LTC4100 Datasheet, PDF (1/24 Pages) Linear Technology – Smart Battery Charger Controller

FEATURES
s _{Single Chip Smart Battery Charger Controller}
s _{100% Compliant (Rev. 1.1) SMBus Support allows}
for Operation with or without Host
s _{SMBus Accelerator Improves SMBus Timing*}
s _{Wide Output Voltage Range: 6.4V to 26V}
s _{Hardware Interrupt and SMBAlert Response}
Eliminate Interrupt Polling
s _{High Efficiency Synchronous Buck Charger}
s _{0.5V Dropout Voltage; Maximum Duty Cycle > 98%}
s _{AC Adapter Current Limit Maximizes Charge Rate}
s _{±0.8% Voltage Accuracy; ±5% Current Accuracy}
s _{Up to 4A Charging Current Capability}
s _{10-Bit DAC for Charge Current Programming}
s _{11-Bit DAC for Charger Voltage Programming}
s _{User-Selectable Overvoltage and Overcurrent Limits}
s _{High Noise Immunity SafetySignal Sensor}
s _{Small 24-Pin Narrow (0.209") SSOP Package}
U
APPLICATIO S
s _{Portable Instruments and Computers}
s _{Data Storage Systems and Battery Backup Servers}
, LTC and LT are registered trademarks of Linear Technology Corporation.
*U.S. Patent No. 6,650,174 **U.S. Patent No. 5,723,970
LTC4100
Smart Battery
Charger Controller
DESCRIPTIO
July 2003
The LTC^®4100 Smart Battery Charger is a single chip
charging solution that dramatically simplifies construc-
tion of an SBS compliant system. The LTC4100 imple-
ments a Level 2 charger function whereby the charger can
be programmed by the battery or by the host. A SafetySignal
on the battery being charged is monitored for tempera-
ture, connectivity and battery type information. The SMBus
interface remains alive when the AC power adapter is
removed and responds to all SMBus activity directed to
it, including SafetySignal status (via the ChargerStatus
command). The charger also provides an interrupt to the
host whenever a status change is detected (e.g., battery
removal, AC adapter connection).
Charging current and voltage are restricted to chemistry
specific limits for improved system safety and reliability.
Limits are programmable by two external resistors. Addi-
tionally, the maximum average current from the AC adapter
is programmable to avoid overloading the adapter when
simultaneously supplying load current and charging
current. When supplying system load current, charging
current is automatically reduced to prevent adapter over-
load.**
TYPICAL APPLICATIO
DCIN
3V
TO 5.5V
CHGEN
ACP
1.13k
54.9k
13.7k
1.21k
0.1µF
17
LTC4100
5
V_DD
DCIN
11
4
DCDIV
INFET
6
CHGEN
24
CLP
10
ACP
23
CLN
7
1
SMBALERT TGATE
9
SCL
3
BGATE
8
SDA
2
PGND
15
THB
21
CSP
16
THA
22
BAT
13
I_LIM
14
V_LIM
20
10k
I_DC
18
V_SET
19
I_TH
12
GND
0.082µF
0.1µF 0.033Ω
5k
20µF _0.025Ω
10µH
6.04k
0.12µF
0.0015µF
0.01µF ^100Ω
0.1µF
SMBALERT#
SMBCLK
SMBDAT
SafetySignal
Figure 1. 4A Smart Battery Charger
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
SMART BATTERY
20µF
SMBCLK
SMBDAT
4100 TA01
sn4100 4100is
1