In this paper, we propose a level shifter circuit capable of handling a wide input voltage range. The circuit is based on a conventional two-stage comparator, and has a distinctive feature in that it operates a current amplification scheme for ultra low-power operation. The proposed circuit can convert low-voltage input digital signals into high-voltage output digital signals. The circuit achieves low power dissipation because it dissipates operating current only when the input signals change. Measurement results demonstrated that the circuit can convert low voltage input signals of 0.4V into 3V output signals. The power dissipation was 0.15µW at 0.4-V and 10-kHz input pulse.