Low-Cost, Multichemistry Battery-
Charger Building Block
MAX172
Typical Operating Characteristics
(Circuit of Figure 1a, V
= 20V, T = +25°C, unless otherwise noted.)
A
DCIN
LOAD-TRANSIENT RESPONSE
LOAD-TRANSIENT RESPONSE
(STEP-IN LOAD CURRENT)
(BATTERY REMOVAL AND REINSERTION)
MAX1772 toc01
MAX1772 toc02
V
V
CCS
BATT
CCI
500mV/div
20V/div
V
CCI
CCS
I
BATT
500mV/div
2A/div
CCV
CCI
V
BATT
20V/div
V
CCI
I
LOAD
500mV/div
V
2A/div
CCV
500mV/div
1ms/div
1ms/div
BATTERY PRESENT
V
= 3.30V
ICTL
CHARGING CURRENT = 2.0A
= 16V
LOAD STEP = 0 TO 3A
V
V
= 0.957V
= 3.3V
ICTL
CTL
V
BATT
I
LIMIT = 5A
SOURCE
LDO LOAD REGULATION
0.4
0.3
0.2
0.1
0
LINE-TRANSIENT RESPONSE
MAX1772 toc03
V
V
V
V
= 0V
= 3.3V
= 20.0V
VCTL
ICTL
DCIN
V
DCIN
= 5.40V
10V/div
LDO
-0.1
-0.2
-0.3
-0.4
V
BATT
(AC-COUPLED)
100mV/div
0
1
2
3
4
5
6
7
8
9
10
LDO CURRENT (mA)
2ms/div
V
V
I
= 16V
= 18.5V TO 27.5V
= 150mA
BATT
DCIN
LOAD
_______________________________________________________________________________________
7
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
