In addition, it provides a dual dimming solution with Analog and PWM (Pulse Width Modulation) for efficient and stable LED dimming, which reduces power consumption and helps achieve a high contrast ratio in UHD TVs. Analog dimming adjusts the brightness of the LED by controlling the amount of current flowing through the LED in a linear manner. With this solution, the LED colour changes when the current fluctuates. By contrast, PWM dimming is a method to minimize the colour change. MagnaChip’s new 3-channel BLU LED Driver is designed to selectively use analog or PWM dimming according to the image signal, thus providing the solution to realize high contrast ratio and power efficiency. The BLU LED driver also provides for high current accuracy within ±1% tolerance by using the average mode of the current control technology. For low PWM dimming, it operates at up to 480kHz to elaborately control the current in the dark area of the image with a narrow pulse width. The chip provides various circuit protection functions, including short-circuit protection and under-voltage lockout, over-duty protection to keep the PWM duty ratio (on/off ratio) constant. It also provides for current-sense resistor short protection, which prevents over-current from flowing into a specific area of the circuit.
MagnaChip Semiconductor – www.magnachip.com