Joerg wrote in news: snipped-for-privacy@mid.individual.net:
Not intentional.. I'm using an LM317. Yes, I know it's not the approved way. It WORKS, far better than expected, and most people who explore weird tricks with an LM317 are mightily impressed with it, from the guy who built a class A headphone amp, or the radio ham who built a transmitter round one...
My physical circuit build, AND the later spice modelling, both indicate that an LM317 for a cheap way to get up to an amp-amd-a-half of DC coupled proportional laser drive at up to 500 KHz is very likely to work well. Maybe the inductance is in the LM317 model, I don't know where else it can be in my simple circuit models. What's crucial is that it is the SAME overshoot I saw in the real circuit so spice is already telling me good things, and I've already improved the driver on the strength of that spice model.
Definitely true. Shunting is my favourite method, and I might return to it with this current indea. But half the fun is trying to see how well I can push this LM317 idea. I've seen circuits that are 'better' that don't seem either much better or worse than mine, which also happens to be very polite at startup, no spikes at that moment at all..