The Design For High-power LED Power Supply

The global energy shortage has been an important issue we faced. The photoelectric conversion efficiency of incandescent, fluorescent and other lighting equipment that we widely used is very low. The energy used for lighting that they consume is very few, which creates the extreme waste of energy. LED are recognized as a new generation of lighting, energysaving, environmentally friendly features will lead to a new era of lighting. Currently, the drive of LED fluorescent tube, bulb light and other low-power products have tended to without power supply. But the driver of LED street lights, tunnel lights and other high-power are still using the high-frequency switching power supply.Accourding to the power level of the LED street lamp on the market, a120W LED street light driver is desiged. This program is high output voltage and low output current, thus reduces the loss of the switching elements. In the case of no need synchronous rectification, can still achieve high efficiency and reduce the current stress of the components without increase the voltage stress. In order to present the Green Lighting advantage of LED, the driver is required enfficiencly and non-polluting to the grid. Based on this, this paper uses three stages drive circuit. The first stage is boost topology. Be used to correct the power factor to reduce the pollution of the grid. The second stage is LLC topology. Be used to achieve the soft switching of main power stage to reduce the loss of switching devices.The third stage is Buck topology. Be used to make LED working on the constant current mode. There are4outputs of this driver. So there are4constant current circuits in parallel in the third stage and each output30W.Firstly, the paper introduces the significance and the working principle of the PFC, determines to select the active power factor correction (APFC), analyses the operating mode of PFC and derives and designs the main circuit parameters. Selects FAN7930C chip whose operating frequency is higher than L6563chip as the controller of APFC, so that the inductor volume is decreased. Secondly, the paper describes the working principle of the LLC resonant converter. With the FHA circuit model to conduct a detailed analysis of LLC characteristics, and completed the design of the resonant network parameters and control circuit parameters. Selects FSFR2100chip which integrates with the High-side MOS and the Low-side MOS as the controller of LLC and greatly simplifies the drive circuit. Then gives out the design of the constant current control circuit based on the Buck topology and calculates the parameters. Finally, draws the PCB of the driver and produces a prototype which is85-264VAC input and4-way600mA output. Test the prototype and gives out the key waveforms of the voltage and current, and analysesit.The experimental results shows the rationality and feasibility of the design.