新型小功率半导体激光器驱动及温控电路设计

Design of new-style driving and temperature control circuit for low power diode laser

为了应对带钢激光平直度测量仪中半导体激光器(LD)输出光功率稳定性对平直度测量精度的影响问题,设计了一款高稳定度的LD恒流驱动、温控电路以及保护电路。系统以现场可编程门阵列(FPGA)为控制核心,利用深度负反馈恒流驱动电路实现对LD驱动电流的精准控制;基于ADN8830温控电路实现了对LD工作温度的有效控制;改进后的慢启动电路可实现LD驱动电流缓慢地线性增加到设定值,且准确控制慢启动时间;限流及静电保护电路能够实现激光器过流保护、有效避免浪涌电流和高压静电的损坏。结果表明,该电路可实现激光器驱动电流在0~75 mA连续可调,电流调节精度达0.025 mA,电流短期稳定度达0.014%,长期稳定度达0.016%;在控制工作温度为25℃时,输出光功率稳定性为0.205%。

In order to deal with the influence of the stability of the output optical power of diode laser(LD)on the flatness measurement accuracy of the strip laser flatness measuring instrument,a high stability diode laser constant current driving circuit,temperature control circuit and protective circuit were designed.FPGA was used as the system control core.Based on the principle of deep negative feedback,the accurate current control was achieved by the constant current driving circuit.The effective control of LD operating temperature was realized by temperature control circuit based on ADN8830.Driving current was slowly and linearly increased to preset value by improved slow-start circuit,and the slow-start time can be controlled precisely.High reliability and high security were realized by current limiting and electrostatic protection circuit.The results show that the driving current can be adjusted continuously from 0 to 75 mA,the adjustment accuracy can reach 0.025 mA,the shortterm stability of current can reach 0.014%and the long-term stability can reach 0.016%.When the operating temperature is controlled at 25℃,the stability of the output optical power is 0.205%.