Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers





Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes
Laser Technology Laser Pointer Parts Lasers by Wavelength
Top 10 Laser Pointer Companies Laser Pointer Company Database Visible Beam Laser Pointers


One laser store meets all your needs

























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Experiments & Modifications



LPF List of Laser Pointer Companies (link opens new window)



Reply
 
LinkBack Thread Tools Display Modes
Old 02-27-2008, 09:34 PM #273
Class 2 Laser
 
Join Date: Nov 2007
Posts: 342
Rep Power: 12
woop will become famous soon enoughwoop will become famous soon enough
woop woop is offline
Class 2 Laser
 
Join Date: Nov 2007
Posts: 342
Rep Power: 12
woop will become famous soon enoughwoop will become famous soon enough
Default Re: Using a DC/DC converter to power the laser

is there much advantage having the case grounded?


woop is offline   Reply With Quote







LPF List of Laser Pointer Companies (link opens new window)







Old 02-27-2008, 10:07 PM #274
phenol's Avatar
Class 2M Laser
 
Join Date: Oct 2007
Posts: 533
Rep Power: 50
phenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond repute
phenol phenol is offline
Class 2M Laser
phenol's Avatar
 
Join Date: Oct 2007
Posts: 533
Rep Power: 50
phenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond repute
Default Re: Using a DC/DC converter to power the laser

it must be on gnd potential if, for instance, its heatsink is not isolated from the chassis of the host and minus terminal of batts is also in contact with it.
generally i prefer to have all massive metal objects/heatsinks/ hooked to the lowest potential in a cct - normally ground/chassis of equipment for safety sakes due to risk of shorts
phenol is offline   Reply With Quote
Old 02-27-2008, 10:08 PM #275
IgorT's Avatar
Class 3B Laser
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
IgorT IgorT is offline
Class 3B Laser
IgorT's Avatar
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
Default Re: Using a DC/DC converter to power the laser

Quote:
Originally Posted by woop
is there much advantage having the case grounded?
Well, if you use a flashlight host or a metal enclosure, and want to use the body as a heatsink, you need the LD negative pole at GND potential, or you short the IC..
Otherwise you have to insulate the AixiZ module from the host, and lose some heatsinking...


I don't care about this, since i'm using plastic enclosures, and a peltier for the open can.


EDIT: I see Phenol already answered, while i was writing the post.. So... What he said..
__________________
Signature temporarily out of order...
IgorT is offline   Reply With Quote
Old 02-28-2008, 01:23 PM #276
Class 2 Laser
 
Join Date: Nov 2007
Posts: 342
Rep Power: 12
woop will become famous soon enoughwoop will become famous soon enough
woop woop is offline
Class 2 Laser
 
Join Date: Nov 2007
Posts: 342
Rep Power: 12
woop will become famous soon enoughwoop will become famous soon enough
Default Re: Using a DC/DC converter to power the laser

Quote:
Originally Posted by phenol
these are two scopeshots of what's on the output /CH1 -> AC coupled, DC component removed/. in the first one channel 1 shows the output noise almost directly across the output cap. the metal shielding barrel of the probe was touching the pcb GND as close as possible to the output cap, and the tip was also as close as possible to the 'hot' end of the same cap. moving the test point by only a millimeter or two resulted in twofold increase in noise amplitude. channel 4 shows the voltage across L2. spiking occurs during rising and falling edges.
in the second pic is one of the spikes dilated in time.
The test conditions were as follows:
Vin=2.72V
Iout=278mA
Vout=2.74V /3x1N4005+1N5819/
what scope do you have?
i am thinking of getting a scope, they are so damn expensive, especially the usb ones
woop is offline   Reply With Quote
Old 02-28-2008, 01:39 PM #277
phenol's Avatar
Class 2M Laser
 
Join Date: Oct 2007
Posts: 533
Rep Power: 50
phenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond repute
phenol phenol is offline
Class 2M Laser
phenol's Avatar
 
Join Date: Oct 2007
Posts: 533
Rep Power: 50
phenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond repute
Default Re: Using a DC/DC converter to power the laser

tek TDS3034B - 300MHz, 4 channels; it has floppy, LAN, rs232, centronics, GPIB...no USB :P ... digital storage scopes are a must if you intend to capture non-periodic events
phenol is offline   Reply With Quote
Old 02-28-2008, 07:33 PM #278
IgorT's Avatar
Class 3B Laser
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
IgorT IgorT is offline
Class 3B Laser
IgorT's Avatar
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
Default Re: Using a DC/DC converter to power the laser

Phenol... Did you manage to get the second sample order through by coilcraft?

