AIC1783A Datasheet, PDF (8/13 Pages) Analog Intergrations Corporation – Battery Charge Controller for Low Power Charging

AIC1783A
The functions and charging states control
mentioned above are illustrated in the function flow
chart of AIC1783A (Fig. 12)
DESIGN GUIDE
Battery Voltage Measurement
The AIC1783A measures the battery voltage
through VBT pin, which is connected to battery
positive terminal through a resistor-divider network,
as shown in Fig. 11.
V_BAT
RA
R5
7
VBT
+ ^100K
RB
C5
C6
AIC1783A
Fig. 11 Battery Voltage Divider
The suggested divider resistance of RA and RB
for the corresponding number of battery cells are
as below:
TABLE 1
BATTERY
CELLS
RA/RB
RA (KΩ)
RB (KΩ)
2~4
2
240
120
3~6
3.3
300
91
4~8
4.9
300
62
5~10
6.4
300
47
6~12
7.8
310
39
8~16
10.8
390
36
Setting the Period of Safety Timer
The AIC1783A provides a method for linearly
adjusting the period of safety timer with an external
resistor connected from TIMER pin to GND. The
relation between safety timer length and the
external resistor (R_TIMER) is shown in Fig. 13. 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.
800
600
400
200
0
0
100
200
300
400
500
Safety Timer (min.)
Fig. 13 Safety Timer vs. R_TIMER
8