Abstract: Micro-electrode-dot-array biochip (MEDA biochip) is a new type of digital microfluidic chip that combines microelectronics and microfluidics. Based on the idea of microarrays, each microcell includes a drive circuit and a detection circuit to realize real-time monitoring of biochemical tests. To reduce external pins, all microcells of MEDA biochip are connected in series by a daisy chain to achieve accurate control of the biochip. As the key data path of the MEDA biochip, even if only one unit fails in the daisy chain, the entire chain will fail. Therefore, an effective fault-tolerant design must be carried out on the daisy chain. In this paper, a daisy chain structure with self-test and fault-tolerant functions is designed for MEDA biochip. The test response triggers the automatic fault tolerance of the daisy chain’s fault unit. When a certain unit of the daisy chain fails, its test response is abnormal, which triggers the automatic repair of the failed unit. If the repair fails, the abnormal test response will trigger the bypass of the unit again, thereby achieving automatic fault tolerance. Experimental results show that the structure can perform effective fault tolerance while testing and diagnosing faults, and bypass it permanently when fault tolerance fails.

Key words: micro-electrode-dot-array biochip, fault diagnosis, fault tolerant design