is a combined White LED (WLED) controller and buck converter often used in monitor backlighting. Its protection features are primarily centered around the OVP (Over-Voltage Protection)
: Monitors the input supply. If the input voltage falls below the UVP (Under-Voltage Protection)
Start: No backlight ↓ Measure PROT pin voltage (with BL enabled) ↓ PROT = 0V? ──No──→ Check EN/PWM/VCC/REG5 ↓ Yes PROT stuck LOW (latch mode) ↓ Remove power → Disconnect LED connectors ↓ Apply power → Measure PROT ↓ PROT now HIGH? ──Yes──→ Fault is in LED strings (open/short) ↓ No PROT still LOW → Check external pull-up, C_PROT, or IC damage ↓ Replace IC if pull-up and VREG5 are correct but PROT remains low mp3378e protection pin
Unlike some older ICs with a single dedicated "PROT" pin, the utilizes several specific pins to monitor different failure modes. The most critical "protection-related" pins include:
In large displays, multiple MP3378E ICs are used. You can wire all PROT pins together (open-drain wired-OR). If any IC detects a fault, it pulls the common line low, shutting down all drivers simultaneously. This prevents uneven backlight brightness during a fault. is a combined White LED (WLED) controller and
Some designers add an external 10kΩ pull-up to 3.3V to improve noise immunity. This prevents the IC from pulling the pin low because the external source fights the internal MOSFET. Result: The IC detects a fault, but the pin stays high, so the MCU never sees it.
According to the official MPS datasheet , the chip includes the following safeguards: Protection Type You can wire all PROT pins together (open-drain wired-OR)
If you have a specific fault waveform or board schematic, share it for a more targeted analysis.
In the MP3378E datasheet and typical application schematics, the protection functionality is often centralized around a specific pin logic, usually labeled (Protection). This pin serves as the system’s "sentry." It is an input pin that monitors the status of external protection circuits.
