Top 5 Power Supply Failures in TPS3825-33DBVR and How to Fix Them

Top 5 Power Supply Failures in TPS3825-33DBVR and How to Fix Them

The TPS3825-33DBVR is a precision voltage supervisor IC widely used in power supply systems for various applications. However, like any electronic component, it can experience failures in certain scenarios. Below, we’ll discuss the top five common power supply failures in the TPS3825-33DBVR and provide easy-to-follow solutions for each one.

1. Incorrect Output Voltage (Not Reaching 3.3V)

Cause: A failure to output the correct 3.3V might occur due to a faulty power supply input or incorrect resistor settings used for the voltage supervisor. The IC needs a stable input voltage (higher than 3.3V) to regulate and output the desired value.

Solution:

Check Input Voltage: Ensure that the input voltage is within the recommended range for the TPS3825-33DBVR (typically 4.5V to 5.5V). If the input voltage is too low, the IC cannot regulate the output to 3.3V. Check Resistor Divider: The TPS3825-33DBVR uses an external resistor divider to set the threshold voltage. If these resistors are incorrectly rated, the output may not be correct. Verify the resistor values against the recommended design guidelines. Replace Damaged Components: If the input voltage is correct and resistors are properly configured, but the IC still fails, the TPS3825-33DBVR might be damaged. Replacing the IC could resolve the issue.

2. Power Supply Not Turning On

Cause: One of the most common failures is the power supply not turning on, often caused by improper power sequencing or a failure in the IC’s reset function.

Solution:

Check Enable Pin (EN Pin): The EN pin controls the activation of the IC. If this pin is not pulled high (logic "1"), the IC will not turn on. Ensure the EN pin is properly connected to the system and has the correct voltage. Verify Reset Timeout: If there is a long reset timeout (over 300ms typically), ensure that your external capacitor s are the right value and have not failed. The reset time is controlled by a capacitor connected to the IC’s reset pin. Inspect Power Sequence: Make sure the power sequence is in order. Sometimes, improper power sequencing in the circuit can prevent the IC from turning on. Follow the recommended power-up sequence in the datasheet to avoid this issue.

3. Frequent Reset Events

Cause: The TPS3825-33DBVR is designed to trigger a reset if the monitored supply voltage falls below the threshold. Frequent resets might happen if there are voltage fluctuations or poor power quality.

Solution:

Check Power Supply Stability: Ensure that the input voltage is stable and does not dip below the threshold for extended periods. If necessary, use filtering Capacitors to stabilize the power supply and reduce noise. Verify Threshold Configuration: Double-check that the threshold voltage is correctly set for your application. If it’s too low, the IC might be too sensitive and cause frequent resets. Adjust the resistor values to increase the threshold if needed. Add Decoupling Capacitors: Adding capacitors (typically 0.1µF to 10µF) near the IC’s power pins can help filter out noise and stabilize the power input.

4. High Current Consumption

Cause: Excessive current draw can lead to overheating and eventual failure of the TPS3825-33DBVR. High current draw can be a result of incorrect connections or a damaged component.

Solution:

Measure Current Draw: Use a multimeter to check the current consumption of the IC. If the current exceeds the recommended operating range, inspect your circuit for possible shorts or incorrectly rated components. Check for Short Circuits: Examine the PCB for any short circuits or solder bridges that could cause excess current to flow through the IC. Replace the IC: If the current consumption is still high after verifying the circuit, the IC itself may be damaged. Replace the component with a new one and verify its functionality.

5. Failure to Detect Voltage Drop (Incorrect Reset Behavior)

Cause: A voltage drop might not trigger a reset if the TPS3825-33DBVR fails to detect a falling voltage properly, often caused by incorrect configuration or component failure.

Solution:

Check Voltage Threshold: Ensure that the threshold voltage setting is accurate and matches the intended value for your system. If it’s incorrectly set, the IC may fail to trigger a reset. Inspect Capacitor Values: The reset signal’s behavior is influenced by external capacitors. If these capacitors are too large or too small, it can cause the IC to behave incorrectly. Verify their values as per the datasheet recommendations. Replace Faulty Components: If the voltage drop is not being detected despite correct configuration, the IC might be defective. Replace the IC and check the system again.

Final Thoughts

To avoid or quickly fix power supply failures with the TPS3825-33DBVR, it’s crucial to ensure proper input voltage, verify resistor and capacitor configurations, and carefully follow the power-up sequence. Regularly checking for shorts, damaged components, and correct voltage threshold settings can significantly reduce the risk of failure and improve system reliability. By following the solutions outlined above, you should be able to quickly diagnose and resolve most common failures associated with this voltage supervisor IC.