Who makes high current modulatable drivers?

[Laser Ben]

Who makes high current power supplies for laser diodes? I need something that can do up to 30 amps with at least TTL and preferably Analogue modulation. I am trying to resurect this Lightwave Half-Note system that I got from Junktronix. It uses a 20W Coherent CCP diode bar that requires 23.6A for 20W output. I don't think that modulating the TEC will be of any use as the laser head is constructed on an inch thck 5" x 8" block of stainless.

I don't want to spend too much on something like this and I would really prefer something that is plug and play, but I am willing to do some work.

Ben

[mixedgas]

Analog Modules Inc.

Please send us a pic of the look on your face when you receive the price list.

Steve

[Laser Ben]

HAHA! Is it that expensive?

[shrad]

that can be made with an industrial darlington transistor like those used on big machines, commonly found on ebay for cheap

the current sensing resistor should be a copper trace on the PCB large enough to handle the 30 amps, and the design is similar to any laser diode driver with darlington

a friend at laserfreak made a driver at 17Amps with such a transistor with no heatsink, it didn't even reach 30°C in temperature

[keeperx]

betcha lava could make one

[mixedgas]

betcha lava could make one

Lava needs to work on finishing his Doctorate.

Betcha I could too.

Problem is, can Ben clone it?

Ben, feel like learning something? Or are you looking for a easy fix to see if the rest of the laser works?

If your looking for easy fix, I'm gonna say surplus lab supply with constant current option and a start/stop relay to protect the diode in the undefined states of the lab supply, ie when it starts up and when it shuts down.
Plus a guard transistor to aid during the shutdown state.

Ie a Kepco, a Sorenson, or a HP. Then you shunt the diode with a power FET for the fast modulation and guard function.

Or we can help you make a "real" supply. Your call.

This place puts the PSUs where I can test them and I'll just bill you for the gas each way :-)

http://www.hgrindustrialsurplus.com

Steve

[daedal]

make a "real" supply

--DDL

[Laser Ben]

Steve,

I know the laser works and I want to have something that will control it. I am fine with making it myself, in fact, I would prefer that just for the learning experience. I have access to one of the best electronic component stores around, so getting components is not a problem.

I am looking at where to start. I know how to do voltage regulation and run a power supply in constant voltage, but I do not know how the constant current setup works.

Ben

Lava needs to work on finishing his Doctorate.

Betcha I could too.

Problem is, can Ben clone it?

Ben, feel like learning something? Or are you looking for a easy fix to see if the rest of the laser works?

If your looking for easy fix, I'm gonna say surplus lab supply with constant current option and a start/stop relay to protect the diode in the undefined states of the lab supply, ie when it starts up and when it shuts down.
Plus a guard transistor to aid during the shutdown state.

Ie a Kepco, a Sorenson, or a HP. Then you shunt the diode with a power FET for the fast modulation and guard function.

Or we can help you make a "real" supply. Your call.

This place puts the PSUs where I can test them and I'll just bill you for the gas each way :-)

http://www.hgrindustrialsurplus.com

Steve

[mixedgas]

copper has the downside of a bad temperature characteristic, in the US, you can get a surplus calibrated industrial shunt for 10-20$ with a near zero tempco.

This is not the brand I like, but here is a example.

http://cgi.ebay.com/Empro-HA-100-100...QQcmdZViewItem

Steve

[mixedgas]

Ok, do you know Vf , the forward voltage for the diode stack?

Your going to do a couple of darlington transistors or industrial fets in parallel.

So, your basic goals are:

I. Protect the diode during the undefined states.
A. startup (diode is shorted out by protection to prevent overvoltage)
b. Shutdown (sense DC fail using a power fail sense chip, common part)
C. prevent Overcurrent failure


II. maintain a constant current

III. Modulate fast, and the easiest way to do this is to short the energy across the diode, while the psu maintains the constant current.

Any other goals???

Steve