u2402b ETC-unknow, u2402b Datasheet - Page 4

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

General Description
The integrated circuit, U2402B, is designed for charging
Nickel-Cadmium (NiCd) and Nickel-Metal-Hydride
(NiMH) batteries. Fast charging results in voltage lobes
when fully charged (figure 3). It supplies two identifica-
tions ( i. e., + d
operation at the proper time.
As compared to the existing charge concepts where the
charge is terminated
to –
U2402B-C takes into consideration the additional
changes in positive charge curves, according to the se-
cond derivative of the voltage with respect to time
(d
switching off the fast charge before overcharging the bat-
tery. This helps to give the battery a long life by hindering
any marked increase in cell pressure and temperature.
Even in critical charge applications, such as a reduced
U2402B
4 (17)
2
5 V
V/dt
V
10
D
V and temperature gradient identification, the
2
). The charge identification is the sure method of
95 10172
Battery insertion
t
2
monitoring
1
formation
V/dt
Battery
= 5 min
–
D
*
V
2
, and –
voltage
Battery
after voltage lobes
check
D
shorted batteries ignored
V ) to end the charge
Figure 3. Charge function diagram, f
Fast charge rate I
*
–
D
according
V,
)
d
dt
2
V
2
O
, active
charge current or with NiMH batteries where weaker
charge characteristics are present multiple gradient con-
trol results in very efficient switch-off.
An additional temperature control input increases not
only the performances of the charge switching character-
istics but also prevents the general charging of a battery
whose temperature is outside the specified window.
A constant charge current is necessary for continued
charge-voltage characteristic. This constant current regu-
lation is achieved with the help of internal amplifier phase
control and a simple shunt-current control technique.
All functions relating to battery management can be
achieved with dc-supply charge systems. A dc-dc-con-
verter or linear regulator should take over the function of
power supply. For further information please refer to the
applications.
)
Gradient recognition
d
osc
dt
2
V
2
= 800 Hz
t
charge rate
2
TELEFUNKEN Semiconductors
v
Top off
1/4 I
20 min
O
Rev. A3, 14-Nov-96
charge rate
1/256 I
Trickle
O
–
D
V
t