What type of driver does a DPSS green have?

[dr-ebert]

I've been in Shanghai for a week and brought back my first green laser (supposedly 50mW, but comparing with my ~270mW red, I'd say it probably is just 15-20mW, they appear more or less similar in brightness... pity I don't have access to a LPM). Now I'm wondering, what drivers do these cheap lasers have? Most likely not a drlava type buck/boost circuit (too expensive), neither a linear driver like the LM317 (wouldn't work due to the high voltage drop). Essentially the driver is delivering an estimated 2.0-2.5V to the diode (depending on current) from a 3V power supply. Does someone have info on the circuitry used?

PS. If you're in China in the next time: the street price for a 10mW green is 40 yuan (~$5.50), don't pay more :shhh:

 

[chipdouglas]

well they might be buck/boost. they only take 3.v input. but to be honest, i really don't know.

 

[Gryphon]

PS. If you're in China in the next time: the street price for a 10mW green is 40 yuan (~$5.50), don't pay more :shhh:

Thanks for the heads up

 

[ElektroFreak]

Most likely buck, but they do not boost. As the batteries die so does the output, which is not characteristic of boost drivers.

Typically it is an op-amp based regulation circuit with some help from a tiny MOSFET or two.. It will be of a type similar to one of the three schematics on this page: http://www.repairfaq.org/sam/laserdps.htm#dpsglp

 

[ndrew2505]

theyre made to drive the IR pump diodes so they only output 2-3v. since the batt combo usually used equals 3v it could be a linear or drop voltage driver.

 

[ElektroFreak]

The link in my last post is wrong..try these


http://www.repairfaq.org/sam/glpdrv1.gif

http://www.repairfaq.org/sam/glpdrv2.gif

http://www.repairfaq.org/sam/glpdrv3.gif

 

[jeffd]

That would be so cool to be able to buy green lasers at stores. Wish we had that here(some stores carry 5mw but cost $80+)