1 watt ir driver problem

[TheTeslaWarrior]

ok i did search this first so if it is a common problem sorry i didn't see it
i'm building a 1 watt ir laser to put on a cnc machine and i made a ddl driver for it thats running off a 6v lantern battery and i checked the voltage out of the driver is about 5.5v isn't the driver supposed to use 3v not .5v?

thanks and again sorry if its a noob question that everyone asks i seriously couldn't find it

edit: my friend who is another forum member straitened this out for me so sorry

 

[MickyP]

Did you check the output voltage of the driver with or without a laser diode or LD dummy load across the output?
What type of driver, specifically, is it?
These questions need to be answered before any further info can be provided.

Edit: Sorry just saw that the issue is resolved.

 

[Meatball]

Its a DDL driver. Its linear, so his PS should be sufficient. How much resistance do you have between pins 1 and 2 on the IC?

 

[billg519]

This circuit is a current regulator. It will only let the voltage rise high enough for the set current to be drawn. If your DMM was the only load, the voltage would be reading high as you saw, because very little current is drawn by the DMM. If you put an ammeter across the output as a load, it should read the set current. Are you using a resistor of about 1 ohm for this regulator? This would give 1250mA. If you are using an LM317 it will need to be well heatsinked.

 

[Benm]

Indeed. Wire your multimeter to its 10/20/40 amp range and see how much current it puts out then. Heatsinking the regulator at these current levels is mandatory too. A lm317 will tune down the current to save its own life, which distorts measurements.

 

[TheTeslaWarrior]

yeah i didn't use a dummy load i don't know what i was thinking, like i said my friend straightened it out. as for heat sinking i have a heat sink that everyone who sees it agrees is overkill.
thanks