LTC1760_1 Datasheet, PDF (1/44 Pages) Linear Technology – Dual Smart Battery System Manager

LTC1760
FEATURES
■ _{SMBus Charger/Selector for Two Smart Batteries*}
■ _{Voltage and Current Accuracy within 0.2% of Value}
Reported by Battery
■ _{Simplifies Construction of “Smart Battery System}
Manager”
■ _{Includes All SMBus Charger V1.1 Safety Features}
■ _{Supports Autonomous Operation without a Host}
■ _{Allows Both Batteries to Discharge Simultaneously}
into Single Load with Low Loss (Ideal Diode)
■ _{SMBus Switching for Dual Batteries with Alarm}
Monitoring for Charging Battery at All Times
■ _{Pin Programmable Limits for Maximum Charge}
Current and Voltage Improve Safety
■ _{Fast Autonomous Power Path Switching (<10µs)}
■ _{Low Loss Simultaneous Charging of Two Batteries}
■ _{>95% Efficient Synchronous Buck Charger}
■ _{AC Adapter Current Limiting* Maximizes Charge Rate}
■ _{SMBus Accelerator Improves SMBus Timing**}
■ _{Available in 48-Lead TSSOP Package}
U
APPLICATIO S
■ _{Portable Computers and Instruments}
■ _{Standalone Dual Smart Battery Chargers}
■ _{Battery Backup Systems}
Dual Smart Battery
System Manager
DESCRIPTIO
The LTC^®1760 Smart Battery System Manager is a highly
integrated level 3 battery charger and selector intended for
products using dual smart batteries. Three SMBus inter-
faces allow the LTC1760 to servo to the internal voltage
and currents measured by the batteries while allowing an
SMBus Host to monitor either battery’s status. Charging
accuracy is determined by the battery’s internal voltage
and current measurement, typically better than ±0.2%.
A proprietary PowerPath^TM architecture supports simulta-
neous charging or discharging of both batteries. Typical
battery run times are extended by up to 10%, while
charging times are reduced by up to 50%. The LTC1760
automatically switches between power sources in less
than 10µs to prevent power interruption upon battery or
wall adapter removal.
The LTC1760 implements all elements of a version 1.1
“Smart Battery System Manager” except for the genera-
tion of composite battery information. An internal multi-
plexer cleanly switches the SMBus Host to either of the
two attached Smart Batteries without generating partial
messages to batteries or SMBus Host. Thermistors on
both batteries are automatically monitored for tempera-
ture and disconnection information (SafetySignal).
, LTC and LT are registered trademarks of Linear Technology Corporation.
PowerPath is a trademark of Linear Technology Corporation.
Protected by U.S. Patents, including *5723970 **6650174
TYPICAL APPLICATIO
Dual Battery Charger/Selector System Architecture
DC
IN
SYSTEM
POWER
LTC1760
SMBus (HOST)
SafetySignal 1
SMBus 1
SafetySignal 2
SMBus 2
1760 TA01
Dual vs Sequential Charging
3500
3000
2500
BAT1
CURRENT
BAT2
CURRENT
2000
SEQUENTIAL
1500
1000
500
0
3500
3000
2500
2000
BAT1
CURRENT
BAT2
CURRENT
DUAL
1500
1000
500
0
100
MINUTES
0 50 100 150 200 250 300
TIME (MINUTES)
BATTERY TYPE: 10.8V Li-Ion (MOLTECH NI2020)
REQUESTED CURRENT = 3A
REQUESTED VOLTAGE = 12.3V
MAX CHARGER CURRENT = 4.1A
1760 TA03
1760f
1