Study On Digital Control System For Laser Power In Accelerated Life Test

According to the need of the test, in the process of accelerated life test of He-Ne laser, current has been used as the accelerated stress, so the process of accelerated life must be take in large current, which requires a larger current scope. There will be weak power or even no light occurs in larger current, for the continuation of accelerated life test, it needs to be fixed at conventional current while testing the power. The paper has studied on digital control system for laser power for the question of current regulation.In the paper, while testing the reliability of straight He-Ne laser, a device has been used successfully, which could alternately convert dual current in single power. A control system has been designed, in which pulse distributor CD4017 and timing controller LM555 are the core, they combine with FET circuit so that eight laser powers could alternately convert between the conventional current and accelerated current. The current regulation tends to quasi-continuous if the digital potentiometer X9241 has replaced the potentiometer, so it has more advantages to complete the test.In the paper, while testing the reliability of ring He-Ne laser. A more precise digital potentiometer X9312 than X9241 has been used in current regulation. 12-bit A/D converter chip TLC2543C will convert the power at first, then microprocessor analyze the light-power, it manipulates the X9312 to complete current regulation. At last the function of threshold current test, the best of current test and the adjustment of accelerated current have been completed.