The input voltage is just limited by the stability(have relativity with architecture) and the Reference Voltage. The coefficient of capacitors decide the stability ." u- Y& E9 B/ {- }5 {: H# `- s
So someone usually make the system modeling decide the coefficient. there are method such as numeration method , Simulated annealing and so on ,it's very difficult. someone also use the experience to decide the coefficient.