
AIC1781
14
temperature is either too low or too high,
same as abnormal battery voltage. Latch for
charge-suspending function is provided for
high temperature protection, but not for low
temperature protection.
(b) V
CC
- 1.4V> SEL3 >
V
2
cc
- 0.4V
Acceptable VBT Range:
Before initial timer: 0.16V~2.7V
After initial timer: 0.69V~2.7V
Temperature Protection Mode:
If temperature is too high, battery charging is
regarded as completed. If temperature is too low,
function of
T/
t detection is disabled, just as
thermistor is not existing.
(c)
V
2
cc
- 0.4V>SEL3 >1.4V
Acceptable VBT Range:
Before initial timer: 0.16V~2V
After initial timer: 1.2V~2V
Temperature Protection Mode:
Entering
charge-suspending
temperature is either too low or too high, same
as abnormal battery voltage. Latch for charge-
suspending function is provided for high
temperature protection, but not for low
temperature protection.
mode
when
(d) 0.3V> SEL3
Acceptable VBT Range:
Before initial timer: 0.16V~2V
After initial timer: 1.2V~2V
Temperature Protection Mode:
If temperature is too high, battery charging is
regarded as completed. If temperature is too low,
function of
T/
t detection is disabled, just as
thermistor is not existing.
Setting the Period of Safety Timer
The AIC1781 provides a method for linearly
adjusting the period of safety timer with an external
resistor connected from TMR pin to GND. The
relation between safety timer length and the
external resistor (R
TMR
)
is shown in Fig. 5. The
table following shows the resistor values for some
of the commonly chosen safety timer periods. Also
shown in the table are their corresponding oscillator
frequencies.
0
100
200
300
400
500
0
200
400
600
800
R
T
(
)
Safety Timer (min.)
Fig. 5 Safety Timer vs R
TMR
R
TMR
(K
)
OSC.
Freq.(KHz)
262.4
Safety timer
(min.)
10
11
23
131.2
20
48
65.6
40
74
43.7
60
100
32.8
80
152
21.9
120
206
16.4
160
314
10.9
240
491
7.3
360
667
5.5
480
Selecting Mode of Operation
The AIC1781 provides three modes of operation:
normal, test, and AC mode determined by the
setting of MODE pin according to TABLE 5. The
AIC1781 will operate normally when the MODE pin
is left floating (a 0.1
μ
F capacitor is recommended