BEOL NEM Relay-Based Inductorless DC-DC Converters

Abstract

BEOL NEM Relay-Based Inductorless DC-DC Converters

Ren Li, Dias Azhigulov, Ahmed Allehyani, and Hossein Fariborzi

Introduction

•The voltage level requirement varies across the integrated circuit chip. Therefore, on-chip voltageconversions are crucial for anychip to be operational.

•This work proposes a novel solution for voltage regulation using Back-End-Of-Line (BEOL)NEM relays.

•The proposed Buck and Boost converters offer low voltage ripple, high conversion efficiency and low area overhead.

Relay and its Operation

•The relay is actuated electrostatically by the voltage difference between G and B.

•Two inherent threshold voltages:VPI (pull-in voltage) and VPO(pull-out voltage).

Relay Buck Converter

•The buck converter uses Switched-Capacitor Buck Converter (SCBC) configuration.

Relay Boost Converter

•The boost converter utilizes Switched-Capacitor Voltage Doubler (SCVD) concept.

Results and comparisons

•Custom Verilog-A relay model is used for Relays

•Validated against a commercialFEM tool, MEMS

Conclusion

The BEOL NEM relay-based converters have the following benefits:

•Capable of handling higher voltages;

•Utilize switched-capacitorconfiguration to avoid bulky on-chip inductors;

•Zero sub-threshold leakage andsharp turn on/off curves;

•Low output voltage ripple and highconversion efficiency.

•Perfect for ultra low power applications, such as IoT and biological, implantable medical devices.

References

1 R. Li, D. Azhigulov, A. Allehyani and H. Fariborzi, BEOL NEM Relay-Based Inductorless DC-DC Converters in 2020 IEEE International Symposium on Circuits and Systems (ISCAS), 2020.

2 D. Ma and R. Bondade, Reconfigurable switched-capacitor power converters: principles and designs for self-powered microsystems, 1 ed. New York: Springer-Verlag New York, 2013, p. 178.

3 R. Li, R. Alhadrami, and H. Fariborzi, BEOL NEM Relay Based Sequential Logic Circuits, in 2019 IEEE International Symposium on Circuits and Systems (ISCAS), 2019.