The Research Of Novel Light Scattering Particle Sensor System

Particulate matter sensor is a kind of gas sensor.As one of the important components of Environmental Monitoring Management System(EMIS),it has attracted more and more attention from society and the country.Particulate matter sensors are not only used in the field of environmental detection,but also play a role in fields such as industry and medical.The light scattering method has the advantages of fast measurement speed,real-time monitoring,high accuracy,no loss,and good portability.In recent years,it has been increasingly used in the market application of particulate matter sensors.This paper mainly conducts in-depth research on light scattering algorithm and particle sensor system,and uses the advantages of high integration of CMOS process,fast transmission speed,and low manufacturing cost to design a novel type of light scattering particle sensor system to improve sensor detection.Performance and integration.The main research work of this paper is as follows:1.Aiming at the problem of decreased detection accuracy of high concentration of traditional particulate matter sensor,a traditional particulate matter sensor based on particle counting method was designed to verify this phenomenon.The composition of the overall architecture of the traditional particulate matter sensor,the algorithm principle and the design flow of the signal processing circuit are analyzed in detail,and the actual object is tested.The final result shows that the traditional particle sensor designed in this paper can accurately detect PM2.5 particles at low concentrations(0?500?g/m~3)(R~2>0.99,average detection error<0.01mg/m~3),but at high concentrations(0.5?1 mg/m~3),the detection error will increase(R~2=0.974,the average detection error>0.02 mg/m~3),and a single detection requires at least 5?10?s.This shows that the particle sensor implemented by the particle counting method and the single-chip microcomputer system has shortcomings.2.Aiming at the problem of the lack of simulation model of the particle sensor photoelectric receiving module,an equivalent circuit model of the photoelectric interface module of the particle sensor is proposed,and the method of establishing the SPICE equivalent model of the high-frequency silicon-based phototransistor and the method of parameter extraction is introduced.By comparing the circuit simulation results with the TCAD simulation results,it is confirmed that the two simulation results have good consistency,and the accuracy of the model to describe the photoelectric characteristics of the device is verified.The operating frequency of the model is 100 MHz?1 GHz,the current gain is about 500,and the optical responsivity is>0.5 A/W.In addition,the feasibility of the model in device simulation and circuit applications is also verified.3.Aiming at the shortcomings of the particle sensor implemented by the particle counting method and the single-chip microcomputer system,a novel particle sensor system based on particle swarm light scattering method is proposed.The principle of the system and the function of each module are described,the design ideas of each module of the system are analyzed in detail,and the designed circuit is simulated under the SMIC 0.18?m process.The results show that the novel particle sensor proposed in this paper can achieve a wide range(0?1 mg/m~3),fast(2?s/time),and low error(<0.01 mg/m~3)detection.4.Aiming at the problem of the missing data storage module of the novel particulate matter sensor,a data storage architecture based on STT-MRAM is proposed.Through the simulation and comparison of the performance of the data storage unit using SRAM or STT-MRAM,it is proved that under the large data capacity,the performance of the STT-MRAM architecture is more excellent.Then,aiming at the problems of high write delay of STT-MRAM and high leakage power consumption of HP(High performance)-type devices,the optimization scheme of STT-MRAM cell configuration under different capacities is studied.The results show that a reasonable configuration scheme can effectively reduce the write delay and leakage power consumption of the STT-MRAM data storage unit(up to 5.4%and 42.1%respectively).