Low-Cost, Multichemistry Battery-
Charger Building Block
Typical Operating Characteristics (continued)
(Circuit of Figure 1a, V
= 20V, T = +25°C, unless otherwise noted.)
A
DCIN
REF VOLTAGE LOAD REGULATION
LDO LINE REGULATION
REF VOLTAGE ERROR vs. TEMPERATURE
1.0
0.8
0.5
0.4
0.20
0.15
0.10
0.05
0
V
= 5.40V
LDO
V
V
= 0V
= 0V
ICTL
VCTL
V
V
= 0V
= 3.3V
VCTL
ICTL
NO LOAD
= 4.096V
0.6
0.3
CELL = 4
= 4.096V
V
REF
V
REF
0.4
0.2
MAX172
0.2
0.1
0
0
-0.2
-0.4
-0.6
-0.8
-1.0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.05
-0.10
-0.15
-0.20
8
12
16
20
24
28
0
50 100 150 200 250 300 350 400 450 500
-40
-15
10
35
60
85
DCIN (V)
REF CURRENT (μA)
TEMPERATURE (°C)
EFFICIENCY vs. BATTERY CURRENT
(CURRENT CONTROL LOOP)
EFFICIENCY vs. BATTERY CURRENT
(VOLTAGE CONTROL LOOP)
100
100
V
V
V
= 0V
= 3.3V
= 3.3V
VCTL
ICTL
REFIN
90
80
70
60
50
40
30
20
10
0
90
80
70
60
50
40
30
20
10
0
CELL = 4
CELL = 2
CELL = 3
CELL = 4
CELL = 3
CELL = 2
V
V
V
= 0V
= 3.3V
= 3.3V
VCTL
ICTL
REFIN
100
1000
BATT CURRENT (mA)
10,000
0.1
1
10
100
1000
10,000
BATT CURRENT (mA)
8
_______________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
