LTC4100_09 Datasheet, PDF (1/30 Pages) Linear Technology – Smart Battery Charger Controller

FEATURES
n _{Single Chip Smart Battery Charger Controller}
n _{100% Compliant (Rev. 1.1) SMBus Support Allows}
for Operation with or without Host
n _{SMBus Accelerator Improves SMBus Timing}
n _{Wide Output Voltage Range: 3.5V to 26V}
n _{Hardware Interrupt and SMBAlert Response}
Eliminate Interrupt Polling
n _{High Efficiency Synchronous Buck Charger}
n _{0.5V Dropout Voltage; Maximum Duty Cycle > 98%}
n _{AC Adapter Current Limit Maximizes Charge Rate}
n _{±0.8% Voltage Accuracy; ±4% Current Accuracy}
n _{Up to 4A Charging Current Capability}
n _{10-Bit DAC for Charge Current Programming}
n _{11-Bit DAC for Charger Voltage Programming}
n _{User-Selectable Overvoltage and Overcurrent Limits}
n _{High Noise Immunity SafetySignal Sensor}
n _{Available in a 24-Pin SSOP Package}
APPLICATIONS
n _{Portable Instruments and Computers}
n _{Data Storage Systems and Battery Backup Servers}
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.
Protected by U.S. Patents including 6650174 and 5723970.
LTC4100
Smart Battery
Charger Controller
DESCRIPTION
The LTC^®4100 Smart Battery Charger is a single chip
charging solution that dramatically simplifies construction
of an SBS compliant system. The LTC4100 implements
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 temperature,
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. Ad-
ditionally, 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, charg-
ing current is automatically reduced to prevent adapter
overload.
TYPICAL APPLICATION
DCIN
CHGEN
ACP
3V
TO 5.5V
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 _SMBALERT
1
TGATE
9
SCL
3
BGATE
8
SDA
2
PGND
15 _THB
CSP ²¹
16
THA
22
BAT
13
I_LIM
14
V_LIM
20
10k
I_DC
18
V_SET
19
I_TH
12
GND
0.068μF
0.1μF 0.033Ω
V_BAT
< 5.5V
> 5.5V
PART
LTC4101
LTC4100
5k
SYSTEM LOAD
20μF _0.025Ω
SMART BATTERY
10μH
20μF
6.04k
0.12μF
0.0015μF
0.01μF ^100Ω
0.1μF
SMBALERT#
SMBCLK
SMBDAT
SafetySignal
Figure 1. 4A Smart Battery Charger
SMBCLK
SMBDAT
4100 TA01
4100fb
1