How to Diagnose Faults in the TPS65987DDHRSHR Voltage Regulation
Diagnosing Faults in the TPS65987DDHRSHR Voltage Regulation
The TPS65987DDHRSHR is a Power Path Controller (PPC) that helps manage the power flow and voltage regulation in systems. It’s commonly used in USB Type-C and Power Delivery applications. Diagnosing faults in the voltage regulation section of this chip can be tricky, but by following a systematic approach, you can effectively troubleshoot and resolve the issue. Below is a step-by-step guide on how to diagnose and fix faults in the voltage regulation of the TPS65987DDHRSHR.
1. Check Power Supply Inputs Possible Fault Cause: Insufficient or unstable input voltage. How to Check: Measure the input voltage to the TPS65987DDHRSHR. The chip typically operates from a 5V to 12V input range. Ensure that the input voltage is within the specified range. If it’s below or above this range, the voltage regulation might not work as expected. Solution: If the input voltage is not within the correct range, adjust your power supply or check the circuit supplying the power to the chip. Make sure there is no excessive noise or ripple in the input power. 2. Verify Enable and Power Good Signals Possible Fault Cause: Issues with the enable or power good signals. How to Check: Check the ENABLE pin and PGOOD (Power Good) signal. The ENABLE pin controls whether the chip is powered on or off. If the ENABLE pin is not being driven correctly, or if the PGOOD signal doesn’t indicate the expected high signal when the chip is operating normally, the voltage regulation could fail. Solution: Ensure the ENABLE pin is correctly configured in the system design. Confirm that the PGOOD signal is being monitored and reflects the actual status of the voltage regulation. If it’s low, this indicates a problem with power delivery. 3. Inspect Output Voltage Possible Fault Cause: Incorrect output voltage regulation. How to Check: Use a multimeter or oscilloscope to measure the output voltage. Ensure the output voltage matches the expected value (for example, 5V, 9V, or 12V depending on your design). If the output voltage is too low or too high, this could point to a problem with the internal voltage regulator. Solution: Check the feedback loop (feedback resistors or capacitor s) involved in regulating the output voltage. Ensure the output capacitors are within the specified values. Faulty capacitors or incorrect values can lead to poor voltage regulation. 4. Check for Overcurrent Conditions Possible Fault Cause: Overcurrent or thermal shutdown. How to Check: Check the ILIM pin, which sets the current limit for the power path. If the current is too high, it may cause the chip to enter thermal shutdown or current limit mode. Measure the current flowing through the circuit, if possible, using a current probe. Solution: If overcurrent is detected, ensure that your load is within the specifications of the power path controller. Use proper heat dissipation (such as heat sinks or cooling) to avoid overheating. Consider adding an external current-limiting circuit if necessary. 5. Monitor Thermal Performance Possible Fault Cause: Overheating due to inadequate cooling or excessive power dissipation. How to Check: Check the temperature of the TPS65987DDHRSHR chip using an infrared thermometer or thermal camera. If the chip is overheating, it could indicate excessive power dissipation or poor thermal management. Solution: Ensure proper PCB layout with adequate thermal vias and ground planes to dissipate heat. If required, add a heatsink to the chip to improve thermal performance. 6. Review the PCB Layout Possible Fault Cause: Poor PCB design or layout issues affecting voltage regulation. How to Check: Inspect the PCB layout for good grounding and power distribution. Ensure that high-current paths are wide and that low-current traces are kept away from power traces. Check for proper decoupling capacitors close to the TPS65987DDHRSHR pins. Solution: Follow the manufacturer’s recommendations for PCB layout to ensure that the chip operates optimally. Improve the power and ground plane routing if necessary. 7. Verify External Components Possible Fault Cause: Faulty or out-of-spec external components. How to Check: Inspect all external components connected to the TPS65987DDHRSHR, including capacitors, inductors, and resistors. Ensure all components meet the manufacturer’s specified tolerances and values. Solution: Replace any components that are damaged or out of spec. This can include replacing capacitors, resistors, or inductors that may be affecting voltage regulation.Final Thoughts
The TPS65987DDHRSHR is a versatile and reliable power management chip, but like any complex component, faults can arise due to various reasons, from input voltage issues to PCB layout problems. By following a step-by-step diagnostic approach, you can systematically narrow down the fault and apply the appropriate solution. Always refer to the datasheet for specific recommendations and check all critical signals to ensure the chip operates within its intended parameters.