Reducing radiated EMI in WLED drivers

All inductive switching converters cause radiated electromagnetic interference (EMI) that is directly proportional to output power. As the size of mobile phone displays increases to accommodate more features, the backlight driver's increased output power results in more EMI. Factors at each design step, from driver-IC selection to board layout, impact the WLED driver's EMI. Therefore, minimizing the WLED backlight driver's radiated EMI so that it does not affect other systems is a major concern for manufacturers of both the backlight driver IC and the mobile phone.