LTC6802-2 Datasheet, PDF (1/32 Pages) Linear Technology – Multicell Addressable Battery Stack Monitor

FEATURES
n _{Measures up to 12 Li-Ion Cells in Series (60V Max)}
n _{Stackable Architecture Enables Monitoring High}
Voltage Battery Stacks
n _{Individually Addressable with 4-Bit Address}
n _{0.25% Maximum Total Measurement Error}
n _{13ms to Measure All Cells in a System}
n _{Cell Balancing:}
On-Chip Passive Cell Balancing Switches
Provision for Off-Chip Passive Balancing
n _{Two Thermistor Inputs Plus On-board}
Temperature Sensor
n _{1MHz Serial Interface with Packet Error Checking}
n _{High EMI Immunity}
n _{Delta Sigma Converter With Built In Noise Filter}
n _{Open Wire Connection Fault Detection}
n _{Low Power Modes}
n _{44-Lead SSOP Package}
APPLICATIONS
n _{Electric and Hybrid Electric Vehicles}
n _{High Power Portable Equipment}
n _{Backup Battery Systems}
n _{High Voltage Data Acquisition Systems}
LTC6802-2
Multicell Addressable
Battery Stack Monitor
DESCRIPTION
The LTC^®6802-2 is a complete battery monitoring IC that
includes a 12-bit ADC, a precision voltage reference, a
high voltage input multiplexer and a serial interface. Each
LTC6802-2 can measure 12 series connected battery cells,
with a total input voltage up to 60V. The voltage on all 12
input channels can be measured within 13ms.
Many LTC6802-2 devices can be stacked to measure the
voltage of each cell in a long battery string. Each LTC6802-2
has an individually addressable serial interface, allowing
up to 16 LTC6802-2 devices to interface to one control
processor and operate simultaneously.
To minimize power, the LTC6802-2 offers a measure mode
to monitor each cell for overvoltage and undervoltage
conditions. A standby mode is also provided to reduce
supply current to 50μA.
Each cell input has an associated MOSFET switch that can
discharge any overcharged cell.
The related LTC6802-1 offers a serial interface that allows
the serial ports of multiple LTC6802-1 devices to be daisy
chained without opto-couplers or isolators.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
TYPICAL APPLICATION
NEXT 12-CELL
PACK ABOVE
V⁺
12-CELL
BATTERY
MUX
STRING
LTC6802-2
DIE TEMP
REGISTERS
AND
CONTROL
SERIAL DATA
4-BIT
ADDRESS
12-BIT
Δ∑ ADC
NEXT 12-CELL
PACK BELOW
V^–
100k NTC
EXTERNAL
TEMP
VOLTAGE
REFERENCE
68022 TA01a
100k
Measurement Error Over
Extended Temperature
0.30
7 REPRESENTATIVE UNITS
0.25 _{VS = 43.2V}
0.20 CELL VOLTAGE 3.6V
0.15
0.10
0.05
0
–0.05
–0.10
–0.15
–0.20
–0.25
–0.30
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
68022 TA01b
68022f
1