Mp3378e Protection Pin Upd – Verified & Authentic

RDS(ON)cap R sub cap D cap S open paren cap O cap N close paren end-sub

If the LEDs fail short, the VLED pin sees an instant surge in voltage. The IC pulls that channel out of operation to protect against cascading thermal destruction. 3. Over-Current Sense (ISENSE)

These four pins act as current sinks for the backlight strings. They also operate as secondary protection monitors:

specifies that the OVP threshold is programmable via external resistors to match the specific LED array's voltage requirements. MPS | Monolithic Power Systems schematic example of how to calculate the resistor values for the OVP pin? MP3378E - Monolithic Power Systems mp3378e protection pin upd

Technicians sometimes attempt to "bypass" or "enable" protection pins to diagnose whether a failure is due to a faulty LED or the driver IC itself.

| Pin Name | Pin # | Function & Protection Relevance | | :--- | :--- | :--- | | | 20 | Bootstrap for buck converter high-side driver. Critical for gate drive; must be monitored for UVLO condition. | | SYNC | 21 | Synchronization input for buck converter. Connect external clock (250kHz-2MHz) to synchronize switching. | | ISENSE | 22 | Current sense input for WLED controller. Senses external inductor current for peak current-mode control and OCP detection. | | GATE | 23 | Power switch gate output for WLED controller. Drives external N-channel MOSFET; OCP detection involves monitoring gate drive. | | VIN1 | 24 | Supply input for WLED controller. Monitored for UVP. | | VCC1 | 25 | Internal 6V linear regulator output for WLED controller. Supplies external MOSFET driver and internal circuitry; bypass to GND. | | COMP | 26 | Error amplifier output for WLED controller. Used for loop compensation; COMP voltage clamping used in inductor/diode short protection. | | EN1 | 27 | Enable input for WLED controller. Pull high to enable; logic-level control for startup/shutdown. | | PWM | 28 | PWM brightness control input. Used for dimming only; not for enabling/disabling controller. | | LED1-4 | 14,13,12,11 | LED string current sense inputs. Monitor LEDX voltages for open/short string detection. | | OVP | 8 | Over-voltage protection sense input. Set OVP threshold via external resistor divider. | | FB | 9 | Feedback for buck converter. Used for output voltage regulation and OVP detection. | | EN2 | 10 | Enable input for buck converter. Pull high to enable; shutdown controlled by EN2, VIN2 UVLO, or thermal shutdown. | | VIN2 | 18,19 | Supply input for buck converter. Monitored for UVLO. | | SW | 20 | Switching node for buck converter. High-dv/dt node; keep away from sensitive analog areas. | | AGND | 21 | Analog ground reference for buck converter. Connect single-point to GND1. | | VCC2 | 22 | Internal 5V regulator output for buck converter. | | GND2 | 23,24 | Power ground for buck converter. | | ADIM | 16 | Analog dimming control. Supports PWM or DC signal for LED current adjustment. |

Bypassing protection permanently is highly dangerous and strongly discouraged for consumer use. Doing so removes critical safeguards against thermal runaway, component degradation, and potential electrical fires. It must only be used as a short-term diagnostic step on a controlled isolation workbench. How Technicians Analyze the OVP Pin RDS(ON)cap R sub cap D cap S open

The UPD (Protection) pin on the MP3378E is a powerful, flexible safety feature. By understanding its 1.22V threshold and 5µA internal pull-up, you can implement external over-temperature, over-voltage, or custom fault detection with minimal components. However, proper PCB layout—shielding the UPD trace from switching noise and adding a small filter capacitor—is essential to avoid false triggering.

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Deep Dive into the MP3378E Protection Pin (UPD) The manufactured by Monolithic Power Systems (MPS) is a highly integrated, single-chip power management solution widely utilized in modern LCD flat-panel displays, monitors, and 2D/3D LCD TVs. This advanced integrated circuit (IC) combines a 4-channel White LED (WLED) backlight controller with a high-efficiency synchronous buck converter . Over-Current Sense (ISENSE) These four pins act as

Specialized protection for inductor and diode short circuits.

The internal error amplifier forces the boost converter to ramp up the output voltage to compensate.

Modifying the resistor divider on the to raise the threshold, preventing premature shutdown due to slight voltage spikes. LED Channel Disable

The MP3378E uses latch-off (not auto-recovery) for UPD faults. Once triggered, only power cycling VCC or toggling the EN pin will reset the IC.