The Design Of The High-power LED Digital Drive Power Supply

Energy crisis and environmental pollution problem has become a bottleneck restricting the development of global economy, and the lighting electricity accounts for about 20% of world energy consumption. LED because of its environmental protection, clean, long life, energy saving, and many other advantages becomes the star of the lighting business. LED cold light source is driven by low voltage DC, its performance is restricted by environment. The driving power supply quality is the key to affect the reliability of LED products. In this paper, according to the characteristics of the LED working current, design a LED digital drive power supply which can communication with the outside world and adjustable output current.The paper introduces the basic principle, the advantages of LED lighting emitting and application of the status, as well as the broad prospects of LED lighting; After many considerations and calculations, this paper choose the digital signal processor DSP(TMS320F28027) as the master control chip, and through the PID adjustment, realize the power of constant current output. The power system communication with the outside world, adjust the PWM duty cycle of the output, change the size of the output current.In view of the market demand, this paper puts forward the design requirement of 100 w high power LED. Power input is 220 v ac,and the output current is adjustable 0 to 3A and constant-current. After comparison and consideration, fly-back topology is selected as the DC/DC converter. The design of LED digital drive power supply includes hardware design and software design. Hardware design includes control circuit, power circuit, the input protection, EMI circuit and auxiliary power circuit, this paper introduces the working principle of the hardware circuit,the circuit of each components selection and the design of the transformer,also illustrates the main points of the power supply PCB design; The software system includes a main program, PID control program,ADC program, PWM program and communication program. Software design introduces the principle and design process of each module, and gives the key code of the module program.Finally, the power supply was tested and analyzed. First of all, made some basic debugging, to ensure correct basic circuit; Furthermore, each function module is tested and analyzed, to ensure the normal operation of each module. Finally test of the whole machine. the experiment shows that the power running stability, meet the design requirements.