Quote:If I use logic signal to control the resistor, means 2b'00 is 0.9*R, 2b'01 is R, 2b'11 is 1.1*R and 2b'11 is 1.2R to get a target bandgap output.
That is a type of trim, so I am still unclear what your question is.
Quote:Suppose in mass production, bandgap from different wafer hasn't good output such as 1.1v, 1.2v, 1.3v, 1.2v etc.
None of the bandgaps that I have ever worked on ever had anywhere near that variation. If it did, it was broken.
Quote:Another question is, can trim techniques tune bandgap output even when there is process variation between different wafer?
In short, yes. Otherwise we wouldn't bandgap circuits in the first place since they wouldn't be manufacturable.
Quote:How to realize it?
If my previous post didn't answer your question, what exactly would you like answered?