The is a integrated circuit that combines a 4-channel White LED (WLED) controller and a high-efficiency synchronous buck converter into a single TSSOP-28 EP package. Technical Summary: MP3378E Protection Pin (OVP)

The protection architecture of the MP3378E is designed to monitor three critical failure modes: LED open circuits, LED short circuits, and power component (inductor/diode) failures.

Understanding that the shuts down for a reason is key to fixing it. The protection circuitry is robust, designed to keep the panel safe, but it can be sensitive to aging LED backlight strips.