A voltage regulator is disclosed which is connected to an external resistor. The voltage regulator provides a regulated voltage and includes first and second transistors. The first transistor has a power terminal connected to a power supply and the second transistor has an output terminal to output the regulated voltage. The second transistor is connected to the first transistor through a common terminal. The external resistive circuit is connected between the common terminal and the output terminal. An output current of the voltage regulator on the output terminal is equal to a sum of a first current passing through the resistive circuit and a second current passing through the second transistor. A control circuit is also provided which is connected to the input of the second transistor to turn on the second transistor for providing the second current when the first current exceeds a predetermined value. The voltage regulator also includes a comparison circuit which feeds back the regulated voltage to an input of the second transistor to regulate the regulated voltage.