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NCKU CSIE EDALAB Shang-Tsung Yu, Sheng-Han Yeh, and Tsung-Yi Ho jidung@eda.csie.ncku.edu.tw http://eda.csie.ncku.edu.tw Electronic Design Automation Laboratory Department of Computer Science and Information Engineering National Cheng Kung University Tainan, Taiwan ISPD 2014 Slide 2 NCKU CSIE EDALAB Outline 2 Introduction Problem Formulation Algorithm Experimental Results Conclusions Slide 3 NCKU CSIE EDALAB Digital Microfluidic Biochips (DMFBs) The architecture of DMFBs 2D microfluidic array: A set of basic cells for biological reactions Droplets: Biological sample carrier as basic units to perform the laboratory procedures on a DMFB Reservoirs/dispensing ports: Generate droplets Optical detectors: Detection of reaction result 3 Slide 4 NCKU CSIE EDALAB Electrowetting-On-Dielectric Chips (EWOD Chips) For EWOD chips, electrodes can be actuated by applying voltage to the electrode. 4 Side view Droplet Bottom plate Top plate Ground electrode Control electrodes Hydrophobic insulation Actuated Droplet Generated electrical field Slide 5 NCKU CSIE EDALAB 5 Operation of Digital Microfluidics (1/3) Transport 25 cm/s flow rates, order of magnitude Slide 6 NCKU CSIE EDALAB 6 Operation of Digital Microfluidics (2/3) Splitting/Merging Slide 7 NCKU CSIE EDALAB 7 Droplet Dispensing Synchronization of many droplets Operation of Digital Microfluidics (3/3) Slide 8 NCKU CSIE EDALAB Chip-Level Design of EWOD Chips Bottom layer contains conduction wires, electrical pads, and a substrate The routing problem: 2D pin array (routing inner electrodes to outside electrical pads) How to control these electrodes 8 Bottom Layer Slide 9 NCKU CSIE EDALAB Pin-Constrained EWOD chips Huge number of electrodes in large-scale DMFBs Limited number of ports in external controller Broadcast addressing technique for pin-constrained - Reduce pin count and fabricate cost 9 Pin Count: 12 Pin Count: 5 Electrodes share the same control pin Slide 10 NCKU CSIE EDALAB X Broadcast Electrode Addressing (1/2) Electrode Actuation Sequence (AS) An AS represents every status demanded at each time step 1: Actuated term 0: Grounded term X: Dont care term Share the same control pin By observing, multiple electrodes can share an identical sequence by replacing X with 1 or 0 10 1X0100X 101XX11 1 00 1 Compatible time step123456 status of electrode10X01X These electrodes can be merged into the same control pin Slide 11 NCKU CSIE EDALAB Broadcast Electrode Addressing (2/2) Broadcast addressing constraint If the actuation sequences are (arent) mutually compatible, they can (cannot) be addressed with the same control pin 11 e1e1 e2e2 e3e3 e4e4 e5e5 e6e6 e7e7 e8e8 e9e9 e 10 e 11 e 12 Electrode groups : {e 1, e 2, e 9, e 10 }, {e 3, e 4, e 5, e 8, e 11, e 12 }, {e 6, e 7 } Pin 1 Pin 2 Pin 3 e1e1 e2e2 e3e3 e4e4 e5e5 e6e6 e7e7 e8e8 e9e9 e 10 e 11 e 12 Compatibility graph Clique partition Electrode Compatible Slide 12 NCKU CSIE EDALAB Reliability Issue (1/2) Arbitrary broadcast addressing will cause huge number of switching times in resulting AS e1e1 e2e2 e3e3 10X0X0 1X0X00 X01X1X 101010 100000 10 e1e1 e2e2 e1e1 e3e3 Slide 13 NCKU CSIE EDALAB Appendix Appendix Broadcast Electrode Addressing Droplet Spacing High voltage to generate an electrical field 0010XXX time X0010XX XX0010X XXX0010 XXXX001 Wire External controller Actuation sequence 00XXX00XXX 00XXX00XXX 1001010010 1001010010 0100101001 0100101001 7 pins -> 4 pins Broadcast addressing Electrode 41 impossible Slide 42 NCKU CSIE EDALAB Appendixes Appendixes CAD Flow (1/2) 42 Sequencing Graph Microfluidic Module Library Design Spec. Architectural-Level Synthesis SchedulingResource Binding O1 O2 ResourceAreaTime Mixer2x2-array7 Mixer1x3-array4 LED1x1 cell10 Storage1x1 cellN/A O3 O4 O5 O6 Store Dispense Store Mix Detection OperationResource O1On-chip O22x2-array O31x1 cell O4LED O51x3-array O61x1 cell Max. Area: 5x5 array Max. Completion Time: 50 seconds O1O3O6 O5 O2 O4 Slide 43 NCKU CSIE EDALAB Appendixes Appendixes CAD Flow (2/2) 43 SchedulingResource Binding OperationResource O1On-chip O22x2-array O31x1 cell O4LED O51x3-array O61x1 cell Placement O2O1 O4O5 O6O3 Physical-Level Synthesis Routing O2O1 O4O5 O6O3 O1O3O6 O5 O2 O4