Post by thread:[OT] Power Supply Confusion

Folks, Background: Vi = 12v (automotive and all the baggage it brings) RS485 network of PICs and the peripherals they control - switches, sensors, displays 2 pair STP for cabling - bus and power I need to design a power supply scheme that can power this network. From reading the archives, I've noticed that there are, at least, two paths to go: 1. Simple LM2490 setup (which there seems to be a lot of PIClist data). 2. More complicated switching setup (not as much data). Since there won't usually be power where the peripherals are, I have to push 5v through the wire. My concern is that the LM2490 path won't be as reliable as a legitimate power supply solution and I'm considering clean, abundant power to be a necessary foundation in this plan. The last thing I want to do is rework the supply circuits after this thing goes into beta. Have any of you messed around with switching supplies in under-the-hood automotive circuits? Any gotchas (other than the obvious spikes and dumps)? I'm the process of ripping apart a dead Bosch Motronic ECU (engine management) box to figure out what they do. While it's not an RS485-bus setup, the damn things are real reliable. Thanks. David Olson