diode driver 150mw red with ttl support. can this be used for green 50mw?

[michelrietveld]

Hi, question about using diode drivers, mine has 230 V input, has a 150 mw red diode attached with blanking support through ttl (0-5V). i also have a salvaged 50 mw green which is much more visible, can i just replace the diodes?
i think not but don't know enough about how drivers work, i assume it sends a restricted amount of current to the diode with a fixed voltage so if i hook up the green 50mw or another red 100mw i might burn it or should i just go ahead and try?

Michel

[edison]

Do not try it. As you mentioned yourself the driver delivers the current for the 100mw red. There is quite a chance you will destroy the green. What you should do is connect a multimeter and open the driver. Maybe there are some pots so you can adjust the current. Measure the current that powers the red and if there is a pot you can slowly turn it. When the amps decrease you are on the right track. Most of the time there is also a pot to set the threshold (the minimal current to get the diode lasing) You have to turn that too to zero. Then connect the green and adjust the pots to the green.

Good luck.

Do you know the current that the green needs? Otherwise you have to measure the green output when setting the driver

[hobbybob]

Hi Michel,

You can also buy a die4drive of Uklasers (also member on the forum here) or a Flexmod from Dr. Lava. Have both and are happy with both.
The new flexmod can power up to 4A and the die4drive does around 1A i believe.
The old flexmod can also deliver 0-1A or 0-6A!

A 50mW green often uses like 500mW IR diode. My 150mW Lasever had a 2W if i am not mistaken (at least when i replaced it with a 2W around 212mW came out!).
So a factor 1 in 10. So you need some current to let it work.

[michelrietveld]

ok, i will check the voltage for the green and red diode in my crappy laser projector, the one i want to salvage the diodes from, they have a driver inside of course but this does not support ttl.
I have ordered 2 laser drivers which do support this and will follow the following procedure, correct me if i am wrong:

1. check voltage for laser module (use volt meter parallel)
2. check current it uses, this will be the current when the diode is running (use multimeter for current measuring in serial with the diode)
3. how do i measure the startup-current needed for the diode???

Then use the laser driver, and tune this to the desired settings, am i correct?

Michel

[hobbybob]

Hey Michel,

You wrote that the drivers inside your projector don't support ttl ?
OK, i don't know which drivers you ordered now, but would be nice to have analogue modulation....

Anyway, your right as i can tell, point 3, that would be the current that is running when NO voltage is applied to modulation input. Since you say you're drivers don't support any, this would probably the current when nothing is displayed ?

With the new drivers you can test this current by CAREFULLY turning up the bias current.
At some point (for a red open can this is somewhere roughly 1between 50 - 100mA the diode starts to emit light ! Just turn em down until they are barely visible (or off) and you reached the sweet spot.

hope this helps, else you know how to reach me.

greetz,
Dimitri