Will this perform properly?

[aaronX987]

Ok, So I have daedal's driver with 33 ohms of resistance and a blue ray diode using two 18650 2500mAh 3.7V batteries.
Since Blue-ray's require more voltage I was wondering if this power supply would cut it. I hope this is still useable and does not require higher voltage because these batteries are hefty and carry an good charge.

P.S. It also states on the batteries that the full charge voltage is 4.2V and the cut-off discharge is 2.75V.

 

[Gazoo]

Measure the voltage between the output and adjust...it should be 1.25 volts. If it isn't the regulator is dropping out. I think you will find you need to use three li-ion batteries to maintain regulation until the batteries are depleted. However the batteries you are using have a high capacity and since the diode only consumes ~38 ma's your blu should run for awhile.

 

[aaronX987]

Gazoo,
Wether it be blue laser or red laser is the cut off still 6V before the regulator drops out?

 

[a_pyro_is]

Gazoo,
Wether it be blue laser or red laser is the cut off still 6V before the regulator drops out?

I'm not Gazoo, but the minimum voltage for driving a BluRay with a LM317 based constant current source is about 8 Volts, and the minimum for a red is about 6 Volts.

 

[aaronX987]

Hmmm, interesting thanks pyro.

 

[aaronX987]

Is there any other voltage regulator out there that does not come with such a high voltage cost?

 

[a_pyro_is]

There are thousands, but none as easy to get and as reliable as our friend the LM317.

 

[Gazoo]

Is there any other voltage regulator out there that does not come with such a high voltage cost?

I am using a 7805 in a TO-92 case to power my blu-ray. It requires 7 volts and I have a 25 ohm multi-turn pot in series with it. I am using it as a voltage regulator because it sucks as a current regulator.

I did find some 5 volt LDO regulators on e-bay which would work well with voltages as low as 5.5 volts.

http://cgi.ebay.com/ULTRA-Precision...oryZ4660QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

[a_pyro_is]

AaronX987, Gazoo is the one to listen to about this. I've only used current regulators on my LDs.

 

[Gazoo]

I would never recommend using a voltage regulator with the red diodes. I have noticed as my blu heats up the current increases by a few ma's. But using a current regulator with my reds, the current holds rock steady.

 

[pseudonomen137]

Problem with a voltage regulator is the diodes resistance changes with temperature. As it runs and temp changes, even if voltage holds steady the current will change. Since current is the important thing to worry about when running a diode, its better to have a current regulator.

A voltage regulator with a little bit of leeway and proper heatsinking on the diode is acceptable - certainly better than direct battery drive with a resistor (or without a resistor  ), but a current regulator is still the best way to go.

 

[Gazoo]

True, but using a voltage regulator with the blu is not a huge problem because it does not get that hot with less than 40ma's. Therefore current is not going to increase by more than a few ma's. I have mine mounted in one of the tiny Aixiz modules so it does heat up much more than if it was mounted in a regular Aixiz module.

 

[aaronX987]

So it is possible o use something else with the blue ray diode. Goo. because that is the one that really needs the change when it comes to having a different regulator. Gazoo, is your driver setup basically the same as daedal's or does a different regulator require lots of changes?

 

[rog8811]

This is the circuit Gazoo is talking about, it works very well

Regards rog8811

 

[Gazoo]

Thanks for reposting that pic Rog...

aaronX987 - The only thing I would add is any multiturn pot between 25 and 100 ohms will work. You can get all of the parts you need from this ebay seller:

http://stores.ebay.com/Techno-Star_W0QQsspagenameZL2222QQtZkm

He had 25 ohm pots but is out of them...however he does have 50 ohm multiturn posts. His prices are very good and he combines shipping.

 

[Benny_Hill]

This circuit works beautifully!!! I finaly gathered the mindset to go ahead and extract the diode and build the driver. For the first time I got lucky and actually had all the parts! The laser is the 27$ psxboy deal and is a strange little beam. It hits its nice brightness at 50ma and has a very fuzzy dot. Does anyone know if its a safe idea to run the red and the BR? Also How are you supposed to get the small piece of board off the back of the diode? (SAFELY)