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a
ADP3801/ADP3802
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 1998
High Frequency Switch Mode
Dual Li-Ion Battery Chargers
FUNCTIONAL BLOCK DIAGRAM
ADP3801/ADP3802
LDO +
REFERENCE
A/B
SELECT
MUX
DRVVCC CS+ CS– A/B
PROG
ADJCOMPGND
SD
VL
RESET
ISET
BATB
BATA
EOC
SD\UVLO
GATE
DRIVE
CURRENT
LOOP
AMP + EOC
COMPARATOR
PWM
FINAL BATTERY
VOLTAGE
PROGRAM
(4.2, 8.4, 12.6)
VOLTAGE
LOOP
AMP
BATTERY
VOLTAGE
ADJUST
610%
SHUTDOWN
UVLO
+
RESET
FEATURES
Stand-Alone Li-Ion Battery Chargers
High End-of-Charge Voltage Accuracy
60.4% @ +258C
60.75% @ –108C to +708C
Intelligent End-of-Charge Output Signal
Pin Programmable Cell Number Select
On Chip 3.3 V LDO Regulator
Programmable Charge Current with High Side Sense
Softstart Charge Current
Undervoltage Lockout
Drives External PMOS
610% Adjustable End-of-Charge Voltage
Charges NiCad, NiMH (with External mController)
PWM Oscillator Frequency:
ADP3801: 200 kHz
ADP3802: 500 kHz
APPLICATIONS
Fast Chargers
Universal Chargers
Cellular Phones
Portable Computers
Portable Instrumentation
Desktop Chargers
Personal Digital Assistants
GENERAL DESCRIPTION
The ADP3801 and ADP3802 are complete battery charging
ICs. The devices combine a high accuracy final battery voltage
control with a constant charge current control and an on-board
Low Drop-Out Regulator (LDO). The accuracy of the final
battery voltage control is guaranteed to – 0.75% to safely charge
Li-Ion batteries. An internal multiplexer allows the alternate
charging of two separate battery stacks. The final voltage is pin
programmable to one of three Li-Ion options: 4.2 V (one Li-Ion
cell), 8.4 V (two Li-Ion cells), or 12.6 V (three Li-Ion cells).
Paired with an external microcontroller for charge termination,
the ADP3801/ADP3802 works as a fast charger for NiCad/
NiMH batteries or as a universal charger for all three battery
chemistries. In addition, a pin is provided for changing the final
battery voltage by up to – 10% to adjust for variations in battery
chemistry from different Li-Ion manufacturers without loss of
accuracy in the final battery voltage.
BATA
BATB
VCC DRV
EOC CS–
CS+
ISET
BATA
ADJGND
RESET
V
IN
VL
ADP3801/ADP3802
SD
BATB
3.3V
40mV
A/B
COMP
PROG
68mH
Figure 1. 4 Amp Dual Battery Charger