Multi-Channel and Fault-Tolerant Control Multiplexing for Flow-Based Microfluidic Biochips

Continuous flow-based biochips are one of the promising platforms used in biochemical and pharmaceutical laboratories due to their efficiency and low costs. Inside such a chip, fluid volumes of nanoliter size are transported between devices for various operations, such as mixing and detection. The transportation channels and corresponding operation devices are controlled by microvalves driven by external pressure sources. Since assigning an independent pressure source to every microvalve would be impractical due to high costs and limited system dimensions, states of microvalves are switched using a control logic by time multiplexing. Existing control logic designs, however, still switch only a single control channel per operation - leading to a low efficiency. In this paper, we propose the first automatic synthesis approach for a control logic that is able to switch multiple control channels simultaneously to reduce the overall switching time of valve states. In addition, we propose the first fault-aware design in control logic to introduce redundant control paths to maintain the correct function even when manufacturing defects occur. Compared with the existing direct connection method, the proposed multi-channel switching mechanism can reduce the switching time of valve states by up to 64%. In addition, all control paths for fault tolerance have been realized.