A Comprehensive Analysis on Level Shifters: Challenges, Opportunities, and Future Directions

Abstract

Level shifter has an important role in low power circuits useful in electronic gadgetssuch as smartphones, tablets, laptops and many other. Basically, level shifters are used to convert voltage levels from lower to higher or higher to lower. Low power dissipation is a major challenge in level shifter circuits. Along with power dissipation this paper includes comparison on delay and voltage range of various level shifter configurations. There is need for level shifter with minimum delay and higher speed which the existing level shifters are lacking from. Modified conventional level shifter shows better performance, consuming less power and has a less delay, making it suitable for applications such as IoT, battery powered devices, wireless networks etc.

Introduction

Overview

Level shifters (LS) act as signal bridges in electronic systems, converting voltage levels so devices with different logic levels can communicate. Modern LS circuits aim to reduce power loss, delay, and voltage variation. With advancements in CMOS technology, designs now focus more on power efficiency, dynamic operation, and voltage adaptability.

Dynamic level shifters adjust their output based on input voltage, minimizing unnecessary power usage. Techniques like multi-threshold transistors, topological modifications, dynamic voltage scaling, and current mirrors further enhance performance.

II. Proposed Methodologies

A. Level Shifter Designs

1. Modified Conventional Level Shifter (MCLS)

   • Uses stacked NMOS (N6, N7, N8) for reduced leakage and delay.

   • Efficient voltage switching based on input conditions.

2. Dynamic Voltage Level Shifter (DVLS)

   • Dynamically shifts voltage levels up or down.

   • Blocks data in standby mode to save power.

3. Modified Single Supply Level Shifter (MSSLS)

   • Adds NMOS (N4, N5) for voltage distribution and leakage control.

   • Maintains output voltage with low power usage.

4. Bypass Enabled Level Shifter (BELS)

   • Switches between SHIFT and BYPASS modes.

   • Reduces contention and allows quick switching with lower power.

5. Bootstrapping Negative Voltage Level Shifter (BNVLS)

   • Uses Cboost capacitors to improve drive strength and reduce leakage.

   • Handles both high-to-low and low-to-high transitions efficiently.

B. Comparative Analysis

III. Results and Discussion

• BNVLS: Offers improved driving capability and lower delay via bootstrapping.

• BELS: Achieves up to 50% power reduction in bypass mode, minimizing unnecessary voltage shifts.

• DVLS: Automatically adjusts voltage, eliminating extra control circuits.

• MCLS & MSSLS: Use stacking to minimize sub-threshold leakage while maintaining operational voltage levels.

IV. Research Gaps and Future Scope

• Need for ultra-low voltage LS (sub-100mV) in IoT and biomedical applications.

• Optimization for both speed and power in high-speed communication remains a challenge.

• Sensitivity to PVT (Process-Voltage-Temperature) variations requires development of self-adaptive LS designs.

• Area overhead in complex LS designs needs reduction via layout optimization and transistor scaling.

• Hybrid LS models combining differential and bootstrapping techniques could enhance both power and speed performance.

Conclusion

DVLS provides the best dynamic voltage which can be used in multi – voltage systems[2]. Modified Single supply LS has the low power consumption which is used in IOT devices and battery – powered systems [11]. Modified Convention level shifter has the lowest delay which is used in low power digital IC and portable devices [13]. BELS has the fastest delay which makes it applicable for high-speed application. But the power consumption is high that is not suitable for ultra-low power designs. This also has broader voltage range [13]. Slowest performance can be seen in BNVLS due to the highest delay which is less useful for Low- voltage energy efficient circuits [20].

References

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Copyright

Copyright © 2025 Sumanth R R, Niveditha , Shashank G K, Priyadarshini K Desai, Jyoti R Munavalli. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.