LTC1440, J-FET based DC/DC converter runs from 300mV input

Circuit shows LTC1440, J-FET based DC/DC converter runs from 300mV input. Adding Q3, Q4 and bootstrapped negative bias generator reduces quiescent current. Comparator directed Q3 switches Q4, more efficiently controlling Q1s gate drive. Q2 and zener diode isolate all loading during Q1 start-up