A Backlight Power Management Framework for the Battery-Operated Multi-Media Systems

Dynamic Luminance Scaling (DLS) reduces the backlight power consumption of color TFT LCD while maintaining the image brightness or contrast. This paper presents extended DLS (EDLS) as a framework for the backlight power management of the transflective LCD panels. The EDLS framework switches between DLS and Dynamic Contrast Enhancement (DCE) depending on the panel mode, which may be transmissive or reflective, and the remaining battery energy. This paper analyzes the energy gain from the backlight and the overhead of EDLS in view of application transparency and hardware-software trade-offs, which visualize the systematic approach for the efficient EDLS implementation. As a result, we demonstrate a compact EDLS system that relies on approximate histogram construction, thereby, achieving a significant reduction in the area and power overhead of the EDLS system with negligible loss of the energy savings in the backlight system. Overall, the compact EDLS system results in an average of 25% power saving in the backlight system for still and moving images, without any modification of the existing applications.