Ultra Low Power Magnetic Flip-Flop Based on Checkpointing/Power Gating and Self-Enable Mechanisms

Abstract

Advanced computing systems suffer from high static power due to the rapidly rising leakage currents in deep sub-micron MOS technologies. Fast access non-volatile memories (NVM) are under intense investigation to be integrated in Flip-Flops or computing memories to allow system power-off in standby state and save power. Spin Transfer Torque MRAM (STT-MRAM) is considered the most promising NVM to address this issue thanks to its high speed, low power, and infinite endurance. However, one of the disadvantages of STT-MRAM for the computing purpose is its relatively high write energy to build up Magnetic Flip-Flop (MFF). In this paper, we propose a power-efficient MFF design architecture to address this challenge based on the combination of checkpointing operation, power gating and self-enable mechanisms. Multi non-volatile storages can be integrated locally in a conventional FF without significant area overhead benefiting from the 3-D implementation of STT-MRAM. We performed electrical simulations (i.e. transient and statistical) to validate its functional behaviors and evaluate its performance by using an accurate spice model of STT-MRAM and an industrial 40 nm CMOS design kit. The simulation results confirm its lower power consumption compared to conventional CMOS FF and the other structures.