Linear Technology DC2100A Demo Manual page 12

DEMO MANUAL DC2100A
Quick start proceDure
Two or More Board Setup and Operation
When connecting two or more DC2100A boards together,
the interface cables must be connected in sequence as
shown in Figure 23 to avoid large inrush currents. When
connecting more than one DC2100A's into a system
containing more than 12 batteries, DC2100A-D are used
in locations 2 through 8. The PC USB port is connected
to the bottom DC2100A-C (J19) board first and then the
next DC2100A-D (J18) may be connected to the bottom
DC2100A-C (J1) with a CAT-5 cable. CAT-5 cables are used
for communication connects between all DC2100A demo
boards in the system. J1 is the output port while J18 is
the input port. The Top DC2100A-D must have the JP6 in
position 1. All other DC2100A will have JP6 in position 0.
The 24 cell should be interconnected as shown in Figure 24
to allow balancing between the two 12 cell stacks.
Additional Circuitry
Additional circuitry has been added to increase the robust-
ness of the design for fault insertions.
Cell 6 Wire Disconnection
A 10A 200V Schottky diode has been added for a high
current path when the connection between battery cells
is broken when a battery stack load is present. The 200V
reverse voltage rating of the diode was selected to mini-
mize the reverse leakage current with cell voltage of 4V.
The 10A current rating was selected for its low forward
voltage drop which will minimize the current in the parallel
diode within the LTC3300-1 as well as surviving the fusing
current of the 12A cell fuses on the DC2100A.
Two overvoltage detection circuits have been added to
the design that will sense an overvoltage condition on
Cell 6 and Cell 7 when a disconnection of the Cell 6 wire
connection between Cell 6 + and Cell 7- of the battery
stack occurs. When Cell 6 is being discharged and other
12
TOP BOARD
CAT-5 CABLE
DC2100A-D
Figure 23. Two DC2100A SPI Connection
cells controlled by the U1, the lower LTC3300-1, and U2,
the upper LTC3300-1 are operational, an overvoltage
can occur on Cell 7. The overvoltage on Cell 7 will shut
down the operation of Cell 7 – Cell 12 but Cell 1 – Cell 6
will continue to operate. The overvoltage sensing circuit
Q4, D8, D10 and R56 will turn off Cell 1 – Cell 6 through
the internal overvoltage protection circuit within the
LTC3300-1 of U1.
DC2100A-D
J1 J18
CAT 5
DC2100A-C
INSTALL R23 0
J1 J18
CAT 5
PC
Figure 24. 24 Cell Interconnecting Stacks
BOTTOM BOARD
USB
DC2100A-C
TOP6_T
CELL 24
C12
BOT6_T
CELL 18
C1
CELL 13
J19
V –
TOP6_T
C12
CELL 12
BOT6_T
CELL 6
C1
J19
CELL 1
V –
USB
PC
dc2100afa