Mp3378e Protection Pin Upd May 2026

is a integrated circuit from Monolithic Power Systems (MPS) designed for monitor applications. It combines a 4-string WLED controller for backlighting with a high-efficiency buck converter for internal power. MPS | Monolithic Power Systems The "protection pin" functionality primarily relates to the OVP (Over-Voltage Protection)

input, which is a critical feedback node used to monitor and protect the IC from fault conditions. Protection Pin Overview (OVP)

The OVP pin is a dedicated input that monitors the output voltage of the step-up converter to prevent catastrophic failures.

: It is typically connected to a resistor divider from the output voltage.

: 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

conditions (e.g., a loose LED connection), where the boost converter would otherwise indefinitely increase voltage trying to maintain constant current. Comprehensive Protection Features

The MP3378E integrates several protection modes for both the WLED controller and the buck converter: MPS | Monolithic Power Systems Controller Part Integrated Protections WLED Controller

OCP, OTP, UVP, OVP, LED Short/Open Protection, Inductor/Diode Short Protection Buck Converter Over-Current Protection (OCP), Thermal Shutdown Fault Handling & Updates LED Open/Short

: The IC monitors individual LED strings. If a string is detected as open or shorted, it can disable that specific string while keeping others active, or shut down depending on the severity. Thermal Protection

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

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

The MP3378E is a highly integrated single-chip solution designed for monitor applications, combining a 4-string White LED (WLED) step-up controller with a high-efficiency buck converter. Central to its reliability is a robust suite of protection mechanisms designed to prevent device failure and ensure long-term stability in display backlighting. Core Protection Infrastructure

The device features independent protection layers for both the WLED controller and the internal buck converter. These safeguards monitor various operational parameters to trigger corrective actions or shutdowns when limits are exceeded. WLED Controller Protections:

Over-Voltage Protection (OVP): This feature is programmable, allowing designers to set the maximum voltage limit to prevent damage to the external MOSFET and output capacitors during open-load conditions.

LED Open/Short Protection: The IC monitors each of the four LED strings. If a string is detected as open or shorted, the device can disable that specific channel or the entire controller to prevent thermal runaway.

Over-Current Protection (OCP): Monitors the current through the external switching MOSFET and LED strings to prevent damage from excessive power draw.

Inductor and Diode Short Protection: A critical safeguard that detects failures in the main power stage components, immediately shutting down to prevent catastrophic board damage. Buck Converter Protections:

OCP and Hiccup Mode: If the buck converter experiences an over-current event, it enters "hiccup mode," where it periodically attempts to restart until the fault is cleared, reducing average power stress. mp3378e protection pin upd

Thermal Shutdown: The device includes recoverable thermal protection. If the junction temperature exceeds its safety threshold, the IC shuts down and resumes operation once it cools. The "Protection Pin" Logic (UPD)

In many contemporary WLED controllers like the MP3378E, the term "protection pin" often refers to the OVP (Over-Voltage Protection) pin or the COMP (Compensation) pin, which are critical for maintaining feedback loops. For users upgrading from older models (such as the MP3398 series), the addition of an explicit protection pin serves to:

Enhance Noise Filtering: Provide better stability under line transients and AC rectifier voltage spikes.

Ensure Stability: To prevent erratic behavior in the oscillator circuit, this pin should never be left floating; it is typically grounded via a resistor (e.g., ) if active protection is not implemented. Summary of Protection Specifications Target Component Protection Type OVP WLED Output Programmable voltage limit OCP MOSFET / Inductor Peak current limiting OTP Junction Temperature Recoverable thermal shutdown UVP Input Voltage Under-voltage lockout Hiccup Mode Buck Converter Periodic restart on fault MP3378E - Monolithic Power Systems

The MP3378E is a versatile, single-chip integrated circuit designed by Monolithic Power Systems (MPS) for liquid crystal display (LCD) monitor applications. It combines a 4-channel White LED (WLED) controller for backlighting with a high-efficiency buck converter for internal system power.

