A TLVH431 is used to control a 555 1-shot. The 6V is a voltage converter which starts up and charges a battery once power is on its input. A TLVH431 (Op-amp, NPN, and 1.24V reference) is used to start a 1-shot when the converter voltage is over 6.47V (a switch across TL431 will also force a one-shot).
Circuit board(s) I am working on:
http://epccs.org/indexes/Board/CC01/
