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A strange bandgap circuit

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I can not find this kind of bandgap architecture in books or papers. Who can tell me how it works. Thanks.
 

This must be a temperature independent voltage generation circuit, where a PTAT current generated in the first two branches is mirrored on to the third branch (output branch) and allowed to pass through the resistor to generate the required voltage. The resistors are so chosen that the positive Tc of the BJT base-emitter voltage difference is negated by the negative Tc of the BJT Vt. But I think the emitter area of the BJT at the output stage is A and not 12 A.
Here the negative feedback happens within the loop, whereas in standard circuits, an additional amplifier is used. Check out the circuits for temperature independent references (in Razavi etc.), and you'll find lots of details on it.
 

Thank you. Your message give me some idea of this circuit. I will simulate it .
 

But I think the emitter area of the BJT at the output stage is A and not 12 A.
Click to expand...


I think the output stage can be A or 12A. But you must change the two resistor ratio to match it.
 

In Razavi's book, it is ' the value of VBE3 and hence the size of Q3 are somewhat arbitray' (P392).
 

In the "circuit design,layout,and simulation" by R. Jocob Baker, Page 478, Figure 21.14,you can find the answer.
 

A little analysis on this circuit for you.
 

ronsmithy said:
A little analysis on this circuit for you.
Click to expand...

Thank you for this result. You give me great help.
 

In case you will be running sims be aware that this circuit does not have any startup - will run ok in sims but probably will not be as good in silicon.
Add any of the Razavi;s startups and you will be fine.
 

r23718 said:
In case you will be running sims be aware that this circuit does not have any startup - will run ok in sims but probably will not be as good in silicon.
Add any of the Razavi;s startups and you will be fine.
Click to expand...

I know it, I did not give the starup circuit in the picture. It is only the basic architecture.
 

how to restrict the change of BGR with the corner?
 

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