Biomedical Engineering Reference
In-Depth Information
Partition 2
Partition 3
Partition
Ti me Span
Y
1
1-7
Partition 23
2
5-16
3
7-14
Partition 1
Partition 4
4
17-20
23.2
10-11
X
23.3
13-14
(a)
(b)
Figure 3.5
(a) Routing result and partitioning; (b) time-span table for the droplets.
during which it contains a droplet. The time spans for all the partitions can
be easily calculated from the operation schedule, module placement, and
droplet-routing results [15]; the overlaps can then be readily determined.
Partitions with nonoverlapping time spans are merged to form a larger par-
tition. This check-merge procedure continues until all partition pairs overlap
in their time spans. By reducing the number of partitions, we can reduce the
number of control pins needed for the array. Note that droplet traces may
have spatial overlap; that is, they may intersect at one or more unit cells on
the array. In this case, the requirement of one droplet per partition is not
met and droplet interference may occur. This problem is handled by simply
modifying the partitioning result.
We next study the case where droplet traces intersect on the array. This
implies that partitions derived by the proposed method overlap in some
regions. Sets of pins from an “overlapping” partition cannot be used in the
overlapped region since the reuse of the pins may lead to droplet interfer-
ence. One solution to this problem is to make the overlapping region a new
partition, referred to as the
overlapping partition
, and use direct-addressing
for it. Again, time-division pin-sharing (TDPS) can be used to reduce the
number of pins since pin sets of the other (nonoverlapping) partitions can be
candidates for direct addressing in the overlapping partition.
An example of this approach is shown in Figure 3.5. The droplet traces are
first derived from the droplet-routing information. Partitions 1, 2, 3, and 4 are
assigned accordingly. Partitions 2 and 3 overlap with each other as shown in
Figure 3.5. Thus, a new Partition 23 is created. From the scheduling result in
Figure 3.5b, the time span for Partition 23 is found to be 10-14 s.
(See Table 3.1.)
Next, the time spans for Partitions 1 and 4 are checked, and it is seen that
their time spans do not overlap with that for Partition 23. Hence, the two sets
of pins (a total of 2 × 5 = 10 pins) in Partitions 1 and 4 can be used to directly
address the nine electrodes in Partition 23.
Partitions that share pins with the overlapping partition are empty, while
droplets are manipulated in the overlapping partition. Therefore, the shar-
ing of pins in these cases does not lead to droplet interference. By introduc-
ing the concept of TDPS, we can significantly reduce the number of pins
