With the introduction of the Internet of Things (IoT), power consumption became a major design issue in modern system-on-chips. In advanced technologies, leakage power has become a dominant component, especially during sleep periods. Leakage mainly comes from volatile memory elements, e.g., flip-flops that cannot be power-gated in order to retain their states. Non-Volatile Flip-Flop (NVFF) using emerging memory technologies, such as Resistive Random Access Memories (RRAM), are popular solutions to address this issue. In NVFF design, the resistance values of the memory element have a direct impact on the area and energy overhead of the structure. In this paper, we present a design methodology for area and energy efficient RRAM-based NVFF. By characterizing the optimal lower bound of the RRAM resistance ratio required for properly restoring the FF, the store and restore operations can be performed using optimal programming circuit area and energy. Four Transmission-Gate (TG) NVFF topologies implemented in 180nm CMOS technology were analyzed using the proposed methodology. The presented methodology shows that differential NVFF provides minimum restore resistance ratio down to 1.02 considering CMOS and RRAM variability. This enables improvements in terms of store energy (34%) and area overhead (40%) compared to reported state-of-the-art NV-TGFFs design approaches.
|Title of host publication||IEEE International Symposium on Circuits and Systems|
|Subtitle of host publication||From Dreams to Innovation, ISCAS 2017 - Conference Proceedings|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|State||Published - 25 Sep 2017|
|Event||50th IEEE International Symposium on Circuits and Systems, ISCAS 2017 - Baltimore, United States|
Duration: 28 May 2017 → 31 May 2017
|Name||Proceedings - IEEE International Symposium on Circuits and Systems|
|Conference||50th IEEE International Symposium on Circuits and Systems, ISCAS 2017|
|Period||28/05/17 → 31/05/17|
Bibliographical notePublisher Copyright:
© 2017 IEEE.
- Non-volatile Flip-Flop