Mp3378e Protection Pin Upd ~upd~ 🎯 Secure
Monitors individual channel voltages. A shorted or completely open LED string skews the expected voltage, forcing the IC into latch protection. Current Sense Feedback
PROT pin oscillated at 1.0V–1.3V at 2Hz. VOUT pulsed to 42V (target 48V), then dropped to 0V. No channel current.
), the OVP resistor divider may be damaged, or the output capacitor is open. Step 3: Check LED Strings (LED1-4)
A common field issue occurs when the . During start-up, the boost output rises. If the OVP divider reaches 2.0V before the PROT pin finishes its soft-start ramp (0→0.8V), the IC will falsely trigger OVP and shut down. mp3378e protection pin upd
+-----------------------+ | MP3378E | | TSSOP-28 | | | ------> OVP (Over-Voltage) | ------> COMP (Compensation) | ------> ISET (Current Set) | ------> EN1 (WLED Enable) | ------> EN2 (Buck Enable) | | | +-----------------------+ OVP (Over-Voltage Protection) Pin
is triggered when the MP3378E detects a potential fault condition (e.g., rising output voltage or current mismatch) but the expected protection response (e.g., PWM dimming cycle termination or soft-start reset) does not occur within a predefined timing window. In essence, UPD indicates that the protection pin is receiving a fault signal under the threshold for normal shutdown, creating an ambiguous logic condition.
Connects to an external resistor divider from the output to ground; if the sampled voltage exceeds the internal latch threshold, it stops the switching cycle. Enable & Loop Compensation Monitors individual channel voltages
The for monitoring the boost converter’s output. By attaching a resistor divider network from the output rail to this pin, the IC samples the stepped-up voltage. If an LED channel opens, the output voltage spikes. When the OVP pin exceeds its pre-programmed threshold, the IC stops switching to prevent over-voltage destruction. 2. LED Channel Feedback (LED1 through LED4 Pins)
The MP3378E uses a resistor divider from VOUT (boost output) to the PROT pin. If the divider is incorrectly calculated or damaged:
Replaced both divider resistors with 0.1% parts (124kΩ upper / 5.23kΩ lower for 48V output). PROT pin locked at 1.25V, backlight restored. VOUT pulsed to 42V (target 48V), then dropped to 0V
The protection features are not just abstract concepts; they are tied to specific pins that require careful consideration during design and debugging.
Cycle-by-cycle over-current protection for the external MOSFET.