How to Implement a BandGap Circuit?

[sys_eng]

1) If someone hand a circuit like belowwith no transistor sizes. What's the first step to begin sizing the transistor for your design?

2) If you have sized the transistor and hand the schematic with sized transistor to a layout person, how does he going implement the CMOS and BJT transistor? He see a CMOS tran, then he would draw a CMOS layout, and he see a BJT tran he would draw a BJT layout. But that's two different processes.

How does a layout person take care of the circuit?

 

[sys_eng]

Also, the sentence describing above.
If the current in the drain of PMOS transistor 7 is smaller or equal to (delta-Vbe)/R, then all of the current from PMOS transistor 7 flows through NMOS transistor 9, and none flows through NMOS transistor 8.

what's delta-Vbe?

 

[d123]

Delta-Vbe is expressed clearly in words and the picture on page 11. Vbe1 - Vbe2.

https://www.uio.no/studier/emner/matnat/ifi/INF4420/v12/undervisningsmateriale/INF4420_02_Bandgaps_Print.pdf

There are hundreds of bandgap pdfs that are highly informative available on the Internet, only yesterday I added a few more to my collection, and I notice there are quite a lot of edaboard threads related to Delta-Vbe.

Question 1 in your first post: I'm not an engineer, so my answer would be - return the circuit to the designer and ask them to include the transistor sizes, as presumably that is a large part of their job duties, unless it's a homework question.

Halfway down the page is good for Delta-Vbe too:
https://www.iascaled.com/delta-vbe-temperature-measurement/