I was in the process of building a 2W laser diode driver and I realized after some debugging that I had a 3.3V constant voltage LM1086 chip instead of an adjustable voltage regulator. I intended to build a constant current source that is adjustable up to 1000mA. The following circuit replicates what I put together on the bench using an LM1086 for regulation. Ignore the LM317, I didn't have an TI LM1086 chip to insert into the simulation.
My wrong chip selection made me wonder, can you use a fixed regulator to create a constant current source or do you need an adjustable one?
As an aside question is this approach in general a good method of driving a 2W laser diode or are there better circuit architectures?