Micropower voltage regulator converted for low voltage

[neazoi]

Hello I have seen this article and I was thinking how could I convert it to regulate lower voltages like 2.5v and even less. I am thinking of using a fed in depletion mode.
I also do not like the LED there, can I replace it with a zener or another transistor?
Any thoughts?

 

[pradeep.g.belchada]

you can vary the o/p by changing r2. zener also can be adopted as a reference & it will give you a very precise o/p

 

[neazoi]

you can vary the o/p by changing r2. zener also can be adopted as a reference & it will give you a very precise o/p

If I want it to regulate below 1v I should use a depletion mode fet so that it is always on?
I am confused because of the transistor action. I was thinking that if the purpose of the transistor is to limit the voltage of the gate in order to keep the fet output voltage constant, then a depletion mode fed will not do any good, because any attempt of the transistor to lower down the gate voltage will not do any good, since the depletion mode fet is always ON at positive gate voltages.

 

[neazoi]

I have tested the circuit and converted it for lower voltage.
The converted circuit is shown here **broken link removed** at the end of the page.

A 3.0V input gives 1.6V output (unloaded).
The voltage drop is too high. Is there any way I could achieve a lower voltage drop?
For example by altering the Gate resistor?