Common Inductor Failures in TPS61165DRVR and How to Resolve Them

Common Inductor Failures in TPS61165DRVR and How to Resolve Them

Common Inductor Failures in TPS61165DRVR and How to Resolve Them

The TPS61165DRVR is a popular boost converter used in various Power Management applications, and like any power management device, it can experience issues, especially related to its inductors. Inductor failures are common in such circuits due to a variety of factors, including overcurrent, overheating, and improper circuit design. Below is a breakdown of common inductor failures, the causes, and solutions to help you resolve them.

1. Inductor Saturation

Cause: Inductor saturation occurs when the current through the inductor exceeds its rated value, causing the core material to saturate. This means the inductor cannot store any more energy, and the performance of the converter deteriorates.

Why It Happens:

High input voltage or load transients.

Incorrect inductor selection (e.g., low inductance or high saturation current).

Operating conditions that push the circuit beyond the inductor’s specifications.

Solution:

Use a higher-rated inductor: Choose an inductor with a higher saturation current rating.

Verify operating conditions: Check that the input voltage, output voltage, and load conditions are within the inductor’s safe operating limits.

Add current sensing: Implement a current sense resistor or a current-sensing IC to protect against overcurrent conditions.

2. Inductor Overheating

Cause: Overheating of the inductor can be caused by excessive power loss within the inductor due to high ripple current or insufficient heat dissipation.

Why It Happens:

High ripple current that exceeds the inductor’s rated current handling capability.

Poor PCB design that doesn’t allow for sufficient heat dissipation.

Using inductors with low-quality cores that have high core losses.

Solution:

Use an inductor with lower DCR (DC resistance): Low DCR inductors generate less heat and are more efficient.

Improve Thermal Management : Ensure proper airflow or add heatsinks to the PCB. Use wide traces or copper pours to dissipate heat more effectively.

Reduce ripple current: Adjust the switching frequency or output capacitance to reduce ripple current in the inductor.

3. Inductor Open Circuit

Cause: An open circuit in the inductor occurs when one of the windings breaks, often due to excessive current, physical damage, or poor manufacturing.

Why It Happens:

Inrush currents or voltage spikes causing physical damage to the windings.

Mechanical stress due to vibration or poor soldering causing loose connections.

Inadequate overcurrent protection or power surges.

Solution:

Replace damaged inductors: Inspect the inductor physically for damage and replace it if needed.

Implement overcurrent protection: Use a current-limiting circuit or fuse to prevent overcurrent from damaging the inductor.

Inspect soldering and PCB design: Ensure proper soldering techniques and ensure that the PCB design minimizes stress on the components, including inductors.

4. Inductor Loss of Inductance

Cause: Inductance can degrade over time due to stress on the core material, causing a loss of the inductor's ability to store energy efficiently.

Why It Happens:

Prolonged exposure to high operating temperatures.

Saturation of the core material from excessive current.

Physical damage to the core due to mechanical shock or vibration.

Solution:

Choose high-quality inductors: Select inductors with cores designed to handle higher temperatures and stresses.

Monitor temperature: Ensure that the circuit operates within the safe temperature range and avoid exceeding the maximum temperature ratings of the components.

Use inductors with a higher thermal rating: Look for inductors specifically rated for high-temperature applications.

5. Inductor Damage from Switching Noise

Cause: Power converters like the TPS61165DRVR operate at high switching frequencies, which can introduce electromagnetic interference ( EMI ) or switching noise that damages sensitive components, including the inductor.

Why It Happens:

High-frequency switching causing noise or voltage spikes that impact the inductor.

Poor layout of the PCB, leading to coupling of high-frequency signals into sensitive components.

Solution:

Improve PCB layout: Ensure proper grounding and shielding to reduce noise. Use ground planes and place the inductor as far from high-noise components as possible.

Use a snubber circuit: A snubber can be used to reduce voltage spikes and ringing during switching events.

Filter high-frequency noise: Use capacitor s or ferrite beads to filter out unwanted high-frequency noise.

General Steps to Resolve Inductor Failures

Identify the Failure: Check for obvious signs like overheating, burning smell, physical damage, or performance degradation. Measure the current through the inductor and monitor the voltage waveform to look for irregularities. Select the Right Inductor: Review the datasheet for the TPS61165DRVR and match the inductor’s specifications with the design requirements, including current rating, inductance, and saturation current. Protect the Inductor: Implement overcurrent protection, thermal monitoring, and proper power management strategies. Ensure that the input voltage, output voltage, and switching frequency are within the designed limits. Improve Thermal Management: Add adequate cooling, heatsinks, or improve PCB layout to manage the heat generated by the inductor. Replace the Faulty Inductor: If any inductor is found to be faulty, replace it with a higher-quality or higher-rated inductor. Ensure the replacement inductor matches the specifications for your application.

By following these steps, you can resolve most inductor-related failures in the TPS61165DRVR and ensure reliable performance for your power management application.