Changing LED into Gold: SEPIC Converters Tame Automotive Battery Fluctuations (.PDF Download)
Use of electronic displays continues to expand in automotive applications (Fig. 1). Behind the wheel, they’re replacing individual electromechanical instruments as well as complete instrument clusters. In infotainment, applications include radios, navigation displays, and headrest displays for rear passengers.
Augmented reality (AR) is another application. A head-up display superimposes an image on the windshield to give the driver key information while they’re concentrating on the road ahead.
1. The automotive dashboard of the future will combine LCD and HUD technologies. (Source: TI Blog: “The sleigh of the future with DLP technology”)
Automotive displays such as these predominantly use liquid-crystal-display (LCD) technology. The illumination source is provided by multiple light-emitting diodes (LEDs) placed around the edge of the flat-panel display screen. This arrangement is known as an LED-backlit LCD.
The number of LEDs depends on application parameters such as the required brightness, the width of the display, and its resolution. The trend is toward displaying more information with larger, higher-resolution units. A 12-in. display with FHD (1920 × 1080) resolution, for example, might require up to 40 LEDs for a brightness of 1000 nits (candelas per square meter).
The LCD panel manufacturer determines the LED configuration. A single string of many LEDs in series is one option, but a more usual configuration is several shorter series strings arranged in parallel.