Design And Research Of Linear Constant Current LED Driver Chip

LED as a new generation of green light, is currently a hot research field of lighting, with more and more extensive application, the market for LED application proposes a series of requirements, for example, low cost, high efficiency, high power factor value and easy dimming. With further research, the way of LED driver more diverse, and performance more excellent. In recent years, sectional linear constant current LED driver technology has been developed rapidly, and great application value has been showed.Based on the original single-switch linear constant current LED driver, I present a high order sectional linear constant current LED driving circuit structure. I design a LED driver chip which based on the 0.35 um 700V high voltage BCD process. I discuss various kinds of LED driver technology deeply in this paper, and then determine the high-order sectional linear constant current LED driver. Then I research the overall architecture of the chip, and design bandgap reference circuit with temperature compensation, without increasing the complexity of the structure under the premise of the circuit, so that over-temperature protection is better; the same design with a line voltage compensation reference source circuit, which can effectively inhibit voltage flash, making power within a certain voltage range essentially unchanged. I based on the set targets, design and simulate of the whole circuit, layout design and post simulation at the same time, and the sample under test.The actual test results show that: the chip driver power reaches 20 W, the drive efficiency can reach 95%, compared with the existing chip were increased by 25%, 10%; at the same time in the guarantee that the PF value is 0.85 basis, to effectively restrain the voltage flash, make sure that each 10 V power changes make less than 0.1W. This study tests show that the linear constant current LED driver chip on several performance metrics beyond traditional AC/DC switching power supply and sectional linear constant current driver chip.