SST-90 True CC Driver 10 Amps Hi/Lo Mode

[Fulgeo]

The bigger problem is that the efficiacy is far not as good as I thought I will be. With full load which was 9.4 Amps I got only 84% efficacy. That means I got like 6 Watts heating up my driver board. Not acceptable!! Front of the PCB with the Top-FET,Bottom-FET and inductance after 5mins on 9,4 Amps. The wierd things going up are the wires.

Great job sector_cleared. I think even 80% efficiancy would be more than acceptable. As for heat, yah its very hot but you do not have it heatsinked. It is just floating in space. For it to even survive unsinked for 5 minutes at 9.4 amps is a testiment to its durability. I would be curious to see a mockup where it is mounted on the back of a SST-90 heatsink like one of the beefy Britelumen sinks with a SST-90 emitter mounted and in a Maglite body. Having the driver mounted to some shark fins would be better yet. I have build one SST-90 and one SST-50 mod so far and have found that about 4.2 amps is about as hard I can drive the mod if I want to run it for long periods of time (say 1 hour). Any higher than about 4 amps and the flashlight gets uncomfortably to hold in your hand. For the me the perfect flashlight with the SST-90 emitter would be one with a low of about 4 amps that you could just turn on and leave on until the batteries are depleted and with a high of 8-9 amps that you could burst run in short runs of say 5 minutes. I think you are being too hard on yourself. I also think that properly heatsinked you have done it:thumbsup:

 

[Techjunkie]

Hey, by the way, what is the height from the bottom of the board to the top of its tallest component? I'm hoping this still fits between the top of the Mag D switch and the bottom of the Britelumens Deluxe SST-90 heatsink, with a few mm to spare for wire management. Something like this might be in order:

I'll ask Jo if he can make some to go with his heatsinks.

 

[sector_cleared]

Hey!

Thanks for the feedback.I will post some normal pictures of the board later this day.

@Fulgeo: Thats why I built in the 2 level control (that doesnt work yet 😗) On the board is a small potentiometer to set the low level between 1Amp and full blast.

@Techjunkie: The overall height is about 13mm. But I will measure it on monday and give you the exact height. How much space is behind a Britelumen heatsink?

 

[rayman]

Don't know the exact space. But I tried to put a 'Der Wichtel'-driver between the BL-heatsink and the switch and it was pretty tight. The driver is a little bit over 20mm and I even had to sandpaper the switch a little bit. So I think your driver would fit even with a driver-heatsink.

rayman

 

[sector_cleared]

As promised some more pictures:


Driver board front view:

Hidden behind the wires is the capacitor bank of the output

Driver board back view:



on the lower left side you can see the potentiometer to adjust the first level. There is two tru-holes underneath it if you like to connect a big potentiometer to have a continous current control of your flashlight.

My awesome wiring diagram :twothumbs:

 

[Mettee]

very cool

 

[aurum]

Hope you'll release a working driver soon

 

[dom]

Looks great 🙂
Why do you need a big pot?(if using this option)

Cheers
Dom

 

[Hack On Wheels]

Looks great 🙂
Why do you need a big pot?(if using this option)

Cheers
Dom

That's actually a pretty darn small pot, I'd say!

It's just a (variable) current sense resistor, right?

 

[arjag]

I think the mention of this big pot is so an external pot can be used to adjust brightness of the lower level.

This sounds similar to the sandwich shoppe SHARK Buck, but that requires the small pot to be removed before installing a larger external pot.

@sector_cleared

Does the small pot need to be removed to use an external pot?

Thanks

 

[dom]

Yes -was referring to sector_cleared mention of having to use a big pot.

Now that arjag mentioned it,he must mean to use a normal size pot - which is big in
comparison to the onboard pot 🙂

Cheers
Dom

 

[arjag]

After reading my post, i was baffled with myself for saying external pot.

I think the term we are searching for is Potentiometer vs the on board Trimpot

http://en.wikipedia.org/wiki/Potentiometer
http://en.wikipedia.org/wiki/Trimmer_(electronics)

 

[1301]

:goodjob:

(any news about pricing and when the final version is going to be ready for selling? :wave🙂

 

[sector_cleared]

FU$"§$"!§$ COMPUTER !!!

I wrote a huge update but its all gone :sick2:

Ok, now the short version:

arjag is right. The prototype has the option to attach an external potentiometer to adjust the current from outside the flashlight. At the moment you have to desolder the trimmer since the tru-holes are underneath. I just didnt have the space to place it somewhere else. I hope in the final version it will be possible to do it without.

I re-calculated the dissipation of the FETs and found a mistake in my initial calculations. Unfortunately the efficiency readings are not that far from the calculations...if you do it correctly 😳

Anyways! I found a better FET (already ordered) for my driver which will allow me to lower the dissipation in the FETs by more than 35%. That should raise the efficiency by 2-3% percent. But I think there is gonna be no way to run the driver on +9Amps for a extended period of time without a thermal connection to the heat sink. Luckily its gonna be quite easy to do that. As you can see on the pics it would be easy to bond a small chunk of aluminium to the MOSFETs with Arctic silver epoxy just as high as the inductance and you can bond the whole thing to the heatsink.

Till the next update :wave:

 

[Aircraft800]

AHHHHH... I'm in! Nice work! That's a very impressive looking driver!

 

[Hetore]

Mister, would be possible to buy 2 complete kits with from you(i.e.):

Driver;

Led;

Heatsink.

Would you accept a Paypal payment?(2MEUS09)

See you soon:devil:

 

[sector_cleared]

@Techjunkie: I'm sorr I totally forgot to post the height of the driver. It is 10,5mm.

@1301: Sorry no news about pricing and date of delivery so far.

@Hetore: In this tread I will document the development of the driver. For sales I will open a tread in the adequate sub-forum. But I won't sell LEDs nor heat sinks, only drivers.

 

[The Dane]

I'm glad of board members like you sir!
A lot of us do mecanical work and gladly share our projects, but electronics take brains and that is a rare commodity indeed :twothumbs
Making a driver for the SST-90 and be the first to boot = Top dollar.
Sharing it with the rest of us = Preiceless.

You need funds just speak up!!!

 

[1301]

I'm glad of board members like you sir!

You need funds just speak up!!!

+1

 

[parawizard]

@Whole Thread

Hello Sector_cleared,

I am a complete noob at electronics and have been working on a driver myself for some front projection. I decided to build off some schematics on webench from national using their LM3409 driver. First iteration did not work and the second one needs some new parts. What IC are you using? Do you have a schematic? I am interested in how you are doing it and what components you are using.

Thanks,

Bryan