RDS(ON)cap R sub cap D cap S open paren cap O cap N close paren end-sub
The MP3378E relies on integrated safety feedback loops to protect both the internal chip architecture and external display components.
Technicians often check the resistor values for the OVP resistor divider to ensure the chip is receiving the correct feedback voltage. Troubleshooting and "Bypassing"
Bypassing protection mechanisms is an advanced diagnostics-only procedure. Disabling safety features permanently removes short-circuit and over-voltage safeguards, which can damage components, melt diffuser sheets, or cause a fire hazard. Use this procedure only to locate faulty components. mp3378e protection pin upd
, up to 24V) into the higher forward voltage needed to power the display backlight. The Buck Converter
MP3378E Protection Pin Setup, Bypass, and Troubleshooting Guide
Monitors current through the external switching MOSFET via a sense resistor to catch short circuits. RDS(ON)cap R sub cap D cap S open
If one string is faulty, grounding that specific LED channel pin through a resistor can sometimes trick the IC into ignoring that string's fault. Technical Specifications
If the internal OVP of the MP3378E (e.g., 80V) is too high for your LEDs, use a resistor divider from the boost output to UPD via a Zener diode.
The OVP lower resistor (10kΩ) had a hairline crack, measuring 10.8kΩ. Recalculated V_PROT: Target 1.25V, actual 1.17V (due to 8% increase). This 0.08V difference fell into UPD zone. The Buck Converter MP3378E Protection Pin Setup, Bypass,
MP3378E Protection Loop +-----------------------+ | MP3378E | VOUT (Boost) --->| OVP Pin (Overvoltage) |---> Shuts down GATE pin | | LED Cathodes --->| LED1-4 Pins (Open/Sh) |---> Disables faulty string | | Inductor/FET --->| ISENSE Pin (OCP) |---> Caps max duty cycle +-----------------------+ 1. The OVP Pin (Over-Voltage Protection Input) The directly checks the boost output voltage ( VOUTcap V sub cap O cap U cap T end-sub ) via an external resistor divider network.
Internal circuits for Over-Current and Over-Temperature protection that shut down the IC to prevent permanent damage. The "Protection Pin Upd" (Update/Bypass)
: The MP3378E features a cycle-by-cycle current limiting mechanism. It uses the external current-sensing resistor (R_SENSE) connected to the ISENSE pin to monitor the peak current through the inductor in real-time. If the current exceeds a preset safe limit, the controller reduces the duty cycle to lower the output.
In modern LCD display systems (TVs, monitors, automotive displays), the LED backlight driver is critical. Among the leading solutions is the from Monolithic Power Systems (MPS), a highly integrated boost controller with 8-channel current sinks.