Understanding the protection pin (often labeled as OVP or FAULT in technician terminology) is critical for troubleshooting backlight failures, such as the "one-second" flash or complete darkness. Key Protection Features of the MP3378E

The MP3378E integrates multiple protection modes to safeguard the IC and the LED strings from damage:

Over-Voltage Protection (OVP): Monitored through a specific resistor divider to prevent output voltage from exceeding safe limits.

LED Open/Short Protection: Detects if an LED string is disconnected or short-circuited.

Over-Current Protection (OCP): Limits current to the external MOSFET and internal buck converter.

Thermal Shutdown: Automatically shuts down the chip if internal temperatures reach unsafe levels.

Inductor/Diode Short Protection: Protects against hardware failures in the boost circuitry. The Role of the OVP Pin in Protection

In many repair scenarios, the OVP pin serves as the primary "protection pin" that triggers a shutdown.

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.

Configuration: Technicians often check the resistor values for the OVP resistor divider to ensure the chip is receiving the correct feedback voltage. Troubleshooting and "Bypassing"

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.

Diagnosis: If the backlight flashes and then turns off, the IC has likely detected a fault (e.g., an open LED string) and triggered its internal protection. is a integrated circuit from Monolithic Power Systems

Common Method: While specific to other ICs like the ACM20005, common technician tricks involve using a diode or resistor to ground a protection pin to see if the backlight stays on. Warning: Bypassing protection on the MP3378E can lead to permanent damage to the IC or the LED panel if the underlying fault (like a short circuit) is not fixed. Pinout Summary (TSSOP-28 EP Package)

The MP3378E is housed in a 28-pin TSSOP package with an exposed pad for heat dissipation. Primary Function OVP

Over-Voltage Protection input; senses output voltage via a resistor divider. LED1–LED4

Current sinks for the 4 LED strings; failures here often trigger protection. ISET

Sets the LED current; a resistor between this pin and ground programs the brightness. EN/PWM

Enables the IC and controls brightness via pulse-width modulation.

For detailed electrical specifications and circuit diagrams, you can refer to the MP3378E Datasheet provided by Mouser Electronics. MP3378E - Mouser Electronics

26 May 2017 — * MP3378E. * WLED Controller: * Buck Converter: * WLED Controller. VIN1 .............................................. - 0.3V to + Mouser Electronics MP3378E - Monolithic Power Systems

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

The OVP pin (Pin 10 in the TSSOP-28 EP package) monitors the boost output voltage through an external resistor divider. It performs several safety-critical tasks:

Over-Voltage Protection: If the voltage at the OVP pin exceeds the threshold (typically 1.23V), the step-up converter shuts down to prevent damage to the external MOSFET and LED strings.

Open-String Protection: If an LED string is disconnected or "open," the IC will keep increasing the output voltage. The OVP pin detects this runaway voltage and shuts down the driver once the safety threshold is reached.

Under-Voltage Lockout (UVLO): The pin also monitors for a minimum operating voltage. If the OVP pin voltage is too low, the step-up converter fails to start. Typical Protection Pin Specifications Value (Typ) OVP Threshold (Rising) VOVP_OVcap V sub cap O cap V cap P _ cap O cap V end-sub 1.23V Triggers shutdown if exceeded. OVP Hysteresis

VOVP_HYScap V sub cap O cap V cap P _ cap H cap Y cap S end-sub 80mV Prevents rapid flickering at the threshold. OVP Pin Number Pin 10 Physical location on the TSSOP-28 package. Troubleshooting & "Bypassing" Protection

In repair scenarios where a monitor shuts down due to aging LEDs (causing a "protection trip"), technicians sometimes modify the OVP circuit. However, for the MP3378E, the protection is programmable.

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.

Stability Tip: If you experience random shutdowns during startup, ensure the OVP pin has a stable signal and is not affected by switching noise. Adding a small capacitor (e.g., 10nF) to ground near the pin can help filter this noise. Testing checklist

Warning: Bypassing protection pins on WLED controllers like the MP3378E from MPS can lead to overheating, burnt LED strips, or permanent damage to the IC.

