The MP3385A is a step-up controller with four regulated current channels designed to drive WLED arrays for mid- and large-sized LCD panel backlighting applications. The MP3385A uses peak-current mode and PWM control architecture for system loop regulation. The MP3385A drives an external MOSFET to boost up the output voltage from a 4.5V-to-33V input supply. The MP3385A employs an I2C digital interface that can flexibly set operation and protection modes, including dimming mode, dimming current and dimming ratio, OCP, OVP, LED short protection threshold, and switching frequency. For easy application use and board debugging, the MP3385A detects and disables the unused LED strings automatically during start-up to avoid charging the output to the OVP threshold. The MP3385A achieves 1.8% current matching between each string. The low regulation voltage on the LED current sources improves efficiency and reduces power loss to achieve a higher current output. The MP3385A supports analog, PWM, and combined analog and PWM dimming modes to meet different application requirements. Full protection features include over-current protection (OCP), over-temperature protection (OTP), under-voltage protection (UVP), over-voltage protection (OVP), LED short/open protection, and inductor/diode short protection. The MP3385A is available in a QFN-20 (4mmx4mm) package.