Laser Diode Driver And Modulation

A new laser diode driver based on a high-integrated laser driver chip is designed in this paper. This driver realizes the common work of a laser diode and makes it emit laser with stable power. Furthermore, it can set the output laser power and modulate the laser signal by setting the modulation signal.First of all, this paper introduces the principle and characters of laser diode and analyses the necessity of designing a special driver power with high quality by referring a lot of domestic and foreign references.Then the power with soft-start function and low ripple is designed according to the demand of a laser driver and relevant technology. It makes a laser diode work drive by iC-WKN and emit stable laser. The fluctuation of the laser diode's temperature impacts the output power seriously. In order to reduce the influence of the laser diode's heat effect, a thermal control device is designed to make laser diode work under a stable temperature.The principle and application of iC-WKN is researched adequately. A signal modulation circuit including D/A converter and chip computer is designed. It can generate high-stable and linear current signal and utilize Butterworth low pass filter to eliminate the noise and ripple in the signal. According to the different functions of different pins, this circuit can modulate and control the output power of the laser diode and modulate the laser signal, which makes this laser diode driver have more valuable application.In the last part of the paper, the feasibility of the theory is validated by experiment data. It proves that the laser diode driver designed in this paper can work under our satisfaction and it can be applied in vision system of robots as a very good interfered light source.