Design Of High-power LED Constant Current Driver Chip With Wide Input Range

Nowadays,the energy crisis is an urgent problem for all countries in the world.Among them,electricity plays an important role in daily life.Saving electricity is an effective means of saving energy.Among the electricity consumed in the world,lighting electricity accounts for a large proportion.Compared with traditional lighting,LED lights save energy because of their high luminosity,high performance and long life.Therefore,energy is scarce,LED lighting is very popular and its application prospects are very extensive,the most critical module in the application is the control chip.Therefore,based on the wide application market of LED control chips,a wide input range high power LED constant current driver chip is designed in this paper.The chip has the advantages of low turn-on voltage,high output current accuracy,wide application range and high conversion efficiency.On the basis of common BUCK circuit control methods,a constant on-time control mode is selected,and an external sampling resistor is used to control the internal on-time timing module to drive the switch tube to achieve constant current output.At the same time,synchronous rectification technology is added.First,this paper proposes the overall circuit architecture and application circuit of the system,and performs circuit design and simulation verification on the voltage reference module,high-voltage LDO module,gate voltage bootstrap module,and on-time module inside the system.The innovations are:using the sub-threshold current to compensate the high-order temperature characteristics of the voltage reference,so that its output accuracy reaches 1.427ppm/℃,improving the level shift circuit,and accelerating the speed of potential conversion.The dead-time control circuit is introduced to make the conversion efficiency up to 98%.The chip of this design has an embedded high-voltage LDMOS.The design and simulation verification of the overall circuit is based on a Taiwan VIS company0.5μm high-voltage BCD 40V process.It allows an input voltage range of 6V to 35V,and can achieve a constant current output of 720m A.It allows maximum output current of 1A,this circuit can drive 1～9 LED lamps in series,the voltage drop of each LED lamp is 3.2V,when the input voltage is 35V,and the load is 9 LED lamps,the working frequency is 280 KH_Z at the same time,The dimming mode and the protection circuit enable it to meet different applications and have a broad market prospect.