Semiconductor Laser Drive Circuit Design

The most prominent advantage of semiconductor laser is a small size,light weight,reliable operation,less consumption and high efficiency,so that it has been widely used in manufacturing,telecommunications,cleaning,etc.Semiconductor laser stable output and the stability of the injection current depend on the operating temperature of the semiconductor laser.Therefore,designing a kind of laser diode driver circuit which has high stability and high efficiency is necessary.This thesis introduces the working principle and characteristic of the semiconductor laser,pointing out the conditions of the semiconductor laser outputting stably,thus definite the main requirements of the power circuit.This design of the laser driver circuit is divided into three parts.:a power conversion circuit,drive current control circuit,laser protection circuit.Power conversion circuit is switch mode supply power,the low voltage and constant voltage output is converted into electricity used by laser.Drive current control based on negative feedback principle,completed by the most commonly used integrated operational amplifier and constant current source circuit composed by power MOSFET.Laser temperature protection circuit based on closed-loop control similarly.It collects temperature by industrial temperature sensors to,through feedback parameters,after adjusting circuit working condition,so as to maintain the normal work temperature of the laser.Finally,do the performance testing on the developed semiconductor laser driver power supply system.Switching power supply can complete small voltage and large current output,constant current source driver can smooth the output design of the ladder current,and stable currernt output,protection circuit can startup normally according to the designed parameters to protect semiconductor laser.