We needed some way of taking the high voltage (22.2v) from our battery packs and regulating it down to both a 6v and a 5v power source. the only problem being we need to be able to draw upwards of 3 amps, with generating more heat that a 15 watt space heater, or catastrophically failing.
Initially we had the idea of maybe running several 7505s (or equivalent for the 6v circuit) together in parallel to enable our 3 amp capacity. (catastrophic failure was the response to our idea)
After speaking with the very nice folks at http://www.gatewaycatalog.com/ a while back, we were informed we needed a switching regulator. The problem was finding one that was easy (for us) to build, and would support a 3 amp draw.
After some searching around BasicMicro came to the rescue with these beauties. Check out their site, they have got a lot of cool stuff.
These are Zeus 3A Switching Regulators:
Input: 5V to 30VDC
Output: Adjustable from 2V to 13V at up to 3Amps
Presets: 5V, 6V, 7.2V and ADJ (Adjustable Setting)
They will easily take the 22.2v input from our monster batteries, and feed a 6v 3amp circuit to our very power hungry USRP. I grabbed the second one, to reroute power to our avionics bay which currently receives power from the payload computer’s power supply. Reboot the on board computer, and risk rebooting the avionics mid-flight, worse still if you accidentally shutdown the payload OS, you shutdown the avionics as well. Either of these scenarios are bad for an airplane several hundred feet off the ground.