LED Driver Current Sink Control for LCD Backlight Uniformity

The patent divides the LED backlight system into N independent LED columns, each with its own current driver circuit. This segmentation allows independent control of current in each column, compensating for manufacturing variations in LEDs and achieving uniform current distribution across all columns, thereby resolving the contradiction between device complexity and current uniformity.

The patent implements local current control by providing each LED column with an individual current driver that can independently adjust and compensate for current variations. This local quality approach ensures that each column receives precisely controlled current tailored to its specific LED characteristics, achieving uniformity without requiring a complex centralized control system.

The patent employs periodic pulse width modulation (PWM) signaling to control the current drivers. By using periodic on/off switching with variable duty cycles rather than continuous high-frequency switching, the system achieves current balance and compensation while significantly reducing energy consumption and heat generation compared to conventional high-frequency switching techniques.

The patent implements dynamic current control where each current driver can independently adjust its output based on feedback or pre-programmed compensation values. This dynamic adjustment capability allows the system to achieve and maintain current balance across LED columns without requiring excessive energy input, as the control is optimized for each column's specific characteristics.

The patent designs the current driver circuits with universal functionality, where each driver can serve multiple purposes: providing current to its associated LED column, compensating for manufacturing variations, and responding to control signals. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity while achieving current uniformity.

The patent implements self-service current compensation where each current driver is capable of independently adjusting its output based on predetermined compensation values or feedback from its own LED column. This self-service capability eliminates the need for complex centralized control mechanisms, allowing individual columns to self-regulate and achieve uniformity without proportionally increasing overall system complexity.

The patent incorporates feedback mechanisms in the current driver circuits, where the actual current delivered to each LED column is monitored and used to adjust subsequent control signals. This feedback control ensures that energy is efficiently utilized by delivering precisely the required current to each column, minimizing energy loss while maintaining relatively simple driver circuit architecture through intelligent control algorithms.

The patent optimizes energy efficiency by dynamically changing control parameters such as PWM duty cycles and switching frequencies based on the specific requirements of each LED column. By adjusting these parameters rather than using fixed high-power driving modes, the system achieves better energy efficiency while keeping the driver circuit structure relatively simple and avoiding the need for complex power management hardware.