User Manual Q&AAnswer
Apr 08, 2025 - 12:29 PM
The Configurable BISR Chain for Fast Repair Data Loading system is designed to speed up the process of loading repair data during system power-up for designs with a large number of memories. Here is how it works and the benefits it provides:
1. General Memory Repair System: The system includes a dedicated repair register for each memory, with a repair enable signal indicating whether a memory needs repair. Most repair registers contain only 0s, allowing compression of repair information in a fuse box.
2. Prior Work: Previous approaches have explored repair sharing, where the same repair solution is used for several memories, and memory bypass, where each repair register can be bypassed. However, these methods have limitations in terms of application and speedup.
3. Configurable BISR Chain: The proposed system extends the idea of bypassing repair registers to bypass longer segments at a time. This reduces the overhead associated with the configuration chain. A Segment Selection Circuit (SSC) is used to select or bypass the associated chain segment, with additional circuitry to identify segments that need repair.
4. Active Scan Path: The system includes an active scan path with a bypassed segment and a left segment included in the scan path because at least one memory needs repair. The right segment is bypassed because none of the memories need repair, and its segment input is forced to 0.
5. Repair Data Programming Sequence: The system follows a specific sequence to program the repair data during power-up. The exact details of this sequence may be provided in the user guide.
6. Benefits: The Configurable BISR Chain for Fast Repair Data Loading system offers significant speedup in the repair data loading process during chip power-up. Experimental results have shown that the number of clock cycles can be reduced by one to two orders of magnitude compared to previous methods. This means that the overall time required to load repair data is greatly reduced, leading to faster system initialization and improved efficiency.
Please refer to the SIEMENS Configurable BISR Chain for Fast Repair Data Loading User Guide for more detailed information on the system's operation, experimental results, and conclusions.
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