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PHR-803t in ultra-small host.


erdabyz

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Yeah and I built it! I also have one laser like that! But mine has green host and quite a few hours on it already...
 

Eudaimonium

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Nice job. Appears to be homemade boost driver.
What's the IC, coil and schottky diode used? Damn fine PCB job if I might add.
 

erdabyz

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Nice job. Appears to be homemade boost driver.
What's the IC, coil and schottky diode used? Damn fine PCB job if I might add.
Ic is LT1930, coil is LPS3008 (or 3010, dunno exactly) 4.7uH from coilcraft, schottky is a MBR0530.

That's not the best PCB i've done (by far) because the soldermask's mask (the photolite used to insolate the soldermask paste to make it harden) moved, I didn't notice it and it turned out misaligned so I had to remove it, which also scratched the copper a bit (scratched, not removed/torn off) and I decided not to apply it again (was too lazy) so the soldering and component alignment aren't as good as they could be, though they have been perfectly soldered and the driver performs just fine.

I can get 8mil resolution without problems using homemade PCB manufacturing techniques xD.
 

Rafa

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Oh yeah I forgot to said, erdabyz gave it to me as a present :D

The other one's host (the one dead) was yellow, but the host got broken too lol

Pics of the old host:


 

erdabyz

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http://cds.linear.com/docs/Datasheet/1930f.pdf

Holy shinto! It has a common negative point, unlike LM3410X I use, where diode must be isolated from case!

I better stock up on these :D

No no and no, LT1930 works exactly like LM3410X, but it's less efficient. LM3410X is just better as it's designed for driving LED's and has a very low reference voltage requiring a much lower value current sense resistor, so less power is wasted there.

LT1930 is intended as VOLTAGE regulator, not as CURRENT regulator. To make it a constant current source you MUST wire it like you'd wire the LM3410, not as it's wired in the datasheet's application schematic, but calculating a different value resistor, as LM3410X has 0.19 volt reference voltage and LT1930 has 1.25 reference voltage.
Using that trick you lose the common ground point, and you end up with the same problem with case negative diodes that you have with the LM3410X.

There is however another IC from linear, LTC3490 Linear Technology - LTC3490 - Single Cell 350mA LED Driver

Which is intended for driving LED's as a constant current driver with high side internal sense resistor (i.e. it has common ground point) that can give you up to 350mA from a 1.5V cell. I have tested it and it works as promised, 350mA can be delievered to a red diode from a 1.5V cell. However, the inductors required for that are quite massive and barely fit into an aixiz module.


You can just swap an LM3410X for a LT1930 in a PCB, swap the current sense resistor and it'll work. They have the same pinout.
 

Eudaimonium

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Ahh, that was a minor disapointment.

Okay, 1.5V boost driver, that sounds tempting enough.

It can deliver 350mA from 1.5V, but at what Vdrop of a load ? Could it power a 5V - 5.5V bluray diode?

Imma go take a look at the datasheet actually.

EDIT :
Features

* Click Here for LTC3490 Evaluation Kit
* 350mA Constant Current Output
* 2.8V to 4V Output Compliance
* 1- or 2-Cell NiMH or Alkaline Input


Ahh, damn, Fixed output.
 

erdabyz

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Ahh, that was a minor disapointment.

Okay, 1.5V boost driver, that sounds tempting enough.

It can deliver 350mA from 1.5V, but at what Vdrop of a load ? Could it power a 5V - 5.5V bluray diode?

Imma go take a look at the datasheet actually.

EDIT :
Features

* Click Here for LTC3490 Evaluation Kit
* 350mA Constant Current Output
* 2.8V to 4V Output Compliance
* 1- or 2-Cell NiMH or Alkaline Input


Ahh, damn, Fixed output.

Keep reading the datasheet! It's not fixed current, you can adjust it via a potentiometer. That potentiometer adjusts the voltage in the CTRL/SHDN pin, and there is a voltage range where you can adjust the output current.
And no, it isn't able to power a blu-ray, but blu-ray diodes we mess with don't have case negative configuration, but case floating, which is fine for LM3410's. LTC3490 is more for reds and that, but it can power a 445nm diode from a 1.5V batt at a "pointer" current.

BTW LTC3490 needs MASSIVE inductors with ferrite core, and VERY SOLID host contacts and switches to even start up. But that's inherent to every driver that boosts voltage so much, so every 1xAA/AAA 1W LED flashlight host from dealextreme does the trick. And it also needs a very precisely designed PCB.
 

ped

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I like your explainations, not just "no" , but the technical reasons behind it.

+1 rep for you.

*EDIT*


:crackup:
 
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