Research On Minimum Energy Point Tracking Technology Based On Adaptive Voltage Scaling

Due to the rapid progress of IC(Integrated Circuit)fabrication processes,the chip’s integration and power consumption also increase dramatically,which makes chip’s power consumption become one of important indicators to measure the performance of chip.Therefore,in order to reduce the energy consumption of IC,the low voltage and low power technique has achieved rapid development in recent years.In the low voltage and low power technique,DVS(Dynamic Voltage Scaling)and AVS(Adaptive Voltage Scaling)techniques,which can regulate adaptively supply voltage of digital circuits with frequency variance and guarantee normally operation of digital circuits in different combination of PVT(Process,Voltage,Temperature),can achieve the purpose of reducing dynamic energy consumption of digital circuits.By comparing total energy consumption of digital circuits in different voltage with combination of PVT variance,MEPT(Minimum Energy Point Tracking)technique can automatic tracking the minimum of total energy consumption and decrease total energy consumption in further.The dissertation has done in-depth research about low voltage and low power technique from various aspects,main include APSM(Adaptive Duty Ratio based on Pulse Skipping Modulation)technique,PSWM(Pulse Skipping Width Modulation)technique,APSM-based DC-DC converter AVS technique and AVS-based MEPT technique,proposing corresponding technology solutions,which are varied by experiment results.The purpose of using low voltage and low power technique to reduce energy consumption of digital circuits is realized.The main work and innovation include:(1)The APSM technique is proposed.The operation principle of APSM technique is presented,the voltage ripple and adaptive duty ratio of control pulse are analyzed and discussed,respectively.APSM technique,which can generate the control pulse with adaptive duty ratio and skipping pulse according to different error between reference voltage and output voltage,realizes adjustment output voltage adaptively,improves the larger voltage ripple problem of PSM and conforms the increasingly subtle and precise requirement of the low power digital circuits for output voltage and energy transfer.The design based on a 0.13μm CMOS process are completed,the simulation and experiment results show that the duty ratio of control pulse can change adaptive with output voltage variance in APSM,which conforms the theoretical analysis of APSM technique.(2)The PSWM technique is proposed.The modulation mechanism of PSWM for output voltage is presented.By comparing the right angle trapezoid and output voltage,the control pulse with adaptive duty ratio within whole the load range and pulse skipping characteristic at light load is obtained in PSWM technique,which realizes regulating output voltage adaptively.The PSWM technique has the advantages of simpler circuit structure and smaller voltage ripple.The simulation and experiment of PSWM controlled DC-DC converter based on a 0.18μm CMOS process is completed.(3)The APSM-based DC-DC converter AVS technique is proposed.The mechanism of voltage regulation and frequency tracking of AVS technique and the operation principle of APSM technique are analyzed.In APSM-based AVS technique,firstly,the critical path of digital circuits is replicated accurately by CPR(Critical Path Replicate)technique,which can simulate the real-time work status of digital circuits.Secondly,the real-time performance parameters of digital circuits can be obtained using AVS to track and probe CPR.Finally,realizing regulating adaptively output voltage,decreasing operation voltage and dynamic energy consumption of digital circuits.At the same time,using APSM technique,the control pulse with adaptive duty ratio as the output voltage change is generated,which achieve the purpose of optimization voltage ripple and efficiency at light load.The simulation and experiment results based on a 0.13μm CMOS process show that the output voltage can change in the range from 0.6V to 1.5V when operation frequency of digital load changes in the range from 30 MHz to 150 MHz,and the voltage ripple about 50 mV.Compared with traditional fixed operating voltage,the APSM-based DC-DC converter AVS technique can save maximum 83% energy consumption.(4)The AVS-based MEPT technique is proposed.The theoretical analysis in detail about MVP(Minimum Voltage Point)and MEP(Minimum Energy Point)are presented.The circuit can adaptively search and track the MVP and MEP is designed using the parabolic characteristic of total energy consumption curve of digital circuits,main consist of AVS voltage regulation loop,MEP tracking loop and initial startup loop.The AVS-based MEPT circuit has the advantages of full digitalized,effectively reduction operating voltage and energy consumption of digital circuits and keeping the optimal circuits performance.The simulation and experiment results of designed circuit based on a 0.18μm CMOS process show that when the operating frequency of digital load is 1.319 MHz,the MVP and MEP by researched and tracked are 425 mV and 450 mV,respectively.When the active factor of digital load becomes from high to low and operating frequency is 5.334 MHz,the MEP increases from 550 mV to 625 mV.At the same time,with the operating frequency and active factor variance,the MEP will different obviously.Compared with traditional fixed operating voltage,the AVS-based MEPT technique can save maximum 91% energy consumption.