An energy-efficient subthreshold level shifter with a wide input voltage range

The level shifters are crucial primitives in the multi-supply voltage circuits and systems. In this paper, an energy-efficient level shifter is proposed to achieve the conversion from the subthreshold voltage to the above threshold voltage. It is a hybrid structure consisting of the Wilson current mirror and the cross-coupled level shifter. By addressing the voltage drop issue of the level shifter based on the Wilson current mirror, the leakage power is significantly reduced, with the advantage of wide input voltage range for the Wilson current mirror level shifter well-preserved. In addition, the multi-threshold CMOS (MTCMOS) technology is employed to provide more flexibility for our ultra-low power design. The reported simulation results using 65 nm CMOS process validate our proposed implementation and an ultra-low power consumption of 19.44 fJ per conversion from 0.2 V to 1.2 V at 1 MHz is achieved without the need of any intermediate power supply.