Energy-Recycling (ER) Technique for a Direct-Lit Intelligent Power Management Backlight Unit (BLU)

A field-sequential-color (FSC) liquid crystal display (LCD) technique with a direct-lit red, green, and blue LED backlight driver is proposed to achieve low weight, thin, perfect image quality, and low-power consumption of LCD television. The FSC technique performs a pseudorandom color sequence in the spatial and temporal domains to reduce color-breakup and motion-blur effects. The direct-lit RGB-LED backlight driver increases brightness, contrast, and uniformity due to the removal of a color filter. In this paper, the proposed FCS-LCD controller uses a single LED driver to switch the driving voltage alternatively between 36 V for driving 12-series G- or B-LEDs and 24 V for 12-series R-LEDs. The proposed energy-recycling technique can harvest the extra energy when the driving voltage switches from 36 to 24 V. Experimental results show that energy saving is higher than 17% of the conventional driving method.

[1]  Ke-Horng Chen,et al.  Switching Loss Calculation (SLC) and Positive/Negative Slope Compensation Dynamic Droop Scaling (PNC-DDS) Technique for High-Efficiency Multiple-Input–Single-Output (MISO) Systems , 2009, IEEE Transactions on Power Electronics.

[2]  Fred C. Lee,et al.  Small-signal modeling of average current-mode control , 1993 .

[3]  Ke-Horng Chen,et al.  Mixed Color Sequential Technique for Reducing Color Breakup and Motion Blur Effects , 2007, Journal of Display Technology.

[4]  Ke-Horng Chen,et al.  A Charge-Recycling Buck-Store and Boost-Restore (BSBR) Technique With Dual Outputs for RGB LED Backlight and Flashlight Module , 2009, IEEE Transactions on Power Electronics.

[5]  Simon S. Ang.  Power-Switching Converters , 1995 .

[6]  S. Mikoshiba,et al.  44.4: RGB‐LED Backlights for LCD‐TVs with 0D, 1D, and 2D Adaptive Dimming , 2006 .

[7]  In-Hwan Oh.  A single-stage power converter for a large screen LCD back-lighting , 2006, Twenty-First Annual IEEE Applied Power Electronics Conference and Exposition, 2006. APEC '06..

[8]  Robert W. Erickson,et al.  Fundamentals of Power Electronics , 2001 .

[9]  Brian H. Berkeley,et al.  P‐51: Advanced Method for Motion‐Blur Reduction in LCDs , 2005 .

[10]  Hyun Ho Shin,et al.  P-25: Acceptable Motion Blur Levels of a LCD TV Based on Human Visual System , 2006 .

[11]  Kazuhiko Ukai,et al.  25.2: Distinguished Student Paper: How Color Break‐Up Occurs in the Human Visual System: Mechanism of Color Break‐Up Phenomenon , 2006 .

[12]  Ke-Horng Chen,et al.  Zero current detection technique for fast transient response in buck DC-DC converters , 2008, 2008 IEEE International Symposium on Circuits and Systems.

[13]  Qadeer Ahmad Khan,et al.  A single supply level shifter for multi-voltage systems , 2006, 19th International Conference on VLSI Design held jointly with 5th International Conference on Embedded Systems Design (VLSID'06).

[14]  R. D. Middlebrook,et al.  Modeling current-programmed buck and boost regulators , 1989 .

[15]  Ke-Horng Chen,et al.  Boost DC-DC Converter With Fast Reference Tracking (FRT) and Charge-Recycling (CR) Techniques for High-Efficiency and Low-Cost LED Driver , 2009, IEEE Journal of Solid-State Circuits.

[16]  Huang-Jen Chiu,et al.  LED Backlight Driving System for Large-Scale LCD Panels , 2007, IEEE Transactions on Industrial Electronics.