Clarification on 445 requirements please

[AUTO XX]

I'm using a dc to dc constant voltage/constant current driver
http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=120621007328&ssPageName=STRK:MEWNX:IT
for a 445 labby I'd like to finish ASAP
Been searching for a couple hours but all I can find on the necessary voltage is this:
http://laserpointerforums.com/f65/3x-445nm-ld-piv-plot-53927-2.html
If I am reading it correctly the graph basically says that at 500mA (my target current) the A140 only requires 2V..... That just doesn't seem right.
It was easy enough to set the current but I just guessed at 4.5V originally and I am quickly developing a nervous twitch at the thought of sacrificing yet another 445 diode to the cause :crackup:

Any info you might have is appreciated

 

[Cyparagon]

Read the legend. All the lines are of power except the last. The RED line is what you need.

 

[GBD]

From all the 445nms ive got, the A-140 has a minimum of a 4.2V forward voltage, and max of 4.8V IIRC, outside of that, you probably won't even lase the thing, and higher then 4.8V (It can probably take it.. but im not personally going to), I wouldn't want to try in fear of killing it. (needs at least 200ma or so too)

set your diode at 4.5V, and go on the current from there. (depending on what output you want)

 

[AUTO XX]

@Cyparagon
*Based specifically on what the red line on the graph says, the voltage requirement is ~2.5V. That is what seemed wrong to me.
@GBD That is basically what I had "felt" was about right but I don't remember where I got the info for that hunch
*Also, what does *IIRC* mean? I can usually figure abbreviations out but that one has me stumped

 

[daguin]

*Also, what does *IIRC* mean? I can usually figure abbreviations out but that one has me stumped

If I Recall Correctly

Peace,
dave

 

[AUTO XX]

Lol, thanks Dave!
Should have guessed that one....

 

[Trevor]

If I Recall Correctly

Peace,
dave

If you recall what correctly?

[/spam]

-Trevor

 

[AUTO XX]

I hooked up to my (3A) dummy load and I don' seem to be getting any accurate readings...
V out is 4.5V current out is .5A (directly through the DMM in 10A mode) but reading across the resistor of my dummy load I'm only getting something like 11mA
I know I'm doing something wrong but I don't understand electronics well enough at this point.
The dummy load is set with six 1n5401 diodes and a 1ohm resistor.

 

[budabob07]

If I remember correctly, a CC driver will adjust the voltage as necessary in order to hit the target current. So, you could just tune it to put out 500 ma, and it should adjust automatically (even a simple LM317 will do this)

 

[pullbangdead]

@Cyparagon
*Based specifically on what the red line on the graph says, the voltage requirement is ~2.5V. That is what seemed wrong to me.

You're reading the chart wrong. 500mA is ~4.1 or 4.2 V on this chart. (this is the same chart you're looking at, correct?)

If you care about power and voltage at a certain current, you go over to that current, then go up to the curve you're interested in. For power, go over to 500mA, up to the blue/pink/purple lines, and read their values on the left axis. For voltage, go over to 500mA, go up to the red line, and read its value on the right axis.

 

[AUTO XX]

You're right, I must have been having a brain fart....
@budabob07 I can't seem to find a CC driver without voltage adjustment "CV" as well (at least not for $10)
Last night I blew up one of these boards because I didn't watch close enough and the battery terminals on the old automotive battery I was testing with are backward from standard (it reads @ almost 17V so I was checking to see how well regulated the Vout was)
Anyway, I hooked the leads up backward, it blew up the main LM2596 chip, spit a bunch of pieces at me, then blew up a small resistor for good measure.
There was a diode inline but I'm guessing it didn't work properly :crackup:

*Those pieces were moving pretty quick when they flew by*