An integrated circuit includes a level shifter configured to receive a first voltage signal that swings between a first voltage level and a second voltage level, outputting a second voltage signal that swings between the first voltage level and a third voltage level. The third voltage level is higher than the second voltage level. An inverter is coupled with the level shifter. The inverter can receive the second voltage, outputting a third voltage signal that swings between the third voltage level and a fourth voltage level. The fourth voltage level is lower than the third voltage level and higher than the first voltage level.