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 > > <http://www.lumex.com/pdf/OED-LDP65001E.pdfTG%20keenly> 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. _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