I just recieved my second sample shipment today, but they only gave me four this time.. They gave my girlfriend 10...


But if they don't want to send you a second sample order, i could probably forward at least these four to you..


If you think the YSD needs a larger coil, i can spare these and maybe more... Let me know...

Alternativelly, i can give you an internal e-mail, of someone, who is much more willing to send samples.
__________________
Signature temporarily out of order...
IgorT is offline   Reply With Quote
Old 02-28-2008, 07:58 PM #279
phenol's Avatar
Class 2M Laser
 
Join Date: Oct 2007
Posts: 533
Rep Power: 50
phenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond repute
phenol phenol is offline
Class 2M Laser
phenol's Avatar
 
Join Date: Oct 2007
Posts: 533
Rep Power: 50
phenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond repute
Default Re: Using a DC/DC converter to power the laser

thanks, igort, i havent ordered yet, these days we had an important customer audit and i have been a little too busy to my liking. im going to carefully revise my need of power coils tomorrow morning and order once again. i would encourage you to keep whatever parts uve gotten for ur ysd samples, as i can find similar coils locally or even wind smth working myself.
thanks again
phenol is offline   Reply With Quote
Old 02-28-2008, 08:23 PM #280
IgorT's Avatar
Class 3B Laser
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
IgorT IgorT is offline
Class 3B Laser
IgorT's Avatar
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
Default Re: Using a DC/DC converter to power the laser

Quote:
Originally Posted by phenol
i would encourage you to keep whatever parts uve gotten for ur ysd samples, as i can find similar coils locally or even wind smth working myself.
thanks again
No problem.. Just trying to be helpfull a bit.. Especially, after bugging you with so many questions...


But you're lucky, that you can actually buy coils locally.. My engineer just told me, that i must be the first one in Slovenia, to actually have CoilCraft coils...
Our shops here don't sell anything like it.. Everything has to be ordered internationally and is very expensive..

If these same coils should also work with the YSD, then i have just the right amount of them and the ICs to build seven circuits... If not, i'll try 10uH ones.


BTW: I finally found some time, and i'm testing my circuit now...
__________________
Signature temporarily out of order...
IgorT is offline   Reply With Quote
Old 02-29-2008, 02:20 PM #281
IgorT's Avatar
Class 3B Laser
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
IgorT IgorT is offline
Class 3B Laser
IgorT's Avatar
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
Default Re: Using a DC/DC converter to power the laser

I just successfully tested my LM3410 circuit, and it works great..

In fact, it even starts up at 2.3V and runs at this voltage with an efficiency of 65.4%, which i think is good for such a low voltage.. I'm amazed by the fact, that it would probably work from only two Ni-MH cells without modification... With it it would suck them dry.

I also tested the current stability at different voltages, and it remains constant, from 5.5V, down to 2.3V.
I didn't measure the efficiency at higher imput voltages yet, simply because i was so impressed at this low voltage.


Oh, i tested the circuit on a LED and on a dead IR LD, which actually worked for a while, without a cap on it at all.. It died completelly later, but i don't think it was the circuits fault.. It died when i was moving it's cables....


Next i'll try it with a good IR LD with a cap on and measure the efficiency at higher voltages, starting with 4.2V and down to 3V..


As it is, it will already work with a single Li-Po cell, and keep the current constant over it's entire voltage range.. It could even run with a primary lithium cell!

I must say i'm very happy with this circuit....



