Design And Implementation Of Fast And High Power LED Driver Chip

With the increasing energy crisis and environmental pollution in modern society,the "high-quality development" of the economy has become the theme of the times since the 19 th National Congress of the Communist Party of China.The development of LED lighting products has been supported due to its characteristics of superior luminous performance,high efficiency,energy saving,environmental protection,etc.LED is a special diode whose core structure is PN junction.Due to the nonlinear volt-ampere characteristics of the PN junction,a constant current chip is required as its driver to ensure the stability of the LED light emission.With the continuous expansion of the lighting market,LED devices tend to develop higher power,higher reliability,and lower power consumption,which also brings new opportunities and challenges to the development of LED driver chips.The quality of the LED driver chip determines the performance indicators such as the quality,stability,and lifespan of the LED.To design high-performance LED driver chips for different application is an important part of the development of the LED industry.This article conforms to the market demand trend to design a fast,high-power LED driver chip.First,the light-emitting principle and characteristic parameters of LEDs are introduced.According to the parameters proposed below,different LED power supply driving methods are compared in detail,the topology of Buck type DC-DC is selected for research.To meet the characteristics of fast startup of the chip and ensure the output accuracy,this paper adopts the segmented control mode.The chip starts up in the RBCOT mode first,and then works in the mode after the loop is established.To ensure that the chip can output high power and save power consumption,the core driver circuit is designed to high d V/dt immunity,and a transient enhancement circuit is introduced.To verify the feasibility of the design,this article also provides with the simulation verification results of the circuits under the 0.18?m 60 V BCD process.The simulation results show that the maximum switching frequency can reach 2.2MHz,and the current can output 3A stably.At a frequency of 309 k Hz,the duty cycle of the power transistor can reach 95.7%,and the maximum output power can reach more than 130 W.This chip has the following advantages: high chip integration since 3A NMOS power transistor is integrated inside;wide voltage input range(6V?48V);wide operating temperature range(-40??125?);high d V/dt immunity;low power consumption of the drive circuit;adjustable switching frequency from 309 k Hz to 2.2MHz;high maximum output power.To improve the reliability of the system,protection circuits such as overcurrent protection circuit,gate drive undervoltage protection circuit,and switch voltage negative voltage detection circuit are designed.The chip can be used in various fields,such as automotive electronic lighting,home decorative lighting,backlight lighting.