As I mention the comparator in this schematic always maintain the base voltages equal, so if Vref=1.5V the Vout must be 3V according divider formula:



You can pick different R1 and R2 ratio if different Vref vs. Vout ratio is needed.

 

As I mention the comparator in this schematic always maintain the base voltages equal, so if Vref=1.5V the Vout must be 3V according divider formula:

View attachment 324536

You can pick different R1 and R2 ratio if different Vref vs. Vout ratio is needed.

Then why are p channel mosfet and 3906 bjt connected? Why not remove them you get vref from comparator anyway?