Are you currently troubleshooting a backlight shutdown issue or designing a new PCB layout for this chip? MP3378E - Monolithic Power Systems

The MP3378E is a versatile integrated circuit from Monolithic Power Systems (MPS)

that combines a 4-channel WLED controller with a high-efficiency buck converter, primarily used in monitor applications. MPS | Monolithic Power Systems

While the datasheet does not have a single pin explicitly named "UPD," the protection logic often relies on "Up-to-Date" monitoring or specific update/feedback pins to ensure safe operation. A "good feature" regarding protection for this chip typically involves its robust fault-handling suite. MPS | Monolithic Power Systems Key Protection Features

The MP3378E includes comprehensive protection mechanisms that monitor various conditions to prevent hardware failure: LED Protection : Detects and responds to both

conditions across its four channels to prevent uneven brightness or circuit damage. WLED Controller Safety : Features Over-Current Protection (OCP) Over-Temperature Protection (OTP) Under-Voltage Protection (UVP) Over-Voltage Protection (OVP) Component Monitoring : Specifically includes inductor and diode short protection

, which is critical for the external boost MOSFET circuitry. Buck Converter Protection : Includes dedicated OCP and thermal shutdown for the internal bus voltage regulator. MPS | Monolithic Power Systems Proposed Feature: Intelligent Fault Latching

If you are looking to "generate" or implement a feature using the protection pins, a common high-end implementation is Intelligent Fault Latching with Auto-Recovery Selective Channel Shutdown

: Instead of shutting down the entire monitor, the chip can disable a single faulty LED string while keeping others active, maintaining a usable (though dimmer) display. Configurable Fault Timer

: Using external resistors or pins to set a delay before a permanent shutdown occurs. This prevents nuisance tripping from transient voltage spikes while still protecting against sustained shorts. Standby Bus Stability

: Leveraging the buck converter's OCP to ensure that even if the backlight fails, the internal standby power remains stable for diagnostic reporting to the main system processor. MPS | Monolithic Power Systems

For specific pin-out details and timing diagrams, you can refer to the official MP3378E Datasheet from Mouser or a specific resistor value calculation for setting the protection thresholds? MP3378E - Monolithic Power Systems

Here’s a useful technical review of the MP3378E focusing on protection pin configuration and UPD (under-voltage protection disable / config) — critical for LED backlight driver design.

Testing checklist

  • Confirm PROT polarity and drive type from datasheet.
  • Verify pull-up resistor value and behavior under temperature extremes.
  • Trigger overcurrent and short-circuit conditions and observe PROT timing (assertion, de-assertion, and any retry intervals).
  • Validate that the system recovers predictably after fault clearance.
  • Test EMI/immunity by injecting expected transient noise and observing false triggers.

6. Summary Table – Protection Pin Setup

| Requirement | PRO pin | UPD setting | |-------------|---------|--------------| | Latch-off on any fault | GND | Disabled (default) | | Auto-restart (hiccup) | >2V | Disabled | | Operate below 4.5V VIN | >2V (auto-restart) | Enabled | | Operate below 4.5V + latch-off | GND + external reset circuit | Enabled (rare) |

Would you like a reference schematic showing PRO pin connection and optional UPD circuit for the MP3378E?

1. PRO Pin Function

  • Pin name: PRO (Protection)
  • Type: Input with internal pull-down
  • Key role: Latches or auto-recovery after fault

| PRO state | Protection response | |-----------|----------------------| | LOW (GND) | Latch-off mode – after fault (OVP, OCP, SCP, UVLO), driver shuts down and stays off until VCC cycled | | HIGH (>2V) | Auto-restart mode – after fault, driver tries to restart periodically (hiccup) |

✅ Use auto-restart (PRO high) for systems where temporary faults shouldn’t require power cycling.
⚠️ Latch-off is safer for permanent faults but requires user reset.

