Current-based testable design of level shifters in liquid crystal display drivers

We propose a testable design method of level shifters inside a liquid crystal display driver IC. The design method enables us to detect open defects in level shifters by supply current testing that are difficult to be tested by voltage testing. Also, we show by circuit simulation that more resistive open defects may be detected by supply current testing than voltage testing, if the level shifter is designed by using the proposed DFT method.