Is there any reasonably simple means using, e.g., low-Rds MOSFETs to replace the standard setup where you have your power to a load coming in through diodes -- one to your battery and one to your regular mains power supply (...that might fail)? I'm looking to avoid the power loss of the diodes while in "battery" mode, and I'm more than willing to throw some extra circuity at the problem if it's relatively easy to do.
The current I need is pushing 3A, so even with Schottky diodes I end up dissipating around a watt in the diodes. (Not a problem when mains power is available, but would be nice to avoid when running off the battery.)
Thanks,
---Joel