a voltage level shifter formed by single - typed transistors comprises two input terminals , two power supply terminals , a plurality of thin - film transistors , and an output terminal . another voltage level shifter formed by single - typed transistors comprises two input terminals , an output terminal , two power supply terminals , two input units , a first thin - film transistor , a disable unit , a feedback unit , and a second thin - film transistor . the voltage level shifters are formed by single - typed tfts . when integrating the voltage level shifters into a substrate of a tft display , the manufacturing processes are simplified . besides , power is saved .