had already ordered components when you sent me that PM.

 

[Kizdawg]

We can look into that in the future... Sorry if I PO'd anyone.. RHD expecially! Sorry!

 

[rhd]

We can look into that in the future... Sorry if I PO'd anyone.. RHD expecially! Sorry!

No worries.

That said, I don't see a huge benefit to a group buy.

At a QTY of less than 50, you basically get most of the big QTY discount benefit. If your purpose of a group buy was to extend those benefits out to people who wanted to order components for fewer than 50 drivers, then I still suspect that most of the cost savings would be eaten up by the re-shipment cost, and time required of the organizer.

Guys, frankly, these drivers are SOOOOO inexpensive to put together. Buy them assembled for $10-$12, or reflow them yourself for (even in small QTYs) less than $5. Last weekend I built 5 SAIKs. It took me ~15 minutes to reflow 10 drivers, and cost about $40. From that $40 investment, I had parallel setups for 5 hosts.

I can't imagine needing to squeeze any additional cost savings out of that equation.

 

[Kizdawg]

Ok I can agree to that at the size they are having Moh make them for you is a bargain.

But if this is a true DIY then there are people who will want to build it. I want to I'm not sure I can yet.. I expect out of my 50 or so boards ordered a bunch are going to be junk. This is all leaning from my misteaks... It's not about squeezing for cash it's getting it 50%+ off by buying in larger quantities! The offer is allready there from digikey!

 

[rhd]

Ok I can agree to that at the size they are having Moh make them for you is a bargain.

But if this is a true DIY then there are people who will want to build it. I want to I'm not sure I can yet.. I expect out of my 50 or so boards ordered a bunch are going to be junk. This is all leaning from my misteaks... It's not about squeezing for cash it's getting it 50%+ off by buying in larger quantities! The offer is allready there from digikey!

It's not though......

Look a the price drops for the parts we sourced in the OP when you move from 1 to 100 QTY:

Inductor: $0.64 down to $0.54
Shottky: $0.46 down to $0.25
LM3410: $1.59 to $1.52

That's a nearly irrelevant savings for moving from 1x to 100x. That savings would be gone the minute you have to start reshipping little group-buy baggies of components to a dozen different people.