Datasheet

MAX846A
Cost-Saving Multichemistry
Battery-Charger System
_______________________________________________________________________________________ 5
1.035
1.020
1.025
1.030
0.990
0 0.4 1.2 2.0
CURRENT-SENSE AMPLIFIER
TRANSCONDUCTANCE vs. ISET VOLTAGE
1.000
0.995
1.015
MAX846-01
ISET VOLTAGE (V)
CSA GM (mA/V)
0.8 1.60.2 1.0 1.80.6 1.4
1.010
1.005
∆V = 165mV
∆V = 200mV
∆V = 250mV
∆V = 100mV
∆V = V
CS+
- V
CS-
80
50
60
70
0
02 6 10
BATTERY INPUT CURRENT
vs. BATTERY VOLTAGE
10
40
MAX846-02
BATT VOLTAGE (V)
BATT INPUT CURRENT (µA)
4815 937
30
20
CELL2 = VL
CELL2 = GND
ON
82kΩ
OFF
128kΩ
80
70
60
50
40
30
20
10
0
-10
-20
180
150
120
90
60
30
0
-30
-60
-90
-120
10 10k 100k1k100 1M

CURRENT-LOOP GAIN
MAX846-03
FREQUENCY (Hz)
GAIN (dB)
PHASE (DEGREES)
C
CCI
= 10nF
GAIN
PHASE

40
30
20
10
0
-10
-20
-30
-40
-50
-60
180
150
120
90
60
30
0
-30
-60
-90
--120
10 10k 100k1k100 1M

VOLTAGE-LOOP GAIN
MAX846-04
FREQUENCY (Hz)
GAIN (dB)
PHASE (DEGREES)

= - Charging at 100mA
= -Charging at 200mA
2 Li-Ion Cells
C
CCV
= 10nF
C
OUT
= 4.7µF
TIP2955 PNP PASS TRANSISTOR
GAIN
PHASE

900
800
700
600
500
400
300
200
100
0
9.0
8.8
8.6
8.4
8.2
8.0
7.8
7.6
7.4
7.2
7.0
0 180 24012060

Li-ION CHARGING PROFILE
MAX846-04
TIME (MINUTES)
CHARGING CURRENT (mA)
BATTERY VOLTAGE (V)
CHARGING CURRENT
BATTERY VOLTAGE

__________________________________________Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)