An Ultralow-Voltage Energy-Efficient Level Shifter

Abstract

This brief presents an energy-efficient level shifter (LS) able to convert extremely low level input voltages to the nominal voltage domain. To obtain low static power consumption, the proposed architecture is based on the single-stage differential-cascode-voltage-switch scheme. Moreover, it exploits self-adapting pull-up networks to increase the switching speed and to reduce the dynamic energy consumption, while a split input inverting buffer is used as the output stage to further improve energy efficiency. When implemented in a commercial 180-nm CMOS process, the proposed design can up-convert from the deep subthreshold regime (sub-100 mV) to the nominal supply voltage (1.8 V). For the target voltage level conversion from 0.4 to 1.8 V, our LS exhibits an average propagation delay of 31.7 ns, an average static power of less than 60 pW, and an energy per transition of 173 fJ, as experimentally measured across the test chips

Low energy/delay overhead level shifter for wide‐range voltage conversion

“…Several improvements to the conventional LS topologies [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] have been recently proposed to mitigate their intrinsic drawbacks when wide-range voltage-level conversion is required. Essentially, most of the solutions based on the DCVS scheme aim to weaken the PUN by means of reduced swing inverters [19] and/or diode-connected n-channel metal-oxide-semiconductor (nMOS)/p-channel metal-oxide-semiconductor (pMOS) [12,16].…”

“…All these solutions facilitate wide-range voltage conversion, but they incur in delay scalability issues, as the PUN is constantly weakened [18]. On the contrary, the LS designs proposed in [17,21] exploit a different mechanism based on PUNs that are able to dynamically adapt their strengths depending on the occurring output transition. The CM-based technique is exploited in [10,15,18].…”

“…The power supply of noncritical sections of the system could be aggressively scaled down to the subthreshold/near-threshold region in order to optimize energy consumption [3,8]. In such a case, low energy/delay level shifters (LSs), able to guarantee reliable wide-range voltage-level conversion, need to be used [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26].…”

A portable class of 3‐transistor current references with low‐power sub‐0.5 V operation

“…[1][2][3][4][5] Current references are key building blocks of analog and mixed-signal circuits used in IoT systems. [1][2][3][4][5] Current references are key building blocks of analog and mixed-signal circuits used in IoT systems.…”

“…The fast-increasing demand for Internet-of-things (IoT) systems poses several challenges to the circuit designers because of their stringent constraints in terms of energy efficiency, low standby power consumption, ultralow voltage operation, low area consumption, and reduced variability in spite of the device miniaturization. [1][2][3][4][5] Current references are key building blocks of analog and mixed-signal circuits used in IoT systems. Their principal task is to fix the bias point of the amplifier stages, thus playing a fundamental role in the performance of the overall system.…”