Testing:

  • Perform protection pin margin test: Inject external voltage (0.5V – 1.5V) into PROT pin via 100kΩ resistor and verify MP3378E responds cleanly without UPD.
  • Run thermal cycle test (-20°C to +85°C) while monitoring PROT pin voltage; leakage can appear only at temperature extremes.
Day D Tower Rush - Screenshot #1Day D Tower Rush - Screenshot #2Day D Tower Rush - Screenshot #3

is a integrated circuit from Monolithic Power Systems (MPS) designed for monitor applications. It combines a 4-string WLED controller for backlighting with a high-efficiency buck converter for internal power. MPS | Monolithic Power Systems The "protection pin" functionality primarily relates to the OVP (Over-Voltage Protection)

input, which is a critical feedback node used to monitor and protect the IC from fault conditions. Protection Pin Overview (OVP)

The OVP pin is a dedicated input that monitors the output voltage of the step-up converter to prevent catastrophic failures.

: It is typically connected to a resistor divider from the output voltage.

: 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

conditions (e.g., a loose LED connection), where the boost converter would otherwise indefinitely increase voltage trying to maintain constant current. Comprehensive Protection Features

The MP3378E integrates several protection modes for both the WLED controller and the buck converter: MPS | Monolithic Power Systems Controller Part Integrated Protections WLED Controller

OCP, OTP, UVP, OVP, LED Short/Open Protection, Inductor/Diode Short Protection Buck Converter Over-Current Protection (OCP), Thermal Shutdown Fault Handling & Updates LED Open/Short

: The IC monitors individual LED strings. If a string is detected as open or shorted, it can disable that specific string while keeping others active, or shut down depending on the severity. Thermal Protection

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

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

The MP3378E is a highly integrated single-chip solution designed for monitor applications, combining a 4-string White LED (WLED) step-up controller with a high-efficiency buck converter. Central to its reliability is a robust suite of protection mechanisms designed to prevent device failure and ensure long-term stability in display backlighting. Core Protection Infrastructure

The device features independent protection layers for both the WLED controller and the internal buck converter. These safeguards monitor various operational parameters to trigger corrective actions or shutdowns when limits are exceeded. WLED Controller Protections:

Over-Voltage Protection (OVP): This feature is programmable, allowing designers to set the maximum voltage limit to prevent damage to the external MOSFET and output capacitors during open-load conditions.

LED Open/Short Protection: The IC monitors each of the four LED strings. If a string is detected as open or shorted, the device can disable that specific channel or the entire controller to prevent thermal runaway.

Over-Current Protection (OCP): Monitors the current through the external switching MOSFET and LED strings to prevent damage from excessive power draw.

Inductor and Diode Short Protection: A critical safeguard that detects failures in the main power stage components, immediately shutting down to prevent catastrophic board damage. Buck Converter Protections:

OCP and Hiccup Mode: If the buck converter experiences an over-current event, it enters "hiccup mode," where it periodically attempts to restart until the fault is cleared, reducing average power stress.

Thermal Shutdown: The device includes recoverable thermal protection. If the junction temperature exceeds its safety threshold, the IC shuts down and resumes operation once it cools. The "Protection Pin" Logic (UPD)

In many contemporary WLED controllers like the MP3378E, the term "protection pin" often refers to the OVP (Over-Voltage Protection) pin or the COMP (Compensation) pin, which are critical for maintaining feedback loops. For users upgrading from older models (such as the MP3398 series), the addition of an explicit protection pin serves to:

Enhance Noise Filtering: Provide better stability under line transients and AC rectifier voltage spikes.

Ensure Stability: To prevent erratic behavior in the oscillator circuit, this pin should never be left floating; it is typically grounded via a resistor (e.g., ) if active protection is not implemented. Summary of Protection Specifications Target Component Protection Type OVP WLED Output Programmable voltage limit OCP MOSFET / Inductor Peak current limiting OTP Junction Temperature Recoverable thermal shutdown UVP Input Voltage Under-voltage lockout Hiccup Mode Buck Converter Periodic restart on fault MP3378E - Monolithic Power Systems

The MP3378E is a versatile, single-chip integrated circuit designed by Monolithic Power Systems (MPS) for liquid crystal display (LCD) monitor applications. It combines a 4-channel White LED (WLED) controller for backlighting with a high-efficiency buck converter for internal system power.