EDIT: Efficiency at 4.2V input 73%... I thought it would be better, but i guess it's not that bad either..
__________________
Signature temporarily out of order...
IgorT is offline   Reply With Quote
Old 02-29-2008, 03:54 PM #282
IgorT's Avatar
Class 3B Laser
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
IgorT IgorT is offline
Class 3B Laser
IgorT's Avatar
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
Default Re: Using a DC/DC converter to power the laser

BTW: Something weird happened, when i was measuring the circuit efficiency..

I had a multimeter attached to the LED, to measure the output voltage. Then i disconnected the positive lead of the PSU from the PCB and it accidentally touched the multimeters positive lead.

I suddenly noticed a rising column of smoke, but i didn't see, where it was coming from.. I thought the IC was dead.. But when i connected everything back again, the thing worked.. It still works just like before, but i think the LED is less bright.. Not sure tho..


I have absolutelly no idea what happened.. Need to look at how everything was connected, to figure out, where the current went and what made the black smoke.
__________________
Signature temporarily out of order...
IgorT is offline   Reply With Quote
Old 02-29-2008, 04:40 PM #283
IgorT's Avatar
Class 3B Laser
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
IgorT IgorT is offline
Class 3B Laser
IgorT's Avatar
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
Default Re: Using a DC/DC converter to power the laser

Right now, i have an IR LD driven by my circuit, to see if it's safe. It has a 1uF ceramic capacitor directly on the leads..

So far so good...
Or not.. The IR LD seems to have dropped in power considerably.. I first noticed, that the faint red spot became even more faint, and it also shows up less on the camera...

Damn.. Maybe i have overdriven it, on the other hand... I don't know how much current it was supposed to take, i had it at 213mA.
Need to do more testing...

Also, with this LD the efficiency was only 63%... With the LED, at 5V and 213mA, the efficiency was 72%... This doesn't make much sense to me.



EDIT: I just tried the circuit with my sick Blue Ray LD, which needs more than 200mA to make a beam.. (I don't understand why it still works at all)
The circuit fed it 5.48V @ 213mA, and the efficiency was 74.2%...

Why is efficiency better at higher output voltages?!?


Next i'll try with a flat chip red, to see if it can take it..
__________________
Signature temporarily out of order...
IgorT is offline   Reply With Quote
Old 02-29-2008, 05:21 PM #284
phenol's Avatar
Class 2M Laser
 
Join Date: Oct 2007
Posts: 533
Rep Power: 50
phenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond repute
phenol phenol is offline
Class 2M Laser
phenol's Avatar
 
Join Date: Oct 2007
Posts: 533
Rep Power: 50
phenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond repute
Default Re: Using a DC/DC converter to power the laser

as of the smoke column - touchin the + to the output of ur circuit would pass current thru the load and the shunt resistor. either, or both, may have smoked. the switch pin of LM is DC decoupled with C3, so no current should have flown there. FB pin is almost grounded by the low resistance of the shunt, so only a very high drop there would cause damage to this input.
regardin IRLD, i killed one at only 150mA, so you may have overdriven it indeed. *furthermore, i also noticed the presence of a start-up transient in the output current almost twice as high as the nominal steady state current. a rather discouraging observation * . it would probably be safe if across the load there is also a 100uF electrolytic cap and a subsquent double-check for presence of oscillations probing the output and the power input terminal with a scope. under some circumstnces i have observed sine oscillations there that went away when i placed a 100uf tantalum at *the output.
in short, this little goodie can be sonofa$%^&*.
phenol is offline   Reply With Quote
Old 02-29-2008, 05:39 PM #285
IgorT's Avatar
Class 3B Laser
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
IgorT IgorT is offline
Class 3B Laser
IgorT's Avatar
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
Default Re: Using a DC/DC converter to power the laser

Quote:
Originally Posted by phenol
i also noticed the presence of a start-up transient in the output current almost twice as high as the nominal steady state current. a rather discouraging observation * . it would probably be safe if across the load there is also a 100uF electrolytic cap and a subsquent double-check for presence of oscillations probing the output and the power input terminal with a scope. under some circumstnces i have observed sine oscillations there that went away when i placed a 100uf tantalum at *the output.
in short, this little goodie can be sonofa$%^&*.
So what now? I can't use it unless i put 100uF tantalums on the LD? Damn... Or is that 100uF tantalum + 100uF electrolytic?
I was really happy when i thought those tiny ceramic SMD caps would do.. But i do have some 47uF tantalums as well.. Should i just put two of them in?

