For input voltage, V=V IN /2 at t=T=log e (2)RC, V=V IN /4 at t=2T, V=V IN /8 at t=3T, and so forth. Less familiar, but just as simple, is the behavior of the same RC topology when you replace R with ...

The controller is FAN2306, which is a constant-on-time controller from Fairchild Semiconductor. The circuit parameters are: V IN = 12V V O = 1.2V F SW = 500kHz L O = 1µH C O = 4x47µF MLCC R T ...