Understanding the protection pin (often labeled as OVP or FAULT in technician terminology) is critical for troubleshooting backlight failures, such as the "one-second" flash or complete darkness. Key Protection Features of the MP3378E

The MP3378E integrates multiple protection modes to safeguard the IC and the LED strings from damage:

Over-Voltage Protection (OVP): Monitored through a specific resistor divider to prevent output voltage from exceeding safe limits.

LED Open/Short Protection: Detects if an LED string is disconnected or short-circuited.

Over-Current Protection (OCP): Limits current to the external MOSFET and internal buck converter.

Thermal Shutdown: Automatically shuts down the chip if internal temperatures reach unsafe levels.

Inductor/Diode Short Protection: Protects against hardware failures in the boost circuitry. The Role of the OVP Pin in Protection

In many repair scenarios, the OVP pin serves as the primary "protection pin" that triggers a shutdown.

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.

Configuration: Technicians often check the resistor values for the OVP resistor divider to ensure the chip is receiving the correct feedback voltage. Troubleshooting and "Bypassing"

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.

Diagnosis: If the backlight flashes and then turns off, the IC has likely detected a fault (e.g., an open LED string) and triggered its internal protection.

Common Method: While specific to other ICs like the ACM20005, common technician tricks involve using a diode or resistor to ground a protection pin to see if the backlight stays on. Warning: Bypassing protection on the MP3378E can lead to permanent damage to the IC or the LED panel if the underlying fault (like a short circuit) is not fixed. Pinout Summary (TSSOP-28 EP Package)

The MP3378E is housed in a 28-pin TSSOP package with an exposed pad for heat dissipation. Primary Function OVP

Over-Voltage Protection input; senses output voltage via a resistor divider. LED1–LED4

Current sinks for the 4 LED strings; failures here often trigger protection. ISET

Sets the LED current; a resistor between this pin and ground programs the brightness. EN/PWM

Enables the IC and controls brightness via pulse-width modulation.

For detailed electrical specifications and circuit diagrams, you can refer to the MP3378E Datasheet provided by Mouser Electronics. MP3378E - Mouser Electronics

26 May 2017 — * MP3378E. * WLED Controller: * Buck Converter: * WLED Controller. VIN1 .............................................. - 0.3V to + Mouser Electronics MP3378E - Monolithic Power Systems

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

The OVP pin (Pin 10 in the TSSOP-28 EP package) monitors the boost output voltage through an external resistor divider. It performs several safety-critical tasks:

Over-Voltage Protection: If the voltage at the OVP pin exceeds the threshold (typically 1.23V), the step-up converter shuts down to prevent damage to the external MOSFET and LED strings.

Open-String Protection: If an LED string is disconnected or "open," the IC will keep increasing the output voltage. The OVP pin detects this runaway voltage and shuts down the driver once the safety threshold is reached.

Under-Voltage Lockout (UVLO): The pin also monitors for a minimum operating voltage. If the OVP pin voltage is too low, the step-up converter fails to start. Typical Protection Pin Specifications Value (Typ) OVP Threshold (Rising) VOVP_OVcap V sub cap O cap V cap P _ cap O cap V end-sub 1.23V Triggers shutdown if exceeded. OVP Hysteresis

VOVP_HYScap V sub cap O cap V cap P _ cap H cap Y cap S end-sub 80mV Prevents rapid flickering at the threshold. OVP Pin Number Pin 10 Physical location on the TSSOP-28 package. Troubleshooting & "Bypassing" Protection

In repair scenarios where a monitor shuts down due to aging LEDs (causing a "protection trip"), technicians sometimes modify the OVP circuit. However, for the MP3378E, the protection is programmable.

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.

Stability Tip: If you experience random shutdowns during startup, ensure the OVP pin has a stable signal and is not affected by switching noise. Adding a small capacitor (e.g., 10nF) to ground near the pin can help filter this noise.

Warning: Bypassing protection pins on WLED controllers like the MP3378E from MPS can lead to overheating, burnt LED strips, or permanent damage to the IC.

