LTC4002_15 Datasheet, PDF (1/16 Pages) Linear Technology – Standalone Li-Ion Switch Mode Battery Charger

LTC4002
Standalone Li-Ion
Switch Mode Battery Charger
FEATURES
■ _{Wide Input Supply Range:}
4.7V to 22V – 4.2 Version
8.9V to 22V – 8.4 Version
■ _{High Efficiency Current Mode PWM Controller with}
500kHz Switching Frequency
■ _{±1% Charge Voltage Accuracy}
■ _{End-of-Charge Current Detection Output}
■ _{3 Hour Charge Termination Timer}
■ _{Constant Switching Frequency for Minimum Noise}
■ _{±5% Charge Current Accuracy}
■ _{Low 10µA Reverse Battery Drain Current}
■ _{Automatic Battery Recharge}
■ _{Automatic Shutdown When Input Supply is Removed}
■ _{Automatic Trickle Charging of Low Voltage Batteries}
■ _{Battery Temperature Sensing and Charge}
Qualification
■ _{Stable with Ceramic Output Capacitor}
■ _{8-Lead SO and 10-Lead DFN Packages}
U
APPLICATIO S
■ _{Portable Computers}
■ _{Charging Docks}
■ _{Handheld Instruments}
DESCRIPTIO
The LTC^®4002 is a complete battery charger controller for
one (4.2V) or two (8.4V) cell lithium-ion batteries. With a
500kHz switching frequency, the LTC4002 provides a
small, simple and efficient solution to fast charge Li-Ion
batteries from a wide range of supply voltages. An external
sense resistor sets the charge current with ±5% accuracy.
An internal resistor divider and precision reference set the
final float voltage to 4.2V per cell with ±1% accuracy.
When the input supply is removed, the LTC4002 automati-
cally enters a low current sleep mode, dropping the battery
drain current to 10µA. An internal comparator detects the
near end-of-charge condition while an internal timer sets
the total charge time and terminates the charge cycle. After
the charge cycle ends, if the battery voltage drops below
4.05V per cell, a new charge cycle will automatically begin.
The LTC4002 is available in the 8-lead SO and 10-lead DFN
packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
1.5A Single Cell Li-Ion Battery Charger
V_IN
5V TO 22V
CHARGE
STATUS
BAT
2k
0.1µF
V_CC
GATE
10µF
LTC4002ES8-4.2
CHRG SENSE
6.8µH
68mΩ
0.47µF
2.2k
COMP
NTC
T
BAT
GND
22µF
+ _Li-Ion
BATTERY
10k
NTC
4002 TA01
NTC: DALE NTHS-1206N02
Efficiency vs Input Voltage
100
(CURVES INCLUDE
INPUT DIODE)
90
V_BAT = 4V
80
V_BAT = 3.8V
70
60
5
10
15
20
25
INPUT VOLTAGE (V)
4002 TA02
4002f
1