脉冲型阵列量子级联激光器驱动电源

设计并研制了一种高精度的可调节阵列量子级联(QC: Quantum Cascale)激光器驱动电源, 以用于中红外多气体检测系统。该系统运用时分复用的思想, 利用并联加串联的方式, 同时驱动多个QC激光器。在硬件方面, 以DSP F28335为主处理器, 采用压控恒流源的原理, 通过大功率半导体器件, 实现脉冲频率(1~10 kHz, 步进0.5 kHz)、 占空比(0.5%~40%, 步进0.5%)、 电流幅值(0~4 A, 步进0.1 A)连续可调的脉冲恒流源。在控制方案上, 采用模拟PI(Proportion Integral)控制算法, 通过两级模拟PI环节的双重反馈方式, 提高了驱动电流的准确性和稳定性。同时, 该系统还设计了电源滤波慢启动电路、 过流保护电路、 过压保护电路、 静电防护电路等, 防止QC激光器被瞬间大电流损坏, 以确保激光器的正常工作。经实验测试, 当设定脉冲电流幅值为2.0 A, 脉冲频率为5 kHz, 脉冲宽度为2 μs时, 输出脉冲电流幅值稳定度优于1.7×10^-3 A, 脉冲宽度稳定度优于2.4×10^-2μs, 脉冲上升时间小于11.9 ns, 脉冲下降时间小于9.6 ns。在同时驱动多个QC激光器长时间测试过程中, 驱动电流稳定, QC激光器发光稳定, 测试指标达到要求。

Pulse Driver Power for Array Quantum Cascade Laser

A digital high precision constant current driver power is designed for array QC(Quantum Cascade) lasers in the Mid infrared gas detection system. Time division multiplexing is applied in this system to drive several QC lasers which are series and parallel. TMS320F28335 is used as a control center and the constant current driver power has a frequency range of 1~10 kHz, duty cycle from0.5% to 40%, current amplitude range of 0~4 A by using big power semiconductor devices. In the control scheme, analog PI(Proportion Integral) control algorithm is adopted to improve the precision and stability of the driving current by using double feedback mode of two level analog PI links. Considering of the security of QC lasers, the system is designed with a slow start circuit, over-current and over-voltage protection circuit, ESD(Electro Static Disoharge) protection circuit, etc. The results show that when working in a certain condition that the pulse amplitude is 2.0 A, pulse frequency is 5 kHz, the pulse width is 2 μsthe stability of output current pulse is better than 1.7×10^-3 A, the stability of pulse width is better than 2.4×10^-2 μs, the pulse rise is lessthan 11.9 ns. and the pulse fall time is less than 9.6 ns. At last, driving several QC lasers for testing at the same time, the results show that there is no glitch regarding the driving current and the center wavelength of the tested QC lasers does not shift. Therefore, the fabricated driver provides superior perform
ance that guarantees the application of the QC lasers in infrared gas detection.