Design Of Fast Adaptive Frequency System With PVT-variation Tolerant Technique

With the rapid development of integrated circuit technology and mobile termination,people's demand for consumer electronics is getting higher and higher.However,due to process,temperature and voltage variations,in convention design,a large amount of timing margin is added to ensure the circuit to work properly at worst case,which leads to waste more performance.Adaptive Frequency Scaling technology is an effective method to release the reserved timing margin and restrain the PVT variation by monitoring the path's timing and controlling the frequency adaptively.The timing-error predictive AFS technology was mainly discussed in this paper.Timing monitor was inserted at the end of the critical path to monitor the timing of the chip,and the system frequency is dynamically adjusted by the monitoring results.Firstly,a new timing monitor with only 16 transistors was proposed,which can operate at 0.5V?1.1V.Secondly,the influence factors of monitoring window width was deduced theoretically,and an circuit of on-chip configuration monitoring window was proposed.Thirdly,a one-cycle fast frequency scaling circuit was designed to handle the timing warning signal,which can work at 65MHz?1000MHz.Finally,a mixed simulation platform based on HSIM-VCS was built to simulate the entire design.The AFS system was applied to Bitcoin verification circuit,which was designed by SMIC 40nm CMOS process.The simulation results show that in the regular voltage(1.1V)region,compared to the baseline frequency of 819MHz,a performance benefit of 21%and a energy efficiency benefit of 11.7%can be achieved according to different process corners and temperatures.In the low voltage(0.66V)region,compared to the baseline frequency of 88MHz,a performance benefit of 110%and a energy efficiency benefit of 39.2%can be achieved.The area cost of the entire AFS system was only 4.3%.In summary,the proposed AFS system achieves significant performance and energy efficiency benefits by frequency scaling with a small area cost and can restrain the PVT variation effectively.