500mw mits: Will this driver work?

[Jstr]

Hi all,
I have been working with blue lasers for over a month now, and now I'm looking for a change. So, I got a 500mw Mitsubishi 638nm diode from DTR. This is my first attempt at a red laser, and I'm not entirely sure if this diode is compatible with my 1.25A driver from survival Lasers.

Driver: Survival Laser Driver

In my search I found many posts and tons of info on the divergence and correcting optics, but nothing on the building of a handheld with the 500mw Mits.

I think the circuit for this diode is fairly simple and similar to that of the m140 I am used to, and I have not found anything that would contradict this, but I would like to be sure.

Mine might be a dumb question, but as someone new to the sport, I would rather err on the safe side and ask than blow 75 dollars.

Will this driver work?

 

[Jstr]

Here is a better picture of the driver

 

[CDBEAM777]

JST...That is the exact driver I am using for the " Dragon's Head" build.....see

http://laserpointerforums.com/f50/optically-corrected-p73-hh-design-1w-no-line-87235.html

Works perfect. Some have driven the P73 up to 1400 mA...I think PB blew his at 1100 mA.....Each diode is a little different..some more efficient...some less efficient..perhaps he had a bad LD ??? IMNSHO...1250mA is a good current to drive the 500mW P73 at.

I recommend that you put this 500 mw in a HH unit with some mass in it....so...a larger vs. a smaller host would be wise. This will help with LD life and allow the P73 to run cooler....thus delivering more mW output.

With no corrective optics, you should get about one (1) watt out the front door.

Lite'em up...CDBEAM=======>

 

[Jstr]

Perfect! Thank you!

 

[honeyx]

Perfect! Thank you!

This is the exact same buck driver offered by DX for around $ 2-3. It might work with a Mitsubishi diode but personally I would go for a driver with a soft start build in.

A simmilar buck driver already killed a few mits for me as some of them are causing little spikes when turning on. The same driver is working well with the 9mm blue diodes but the mits are more sensitive.

So either get a driver with a softstart build in or when using such cheap buck drivers without a softstart, add yourself a circuit that will do this for you.

 

[Jstr]

This is the exact same buck driver offered by DX for around $ 2-3. It might work with a Mitsubishi diode but personally I would go for a driver with a soft start build in.

A simmilar buck driver already killed a few mits for me as some of them are causing little spikes when turning on. The same driver is working well with the 9mm blue diodes but the mits are more sensitive.

So either get a driver with a softstart build in or when using such cheap buck drivers without a softstart, add yourself a circuit that will do this for you.

How much is the input spike typically?

Also how would you build a circuit that would provide a soft start?

 

[honeyx]

How much is the input spike typically?

Also how would you build a circuit that would provide a soft start?

Can´t tell now how much mV but high enough to kill a mits diode even at way lower currents than most here are driving the mutsubishis. I just checked these drivers with a DSO to see why some of them were killing my mitsubishi dodes and could see the spikes.

The simpliest way to add a softstart is to use a LM317 as a constant voltage source between the driver and the batteries and use this as the soft start circuit. For this you only need to add a capacitor in parallel to the buttom resistor.

The way better solution is by directly buying a driver which has this build in.

Some members here are offering such drivers. They cost a bit more but are worth the money.

 

[Jstr]

If I have protected 18650 batteries, does that mean that they output a constant voltage? Would that mean I don't need a LM317?

 

[honeyx]

Nope the pretection circuit only disconnects the battery if there is a shortcut between the + and - to prevent overheating and/or exploding. So you will still need a softstart circuit to not to demage your diode.

 

[Jstr]

Ok thanks! Will do

 

[CDBEAM777]

Read the technical section from Survival Laser concerning their 1250mA fixed driver...which I believe is the driver you originally considered. ...and the one I have trialed and plan to use in the Dragon's Head build. I also spoke with Greg at SL. I am convinced this driver is OK to use.

NO SPIKES...NO OVERSHOT !! I guess it is a matter of trust !!

Lite'em up CDBEAM=======>

 

[Jstr]

Yeah I went ahead and tried it. It worked fine. Thanks!

 

[honeyx]

Well I didn´t say all produced spikes but some of them did. This driver is also an exact same copy of the driver offered on DX.com and I don´t see any extra parts to prevent spikes.

It´s like said it may work but if you get one that is producing spikes you also may kill the diode. So this is just my personal opinion and therefore I would spend a little bit more for a driver with a build in softstart rather than buying an expensive diode but then going for the cheapest driver aviable.

Yes it´s a matter of trust and I don´t trust these drivers anymore since one killed 4 diodes for me.

DTR and Lazeerer is selling good drivers that can be trusted. I also would never buy a $800 1W Green diode and drive it with such a $5 driver. For this I would better spend the few extra $$ to not to risk to kill it or the golden contacts get melted on a cold turn.

 

[Jstr]

Well I didn´t say all produced spikes but some of them did. This driver is also an exact same copy of the driver offered on DX.com and I don´t see any extra parts to prevent spikes.

It´s like said it may work but if you get one that is producing spikes you also may kill the diode. So this is just my personal opinion and therefore I would spend a little bit more for a driver with a build in softstart rather than buying an expensive diode but then going for the cheapest driver aviable.

Yes it´s a matter of trust and I don´t trust these drivers anymore since one killed 4 diodes for me.

DTR and Lazeerer is selling good drivers that can be trusted. I also would never buy a $800 1W Green diode and drive it with such a $5 driver. For this I would better spend the few extra $$ to not to risk to kill it or the golden contacts get melted on a cold turn.

I understand where you are coming from and it would have been smart of me to follow your advice but I simply did not have room in my host to stick an LM317 in.

Next time I will get a driver with a soft start.

Thank you for your input.

 

[Garoq]

Honeyx, do you have any o'scope traces of these drivers that have produced spikes? I have not seen any examples of them producing spikes, at least from the ones we have tested.

Part of the problem with this driver is that it is very easy to short out a critical area on the board when soldering it to the brass ring. We apply a layer of sealant to the critical area to combat this problem, as well as test every driver for proper operation prior to shipment. So it is not actually the "exact same copy of the driver offered on DX.com".

The 1.25A driver has been used extensively by numerous LPF members and sellers with the 445nm diodes. FYI this particular driver is very popular due to its low price but we also offer several other fixed current and adjustable drivers that many LPF members have had good success with.