SMBus Level 2 Battery Charger
with Remote Sense
Typical Operating Characteristics (continued)
(Circuit of Figure 1, adapter = 19.5V, ChargeVoltage() = 16.8V, ChargeCurrent() = 3.854A, InputCurrent() = 3.584A, T = +25°C,
A
unless otherwise noted.)
CHARGE-VOLTAGE ERROR
vs. CHARGE-VOLTAGE SETTING
BATTERY-VOLTAGE ERROR
vs. CHARGE CURRENT
0.6
0.4
0.3
0.2
0.1
0
0.2
2 CELLS
0.0
-0.2
-0.4
-0.6
4 CELLS
-0.1
-0.2
-0.3
3 CELLS
4
8
12
16
20
0
1
2
3
4
5
6
CHARGE-VOLTAGE SETTING (V)
CHARGE CURRENT (A)
BATTERY REMOVAL
SYSTEM LOAD TRANSIENT
MAX8731A toc12
MAX8731A toc13
V
OUTPUT CAPACITOR = 10μF
OUT
13.5V
5A
0A
LOAD
CURRENT
13.0V
12.5V
ADAPTER
CURRENT
5A
0A
5A
V
OUTPUT CAPACITOR = 22μF
OUT
INDUCTOR
CURRENT
ChargeVoltage( ) = 12.6V
0A
CCS
CCI
CCS VOLTAGE
500mV/div
500mV/div
CCI
CCI VOLTAGE
500mV/div
500mV/div
CCS
20μs/div
200μs/div
EFFICIENCY vs. CHARGE CURRENT
LDO LOAD REGULATION
100
95
90
85
80
75
70
65
60
0
-5
CHARGER OFF
4 CELLS
3 CELLS
-10
-15
-20
-25
-30
-35
-40
2 CELLS
0
2
4
6
8
0
20
40
60
(mA)
80
100
CHARGE CURRENT (A)
I
LDO
______________________________________________________________________________________ 11
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
