Introduction

Logic Built-In Self-Test (LBIST) is a powerful technique for testing digital logic circuits, ensuring that they function as expected. Traditionally, LBIST has been used during manufacturing testing to verify the integrity of digital logic; however, when it comes to online diagnostics, LBIST takes on a crucial role in continuous, real-time fault detection. This capability is particularly important for mission-critical applications, such as automotive, aerospace, and industrial systems, where uptime and reliability are paramount.

Implementing LBIST for online diagnostics brings its own set of challenges. These challenges must be addressed to ensure seamless operation, real-time detection, and efficient fault correction during device operation.

Problem Statement

When deploying LBIST for online diagnostics, four key challenges must be addressed to ensure effective and efficient real-time fault detection:

1. Seamless LBIST Insertion for Online Operation

• Implement an LBIST controller that integrates into the system with minimal impact on system performance. The controller should be activated on-demand using low-overhead mechanisms to avoid disrupting normal operation.
• Use clock gating and scan chain optimization techniques to limit the operational overhead while ensuring comprehensive logic testing when required.

2. Adaptive Test Pattern Generation for Real-Time Fault Detection

• The test patterns used for online diagnostics must be dynamic and capable of identifying faults in real-time without disrupting the system’s normal performance. Balancing test coverage with power consumption is a key challenge.

3. Real-Time Fault Detection and Reporting

• Faults need to be detected promptly during operation, and the system must report the faults to the diagnostic system without delay. Ensuring that fault detection is both accurate and timely is essential for online diagnostics.

4. Efficient Fault Diagnosis and Correction

• Once a fault is detected, it is essential to isolate and diagnose it in real-time. Implementing efficient repair mechanisms or error recovery strategies can minimize downtime and prevent system failure.

Conclusion

The successful implementation of LBIST for online diagnostics involves overcoming challenges related to integration, test pattern generation, real-time detection, and fault diagnosis. 

At AiSemi Private Limited, we provide customized LBIST solutions that enhance test efficiency and product reliability. Contact us today to learn how our expertise can help optimize your chip testing strategy.