LTC6801 Datasheet, PDF (1/28 Pages) Linear Technology – Independent Multicell Battery Stack Fault Monitor

Electrical Specifications Subject to Change
LTC6801
FEATURES
n _{Monitors Up to 12 Li-Ion Cells in Series (60V Max)}
n _{Stackable Architecture Enables > 1000V Systems}
n _{Adjustable Overvoltage and Undervoltage}
Detection
n _{Self Test Features Guarantee Accuracy}
n _{Robust Fault Detection Using Differential Signals}
n _{Simple Pin-Strapped Configuration Allows Battery}
Monitoring without a Microcontroller
n _{15ms to Monitor All Cells in a System}
n _{Programmable Response Time}
n _{Two Temperature Monitor Inputs}
n _{Low Power Idle Mode}
n _{36-Lead SSOP Package}
APPLICATIONS
n _{Redundant Battery Monitor}
n _{Hybrid Electric Vehicles}
n _{Battery Backup Systems}
n _{Power Systems Using Multiple Battery Cells}
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.
Independent Multicell
Battery Stack Fault Monitor
DESCRIPTION
The LTC^®6801 is a multicell battery monitoring IC incor-
porating a 12-bit ADC, a precision independent voltage
reference, sampled comparator, and a high voltage input
multiplexer. The LTC6801 can monitor as many as 12 series
connected battery cells for overvoltage, undervoltage, and
overtemperature conditions, indicating whether the cells
are within specified parameters. The LTC6801 generates
a clock output when no fault conditions exist. Differential
clocking provides high noise immunity and ensures that
battery stack fault conditions cannot be hidden by frozen
bits or short circuit conditions.
Each LTC6801 can operate with a battery stack voltage up
to 60V and multiple LTC6801 devices can be stacked to
monitor each individual cell in a long battery string. When
multiple devices are stacked, the status signal of each
LTC6801 can be daisy-chained, without opto-couplers or
isolators, providing a single status output for the entire
battery string.
The LTC6801 is configurable by external pin strapping.
Adjustable overvoltage and undervoltage thresholds sup-
port various Li-Ion chemistries. Selectable measurement
times allow users to save power.
BLOCK DIAGRAM
NEXT HIGHER
CELL PACK
1 V+
C12
2
3 ^C11
12 ^C2
MUX
C1
13
V–
14
LTC6801
CONTROL
12
LOGIC
ADC
ENABLE ISOLATION
INPUT
“CELLS GOOD”
20
CLOCK SIGNAL
INPUT ENABLES
THE LTC6801
NEXT LOWER
CELL PACK
V_TEMP1 V_TEMP2
15
16
NTC
V_REF
17
REFERENCE
NTC
22
STATUS
OUTPUT
6801 TA01a
CLOCK SIGNAL
OUTPUT INDICATES
SYSTEM “OK”
0V Detection Level Error
1.0 _{V+ = 43.2V}
0.8 OV = 4.120V
0.6
5 TYPICAL UNITS
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
–40 –25 –10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
6801 TA01b
6801p
1