Patent ID: 8373396

Claim:
An adaptive two-stage voltage regulator, comprising: a voltage regulator for converting an input voltage (Vin) to a middle voltage (Vm), wherein the input voltage is smaller than or equal to a maximum value (Vin_max), Vin≦Vin_max; a linear regulator for converting the middle voltage to an output voltage (Vout); and a middle voltage controller for adjusting the middle voltage according to (1) an input voltage indicator and one of (2a) an output voltage indicator and (2b) a predetermined first reference signal, wherein the input voltage indicator and the output voltage indicator or the predetermined first reference signal determines a second reference signal which is supplied to the voltage regulator, such that when Vin≦Vout, Vm=Vout+ΔV and (Vout+ΔV)<Vin_max.