A voltage converter is provided for receiving a low input DC voltage and driving a piezoelectric actuator of a fluid transportation device. The voltage converter includes plural capacitors, a resistor and a boost chip. The boost chip is connected with the plural capacitors and the resistor, has a switch element and a polar switching circuit, and receives the low input DC voltage. The low input DC voltage is increased and multiplied to a high DC voltage by a switching operation of the switch element. The high DC voltage is converted into an output AC voltage by the polar switching circuit so as to drive the piezoelectric actuator. An operating frequency of the boost chip is controlled by the plural capacitors and the resistor.