Current Mode Wled Boost Constant Current Driver

The development of semiconductor physics has been promoting white light emitting LED (WLED) display and backlight technology. WLED high luminous efficiency and environmentally friendly features have WLED be the best choice for backlighting and lighting in the near future. The forward voltage drop is high for WLED. WLED brightness is sensitive to the applied forward voltage between the anode and cathode of WLED. For certain brightness, different WLEDs have very different forward voltage requirements. The above mentioned reasons lead to call for efficient, uniform brightness of power management ICs to drive the WLEDs. The current mode inductive step-up series drivers have high efficiency and uniform brightness characteristics. Current sources have great brightness control characteristics. Therefore the combination of them has become the universal application of the backlight driver IC solution.This thesis studies the current-mode pulse width modulation switching supply with inductor and designs a high efficiency boost switch controller IC for WLED drivers with adaptive output voltage and adjustable output current inductive boost switch controller IC for WLED drivers. It can power up to 20 high brightness WLED backl ight. The current adjustments range is from 36mA to 55mA. The mismatch between two strings can be less than 2.5%. The input voltage varies from 7V to 15V. The PWM controller frequency is 1MHz. The chip is in DFN 3mmX3mm 12L package.The thesis starts from the introduction of the high voltage CDMOS process used in the design. It provides the principle of switching converter and peak current mode technology, and the principle of small-signal analysis of current mode switching converter. Meanwhile it begins to set a model for the total macro system for specifying the parameters of the macro system and then expand the specific sub-block design hierarchically. At last, design the top cell view with detailed sub-blocks and simulate to verify the IC stability and performance. Keywords:WLED driver, Boost, inductive step up, current mode Classification Code:TN4...