LTC1732-4_15 Datasheet, PDF (1/12 Pages) Linear Technology – Lithium-Ion Linear Battery Charger Controller

LTC1732-4/LTC1732-4.2
Lithium-Ion Linear
Battery Charger Controller
FEATURES
s _{Complete Linear Charger Controller for 1-Cell}
Lithium-Ion Batteries
s _{Preset Charge Voltage with 1% Accuracy}
s _{Programmable Charge Current}
s _{C/10 Charge Current Detection Output}
s _{Programmable Charge Termination Timer}
s _{Small, Thin 10-Pin MSOP Package}
s _{Select Pin Charges 4.1V or 4.2V Cells (LTC1732-4)}
s _{Input Supply (Wall Adapter) Detection Output}
s _{4.5V to 12V Input Voltage Range}
s _{Automatic Sleep Mode When Input Supply}
is Removed (Only 7µA Battery Drain)
s _{Automatic Trickle Charge of Low Voltage Cells}
s _{Programmable for Constant-Current-Only Mode}
s _{Battery Insertion Detect}
s _{4.05V Recharge Threshold for 4.2V Cells}
(LTC1732-4.2)
s _{3.8V Recharge Threshold for 4.1V or 4.2V Cells}
(LTC1732-4)
U
APPLICATIO S
s _{Cellular Phones}
s _{Handheld Computers}
s _{Charging Docks and Cradles}
DESCRIPTIO
The LTC^®1732 is a complete constant-current/constant-
voltage linear charger controller for lithium-ion
(Li-Ion) batteries. Nickel-cadmium (NiCd) and nickel metal-
hydride (NiMH) batteries can also be charged with con-
stant current using external termination. Charge current
can be programmed with 7% (max) accuracy using exter-
nal sense and program resistors. An internal resistor
divider and precision reference set the final float voltage
with 1% accuracy. The SEL pin allows users to charge
either 4.1V or 4.2V cells.
When the input supply is removed, the LTC1732 automati-
cally enters a low current sleep mode, dropping the battery
drain current to 7µA. An internal comparator detects the
end-of-charge (C/10) condition while a programmable
timer, using an external capacitor, sets the total charge
time. Fully discharged cells are automatically trickle charged
at 10% of the programmed current until cell voltage
exceeds 2.457V.
The LTC1732 begins a new charge cycle when a discharged
battery is connected to the charger or when the input power
is applied. In addition, if the battery remains connected to
the charger and the cell voltage drops below 3.8V for the
LTC1732-4 or below 4.05V for the LTC1732-4.2, a new
charge cycle will automatically begin.
The LTC1732 is available in the 10-pin MSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Single Cell 4.2V Li-Ion Battery Charger
V_IN = 6V
MBRM120T3
R1
1k
C_TIMER
0.1µF
R2
8
1k
V_CC
3
CHRG
2
SEL
9
SENSE
DRV ⁷
LTC1732-4
10
ACPR
1
BAT
4
6
TIMER PROG
GND
5
R_PROG*
19.6k
R_SENSE
0.2Ω
1µF
Q1
Si9430DY
I_BAT = 500mA
10µF
+ ^4.2V
Li-Ion
CELL
*SHUTDOWN INVOKED BY FLOATING THE PROG PIN
1732 TA01
1