小型液晶顯示器背光led驅(qū)動系統(tǒng)

　　把一個系統(tǒng)級的方法來驅(qū)動LED液晶背光是小格式。

　　發(fā)光二極管（LED）技術(shù)被廣泛應用于為電池供電的小型液晶顯示器（LCD）中的像素提供照明。發(fā)光二極管發(fā)出的白光通過偏光鏡傳遞到LCD，在那里液晶可以被阻擋或衰減，并發(fā)送到RGB彩色濾光片上以產(chǎn)生彩色光。

　　Figure 1 shows a system-level view of a backlight LED driver which consists of a DC/DC converter and one or more regulated current sources. Moreover， RGB-LED-based backlights require a temperature based feedback control， which translates to a much higher cost than white-LED-based backlights. How much PCB area can be used？ What features are needed？ How much power will the system consume？ Answering these questions can guide the designer in the selection of the appropriate backlight LED driver.

　　DC/DC converters for LED backlight

　　In portable applications with a single-cell Li-Ion source， the sum of the voltage drop across the white， green， or blue LED and the current source can be lower or higher than the battery voltage. This means that， whereas a red LED can be powered directly from a single-cell Li-Ion battery， a white， blue， or green LED requires the battery voltage to be sometimes boosted.