An Energy-Efficient Current-Controlled Write and Read Scheme for Resistive RAMs (RRAMs)
Hassen Aziza, Mathieu Moreau, Moritz Fieback, Mottaqiallah Taouil, Said Hamdioui
Abstract
Energy efficiency remains one of the main factors for improving the key performance markers of RRAMs to support IoT edge devices. This paper proposes a simple and feasible low power design scheme which can be used as a powerful tool for energy reduction in RRAM circuits. The design scheme is exclusively based on current control during write and read operations and ensures that write operations are completed without wasted energy. Self-adaptive write termination circuits are proposed to control the RRAM current during FORMING, RESET and SET operations. The termination circuits sense the programming current and stop the write pulse as soon as a preferred programming current is reached. Simulation results demonstrate that an appropriate choice of the programming currents can help obtain <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4.1X</i> improvement in FORMING, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9.1X</i> improvement in SET and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.12X</i> improvement in RESET energy. Also, the possibility to have a tight control over the RESET resistance is demonstrated. READ energy optimization is also covered by leveraging on a differential sense amplifier offering a programmable current reference. Finally, an optimal trade-off between energy consumption during SET/RESET operations and an acceptable read margin is established according to the final application requirements.