rhd
0
- Joined
- Dec 7, 2010
- Messages
- 8,475
- Points
- 0
Best post ever ^ 
LPF Donation via Stripe | LPF Donation - Other Methods
Links below open in new window
ArcticMyst Security by Avery
New Ultra-Low Drop-Out Constant Current Driver Design!
- Thread starter Wolfman29
- Start date
- Joined
- Jan 14, 2011
- Messages
- 3,816
- Points
- 63
I disagree!
- Joined
- Apr 23, 2011
- Messages
- 212
- Points
- 0
Well darn.... that kinda sucks... I have hard time believing though that a diode can run straight DC at say 420mA but a 1A spike could kill it. I have yet to hear of this "COD" term...... very interesting. I doubt many people have done to much testing with that?
rhd
0
- Joined
- Dec 7, 2010
- Messages
- 8,475
- Points
- 0
1) No? I'll sell you a LOC. Try spiking it with 1A.
2) I would bet that nearly everyone on this board has had a few "experiments" that involved COD
- Joined
- Dec 23, 2008
- Messages
- 3,948
- Points
- 63
there is not testing for cod. it is fairly common here. i think they are also called zombie diodes. they can be used as dummy loads.
michael.
michael.
qumefox
0
- Joined
- Mar 26, 2010
- Messages
- 3,220
- Points
- 0
It's more commonly known as 'LEDing your diode' because when the coatings go poof, that's what your left with. An LED. And I have many LED'd laser diodes.. even 445's.
People forget laser diodes are still cavity devices. They have HR and OC coatings on the facets that forms the cavity.. and the power density in the cavity is going to be MUCH higher than what actually comes out of the diode as usable output. The coatings can only take so much power before they burn off.
Actually in most laser diodes, LOC's in particular, the coatings are the limiting factor, and not the current capacity of the PN junction.
People forget laser diodes are still cavity devices. They have HR and OC coatings on the facets that forms the cavity.. and the power density in the cavity is going to be MUCH higher than what actually comes out of the diode as usable output. The coatings can only take so much power before they burn off.
Actually in most laser diodes, LOC's in particular, the coatings are the limiting factor, and not the current capacity of the PN junction.
- Joined
- Dec 29, 2009
- Messages
- 3,136
- Points
- 63
COD is also known as LED-ing a diode. Basically, instead of discreet mirrors, the diode's ends are cleaved ultra flat and ultra polished to serve as the mirrors for the cavity. If too much light goes through these "mirrors," they burn up and don't reflect light back into the cavity to gain.
Where LEDs' damages occur due to overheating or obliterating the current spreaders or bond wires, laser diodes can die from too much light too, not necessarily too much heat. This is why some people have diodes that die from laser light reflecting back INTO the laser, focused back onto the front facet of the die by the same lens that focuses the output into a beam.
Where LEDs' damages occur due to overheating or obliterating the current spreaders or bond wires, laser diodes can die from too much light too, not necessarily too much heat. This is why some people have diodes that die from laser light reflecting back INTO the laser, focused back onto the front facet of the die by the same lens that focuses the output into a beam.
- Joined
- Jan 14, 2011
- Messages
- 3,816
- Points
- 63
^ Exactly.
qumefox
0
- Joined
- Mar 26, 2010
- Messages
- 3,220
- Points
- 0
There's an echo in here.
- Joined
- Dec 29, 2009
- Messages
- 3,136
- Points
- 63
Gah! How the heck did you.. bah! We should call you the ninja poster :beer:
- Joined
- Apr 23, 2011
- Messages
- 212
- Points
- 0
Verrry informative! Quite a pity though... was hoping I could test my laser out when its -40C outside and jack it with current and see how much power I could get. =( Hmm... will now make sure to put a cap on my drivers. Thanks
qumefox
0
- Joined
- Mar 26, 2010
- Messages
- 3,220
- Points
- 0
Don't you think if it had been possible, that you'd have seen 1W supercooled LOCs and 3W 445s posted by now?
Last edited:
