Mp3378e Protection Pin Upd Fix < 100% Trusted >

Some designs allow the host controller to read the PROT pin via an ADC. If UPD is persistent but the backlight is functional at reduced brightness, implement:

: If the voltage at the OVP pin exceeds a preset internal threshold, the IC shuts down the PWM generator and disables the MOSFET drivers to prevent thermal runaway or component damage. : This protects against open-circuit

: Includes recoverable thermal shutdown, meaning the device will restart once it cools to a safe operating temperature. External Control MP3378E datasheet

Both stages are monitored by a combined array of protective sensors. The IC tracks parameters across multiple pins to trigger a shutdown if conditions become unsafe: (Over-Current Protection) OVP (Over-Voltage Protection) UVP (Under-Voltage Protection) OTP (Over-Temperature / Thermal Shutdown) LED Short/Open Protection Inductor/Diode Short Protection 2. Key Pins Related to Fault Protection mp3378e protection pin upd

Measure the voltage on the LED current sink pins (usually labeled LED1–LED4) while turning the set on.

| Protection Type | Detection Method | Fault Response & Thresholds | Critical Pins | | :--- | :--- | :--- | :--- | | | Monitors inductor current via internal sensing | Event : Current limit exceeded. Response : Hiccup mode protection; converter attempts restart after fault clears. Benefits : Protects internal power MOSFETs and external components during output overload or short circuit. | SW, VIN2 | | Thermal Shutdown Protection | Monitors silicon die temperature via internal sensor | Event : Junction temperature exceeding thermal limit. Response : Buck converter shuts down; recoverable when temperature falls below threshold. Benefits : Prevents thermal runaway in high-power or high-ambient temperature conditions. | Internal | | Under-Voltage Lockout (UVLO) | Monitors VIN2 voltage | Event : VIN2 below UVLO rising threshold (typ. 4.2V). Response : Entire buck converter shuts down, preventing operation with insufficient supply. Hysteresis prevents oscillations near threshold. Benefits : Protects against brownout conditions and ensures proper startup. | VIN2, VCC2, EN2 | | Output Over-Voltage Protection | Monitors VOUT via FB divider | Event : VOUT exceeds regulation due to fault. Response : Internal mechanism regulates output; excessive OVP triggers shutdown. Benefits : Prevents damage to downstream circuits from over-voltage. | FB |

The confusion over a single pin likely stems from the MP3378E's robust set of internal safety features. Rather than a single pin, protection is distributed and monitored across various pins and internal circuitry, all designed to prevent damage to the IC and the LED strings it controls. Some designs allow the host controller to read

+-----------------------+ | MP3378E | | TSSOP-28 | | | ------> OVP (Over-Voltage) | ------> COMP (Compensation) | ------> ISET (Current Set) | ------> EN1 (WLED Enable) | ------> EN2 (Buck Enable) | | | +-----------------------+ OVP (Over-Voltage Protection) Pin

The MP3378E includes several safety mechanisms that can trigger a shutdown: Monitored via the OVP pin .

The MP3378E's multiple protection mechanisms can sometimes trigger unexpectedly, especially in field repairs or derivative designs. Here are common issues: External Control MP3378E datasheet Both stages are monitored

For a robust design, engineers must calculate the protection thresholds based on the MP3378E Datasheet specifications: Typical Threshold VOVP_OVcap V sub cap O cap V cap P _ cap O cap V end-sub LEDX Regulation Voltage VLEDXcap V sub cap L cap E cap D cap X end-sub 800 mV (at 330 mA) LEDX Over-Voltage Threshold

The MP3378E is a highly integrated, single-chip solution from Monolithic Power Systems (MPS) designed for monitor backlighting applications. It combines a 4-channel WLED (White Light-Emitting Diode) controller and a high-efficiency buck converter in a single TSSOP-28 EP package.

The WLED controller includes multiple layers of protection to ensure robust operation in monitor backlighting applications.