This paper deals with a wide‐range dimming control of a LED backlight for avionic AMLCDs. The design and implementation of a digital dimming controller using a current‐controlled buck converter and light sensor feedback are presented. The proposed system provides a brightness control capability in a wide dimming range of from 200fL to 0.05fL (4,000:1), which is suitable for avionic displays. The experimental results are provided to verify the control performance.