A voltage regulator apparatus includes operational amplifier, first resistor, second resistor, driving transistor, amplifier circuit, and output circuit. The operational amplifier has first input terminal coupled to reference voltage, second input terminal, and output terminal. The first resistor has first terminal coupled to second input terminal. The second resistor is coupled between first resistor and ground level. The driving transistor has control terminal coupled to output terminal of operational amplifier and first terminal coupled to second terminal of first resistor. The amplifier circuit is coupled to output terminal of operational amplifier and configured to sense output voltage of voltage regulator apparatus to amplify the sensed voltage with specific gain to regulate a transistor of output circuit. The transistor has control terminal controlled by amplifier circuit. The output voltage is generated at first terminal of the transistor.