NiCd /NiMH Ba t t e ry
Fa s t -Ch a rg e Co n t ro lle rs
2/MAX713
ELECTRICAL CHARACTERISTICS (continued)
(I + = 10mA, T = T
to T , unless otherwise noted. Refer to Typical Operating Circuit. All measurements are with respect to
MAX
V
A
MIN
BATT-, not GND.)
PARAMETER
FASTCHG Low Current
CONDITIONS
= 0.4V
MIN
TYP
MAX
UNITS
mA
µA
V
2
FASTCHG
V
= 10V
10
FASTCHG High Current
FASTCHG
A/D Input Range (Note 4)
Battery voltage ÷ number of cells programmed
1.4
1.9
V
Note 1: The MAX712/MAX713 are powered from the V+ pin. Since V+ shunt regulates to +5V, R1 must be small enough to allow at
least 5mA of current into the V+ pin.
Note 2: Offset voltage of THI and TLO comparators referred to TEMP.
Note 3: t is the A/D sampling interval (Table 3).
A
Note 4: This specification can be violated when attempting to charge more or fewer cells than the number programmed. To ensure
proper voltage-slope fast-charge termination, the (maximum battery voltage) ÷ (number of cells programmed) must fall
within the A/D input range.
__________________________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(T = +25°C, unless otherwise noted.)
A
CURRENT-SENSE AMPLIFIER
CURRENT-SENSE AMPLIFIER
FREQUENCY RESPONSE (with 15pF)
FREQUENCY RESPONSE (with 10nF)
20
10
40
0
20
10
40
0
C2 = 15pF
FASTCHG = 0V
C2 = 10nF
FASTCHG = 0V
A
V
A
V
Φ
0
-40
0
-10
-20
-40
-80
Φ
BATT-
+
CC
-80
-10
-20
+
CURRENT-
SENSE
AMP
V
V
OUT
-
IN
-
GND
BATT-
-120
-120
100k
FREQUENCY (Hz)
1k
10k
1M
10M
10
100
1k
10k
FREQUENCY (Hz)
ALPHA THERMISTOR PART No. 13A1002
STEINHART-HART INTERPOLATION
CURRENT ERROR-AMPLIFIER
TRANSCONDUCTANCE
SHUNT-REGULATOR VOLTAGE
vs. CURRENT
100
5.8
1.6
1.4
1.2
35
30
25
FASTCHG = 0V, V+ = 5V
DRV NOT SINKING CURRENT
5.6
5.4
5.2
5.0
4.8
10
1
1.0
20
DRV SINKING CURRENT
0.8
0.6
15
10
4.6
4.4
4.2
0.4
0.2
5
0
0.1
1.95
4.0
1.97
1.99
2.01
2.03
2.05
0
10
20
30
40
50
60
0
10
20
30
40
50
60
VOLTAGE ON CC PIN (V)
BATTERY TEMPERATURE(°C)
CURRENT INTO V+ PIN (mA)
_______________________________________________________________________________________
3
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
