An ultra-low power voltage level shifter for passive wireless microsystems

An ultra-low power voltage level shifter that can shift a unipolar voltage to a bipolar voltage is proposed. A stable voltage swing at the output of the voltage level shifter is obtained by injecting a compensation current. To interface with other circuits with a higher supply voltage, a 2-stage dual-supply voltage bridging amplifier is also proposed. The supply voltages of the inverter-based bridging amplifier are carefully chosen such that the static power consumption of the inverters is minimized. Simulation results demonstrated that the power consumption of the proposed voltage level shifter is just a few nWs and the power consumption of the voltage bridging amplifier is within a few μWs, making it particularly suitable for passive wireless microsystems such as RFIDs and biomedical applications.