: The OVP pin monitors the output voltage of the step-up converter via a resistor divider.
[System powers on] | v [PROT pin ramps 0V → 0.8V?] ---No---> [Check C_PROT soldering; replace with 22nF-100nF] | Yes | v [VOUT rises. PROT pin hits 2.0V?] ---Yes---> [OVP trip. Increase C_PROT or lower output target] | No | v [Backlight turns on. Stable operation.]
Once diagnostics point to the underlying issue, use the following steps to ensure a long-lasting repair:
It is typically connected to a resistor divider from the step-up converter's output to ground. This allows users to program the specific voltage level at which protection activates. Comprehensive Protection Features mp3378e protection pin upd
pin detects an over-current spike, triggering an immediate OCP shutdown.
This technical guide covers how the protection system works, why it trips, and how to safely modify or disable the protection pin for diagnostic and repair purposes. Technical Specifications of the MP3378E
The MP3378E's protection mechanisms are divided between its two main functional blocks, each with dedicated fault detection and response features. : The OVP pin monitors the output voltage
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.
Below is an in-depth breakdown of the MP3378E's protection framework, pin functionalities, and essential troubleshooting updates ( upd ) for repair technicians and hardware engineers. Core Hardware Framework of the MP3378E
The MP3378E includes several built-in safety mechanisms for both the WLED controller and the buck converter: Protection Type Mechanism / Details Increase C_PROT or lower output target] | No
I can then provide tailored pinout values and circuit testing procedures for your repair. MP3378E - Monolithic Power Systems
The internal error amplifier forces the boost converter to ramp up the output voltage to compensate.
Measure the voltage on pins 5, 6, 7, and 8. They should ideally be similar. A significantly higher or lower voltage than others indicates a faulty LED string. 4. Troubleshooting "Protection Pin UPD" (UVP/OVP/LED Short)
These four pins act as current sinks for the backlight strings. They also operate as secondary protection monitors: