Datasheet

LTC6802-2
11
68022fa
operaTion
Figure 1. 96-Cell Battery Stack, Isolated Interface. In this Diagram the Battery Negative is Isolated from Module Ground.
Opto-Couplers or Digital Isolators Allow Each IC to be Addressed Individually. This is a Simplified Schematic Showing
the Basic Multi-IC Architecture
V2
–
OE2
V2
–
V2
+
V1
–
OE1
V1
–
V1
+
DIGITAL
ISOLATOR
BATTERY
POSITIVE
350V
3V
3V
MODULE
IO
ADDRESS 0
V
+
C12
S12
C11
S11
C10
S10
C9
S9
C8
S8
C7
S7
C6
S6
C5
S5
C4
S4
C3
S3
C2
CSBI
SDO
SDI
SCKI
A3
A2
A1
A0
GPIO2
GPIO1
WDTB
MMB
TOS
V
REG
V
REF
V
TEMP2
V
TEMP1
NC
V
–
S1
C1
S2
LTC6802-2
IC #1
MISO
CS
MOSI
CLK
MPU
68022 F01
V2
–
OE2
V2
–
V2
+
V1
–
OE1
V1
–
V1
+
DIGITAL
ISOLATOR
3V
ADDRESS 1
V
+
C12
S12
C11
S11
C10
S10
C9
S9
C8
S8
C7
S7
C6
S6
C5
S5
C4
S4
C3
S3
C2
CSBI
SDO
SDI
SCKI
A3
A2
A1
A0
GPIO2
GPIO1
WDTB
MMB
TOS
V
REG
V
REF
V
TEMP2
V
TEMP1
NC
V
–
S1
C1
S2
LTC6802-2
IC #2
V2
–
OE2
V2
–
V2
+
V1
–
OE1
V1
–
V1
+
DIGITAL
ISOLATOR
3V
ADDRESS 15
V
+
C12
S12
C11
S11
C10
S10
C9
S9
C8
S8
C7
S7
C6
S6
C5
S5
C4
S4
C3
S3
C2
CSBI
SDO
SDI
SCKI
A3
A2
A1
A0
GPIO2
GPIO1
WDTB
MMB
TOS
V
REG
V
REF
V
TEMP2
V
TEMP1
NC
V
–
S1
C1
S2
LTC6802-2
IC #8
IC #3 TO IC #7
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
between C2 and C4 after several cycles of measuring cells
B3 and B4. Thus the measurements for B3 and B4 may
indicate a valid cell voltage when in fact the exact state of
B3 and B4 is unknown.
To reliably detect an open connection, the command
STOWAD is provided. With this command, two 100µA
current sources are connected to the ADC inputs and
turned on during all cell conversions. Referring again to
Figure 3, with the STOWAD command, the C3 pin will be
pulled down by the 100µA current source during the B3
cell measurement AND during the B4 cell measurement.
This will tend to decrease the B3 measurement result and
increase the B4 measurement result relative to the normal
STCVAD command. The biggest change is observed in the