A voltage converter for providing an output voltage signal at an output port according to an input voltage signal is disclosed. The voltage converter comprises a feedback circuit, a transmission switch circuit, a voltage converting circuit, and a pre-bias circuit. The feedback circuit generates a feedback voltage signal according to the output voltage signal. The transmission switch circuit selectively transmits a converted voltage signal to the output port of the voltage converter in a normal mode or transmits the input voltage signal to the output port of the voltage converter in a pre-bias mode. The voltage converting circuit converts the input voltage signal into the converted voltage signal in the normal mode and references the feedback voltage signal and the reference voltage signal to adjust the output voltage signal in the normal mode. The pre-bias circuit controls a magnitude of a current passing through the transmission switch circuit.