Built-in self-test and fault diagnosis for lab-on-chip using digital microfluidic logic gates

Dependability is an important system attribute for microfluidic lab-on-chip. Structural test and functional test are needed to detect defects and malfunctions, respectively. Previously proposed techniques for reading test outcomes and for pulse-sequence analysis are cumbersome and error-prone. We present a built-in self-test (BIST) method for digital microfluidic lab-on-chip. This method utilizes digital microfluidic logic gates to implement the BIST architecture; AND, OR and NOT gates are used to compress test-outcome droplets into one droplet signature. This approach obviates the need for capacitive sensing test-outcome circuits for analysis. An efficient diagnosis method based on a microfluidic encoder is also proposed to locate a single defective electrode in a microfluidic array. Finally, reconfiguration is used during test and diagnosis to enable BIST with low area overhead. 1