The Design Of Semiconductor Laser Driver Based On FPGA

This paper is mainly engaged in the semiconductor laser driver based on FPGA design of power. As a new kind of semiconductor laser has the advantages of small size, light weight, high efficiency, low power, can be directly modulation and so on a series of advantages. In biomedical fields, military communications, semiconductor laser is widely used. Since the 1990s, the output power of semiconductor laser has improved significantly. In the aspect of domestic output device has reached 600W samples, and foreign kilowatt of high power laser diode has commercialization, we can see from the advanced world level, we still have certain disparity. In addition, foreign design USES power module design, while in China directly is still a division element. So far, with foreign modular power will develop in China is the fundamental direction for future development.Based on FPGA power management system is the important part of the paper, according to the actual needs of the company, Altera Cyclone series of EP1C6Q240 chip. In this article, highlighting the FPGA with a number of touch converter, ADC, keyboard, display, digital potentiometer such as the connection, FPGA with these devices have completed management system. Realized the power constant current control, temperature control and data display. The high-precision current of laser diode is realized in the controlling part by using the technology of FPGA, at the same time, the temperature control of laser diode is realizede in the controlling part by using the FPGA and the temperature sensor and soon, these played a role in the protection of the laser The system integrated into the monolithic control of internal FPGA chip. So it can greatly reduce the number of external circuits which process periphery expand and improve the system integration, reduce the complexity of the external circuit layout to the alignment and improve the anti-jamming capability. At last, the design plan and the flow chart of the software which based on VHDL are introduced, and in accordance with specific design features of the corresponding module for the smooth development of the next step of work laid the foundation.In a semiconductor laser driven by simulation technology in the power supply most of the hardware circuit and control, the low automatic degree complex. The circuit is complex and low degree automation. Although the driver of semiconductor laser diode based on SCM can solve the question of signal mode and realize the stabilization driver by more mode, but the stability, the degree of distinguish and the precision of temperature controlling of the system is needed to improve further. This design tried to adopt a combination of hardware and software and use the technology of FPGA to realize the digitizing controlling. At the same time, it can optimize the design of circuit and increase the reliability of the system. Consequently the driver has some excellence such as high degree intelligence, strong anti-jamming ability, high precision temperature controlling, high power stability and no damage to laser diode and so on, produce IP Core of LD driver which it self-owned intellectual property rights to apply it to a good many fields in China.The top-down method was adopted in the design. It can be divided into constant current source, protecting-circuit, anti-surge circuit, analog-digital converter and digital-analog converter, the peripheral power circuit et al. It is easy to expand and update for the system because of the programmability of FPGA. Not only saves the cost of the hardware, but also has the advantages of flexible, easy to maintain. Main control loop design is the core of this article. Through the master circuit design, semiconductor laser driver power supply to achieve the required constant current output, but also enables the control voltage 0~5V and the flow through the LDA's 0~50A continuously adjustable steady flow source to build a linear correlation in order to adapt to different specifications of semiconductor laser arrays needed for the operation, that is, the system achieved the requirements of semiconductor laser output 40A. Through the driving power reference source is designed to provide precise control voltage 0~5V, in order to achieve constant current output of 0~50A. Over-current protection circuit designed to drive power through the over-current protection circuit design, can make laser driver power supply to avoid damage to surge current protection of lasers. Design of laser temperature protection circuit by the temperature protection circuit, you can eliminate the damage of high temperature on laser.Using Pspice software to control loop simulation analysis, the feasibility of the conclusion: The drive power is stable and reliable to meet the requirements. The final adoption of the semiconductor laser models were tested and data analysis, in order to verify that the drive power performance, at room temperature 25 degrees Celsius when the use of drive power to the semiconductor laser model-driven, continuous 1 hour, every five minutes to conduct a test, in the Boot drive power within 20 minutes of work in this accurate and stable over time, increasing the error occurred, at work 1 hour later, the error in the 0.2A, consistent with design requirements, and errors are analyzed.As a new kind of semiconductor laser has the advantages of small size, light weight, high efficiency, low power, can be directly modulation and so on a series of advantages. In bio-medical, military communications in areas such as semiconductor lasers have a wider application. Set out the contents of this article can be achieved with independent intellectual property rights of the semiconductor laser drive circuit IP core, in order to meet the domestic application of many other fields. The design of hardware and software used in power within the combined approach, using FPGA technology to achieve digital control, so that drive power with a high intelligence and anti-interference ability, temperature control, high precision, high stability power supplies for lasers without damage and so on. The whole circuit is decomposed into master current source circuit, over-current protection circuit to prevent the surge hit the circuit, temperature protection circuit and digital-analog and analog-to-digital conversion circuit and a series of sub-circuit. The experimental verification of these circuit stability, in line with current source design. In the circuit design process, there are many deficiencies in the learning process in the future talk about continuous improvement.