[SOLVED] Current Mode Reverse Bandgap Reference Circuit - How does it work?

[memoslw]

Hello all,

I am designing a Current Mode Reverse-Bandgap Reference (R-BGR) circuit, with a low supply voltage of 0.8V. I can't comprehend how does the circuit functions (e.g. how does the reference voltage output stays the same) to save my life. Can you give me an explanation for me to understand the behaviour of the circuit? What is the mechanism that makes the voltage output constant over the temperature range? I have read some papers on the topic but I am still lost, any explanation will be really appreciated.

 

[arthorios]

Show the schematics.

 

[dick_freebird]

The basics are always the same, the topology may be
"folded" to work with less headroom.

You need a current with a known tempco, and elements
with both positive and negative tempcos, which you will
sum to a near-zero tempco and then scale to get voltage
(a bare bandgap's natural 1.23V, not fitting within 0.8V
rails - though charge pumping a higher supply and then
dividing the output, could be another way to go).