LTC6803HG-2#TRPBF-ES Linear Technology, LTC6803HG-2#TRPBF-ES Datasheet - Page 33

• Manufacturer Part Number: LTC6803HG-2#TRPBF-ES
• Description: SC-Special Function, Battery Stack Monitor, Addressable SPI
• Manufacturer: Linear Technology
• Type: Battery Monitoringr

Specifications of LTC6803HG-2#TRPBF-ES

• Battery Type: Li-Ion
• Operating Supply Voltage (min): 4V
• Operating Temp Range: -40C to 125C
• Package Type: SSOP
• Mounting: Surface Mount
• Pin Count: 44
• Operating Temperature Classification: Automotive
• Lead Free Status / Rohs Status: Compliant

APPLICATIONS INFORMATION
V
V
TEMP2
TEMP1
GPO1
CPO2
V
REG
Figure 17. Using Diode Sensors as Hot Spot Detectors
V
Figure 16. Expanding Sensor Count with Multiplexing
–
4
–
1/2 LT6004
6
7
+
1/2 LT6004
5
1
LTC6803-4
8
8
4
V
V
+
–
TEMP2
TEMP1
V
V
REG
REF
NC
3
2
V
–
1
2
3
4
5
6
7
8
Y0
Y2
Y
Y3
Y1
INH
V
GND
EE
200k
74HC4052
1µF
LTC6803-2
200k
Figure 18. Providing Measurement of Calibration Reference
V
X2
X1
X0
X3
CC
V
X
A
B
GPIO1
TEMP1
V
TOP CELL POTENTIAL
REG
16
15
14
13
12
11
10
9
V
–
680324 F17
35
31
28
26
1M
680324 F16
1µF
PROBE8
PROBE7
PROBE6
PROBE5
PROBE4
PROBE3
PROBE2
PROBE1
CZT5551
Si2351DS
10µF
ADDING CALIBRATION AND FULL-STACK
MEASUREMENTS
The general purpose V
tize any signals from 0V to 4V with accuracy corresponding
closely with that of the cell 1 ADC input. One useful signal
to provide is a high accuracy voltage reference, such as
3.300V from an LTC6655-3.3. From periodic readings of
this signal, the host software can provide correction of
the LTC6803 readings to improve the accuracy over that
of the internal LTC6803 reference and/or validate ADC
operation. Figure 18 shows a means of selectively pow-
ering an LTC6655-3.3 from the battery stack, under the
control of the GPIO1 output of the LTC6803-2. Since the
operational power of the reference IC would add significant
thermal loading to the LTC6803 if powered from V
external high voltage NPN pass transistor is used to form
a local 4.4V (V
GPIO1 signal controls a PMOS FET switch to activate the
reference when calibration is to be performed. Since GPIO
signals default to logic high in shutdown, the reference
will automatically turn off during idle periods.
Another useful signal is a measure of the total stack poten-
tial. This provides a redundant operational measurement
of the cells in the event of a malfunction in the normal
acquisition process, or as a faster means of monitoring
the entire stack potential. Figure 19 shows how a resis-
tive divider is used to derive a scaled representation of a
full cell group potential. A MOSFET is used to disconnect
100nF
1
2
3
4
SHDN
V
GND
GND
LTC6655-3.3
IN
LTC6803-2/LTC6803-4
be
V
V
OUT_S
OUT_F
below V
GND
GND
TEMP
8
7
6
5
680324 F18
REG
ADC inputs may be used to digi-
) from the battery stack. The
33
REG
680324f
, an