| Under the trend of energy-saving and environmental protection, light-emitting diode(LED) lighting came into being. LED lighting with its high luminous efficiency, extremely long life time, lower price and more attractive appearance, gradually entered people’s vision.From the beginning of 2013, the market of LED lamps became very hot. Of course, the competition is very fierce, too. In order to win in the fierce competition, higher performance and reliability, and lower prices sought by various manufacturers.Currently, LED’s price has been very low. It is limited to continue to cut the price. So, if you want to reduce the price of LED lamps, the method most likely to be achieved through the LED driver circuit to start. In order to reduce the cost and ensure the reliability of the drive circuit, it has become a trend that the internal circuitry of the driver and the application circuit should be as simple as possible.Traditional LED driving circuits are based on AC-DC converters, using the application circuit with a slight adjustment for the characteristics of the LED load. This method not only bulky, difficult to be installed in the limited space of lamp shell and limits its applications, but also costly. Its cost on the one hand due to overly complex application circuit, on the other hand, due to many features of the chip has not been fully utilized. In addition to higher costs, their security of traditional LED drivers is also debatable because the driver is not customized for LED lighting application.This paper firstly introduces the trend of the development of LED lighting driver, based on high accuracy and reliability, an especially tailored switching driver XD1413 is proposed for LED lighting application. And secondly, an equivalent structure is given from the light-emitting principle view of LED. Based on the understanding of the characteristics of the load to drive, the basic principles of various switching converters are introduced. For the current sensitive characteristic of LED, a constant current control method for XD1413 is proposed to accurately control the current flowing through the LED. Through the whole loop stability analysis and design to ensure that within a 85 V AC~265V AC large input voltage range, the system can achieve ±3% output current accuracy. Perfect protection circuits, such as over voltage protection, over current protection, and over temperature protection, ensure the security in a variety of complex environments. Further, in the design process of the XD1413, the effect of electromagnetic interference has been taken into consideration. By the periodic variation of internal oscillator frequency with time, the electromagnetic interference energy is uniformly distributed within a certain range of frequency, so that the design of the periphery of the application circuit can meet the electromagnetic compatibility requirements more easily.Based on the design of a 1μm 5V/20V/500 V BCD process, the functions and electrical characteristics of XD1413 are verified with the simulation tool Hspice. Through the analysis of simulation results, it is verified that in the context of an extremely streamlined application circuit and internal structure, the XD1413 circuit can achieve a high accuracy and security witch fulfills the design requirements. |
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