摘要
目的:在生命科学仪器中应用发光二极管作为激发光源已成为趋势,分析影响发光二极管型激发光源性能的相关因素,使之能采取相应措施提高发光二极管型激发光源的稳定性及其精度。方法:对现有典型的发光二极管型激发光源“恒流”驱动电路进行分析,针对发光二极管型激发光源的稳态精度、动态稳定性、时间稳定性和温度稳定性采取了改进措施。在恒流驱动电路基础上,增加可分别调整P,I,D参数的PID控制电路来提高发光二极管型激发光源的稳态精度和动态稳定性,采用光反馈技术的“恒光功率”驱动电路来提高发光二极管型激发光源的时间稳定性和温度稳定性。结果:不加PID控制电路时,ε≤0.6mA,△IP≤7.8%,tW≤13μs。采用PID控制电路后稳态精度提高到ε≤0.05mA,动态特性提高到:超调量为△IP≤3%,动态过程时间tW≤87ns。采用“恒光功率”驱动电路后抑制了温度波动的影响,使用寿命增长。结论:恒流驱动电路适用于工作温度变化不大和不考虑时间稳定性(发光二极管老化问题)的场合;而当工作温度变化较大并且需要考虑时间稳定性的场合,就要采用恒功率驱动电路为好。无论恒流驱动还是恒功率驱动电路,加入PID控制之类的调节电路可以获得好的动态特性和提高稳态精度。
AIM： To improve stability and precision of light emitting diode （LED） excitation light source, analyze the related factors to LED light source performance, which has been widely used in life sciences instruments.
METHODS： First, the current typical ＂constant current＂ drive circuit of LED excitation light source was analyzed. The corresponding technique methods were taken to improve stable status precision, dynamic stability, time stability＂and temperature stability of LED source. On the basis of the constant current drive circuits, stable status precision and dynamic stability of LED excitation light source were improved by adding the PID control circuit that could adjust solely PID parameters. Additionally, the time stability and temperature stability of LED excitation light source were improved by the ＂constant light power drive circuit＂ using light feed back.
RESULTS： Without PID control circuit, the parameters were ε〈0.6 mA, ΔIp≤7.8%, tw≤ 13 p.s. By using the PID control circuit, the stable status precision had increased to ε≤0.05 mA, the dynamic stability had improved to overshoot ,ΔIp≤3% and dynamic process time tw≤87 ns. The use of ＂constant light power＂ drive circuit inhibited the effect of temperature ripple and increased service life.
CONCLUSION： The constant current drive circuit is fit for the case of work temperature change is smaller and time stability （LED aging problem） is not considered. Otherwise, when work temperature change is not smaller and time stability is considered necessarily, should take the constant light power drive circuit. No matter constant current drive or constant light power drive circuit, the adjusting circuit with PID control can improve the dynamic characteristics and stability precision.
出处
《中国组织工程研究与临床康复》
CAS
CSCD
北大核心
2007年第9期1692-1694,共3页
Journal of Clinical Rehabilitative Tissue Engineering Research
