Fixing TPS61169DCKR Start-Up Failures in Power Circuits

Fixing TPS61169DCKR Start-Up Failures in Power Circuits

Fixing TPS61169DCKR Start-Up Failures in Power Circuits

The TPS61169DCKR is a highly efficient DC-DC boost converter designed for power supply applications in various devices. However, like any electronic component, it can encounter start-up failures under certain conditions. This guide will walk you through the analysis of potential causes, explain why these failures happen, and provide step-by-step solutions to resolve them.

1. Understanding the Start-Up Process of TPS61169DCKR

The TPS61169DCKR operates by boosting a lower input voltage to a higher output voltage. During start-up, the device begins its internal switching process, which includes:

Initial power-up and stabilization of the input voltage. The establishment of feedback and regulation loops. Activating the internal components like the switching transistor and the inductor to create the necessary output voltage.

Any disruption in this sequence can result in a start-up failure.

2. Common Causes of Start-Up Failures

A. Insufficient Input Voltage

The TPS61169DCKR requires a minimum input voltage to function properly, typically around 2.0V to 2.5V. If the input voltage is below this threshold, the device will fail to start up.

Cause:

A weak power supply or battery, or a power drop at the input can cause this issue.

Solution:

Ensure that the input voltage is within the recommended range (usually 2.0V to 5.5V for proper operation). Check for any voltage dips, weak battery, or unstable power source. B. Inadequate External Components (Inductor and Capacitors )

The TPS61169DCKR requires specific external components such as an inductor, input capacitor , and output capacitor. If these components are improperly sized or connected, the converter may fail to start.

Cause:

Using the wrong inductor value or insufficient output/input capacitors. Poor PCB layout resulting in noise or voltage spikes.

Solution:

Verify that the inductor and capacitors are selected according to the datasheet's recommendations. The correct inductance value is typically around 10µH to 22µH. Ensure the capacitors have the proper voltage ratings and sufficient capacitance to support stable operation (e.g., 10µF to 22µF on the input and output). Optimize PCB layout to minimize noise, ensuring proper grounding and trace width for current handling. C. Feedback Loop and Enable Pin Issues

The TPS61169DCKR uses feedback control to regulate its output voltage. If there is an issue with the feedback loop or the enable pin (which turns the device on), the start-up may fail.

Cause:

The feedback resistors are not correctly configured, leading to improper voltage regulation. The enable pin may not be properly driven or could be floating.

Solution:

Check the feedback resistors and ensure they are configured according to the desired output voltage. Verify that the enable pin is either pulled high or low (depending on the design), and is not left floating. A floating enable pin can result in erratic start-up behavior. D. Overcurrent or Overvoltage Protection Triggering

The TPS61169DCKR includes built-in overcurrent and overvoltage protection to safeguard against faulty conditions. If the circuit experiences a fault such as a short circuit or excessive voltage on the output, these protections will prevent start-up.

Cause:

Short circuits on the output or excessive load could cause the device to go into protection mode. An excessive output voltage may be sensed, prompting shutdown to avoid damage.

Solution:

Inspect the output for any short circuits or incorrect wiring. Ensure the load connected to the output is within the recommended specifications. If necessary, add current-limiting features to your circuit to prevent excessive load at startup.

3. Step-by-Step Troubleshooting Procedure

If you're facing start-up failures with the TPS61169DCKR, follow these steps to resolve the issue:

Step 1: Verify Input Voltage Measure the input voltage at the power supply pin (VIN). Compare it with the recommended operating range (usually 2.0V to 5.5V). If the voltage is too low, check the power supply or battery and ensure stable operation. Step 2: Inspect External Components Check the inductor and capacitors. Verify their values are within the recommended range (e.g., inductance of 10µH to 22µH and capacitors of 10µF to 22µF). Inspect their placement on the PCB and ensure there are no soldering issues or shorts. Step 3: Check Feedback Loop Examine the feedback resistors to ensure they are properly sized and correctly positioned for the desired output voltage. Ensure that the feedback pin is not floating and is properly connected to the voltage divider network. Step 4: Test the Enable Pin Check the voltage on the enable pin (EN). It should be pulled high for the device to start. If necessary, use a pull-up resistor to ensure that the enable pin is driven to the correct logic level. Step 5: Investigate Protection Features Check for any signs of overcurrent or overvoltage conditions. Verify the load connected to the output is within the safe operating range. Step 6: Double-Check PCB Layout Ensure the PCB layout follows the guidelines for minimizing noise and ensuring proper current flow. Check for issues like excessive trace lengths, improper grounding, or traces running near noisy power rails.

4. Final Thoughts

By following the above steps, you should be able to diagnose and resolve the start-up failures in TPS61169DCKR circuits. It's essential to follow the component selection guidelines, ensure stable input voltage, and have a solid PCB layout. Once you’ve confirmed these factors are correct, the TPS61169DCKR should power up reliably.

If issues persist, consider reviewing the device's datasheet for any additional troubleshooting guidelines or reach out to the manufacturer’s support for further assistance.