Possible Driver for those 3.8mm 660nm Diodes

[LuxorLasers147]

Hi everyone

I`ve been testing a few drivers just for fun and I came across this one. The results are interesting so I´d like to share them


This driver was inside the 1xAAA and 2xAAA MXDL pen hosts.




When i first test it, the driver was outputing 350mA with 4 diodes. Then i tried to parellel them and i got this.



I thoght, well, 440mA seems good and i have a few LOCs, lets try to power one up. It blew instantly :crackup:. So i knew i had to check the reading with 3 diodes not 4.


With 3 diodes, i got this:



Angelos recommend not passing ~750mA so its spot on.

The driver gets hot after 20 secs so i heatsink the driver including the inductor wich gets hot and needs heatinking if i dont do it the power drops.

In 5 mins, the power goes from 750 to 725mA (the first 30sec it drops very quicly to 735mA and then starts to drop very very slowly. I know its not regulating but the rate of the drop seems acceptable.

It`s also continuos negative.


With a few cuts, it fits nicely in a C6 pill and theres still room for a cap you want.




I dont know much about drivers but this seems usable

 

[benmwv]

I think this is a voltage regulating driver. The chip is probably one of the pre-set 3.3v ones.

 

[LuxorLasers147]

I think this is a voltage regulating driver. The chip is probably one of the pre-set 3.3v ones.

The problem with the voltage regulated drivers is that the current increases as the load gets hotter right? This isnt the case because the current drops right away.

You think i could use this driver? My concern is if the 3 diodes are acurate with this driver.

 

[benmwv]

If you really want to use it you can, with a little bit of work.

First you will need to get the diode and run some tests from a bench supply or know good driver. Measure it's Vf at the current you plan on driving it. Next check to see exactly what voltage the driver puts out. Subtract the diodes Vf from the drivers output voltage. Divide the number you get by your desired current to get a resistance. Add 10%, maybe more to the resistance you get. Put that resistor between the diode and the driver.

But I really don't think it's a good idea to do something like this to such a nice diode. For a cheap spare parts LOC build sure, but I wouldn't risk much else with it.

 

[lazeerer]

Dont Use it. It is Not able to run on 4.2V.

The Tiny S4 or whatever that diode is gets extremely hot. If this Fails "Which it will" at 4.2v you will loose your diode.

I was messing with these quit a long time ago when i got one of the 2x AAA ones for my 685nm build last year.

As Ben said its a Voltage regulated driver. THe reason why its dropping in currant rather then Increasing its because its getting Stupid Hot and the Driver is getting hotter faster then the load which is what makes a voltage driver increase in currant.

In other words the driver is getting hot way before the Load which is giving you the false impression that its not a Voltage base driver.

Even if you heatsink the driver the little diode on the board will fail at 4.2v. They where not designed for 4.2v... I cant remember at 3v input what the currant was though even then i would not use it.

 

[LuxorLasers147]

If you really want to use it you can, with a little bit of work.

First you will need to get the diode and run some tests from a bench supply or know good driver. Measure it's Vf at the current you plan on driving it. Next check to see exactly what voltage the driver puts out. Subtract the diodes Vf from the drivers output voltage. Divide the number you get by your desired current to get a resistance. Add 10%, maybe more to the resistance you get. Put that resistor between the diode and the driver.

But I really don't think it's a good idea to do something like this to such a nice diode. For a cheap spare parts LOC build sure, but I wouldn't risk much else with it.

Dont Use it. It is Not able to run on 4.2V.

The Tiny S4 or whatever that diode is gets extremely hot. If this Fails "Which it will" at 4.2v you will loose your diode.

I was messing with these quit a long time ago when i got one of the 2x AAA ones for my 685nm build last year.

As Ben said its a Voltage regulated driver. THe reason why its dropping in currant rather then Increasing its because its getting Stupid Hot and the Driver is getting hotter faster then the load which is what makes a voltage driver increase in currant.

In other words the driver is getting hot way before the Load which is giving you the false impression that its not a Voltage base driver.

Even if you heatsink the driver the little diode on the board will fail at 4.2v. They where not designed for 4.2v... I cant remember at 3v input what the currant was though even then i would not use it.

Yeah if you guys say its constant voltage and the input is to high, then i wont risk the diode as i only have one coming :/
I will have to find another driver then.
Thanks for helping guys :yh:

 

[Cyparagon]

There aren't enough pins on that package. I bet there's no regulation at all. Try changing the input voltage to test it out.

My guess is it pulses the inductor at a set frequency, and whatever happens on the other end is close enough for the LED.