about the ratio between bias circuit and main circuit

[yixiusky]

Hello everyone:

I would like to ask one question about the ratio between bias circuit and main circuit.

The bias reference current is 100uA, the main circuit current is 10mA.

There are two choice to decide the ratio (1) 1:100 (2) 1:10: ~ 10:100 use two branch

(a) Which one is better considering about mismatch,...?

(b) And except simple current mirror, is there any method or reference talk about high ratio (1:100) current mirror?

Thank you very much

 

[mengcy]

Two branch is better only if the structure doesn't bring any other mismatch.
Matching of 1:100 is more difficult and also cost more layout area because of the process ununity.