Low M140 output @ 1.05A output. (UPDATE PAGE 2)

I am using a driver with 3x AMC7135 current limiting chips, outputting 1.05A. To ensure the forward voltage wasn't too low, I used 2x primary CR123's for testing at around ~6v

The tailcap current measurement is accurate. Yet, my output is barely over 100mW on my coherent laser meter. Any idea what's wrong? What kind of output should I be expecting here? Certainly it is more than ~100mW.

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

If you are measuring 1.05A on the tailcap, then your diode is certainly zombied. That means it either took damage when soldering leads to it, took static electrical damage, or it was a zombie when you purchased it :\

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

I've seen those diodes eat around 5.2v your getting about 1.2v of drop through the driver so I'd say your not getting enough forward voltage to regulate the current.

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

1.05A should give around 800mW with a glass lens. There must be something wrong if you only get 100mW out of it.

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

You should try a different driver. I don't think AMC7135 is best for diodes that need more then 3.5V. (thats my opinion) try building a DDL driver instead. they only cost about 2$ to build one and then try with the li-ion batteries.

-Anthony

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

Yep, you need to make sure the Vf is fully satisfied before you do anything else. If the diode doesn't get enough voltage it won't let full current through.

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

Can you take a picture of the raw output without a lens?

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

Wolfman29 said:

If you are measuring 1.05A on the tailcap, then your diode is certainly zombied. That means it either took damage when soldering leads to it, took static electrical damage, or it was a zombie when you purchased it :\

Click to expand...

It was not a zombie on arrival, and it still doesn't seem like one now. Judging by the work he did, it looked like he took all of the precautions, including soldering the leads together for shipment.

jander6442 said:

I've seen those diodes eat around 5.2v your getting about 1.2v of drop through the driver so I'd say your not getting enough forward voltage to regulate the current.

Click to expand...

I thought the voltage drop was .15 for the chips. Are you sure? In either case, if the driver dropped the voltage below the Vf, then I wouldn't be reading 1.05A at the tailcap would I?

DTR said:

Can you take a picture of the raw output without a lens?

Click to expand...

Pic quality isn't that great. The distance is about 15 feet across. Let me know if you need me to take another in a different setting.

http://i.imgur.com/Nsp0c.jpg

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

The diode looks zombied.
The main lines in the middle should be brighter than the outside lines.
It still lase but not fully.

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

It's definitely zombied. That beam pattern is a sign that the middle emitters have blown but you still have some emitters on the edges - that's what a zombie is. Some lasing, but extraordinarily inefficient.

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

Yep it looks Zombie to me. As has been said the center lines should be brighter than the outside ones. Is this a flashlight driver or a home made one?

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

DTR said:

Yep it looks Zombie to me. As has been said the center lines should be brighter than the outside ones. Is this a flashlight driver or a home made one?

Click to expand...

It was one of these drivers:
AMC7135 1050mA Regulated Circuit Board for DIY Flashlights 10-Pack - Free Shipping - DealExtreme

I figured a perfectly current limited buck circuit was a no-brainer. I'm good with electronics, I and took all of the precautions. This is disappointing.

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

DTR didn't kill your diode. So you might wanna change the title "DTR's M140 Output sucks" almost sounds like your trying to say his product sucks.

I've ordered probably 30 diodes off of DTR never having a problem. I highly doubt this has anything to do with him.. There is a chance, but highly unlikely unless some major fluke

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

jakeGT said:

DTR didn't kill your diode. So you might wanna change the title "DTR's M140 Output sucks" almost sounds like your trying to say his product sucks.

I've ordered probably 30 diodes off of DTR never having a problem. I highly doubt this has anything to do with him.. There is a chance, but highly unlikely unless some major fluke

Click to expand...

I'm giving him the benefit of the doubt. I didn't mean to imply wrongdoing by the title, just a factual statement. I changed it just in case there was confusion.

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

Jayls5 said:

It was one of these drivers:
AMC7135 1050mA Regulated Circuit Board for DIY Flashlights 10-Pack - Free Shipping - DealExtreme

I figured a perfectly current limited buck circuit was a no-brainer. I'm good with electronics, I and took all of the precautions. This is disappointing.

Click to expand...

I don't have any experience with that exact driver so I can't tell you if it is safe to use with a laser diode. There are some common issues with using LED drivers with LD's though. Being designed to drive LED's which are much more robust than LD's means that they don't need to have the same tolerances as the driver that the community here has designed. Most notably being power up spikes. These can only be detected via a scope. Also it is very important to use a test load to see what the driver will actually be feeding the diode based on the forward voltage of the load. Also it is best to do this with a variable power supply so you can lower and raise the voltage from the power source to see if the driver truly is acting as a constant current driver.

Now there are some flashlight drivers that have been used successfully and I would recommend if you wanted to go this route to do a search and see if they have been scoped and deemed safe.

Can you tell if the driver has a capacitor on the output? Did you test the driver on a test load?





Hopefully some other member can chime in that have tired this driver as well.:beer:

Re: DTR's M140 output sucks & 1.05A output. Anyone good at troubleshooting?

DTR said:

I don't have any experience with that exact driver so I can't tell you if it is safe to use with a laser diode. There are some common issues with using LED drivers with LD's though. Being designed to drive LED's which are much more robust than LD's means that they don't need to have the same tolerances as the driver that the community here has designed. Most notably being power up spikes. These can only be detected via a scope. Also it is very important to use a test load to see what the driver will actually be feeding the diode based on the forward voltage of the load. Also it is best to do this with a variable power supply so you can lower and raise the voltage from the power source to see if the driver truly is acting as a constant current driver.


Can you tell if the driver has a capacitor on the output? Did you test the driver on a test load?

Hopefully some other member can chime in that have tired this driver as well.:beer:

Click to expand...

No cap on the driver. Have tested them on loads.

I read the datasheet a long time ago and it seemed like a reliable current regulator. I can't find the sheet now. I think there may have been select instances where a cap was suggested, for long wire and such.

I have got a variable power supply, and I have tested a number of drivers using this chip for LED's. It is always constant current, regardless of forward voltage. That's why I figured it would be safe.

As for the waveform: I was just about to purchase a pocket oscilloscope to test stuff like this, but I suppose it was a few days too late.

DTR said:

Now there are some flashlight drivers that have been used successfully and I would recommend if you wanted to go this route to do a search and see if they have been scoped and deemed safe.

Click to expand...

Yeah... I know it has been mentioned here before. I just looked one up and found it with a 2 second search. Not much follow up on it though, and the information isn't entirely accurate:
http://laserpointerforums.com/f65/dx-amc7135-driver-55767.html