A level shifter in digital electronics, also called a logic-level shifter, is a circuit used to translate signals from one logic level or voltage domain to another, allowing compatibility between ICs with different voltage requirements, such as TTL and CMOS.[1][2] Many modern full featured systems use level shifters to bridge domains between low-power application processors running at 1.8 V and other system functions like sensors or other analog intensive applications running at 3.3 or 5V. Wikipedia