I would like to test the circuit with the flat chip red, but i kinda promissed someone i would turn it into a laser.. So i don't necessarily want to kill it.
What about tantalums on the output of the circuit for this spike? Or should i do both (the more the merrier...)?


I don't want to just accept defeat, after spending so much time on this circuit. I want it to work..

Unfortunatelly, i don't have a scope at home, and i couldn't find the time to test it at work. On the other hand, i finally have time to play with it, so i don't want to waste it.


BTW, do you have any idea, why my efficiency get's better, when the output voltage is higher (current being the same in all cases)?
__________________
Signature temporarily out of order...
IgorT is offline   Reply With Quote
Old 02-29-2008, 08:26 PM #286
IgorT's Avatar
Class 3B Laser
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
IgorT IgorT is offline
Class 3B Laser
IgorT's Avatar
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
Default Re: Using a DC/DC converter to power the laser

I put a large ceramic SMD capacitor (value above 20uF, don't know exactly) and a 47uF tantalum directly on the leads of the flat chip 16x red LD and another 47uF tantalum directly across the circuit output..


It seems to work fine... I'm gonna try running it for a longer time, to see what happens.


Would this current ripple show it's effects immediatelly, or would it just slowly decrease the LDs lifetime?
__________________
Signature temporarily out of order...
IgorT is offline   Reply With Quote
Old 02-29-2008, 08:30 PM #287
phenol's Avatar
Class 2M Laser
 
Join Date: Oct 2007
Posts: 533
Rep Power: 50
phenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond repute
phenol phenol is offline
Class 2M Laser
phenol's Avatar
 
Join Date: Oct 2007
Posts: 533
Rep Power: 50
phenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond reputephenol has a reputation beyond repute
Default Re: Using a DC/DC converter to power the laser

well, the ceramic should almost completely notch out those short-lasting spikes. cycling the power on-off may push a strong startup pulse/much longer than the periodic spikes) thru the diode. the 47u cap will probably suffice in absorbing it
phenol is offline   Reply With Quote
Old 02-29-2008, 09:23 PM #288
IgorT's Avatar
Class 3B Laser
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
IgorT IgorT is offline
Class 3B Laser
IgorT's Avatar
 
Join Date: Oct 2007
Location: Slovenia, EU
Posts: 4,177
Rep Power: 55
IgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond reputeIgorT has a reputation beyond repute
Send a message via Skype™ to IgorT
Default Re: Using a DC/DC converter to power the laser

Quote:
Originally Posted by phenol
well, the ceramic should almost completely notch out those short-lasting spikes. cycling the power on-off may push a strong startup pulse/much longer than the periodic spikes) thru the diode. the 47u cap will probably suffice in absorbing it
Thanks.. Do you think that the second 47uF tantalum directly on the PCB is helping any with these power on spikes, or would it be better to have both of them on the LD? Does this matter with the startup pulses?


If the swithch on spikes could be absorbed on the board itself, it would all be MUCH easier.. Soldering these to the leads directly is not much fun... Especially, since they don't fit without extending the leads.. I would rather have both tantalums on the PCB.. The small ceramic ones are much easier, when it comes to this... You think this would work?



I'm gonna let the red run for a while now.... See what happens... I really want to be able to drive my lasers from a single Li-Po or even two Ni-MHs...
It's been working for around 10 minutes now, with no drop in the brightness..




BTW: I'm getting 67.5% efficiency with the red LD.. It could be worse, but i still don't understand why it gets better at higher output voltages.. What kind of efficiency did you get, and is it constant at different output voltages?
__________________
Signature temporarily out of order...
IgorT is offline   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 11:54 AM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC