Design And Implementation Of DVFS Controller For Wide Supply Voltage

Dynamic Voltage and Frequency Scaling(DVFS)is a technique to reduce power consumption by adjusting the voltage and clock frequency dynamically with the throughput constraints.When a chip works at a wider range of supply voltage by adopting the DVFS strategy,energy efficiency of the chip will be higher.However,when the supply voltage is adjusted over a wider range,the design margin of the circuit at different operating points and the cost of switching between operating points will be higher.The thesis aims at a wide operating voltage range,and designs a hybrid DVFS regulation strategy that combines on-chip power rail switching and off-chip DC-DC voltage regulation,completes the design of the DVFS controller,and completes the development of the verification system based on the RISC-V processor.First,the dual-rail switching technology with a wide voltage range was studied.Based on the analysis of the voltage noise variation of the processor during the power rail switching from VDD/2 to VDD,a power gating circuit based on configurable speed and a clock gating circuit based on short pulse detection were designed to reduce switching noise,and completed the design of the dual-rail switching voltage regulator circuit.The simulation results show that the designed dual-rail switching method has a switching speed between 80ns/V-120ns/V in a wide voltage range from VDD/2 to VDD,which is a significant improvement over the traditional method.Secondly,the design of the DVFS controller is completed.Among them,the frequency modulation circuit is designed based on the clock frequency fast switching technology,the off-chip voltage regulation control circuit is designed based on the control method of the off-chip DC-DC voltage regulator chip,and the power management circuit is designed based on the mixed regulation strategy of two voltage regulation methods.The simulation results of the DVFS controller show that the energy-delay product(EDP)of a 32-bit adder under the hybrid regulation method is reduced by 29.74%compared with the single off-chip DC-DC regulation.Finally,based on the above DVFS controller,the interface between it and the RISC-V processor is designed,and a RISC-V SOC system with a DVFS controller is built.Using TSMC 28 nm process,through the Unified Power Format(UPF)low power design method,the multi-voltage domain design and physical implementation of the SOC are completed.The twodimensional convolution test program shows that the interface circuit function of the DVFS controller is correct,and the SOC system has correctly adjusted the voltage and frequency under program control.