Based on the fundamental relationship among the circuit power, the circuit delay and the supply voltage, four theorems associated with the application of dynamic voltage scaling （DVS） policies are proposed and prove...Based on the fundamental relationship among the circuit power, the circuit delay and the supply voltage, four theorems associated with the application of dynamic voltage scaling （DVS） policies are proposed and proved. First, the existence characteristics of the optimal supply voltage for a single task are proved, which suggests that the optimal supply voltage for the single task should be selected only within a one-dimensional term, and the corresponding task end time by the optimal supply voltage should be identical with its deadline. Then, it is pointed out that the minimum energy consumption that the DVS policy can obtain when completing a single task is certainly lower than that of the dynamic power management （DPM） policy or the combined DVS＋DPM policy under the same conditions. Finally, the theorem of energy consumption minimization for a multi-task group is proposed, which declares that it is necessary to keep the processor in the execution state during the whole task period to obtain the minimum energy consumption, while satisfying the deadline constraints of any task.展开更多
For the high resolution required in a digital interface circuit of an accelerometer used in feeble gravity measurement, a switched-capacitor （SC） sigma-delta modulator （SDM） is proposed. Based on the principle and...For the high resolution required in a digital interface circuit of an accelerometer used in feeble gravity measurement, a switched-capacitor （SC） sigma-delta modulator （SDM） is proposed. Based on the principle and the topology structure of the SDMs, the influence of oversampling ratio, bits of an internal quantizer and the cascaded structure on weak signal detecting precision is analyzed, and an ideal low-distortion SDM with a second-order 1-bit structure satisfying the high- resolution interface circuit of an accelerometer is designed. With the research on non-idealities of each SDM block in the SC circuit implementation and their impacts on power consumption, the realized parameters of low-power SDMs based on different bandwidths are devised and the power consumption of each SDM is estimated. Time-domain behavioral simulation is explored based on Simulink. The results demonstrate that a 21- bit resolution of the designed SDMs can be achieved on the premise of low power, and the parameters for the circuit implementation can be directed to the transistor-level circuit design.展开更多
A piezoelectric sensor charge/voltage conversion circuit is designed based on the principle that piezoelectric sensor can convert the vibration or shock acceleration into the charge proportionally.Effect of temperatur...A piezoelectric sensor charge/voltage conversion circuit is designed based on the principle that piezoelectric sensor can convert the vibration or shock acceleration into the charge proportionally.Effect of temperature characteristic of feedback capacitor on the switching circuit output is analyzed based on the acquisition and measurement system in this paper.The characteristics of different filters are analyzed,and the corresponding filter circuit is configured according to the actual sensor bandwidth.Experiments show that the circuit can effectively filter out noises among the vibration signal and obtain vibration signal accurately.展开更多
文摘Based on the fundamental relationship among the circuit power, the circuit delay and the supply voltage, four theorems associated with the application of dynamic voltage scaling （DVS） policies are proposed and proved. First, the existence characteristics of the optimal supply voltage for a single task are proved, which suggests that the optimal supply voltage for the single task should be selected only within a one-dimensional term, and the corresponding task end time by the optimal supply voltage should be identical with its deadline. Then, it is pointed out that the minimum energy consumption that the DVS policy can obtain when completing a single task is certainly lower than that of the dynamic power management （DPM） policy or the combined DVS＋DPM policy under the same conditions. Finally, the theorem of energy consumption minimization for a multi-task group is proposed, which declares that it is necessary to keep the processor in the execution state during the whole task period to obtain the minimum energy consumption, while satisfying the deadline constraints of any task.
基金The National High Technology Research and Development Program of China (863 Program) ( No. 2006AA12Z302)
文摘For the high resolution required in a digital interface circuit of an accelerometer used in feeble gravity measurement, a switched-capacitor （SC） sigma-delta modulator （SDM） is proposed. Based on the principle and the topology structure of the SDMs, the influence of oversampling ratio, bits of an internal quantizer and the cascaded structure on weak signal detecting precision is analyzed, and an ideal low-distortion SDM with a second-order 1-bit structure satisfying the high- resolution interface circuit of an accelerometer is designed. With the research on non-idealities of each SDM block in the SC circuit implementation and their impacts on power consumption, the realized parameters of low-power SDMs based on different bandwidths are devised and the power consumption of each SDM is estimated. Time-domain behavioral simulation is explored based on Simulink. The results demonstrate that a 21- bit resolution of the designed SDMs can be achieved on the premise of low power, and the parameters for the circuit implementation can be directed to the transistor-level circuit design.
文摘A piezoelectric sensor charge/voltage conversion circuit is designed based on the principle that piezoelectric sensor can convert the vibration or shock acceleration into the charge proportionally.Effect of temperature characteristic of feedback capacitor on the switching circuit output is analyzed based on the acquisition and measurement system in this paper.The characteristics of different filters are analyzed,and the corresponding filter circuit is configured according to the actual sensor bandwidth.Experiments show that the circuit can effectively filter out noises among the vibration signal and obtain vibration signal accurately.
