Woe...
I'm using ten of these and parallel. I WAS going to just use a 1 amp 5 vdc power supply with a 2.8 V zener diode to adjust the voltage to 2.2 V. I take it this is too simple.
> <http://www.lumex.com/pdf/OED-LDP65001E.pdfTG%20keenly>Robert Butts wrote:
>
> Below is the link to the datasheet of a laser diode in using. It's
> not clear how I would wire this. Any suggestions on how to wire these?
>
> Digikey link:
> http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=67-1500-ND
>
> Datasheet link: http://www.lumex.com/pdf/OED-LDP65001E.pdf
>
These devices usually have a laser diode and a PIN diode facing the back
facet of the main diode. The PIN diode is to sense the power output of
the main diode, and can be used in a control loop to servo it. The data
sheet shows the current through the PIN diode when the laser is
operating at 5mW, this information can be used to design a control circuit.
The terminals you are interested in for the main diode are the ones
labled LD+ and LD-. The PIN diode is connected across the terminals
labled PD+ and PD-. (The + is probably the anode and the - is the cathode.)
The typical circuit to drive one of these things is a constant current
source, I have seen circuits that have an op-amp that controls a FET
with a series resistance on the ground side to measure the current, and
feed it back to be compared to a reference control voltage. If you can
get your hands on a dollar store laser pointer, you will probably find a
simple circuit with a single transistor to limit the current, this will
probably work fine but won't protect against the thing
self-destructing. Either the sense resistor or the current from the PIN
diode (or both) can be fed back to control the output power.
You do have to be a bit careful with the voltage and current on one of
these things, if the power gets to high they run away and self
destruct. Don't exceed the operating voltage or current with your
current source. Don't hook it up backwards, as this will also wreck it.
You will also need some optics as the beam coming out of this device
won't be colimated. Note too that the beam is quite oval shaped, 9
degrees in the horizontal and 35 degrees in the vertical.
Hope this helps.
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