Patent ID: 8836302

Claim:
A low dropout voltage regulator, comprising: a comparison unit, receiving a reference voltage and a feedback voltage, outputting a first voltage, and comparing the reference voltage and the feedback voltage to output a first voltage; a buck unit, electrically connected to the comparison unit, the buck unit receiving an input voltage and the first voltage and having the input voltage stepping down to an output voltage, wherein the buck unit outputs a first current according to the first voltage and the output voltage; a feedback unit, electrically connected between the buck unit and the comparison unit, the feedback unit receiving the output voltage, and after converting the output voltage to the feedback voltage, the feedback unit transmitting the feedback voltage to the comparison unit; and a current-drawing unit, receiving the input voltage and output voltage; wherein when the input voltage is smaller than a start-up voltage, the current-drawing unit turns off and a second current flowing through the feedback unit is equal to the first current substantially, wherein when the output voltage is larger than the start-up voltage, the current-drawing unit draws a third current and the third current is equal to a sum of the first current and the second current.