控制半导体激光器的高稳定度数字化驱动电源的设计

Design of high stability digital control driving system for semiconductor laser

以TMS320F28335为控制核心,设计了一种用于驱动半导体激光器的数控电流源。电源的外围电路包括指示灯模块、语音模块、LCD模块以及键盘控制模块。语音与指示灯模块负责系统工作状态提示,LCD负责显示实际电流以及目标电流,键盘模块负责电源的启动、关闭、电流设置、电流步进等操作。电路设计中利用深度负反馈原理来提高系统的稳定度,设计了双MOS管进一步减小漏电流引起的偏差(小于0.5%),优化了电压—电流线性度;软件设计中采用了PID算法缩短了系统的动态平衡时间;系统具有完备的保护措施,如防上电/断电冲击保护电路、延时软启动电路、过流保护电路以及纹波抑制电路,保证了激光器稳定可靠地工作。在激光器的驱动测试过程中,激光器工作状态稳定,中心波长未出现漂移,驱动电流无毛刺出现。

A digital control current supply is designed for driving semiconductor lasers by taking the TMS320F28335 as a control center,which consists of a guiding light module,a phonetic module,a liquid-crystal display（LCD） module and a keyboard module.The phonetic module and light module are responsible for prompting the working condition of the system,the LCD is used to show the actual current and setting current,and the keyboard module is taken to control the start-up,turn-off,current setting and current adjustment.In circuit design,the deep feedback theory is researched to greatly enhance the stability and two MOSFET are designed to neutralize their own leakage current,decrease the current deviation（less than 0.5%） and optimize the linear dependence between voltage and current.In software design,the PID algorithm is employed to shorten the time to establish dynamic equilibrium for the system.The system can provide complete protective measures,such as surge-prevent,power on/off-prevent,time delay soft start,over current protection for ensuring the LD to work stably and reliably.During the driving test,the LD can work in a steady state without center wavelength drifting and driving current fluctuation.