The MP3378E is a dual-function integrated circuit commonly found in monitors, combining a 4-channel LED backlight driver with a high-efficiency buck converter. When repairing backlight issues, technicians often look for ways to "bypass" or "update" the protection behavior to diagnose whether the fault lies in the LEDs or the driver itself. Key Protection Features
Design formula: Choose R_pullup such that at the desired trip temperature, ( V_UPD = 5V \times \fracR_NTC(T_trip)R_NTC(T_trip) + R_pullup < 1.22V ).
Design rule: Keep ( R_BOTTOM < 100k\Omega ) to avoid noise injection. mp3378e protection pin upd
The MP3378E is a highly integrated 4-channel WLED controller designed for LCD backlighting, commonly found in monitors and flat-panel displays. A critical part of its reliability is the Over-Voltage Protection (OVP) pin, which serves as the primary "protection pin" for monitoring output stability and preventing hardware failure. Key Functions of the Protection (OVP) Pin
Normal Setup: Use a resistor divider between the boost output and ground. Calculate the resistors so that the OVP pin reaches ~1.2V only when the output is at its maximum safe limit. The MP3378E is a dual-function integrated circuit commonly
If you need to reduce the current to extend the life of new LEDs (a common "update" after repair), you can increase the resistance of the resistor connected to the ISET pin. This lowers the current across all four strings. MP3378E - Monolithic Power Systems
Function: Open-string protection is achieved by monitoring the voltage on the OVP pin. If an LED string fails, the controller may boost output voltage excessively; if it hits the programmed OVP threshold, the chip shuts down to prevent damage. Behavior modes (latched vs
The UPD pin update procedure is as follows:
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