For my project I have to design an voltage stabilizer with 5V on input and 3.3V on output.In order to do it , I selected a Zener diode for my reference (D1 and R1) , A divider for negative reaction (R7+R6),current limitation(Q7 +R9) and an error amplifier ( I must use discrete components only ) . On my design I can't make the output voltage to be higher than 1.2V when R3 is almost 0 . I used Vbe=0.6V and Ic=2mA for bipolar transistors . IRFRU120N represents a MOSFET type N as my series regulator element. (1-Drain, 2-Gate, 3-Source).
In order to rise the output i tried to : redimension the divider and adjust every single resistance but nothing happened .
How can I rise the output ? Is something wrong with my design? What can I change on schematic to make it work properly ?