Research And Design Of Sub-Threshold Digital Circuit Based On Adaptive Technique

In recent years, thanks to the booming of Internet of Things, wearable, mobile phone and tablet market, research field of integrated circuit chips for wireless networks becomes more and more popular. However, the chip power density has a rapid increase with the decrease of CMOS process dimension, the problem of high energy consumption is becoming an important Obstruction in the development of the portable device market. Sub-threshold digital circuits belongs to ultra low voltage digital circuits fields. the energy consumption of the chip to complete a single operation to minimum by lowering the supply voltage to the sub-threshold region. Sub-threshold digital circuit has great application prospects in mobile networks, medical implants, environmental monitoring integrated circuit chip etc., and now has already become an important research direction in the field of low power consumption. In this paper, in-depth discussion about significance, the theoretical basis, design difficulties, and design methods for the design of sub-threshold digital circuits is done.Firstly, based on the latest chip technology and semiconductor markets, this paper analyzes the research value of sub-threshold digital circuits, and introduces the background of sub-threshold circuit and latest developments. Secondly, this paper analyzes the theoretical basis for subthreshold digital circuit design. Including the composition of digital circuits energy, deriving of theoretical minimum energy point, and the importance and difficulty of the PVT compensation in sub-threshold digital circuit design. Thereafter, the paper studies the design method of subthreshold digital circuits, the method uses the "standard cell library re-characterization" technique. to complete the design subthreshold digital libraries, and then presents a suitable subthreshold digital circuit design combining the standard cell library(SCL) and digital circuit design flow process. Then, a digital FIR filter which is suitable for sub-threshold voltage is proposed, the filter adopts sub-threshold digital circuit design flow,including logic synthesis and simulation, verify the feasibility of the design flow. Finally, because of the importance of PVT(Process,Voltage,Temperature)compensation in sub-threshold circuits, this paper proposed an adaptive voltage regulator(Adaptive Voltage Scaling, AVS) system, to ensure the normal function of subthreshold digital circuits at different PVT corners. In this paper, the FIR filter and AVS system is based on 180 nm standard CMOS technology, and the design and simulation of the whole the circuit is completed.