The term “UPD” is not a standard protection mode like OVP or OCP. Instead, it is a diagnostic state within the MP3378E’s internal state machine.
| Cause | Solution | |-------|----------| | OVP divider tolerance stack-up | Use 0.1% resistors for R_upper and R_lower. Recalculate for 15% margin below OVP max. | | Leakage current | Ultrasonic clean the PCB with saponifier. Replace flux. Add guard ring around PROT pin. | | Mismatched sense resistors | Measure each RISET (typically 10–100Ω) to GND. Replace all with 0.5% tolerance, matched batch. | | Bootstrap capacitor | Replace C_BST (usually 100nF, 25V X7R). Place as close as possible to BST and SW pins. | | Noisy input supply | Add 10µF + 0.1µF ceramic directly across VIN and GND of MP3378E. | | Faulty MP3378E itself (rare) | Replace IC. Note: UPD is not usually a symptom of die damage unless OVP comparator is broken. | mp3378e protection pin upd
Set the over-voltage protection threshold using a resistor divider from the boost output (VOUT) to PROT. The term “UPD” is not a standard protection
Disconnect the LED+ and LED- cables from the driver board. Replace with a dummy load (e.g., 1kΩ resistor from SW to GND and a 47kΩ from VOUT to GND). This removes actual LEDs from the equation. Recalculate for 15% margin below OVP max
The MP3378E protection pin (UPD) is a key feature that ensures safe and reliable operation of the IC and the system. The UPD pin provides a mechanism for reporting protection events and updating the IC's internal registers. By understanding the functionality, configuration, and usage of the UPD pin, designers can create systems that are robust, reliable, and efficient.