Design Of Digital Temperature Sensor Using 1-Wire Bus

With the development of science and technology,temperature sensors have wide application in industrial production,medical instruments and environmental monitoring.At present,the widely used temperature sensors mainly come from famous foreign semiconductor manufacturers.However,the domestic IC industry started late and the development of temperature sensors still lags behind foreign semiconductor companies.Therefore,research on high-accuracy and intelligent digital temperature sensor is still necessary.In this paper,a temperature sensing circuit based on BJT is proposed.On this basis,a digital temperature sensor is realized with a 1-wire bus digital interface and various auxiliary functions.The main work is as follows:1.The structure of the temperature sensor is finalized.By analyzing the commercial temperature sensors,the structure of integrated intelligent temperature sensor is determined.The proposed sensor first outputs a temperature-related electrical signal.And then a signal conditioning circuit converts the electrical signals into digital signals and sends them to the control unit.Finally,a digital temperature sensor is realized with bus interface.2.The temperature sensing module is studied and realized.According to the temperature sensing principle of BJT,the core temperature sensing circuit is designed.DEM(Dynamic Element Matching)and chopper stabilization technology are used to reduce the errors caused by element mismatch and noise.An analog-to-digital conversion circuit based on duty-cycle-modulation is designed for the output characteristics of the temperature sensing circuit.3.The digital interface of the temperature sensor is designed based on 1-wire bus protocol.The 1-wire bus protocol mainly consists of interface module,memory and controller.It can complete bidirectional communication only through a single bus,which saves I/O(Input/Output)port resources and can realize multi-point temperature measurement system.The high-low temperature test results of the temperature sensing module show that it works steadily between-45? and 75? and the inaccuracy is within ±0.6?.The cooperative verification results of 1-wire bus protocol and the temperature sensing module show that the protocol can convert the parallel temperature value into serial output and realize the functions of single line communication,real-time temperature measuring and alarm searching.Finally,the overall layout of the digital temperature sensor and its post-simulation verification are completed.