Adaptive Voltage Frequency Scaling System Design For Wide Voltage Range SoC

With the rapid development of integrated circuit technology, wide voltage range circuit as an effective method to take account of the high performance and high efficiency requirements at the same time has got widespread attention.However, how to guarantee high performance while reducing power consumption under the regular voltage and achieve high energy efficiency while resisting the PVT variation in the near-threshold voltage region becomes the bottleneck of wide voltage range design. Adaptive voltage frequency scaling (AVFS) technology is an effective method to overcome the bottleneck, which utilizes on-chip critical path monitors to regulate the supply voltage and clock frequency in real time.Considering the serious local PVT variation under advanced manufacturing technology, and comparing the popular AVFS methods, the design based on in-situ timing-error prediction method was mainly discussed in this paper. Firstly, an in-situ timing-error prediction monitor was proposed which was delay-configurable and applicable in the wide voltage range application, and then an innovative method of selecting monitoring point was designed along with its applying effect on a taped-out chip. Secondly, the AVFS control module and a SoC verification circuit based on Cortex-M3 was completed using SMIC 40nm technology with 4.7% area overhead caused by AVFS control module. Finally, a mixed simulation platform based on HSIM and VCS was built to simulate the whole design.Simulation results show that in the regular voltage (1.1V) region,28.5%-54.3% power consumption benefit can be achieved according to different process corners and temperature; in the low voltage (0.6V) region, besides resisting the PVT variation, the power gains can be at most 73.2%. When turn on the AVFS function, the energy efficiency in low voltage (0.6V) region can achieve 3x improvement compared to which in the regular voltage region. In conclusion, this design can distinctly reduce power consumption and improve energy efficiency, besides effectively resisting the PVT variation.