Bob, I think he was talking about the designs to turn off the device. In 'the good ol days', they used and on-off switch and a human to turn them off. Later, inactivity timers took the job on and did a pretty well. These days, they actually sample the current and shut down when the battery or other device their hooked to stops pulling current; actually, they don't shut down completely, just drop really, really low. It's a green thing.