An Energy-Efficient Level Shifter Using Time Borrowing Technique for Ultra Wide Voltage Conversion from Sub-200mV to 3.0V

Level converting is increasingly difficult in ultra-low voltage circuits with the aggressive scaling down of the input voltage. In this paper, we proposed a wide output range level shifter (LS) with the ultra-low input voltage. The proposed LS is integrated with a positive flip-flop function with a three-phase time borrowing scheme at the sampling edge. The working principle eliminates the current contention problem in the conventional cross-coupled level shifters, which allows a much higher output range at ultra-low input. The time borrowing technique also allows a relaxed timing constraint, which increases the timing margin and improves robustness against variation in ultra-low voltage circuits. The proposed LS is implemented with 45nm CMOS technology. Simulation results show that the proposed structure achieves a propagation delay of 10.01ns, power consumption of 11.23pW, and a power-delay-product (PDP) of 112,412ns-nW when converting an input signal of 200mV to an output level of 3 V.