u2402b ETC-unknow, u2402b Datasheet - Page 7

• Manufacturer Part Number: u2402b
• Description: Fast Charge Controller Nicd/nimh Batteries
• Manufacturer: ETC-unknow

TELEFUNKEN Semiconductors
Rev. A3, 14-Nov-96
Battery Voltage Measurement
The
(ADC-converter) has a range of 0 V to 4 V, which means
a battery pack containing two cells can be connected
without a voltage divider.
If the AD converter is overloaded (V
switch off occurs. The fast charge cycle is terminated by
automatically changing to the trickle charge.
Precaution should be taken that under specified charge
current conditions, the final voltage at the input of the
converter, Pin 10, should not exceed the threshold voltage
level of the reset comparator, which is 5 V. When the
battery is removed, the input (Pin 10) is terminated across
the pulled-up resistance, R
5 V-reset-threshold. In this way, the start of a new charge
sequence is guaranteed when a battery is reinserted.
If the battery voltage exceeds the converter range of 4 V,
adjusting it by the external voltage divider resistance, R
and R
Table 1. valid when V
V
R
Cell No.
Smin
B3
B3
battery
(k
(V)
is recommended.
W)
V
B
voltage
95 10174
1
8
–
V
10max
6
Battery
2
8
–
R
= 3.5 V
I
measurement
sh
ch
Figure 5. Input configuration for the battery voltage measurement
B1,
51
3
8
R
R
R
Batt
to the value of
B2
B3
B1
w
16
4
9
at
4 V) a safety
V
Pin
Batt
11
10
5
15
10
10
B2
7 V
V
V
12 mV
7.5
Ref
13
S
6
Value of the resistance, R
R
The minimum supply voltage, V
reset function after removing the inserted battery
according to:
where:
V
V
V
The voltage conditions mentioned above are measured
during charge current break (switch-off condition).
V
=
R
B1
10max
Smin
Bmax
smin
B3
Reset
= 1 k
+
=
+
5.6
15
7
V
4.3 V
R
0.03mA
= Max voltage at Pin 10
= Min supply voltage at the IC (Pin 15)
= Max battery voltage
Ref
W
B2
, R
V
V
=
V
V
Bmax
Ref
B2
DAC
DAC
4.7
17
8
@
V
= 10 k
= 0.1 V
R
10max
– V
B3
–
+
+
+
–
–
R
10max
DAC control
- dV Recognition
comparator
B1
W
comparator
3.9
19
9
, as follows:
Reset
)
B3
R
B2
is calculated by assuming
R
B3
)
3.3
10
21
smin
U2402B
5V R
, is calculated for
B1
11
23
3
)
R
B2
7 (17)
)
2.7
12
25
R
B3