If any LED pin is shorted to ground, the internal current sink tries to pull maximum current. If the voltage at the LED pin falls below a specified operational minimum (short-circuit threshold) while the boost is running, the MP3378 detects this fault.
The integrated buck converter includes its own Over-Current Protection (OCP) with Hiccup Mode . In a short-circuit event on the buck output, it will periodically attempt to restart, significantly reducing power dissipation during the fault. Technical Summary Table Protection Mechanism Pin Involvement Backlight Safety Over-Voltage (OVP) OVP Pin (via resistor divider) String Integrity Open/Short LED Protection LED1 - LED4 Pins System Power Buck Over-Current (OCP) Internal Sensing (Hiccup Mode) Thermal Safety Recoverable Shutdown Internal Die Temperature Sensor MP3378E - Monolithic Power Systems mp3378e protection pin upd
The MP3378E uses latch-off (not auto-recovery) for UPD faults. Once triggered, only power cycling VCC or toggling the EN pin will reset the IC. If any LED pin is shorted to ground,
If your MP3378E is entering a protection state (shutting down shortly after power-up), check these common failure points: In a short-circuit event on the buck output,