I have question about Vbias of some LDO. in the gerneral idea what is the benefit of Vbias? efficiency improvement or control purpose?

 

Vbias is what powers the control circuit of the LDO regulator.
Without Vbias, the regulator won't work.

 

I didn't know that. Good question Pitsa and nice answer Sgt.

 

Yeah, it's kind of like, "What is the benefit of gasoline in a car?" It won't run without gas (Vbias).