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FrozenGate by Avery

LM2596 DC-DC Step Down CC/CV Adjust Power Supply Module

Joined
Sep 12, 2007
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I can't find the post, but someone wanted to know how one of these would work as a driver. I bought one (from a different seller than this) but it never arrived. I got a refund and bought from this guy instead. Arrived in a couple weeks or something - standard China shipping.

$T2eC16F,!)kE9s4Z-URLBQtm+nIlIw~~60_3.JPG


The left pot adjusts voltage; the right pot adjusts current limit; the center pot... doesn't seem to do anything:thinking:. If anyone has an idea, lemme know. Green LED indicates power on; one red LED indicates current is being drawn; two red LEDs indicate current limit is in effect.

I used a standard 3-diodes with 1Ω shunt for the load. I varied the input voltage from 7V to 15V. They claim up to 92% efficiency, but I got anywhere from 68-75% with this load. Higher output current and lower input voltage both translate to slightly better efficiency.

If you're only interested in IF this will work as a laser driver, the answer is large pile of no; you may now close the tab. :p
If you're interested why it won't; read on.

Problem #1:
Current limit inexplicably stops working (jumps to >2A) if the input voltage is less than ~3.3V above load voltage.

Problem #2:
Thermal ratings are evidently designed for higher output voltage than laser diodes. It's supposed to be rated for 15W or 3A output - whichever is lower presumably. But here it is at 1A (~3W). Already getting pretty toasty:

IR_0128_zpsd37a353f.jpg


IR_0130_zps060cc574.jpg


And here it is with 2.5A (10W) dumped into a resistor

IR_0131_zpsca948f19.jpg


And the poor diode in the upper right is cooking away at 220F. I don't think it'll last much more than a few hours at that temperature.

Problem #3:
Startup spikes are downright terrifying. And it would probably be worse (to the point of blowing up my test load perhaps??) If the voltage set point was higher. As always, note the time base in each image because they change to show detail.
At 1.8A switched before the driver:

NewFile0_zpsa97b6776.png


And 1.8A switched after the driver:

NewFile1_zpse1f3fd79.png


At 500mA switched before the driver:

NewFile3_zpsed6e9793.png


At 500mA switched after the driver:

NewFile2_zps761cf608.png


TL;DR: Good for battery charging, torturous death trap for laser diodes.
 
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Thanks for testing it out. I love seeing the thermo pictures. They are very handy to find the hotspots.
 
Nice detailed review...:gj: Thanks.

I had my doubts about those $3.00 3A CV/CC power
supplies. Especially the output spikes on start up and
even on normal running after start up for use with LDs.


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
 
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I can't find the post, but someone wanted to know how one of these would work as a driver. I bought one (from a different seller than this) but it never arrived. I got a refund and bought from this guy instead. Arrived in a couple weeks or something - standard China shipping.

The left pot adjusts voltage; the right pot adjusts current limit; the center pot... doesn't seem to do anything:thinking:. If anyone has an idea, lemme know. Green LED indicates power on; one red LED indicates current is being drawn; two red LEDs indicate current limit is in effect.

TL;DR: Good for battery charging, torturous death trap for laser diodes.

Thanks for putting the scope photos up.

The driver was made primarily for battery charging.

The center pot is to adjust when current has dropped to a predetermined level,

(default is 10%) so charge LED is activated.

LarryDFW
 
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