LTC6802-2_15 Datasheet, PDF (1/34 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 Onboard}
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, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
NEXT 12-CELL
PACK ABOVE
+
12-CELL
BATTERY
STRING ₊
+
NEXT 12-CELL
PACK BELOW
V⁺
LTC6802-2
DIE TEMP
REGISTERS
AND
CONTROL
MUX
SERIAL DATA
4-BIT
ADDRESS
V^–
100k NTC
12-BIT
∆∑ ADC
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
68022fa