A Power Efficient Test Data Compression Method on Count Compatible PRL Coding

Abstract

A realistic test sets compression method is proposed to effectively reduce test data volume and test application time during system-on-chip (SoC) scan testing, count compatible pattern run-length (CCPRL) coding method counts the consecutive number of the equal to or contrary to the retained patterns, it modifies the compatible code of variable-length pattern run-length (VPRL) coding rules and adds a count code block to replace original rules for increasing compression ratio. Next, the decoder architecture and the state diagram of finite state machine (FSM) are designed. In addition, the power model of test vectors is analyzed, and the power consumption of scanned-in vectors is roughly evaluated. The six largest ISCAS'89 benchmark circuits verify the proposed coding method has a shorter codeword. Experiment results shows that all compression ratios have been increased as much as possible, test data decompression is lossless, less test application time is consumed, yet the peak power and average power consumption of scanned-in test vector needs to be further improved for modern circuit scan testing.