I have a question regarding a circuit providing low current capacity voltage for device powering, that goes down from a lot higher voltage:
How does it exactly work? I understand that the Q1 gate is biased at 5.6 V no matter what is the voltage level on the Q1 drain (because of the zener diode). But how come there is around 4V at Q1 source? The Vgs of the Q1 is around 2.5 V (2N7002-7-F). The voltage at Q1 drain can vary and the voltage at source stays around 4V. This schematics is a part of circuit found in the BQ34110 datasheet. I would appreciate all hints.