Why are two diode connected transistors used in inverter based Power on reset?
Reference: Low cost low power POR circuit for low voltage sensing using adaptive bulk biasing
Authors: Manoj Kumar Tiwari and Mohd Rizvi
2016 11th International Conference on Industrial and Information Systems
Seems like a crappy scheme to me, having designed many
PORs into production ICs. The first inverter will make the
second stage poorly driven and draw current full time, with
its value pretty variable.