TPS63060DSCR Overvoltage Lockout Causes and Solutions

Analysis of TPS63060DSCR Overvoltage Lockout: Causes and Solutions

The TPS63060DSCR is a highly integrated, step-up/down DC-DC converter. One of the issues users may face with this device is overvoltage lockout (OVLO), which occurs when the input voltage exceeds a predefined threshold. This problem can lead to system failure or unstable operation. In this guide, we’ll analyze the causes of overvoltage lockout, explain how it happens, and provide a step-by-step solution to resolve this issue.

1. Understanding Overvoltage Lockout (OVLO)

Overvoltage lockout is a protective feature that prevents the device from operating if the input voltage exceeds the safe operational range. When the input voltage is higher than the set threshold, the TPS63060DSCR will shut down to avoid damage to the internal circuitry or instability in the output voltage.

The device is designed to operate within a specific input voltage range, typically between 2.3V and 5.5V. If the voltage exceeds the upper threshold (typically around 5.8V for this chip), the OVLO feature is triggered, and the converter goes into a shutdown state. The system will not function normally until the input voltage drops below the overvoltage threshold.

2. Causes of Overvoltage Lockout in TPS63060DSCR

There are several potential causes for OVLO in the TPS63060DSCR:

Excessive Input Voltage: The most common cause of OVLO is simply an input voltage that exceeds the maximum allowable value. This can happen if the input Power source is unstable or if it is not properly regulated.

Power Supply Instability: Fluctuations in the power supply, such as spikes, surges, or noise, can cause the input voltage to momentarily exceed the threshold, triggering the lockout.

Incorrectly Configured OVLO Threshold: Some systems may use external components to set the OVLO threshold. If these components are incorrectly chosen or malfunctioning, the threshold may be set too low, causing premature lockout.

Faulty or Inconsistent Sensing Circuits: The TPS63060DSCR uses a feedback mechanism to monitor input voltage levels. If there is a fault in the feedback network (e.g., poor connection, defective resistors), the device may misinterpret the voltage level and incorrectly trigger OVLO.

3. How to Resolve Overvoltage Lockout Issues

To resolve the overvoltage lockout problem, follow these step-by-step solutions:

Step-by-Step Troubleshooting and Solutions

Step 1: Check the Input Voltage

Measure the Input Voltage: Use a multimeter to check the input voltage being supplied to the TPS63060DSCR. Ensure that it is within the recommended range of 2.3V to 5.5V. If the voltage exceeds 5.5V, the system will be in overvoltage lockout.

Verify Power Source Stability: Ensure that your power source is stable and provides a constant voltage. If the input voltage is unstable, consider using a regulated power supply or adding voltage regulation components to stabilize the input voltage.

Step 2: Investigate Possible Spikes or Surges

Check for Voltage Spikes: Use an oscilloscope to monitor the input voltage for any spikes or transients that may be exceeding the overvoltage threshold. These short-lived spikes could be causing the lockout.

Add Filtering capacitor s: If voltage spikes are detected, add decoupling capacitors (e.g., 10µF or 100µF) at the input to help smooth out any transient voltage. A low-pass filter can also be useful in filtering high-frequency noise that may cause temporary overvoltage conditions.

Step 3: Verify the Overvoltage Lockout Threshold Configuration

Review External Components: If the OVLO threshold is configured externally, review the external components (such as resistors or voltage dividers) that set this threshold. Ensure that the resistors are within the correct tolerance and that the voltage divider circuit is properly designed.

Adjust the Threshold: If needed, adjust the external components to set the OVLO threshold appropriately for your system’s voltage requirements.

Step 4: Check for Faulty Feedback or Sensing Circuits

Inspect Feedback Network: Check the feedback network (comprising resistors and capacitors) to ensure there are no loose connections or faulty components. A broken or poorly connected feedback loop could cause incorrect voltage sensing and false overvoltage detection.

Replace Faulty Components: If any components in the feedback network are found to be defective, replace them with new ones and verify the circuit’s functionality.

Step 5: Reboot and Monitor the System

After addressing the above issues, power on the system and monitor the device’s performance. Ensure that the overvoltage lockout is no longer triggered and that the TPS63060DSCR operates normally.

Test Under Load: Test the system under normal operating conditions (with the load connected) to verify that the output voltage is stable and the device is not shutting down due to overvoltage.

Step 6: Optional - Add Protection Features

To prevent future overvoltage conditions from damaging your system, consider adding protection features such as:

Surge Protectors: Install surge protectors or Zener diodes to protect against voltage spikes that exceed the safe operating limits of the TPS63060DSCR.

Crowbar Circuits: Add a crowbar circuit that will short the input to ground in the event of an overvoltage condition, thereby protecting the system.

Conclusion

Overvoltage lockout in the TPS63060DSCR is typically caused by excessive input voltage, unstable power supply, incorrect threshold configuration, or faulty feedback circuits. To resolve this issue, you should:

Verify the input voltage and ensure it is within the proper range. Check for voltage spikes and add filtering if necessary. Review and adjust the OVLO threshold configuration. Inspect the feedback circuit for any faults. Test the system after addressing the issue.

By following these steps, you can troubleshoot and resolve overvoltage lockout in the TPS63060DSCR, ensuring that the system operates reliably and safely.