Dsp-based High-precision Temperature Control System Study

With the development of the optical fiber communication, semiconductor laser as light source has been widely used in optical fiber communication systems. The heat generated by laser has serious impact on the thermal properties, such as output power, wavelength etc. In order to ensure constant output wavelength and constant optical power, we need to do high-precision temperature control to the laser.This topic A/Dopted thermistor as temperature sensor, used Thermoelectric Cooler (TEC) as system component and developed a high-precision temperature control system based on Digital Signal Processor (DSP).In this paper, the contents of the following areas were researched: First, analyzed the significance and states of research on semiconductor laser temperature controller; Second, based on the analysis of existing system and principle, designed the control system and selected some peripheral devices, which could meet the need of the system. Taking A/Dvantage of thermal resistance through the constant current source putting the temperature into voltage, and then by 24-bit high-precision A/D converter a convenient digital signal imported into DSP. DSP utilized digital PID algorithm to control difference between measuring temperature and setting temperature. PWM signal controlled DRV592 H bridge circuit and drived TEC to control temperature. LED displayed real-time temperature, at the same time, the data was transported to PC through the RS-232 serial port, allowing for analysis and display control curve. The software part used c language under CCS compiler to develop and debug. The temperature control objective of the system was±0.2℃. Finally, the testing debug of this system meet its all functions and parameters target preferably.This article concluded some shortcoming and improved methods of this system. The design of this system also has some referred significance to other similar systems.