The Research And Design Of A Backlight LED Driving Chip

Because of the advantages of long life for use and low power dissipation, white LED provides a perfect backlight method. Most of white LED drivers consist of either current controlling mode or voltage controlling mode. Current controlling mode white LED driver is hotspot because of its good line regulation and load regulation. This dissertation designs a current mode switching regulator used in driving white LEDs for display backlight of variety of portable facilities. The part operates over a wide input voltage range, from 2.7V to 30V. And adopt BOOST circuit framework. The chip integrated power switch and the build-in thermal protection to prevent the chip over heat damage. This dissertation firstly introduces the developments and investigation significations about LED driving chip in the intestine and international. Follow expound white LED's basic principle and DC-DC transition circuit's realization mode. Then build chip's whole truss,and design module of chip's inner and the connect of them,and design chip's pin. Whereafter design and analyze the actualize circuit and the function of each module. Finally simulation the chip of type applied. Simply introduce BJT's layout and technics. Design the layout of each module. The sub-block and whole-chip simulation results with HSPICE indicate that the IC has achieved its function target and the expected electrical characteristics,also have validated the circuit's function.