Are you currently troubleshooting a backlight shutdown issue or designing a new PCB layout for this chip? MP3378E - Monolithic Power Systems

The MP3378E is a versatile integrated circuit from Monolithic Power Systems (MPS)

that combines a 4-channel WLED controller with a high-efficiency buck converter, primarily used in monitor applications. MPS | Monolithic Power Systems

While the datasheet does not have a single pin explicitly named "UPD," the protection logic often relies on "Up-to-Date" monitoring or specific update/feedback pins to ensure safe operation. A "good feature" regarding protection for this chip typically involves its robust fault-handling suite. MPS | Monolithic Power Systems Key Protection Features

The MP3378E includes comprehensive protection mechanisms that monitor various conditions to prevent hardware failure: LED Protection : Detects and responds to both

conditions across its four channels to prevent uneven brightness or circuit damage. WLED Controller Safety : Features Over-Current Protection (OCP) Over-Temperature Protection (OTP) Under-Voltage Protection (UVP) Over-Voltage Protection (OVP) Component Monitoring : Specifically includes inductor and diode short protection

, which is critical for the external boost MOSFET circuitry. Buck Converter Protection : Includes dedicated OCP and thermal shutdown for the internal bus voltage regulator. MPS | Monolithic Power Systems Proposed Feature: Intelligent Fault Latching

If you are looking to "generate" or implement a feature using the protection pins, a common high-end implementation is Intelligent Fault Latching with Auto-Recovery Selective Channel Shutdown

: Instead of shutting down the entire monitor, the chip can disable a single faulty LED string while keeping others active, maintaining a usable (though dimmer) display. Configurable Fault Timer

: Using external resistors or pins to set a delay before a permanent shutdown occurs. This prevents nuisance tripping from transient voltage spikes while still protecting against sustained shorts. Standby Bus Stability

: Leveraging the buck converter's OCP to ensure that even if the backlight fails, the internal standby power remains stable for diagnostic reporting to the main system processor. MPS | Monolithic Power Systems

For specific pin-out details and timing diagrams, you can refer to the official MP3378E Datasheet from Mouser or a specific resistor value calculation for setting the protection thresholds? MP3378E - Monolithic Power Systems

Here’s a useful technical review of the MP3378E focusing on protection pin configuration and UPD (under-voltage protection disable / config) — critical for LED backlight driver design.

Testing checklist

  • Confirm PROT polarity and drive type from datasheet.
  • Verify pull-up resistor value and behavior under temperature extremes.
  • Trigger overcurrent and short-circuit conditions and observe PROT timing (assertion, de-assertion, and any retry intervals).
  • Validate that the system recovers predictably after fault clearance.
  • Test EMI/immunity by injecting expected transient noise and observing false triggers.

6. Summary Table – Protection Pin Setup

| Requirement | PRO pin | UPD setting | |-------------|---------|--------------| | Latch-off on any fault | GND | Disabled (default) | | Auto-restart (hiccup) | >2V | Disabled | | Operate below 4.5V VIN | >2V (auto-restart) | Enabled | | Operate below 4.5V + latch-off | GND + external reset circuit | Enabled (rare) |

Would you like a reference schematic showing PRO pin connection and optional UPD circuit for the MP3378E?

1. PRO Pin Function

  • Pin name: PRO (Protection)
  • Type: Input with internal pull-down
  • Key role: Latches or auto-recovery after fault

| PRO state | Protection response | |-----------|----------------------| | LOW (GND) | Latch-off mode – after fault (OVP, OCP, SCP, UVLO), driver shuts down and stays off until VCC cycled | | HIGH (>2V) | Auto-restart mode – after fault, driver tries to restart periodically (hiccup) |

✅ Use auto-restart (PRO high) for systems where temporary faults shouldn’t require power cycling.
⚠️ Latch-off is safer for permanent faults but requires user reset.

Testing:

  • Perform protection pin margin test: Inject external voltage (0.5V – 1.5V) into PROT pin via 100kΩ resistor and verify MP3378E responds cleanly without UPD.
  • Run thermal cycle test (-20°C to +85°C) while monitoring PROT pin voltage; leakage can appear only at temperature extremes.