Too much voltage from driver boost

[AMooMooCow]

Please delete

I've burned about five 120mw diodes now before I realized that the drivers I've been buying specifically for these 405nm diodes have a voltage boost.
My measurements:
input- 1.5v
output- 6.93v, .104A
And then I thought hey! Let's use Ohm's law! So to get the diode working on the 2-4v it's supposed to, I went and said 3.7=.104*wumbo (where wumbo is omega) so I went to Radio Shack and got a 33ohm resister.
I applied the resister to my LD- wire, and measured again 6.93v.
Does anyone know what I'm doing wrong that the laser gods do not like?

 

[lasersbee]

You must check the output voltage under load.

Use a Laser Test Load....
Use the Search bars to find how to build a cheap
Laser Test Load and use it properly..


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

 

[MarioMaster]

He said he put the resistor in series with the laser diode (implying it was connected during testing)

Since you're using a switchmode driver it will boost the output voltage as necessary to reach the current setting. Adding a resistor on the output of a boost driver simply reduces your system efficiency as the boost driver will increase its output voltage to compensate.

So your problem probably stems from something else - either the diodes you're using can't handle 104mA, you're not making sure the driver capacitors are totally discharged before connecting it to the diode or are disconnecting and reconnecting the load from the driver while it has power.

A bit more info about your wiring and setup might help us figure out where your problem is

 

[lasersbee]

He said he put the resistor in series with the laser diode (implying it was connected during testing)

A bit more info about your wiring and setup might help us figure out where your problem is

He also stated that he alreasdy blew 5 LDs with the
same setup.
He did not state that he tested the output yet a 6th
time to Blow another one... perhaps the 6th LD is also
dead.

Like you said we need more info..


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

 

[AMooMooCow]

Here is my circuit. The driver I'm using is one of these_405nm 100 300mW Laser Diode Driver Reverse Protection | eBay
I was just testing it out on 1.5v before, but I want to use 3v in my final build
edit: I am a noob electrician btw. I just think it would be really cool to put a laser into an Altoid's canister

 

[MarioMaster]

Since the driver is switchmode, running the driver below its minimum operating voltage is likely to cause instability and improper operation. You must run it within its specifications to get useful measurements.

 

[AMooMooCow]

Since the driver is switchmode, running the driver below its minimum operating voltage is likely to cause instability and improper operation. You must run it within its specifications to get useful measurements.

ok, so to recap, what I should do is run the driver at 3.7v into a test load, measure the output close to 4.5v/100mA so the diode doesn't blow. If there is too much voltage, the diode will heat up and its life will shorten; ?but the driver supposedly will take care to regulate the voltage?. And then very carefully connect the driver to the laser and then the battery to the switch and then connect the switch to the driver and battery.
Any other suggestions? I've been really disheartened by this quest over the last two years, and I would kiss you and send you a tub of cookie dough if you wrote me exact steps

 

[MarioMaster]

Current is a function of voltage and vice versa. If your current is set to a value appropriate for your diode, the driver will regulate its output voltage to achieve the current you set it for.

Once the driver is set to your specified current with it connected to a test load, you will need to remove all power, disconnect the test load and then short the input and output of the driver to discharge any possible remaining voltage in the driver, connect the driver to the laser diode and then power it up. You should be in business.

 

[AMooMooCow]

Once the driver is set to your specified current with it connected to a test load, you will need to remove all power, disconnect the test load and then short the input and output of the driver to discharge any possible remaining voltage in the driver, connect the driver to the laser diode and then power it up. You should be in business.

haha, nice. thank you so very much. One day, you won't remember this thread anymore, and come wintertime there'll be a 10gallon tub of sugar cookie dough on your coffee table.