Design and test about tandem and adjustable constant current tube driving laser

The accident damage of the present semiconductor laser constant current source often damages the expensive semiconductor laser directly.In order to protect the laser working normally and save the complex high-speed protection circuit,the synchronously adjustable constant current tube tandem type laser constant current source is designed.It adopts two constant current tubes to be adjusted synchronously.Both of them can be kept working in the constant current area,and their output currents are equivalent to a large extent in the whole adjustment range.When the laser is working in 400mA,the current aggrandizement caused by the momentary damage of any transistors is only 15mA.It is concluded that the laser constant current source made of the synchronously adjustable tandem constant current tube has high constant current characteristic and protective property.