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Modify existing driver for LD with PD. How?

MattIsHere

MattIsHere

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Most of the laser drive available have LD+ and LD- connection pin only. How to use these driver for LD with PD? Can I simply leave PD pin unconnected?
 





The PD ( I'm assuming its photo diode ) is only used for power regulation of the diode

The reason most of the drivers available ( I'm assuming for pointers ect ) are only LD+/LD- is they are simply designed to drive the diode at a given
current with no feedback as is the case on here ; there is no need / point of it and some of the diodes don't have a photodiode in .

The diode will run no different with or without the photo diode connected , its there for when output power regulation is needed , if the driver doesn't have a photodiode input you can still run the diode as normal .
 
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Indeed, most drivers just ignore the photodiode pin if available at all.

They used to be very common on things like low power red diodes for pointers, but on many modern diode the photodiode isn't available, and you typically apply power between the two pins not needing to keep any connections to the case in mind at all.

You should always check this with datasheets though, since there are quite some diodes where the case is connected to on of the diode terminals. This is fairly rare in modern reds and blues, but it often is in 808 nm pump diodes in dpss geen lasers (case is often positive there too, so beware!).
 
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