relationship between input and output voltage of power booster circuit

[khatus]

This is a power booster circuit. Here Q1 is a power transistor. I want to determine the relationship between input voltage(Vin) and output voltage (vout) here. and also want to determine Vout.




Please,Some derive me the relation between Vin and vout .How i get the 13.28 volt output from 15 volt input.please show

I have found that,



Here is my simulation. If the input voltage Vin = 15 volt The output voltage is fixed at = 13.28 volt i.e vout = 13.28. The VCC of transistor is 30 volt i.e VCC= 30 volt.the output voltage Vout is independent of transistor collector voltage i,e VCC. And if we increase the VCC from 30 volt to 50 volt the whole increased voltage (50V -30V = 20V) is dropped across VCE of transistor Q1.


Please derive me the relation between Vin and vout. how 15 volt inputs gives 13.28 volt output volatge. Please show me the calculation.

 

[KlausST]

Hi,

there is no calculation, because you operate the OPAMP outside of it´s linear operation range.

And "outside" the range depends on the OPAMP type. We don´t know the OPAMP type.

--> My recommendation: Read the OPAMP´s datasheet and operate the OPAMP within it´s recommended operation range. (input and output wise)

Klaus

 

[danadakk]

Are you trying to build a constant current sink for the load in the
collector of the NPN ?

Clue on analysis, since there is - fdbk, the V at V^-
= Vin;

Regards, Dana.