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How to power a High power laser diode? Answered

If I build a 42A Constant Current PSU which can supply 1.2-6v, will the laser diode only draw 1.8-2V or will it try to draw to much voltage and damage its self?

I have a 40W CCP CW Laser diode, here are some characteristics.
Operating Voltage (V) <2.0 (1.8 typ.)
Operating Current (A) <46 (42 typ.)

I know that laser diodes will try to draw as much current as possible and suffer thermal runaway, so they need constant current power supply's.
If anyone has any information on how to power high power laser diodes please let me know.

All help will be greatly appreciated! 

7 Replies

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Josehf Murchison (author)2014-11-04

That is a very high amp low voltage supply you need.

If you can build a 42 amp 1.2 to 6 volt PSU where the voltage can be set for 2 volts and the voltage regulated so that the voltage never exceeds the desired voltage as the laser diode draws the 42 amps it needs? That is what you need.

To buy an adjustable regulated supply that powerful ie 42 amps and 1.2 to 6 volts, you could be looking at over $300.00

If you build the PSU I would suggest testing it on a dead load recording the amperage and voltage on the dead load.

In case you don't know what I mean by a dead load it is a low impedance high current capacity load like 10 feet of #1 gage cable that doesn't do anything but draw power when connected to the supply.

Joe

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iceng (author)Josehf Murchison2014-11-05

If I understand the suggested process.

There is an upper, never exceed voltage setting followed by or delivered to a 42 amp constant current regulator which really drives the solid state laser diode.

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steveastrouk (author)iceng2014-11-05

PROPER power supplies ! Nice link.

Same site. More appropriate link ;-)

http://www.repairfaq.org/sam/laserdps.htm#dpstoc

Stresses the importance of a true constant current supply.

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petercd (author)2014-11-03

Operating Voltage (V) <2.0 (1.8 typ.)

This line usually means max supply voltage, Im guessing your 6v will fry it.

Your psu needs to be a constant 42A at a maximum of 2V.

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steveastrouk (author)petercd2014-11-03

1.2..6V is the compliance range of the constant current source. Outside those limits, it won't work, as I explained. It can't GIVE 6V to the load described.

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steveastrouk (author)2014-11-03

If you don't understand basic concepts of electricity like what constant current means, you really shouldn't try and build a 42A constant current source.

The best way is to buy a supply Laser diodes are EXTREMELY sensitive to current transients, and be destroyed by them.

The whole idea of a constant current source is the output current is CONSTANT ! Yes, if you connect your diode, it will draw a fixed 42A. If the voltage drop was more than 6V, then the output current would fall below 42A, if the voltage was less than 1.2 V, then the current might exceed 42A- a BAD design. Your spec should read 0..6V @42A to be safe.

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