Datasheet

t
WAKE
t
DISCHRG1
V
OREG
2V/cell
I
WAKE
-I
DISCHRG1
Yes
Battery
Detected
No
Battery
Detected
No
Battery
Detected
Battery
Connected
VBAT
IBAT
t
DISCHRG1
C
MAX_DIS
+
I
DISCHRG1
t
DISCHRG1
V
OREG
* V
SHORT
C
MAX_DIS
+
400 mA 1s
4.2 V * 2 V
C
MAX_DIS
+ 182 mF
C
MAX_WAKE
+
I
WAKE
t
WAKE
ǒ
V
OREG
* V
RCH
Ǔ
* 0 V
C
MAX_WAKE
+
2 mA 0.5s
(4.2 V * 0.1 V) * 0V
C
MAX_WAKE
+ 244 mF
bq24100, bq24103, bq24103A
bq24104, bq24105, bq24108, bq24109
bq24113, bq24113A, bq24115
SLUS606O –JUNE 2004–REVISED MARCH 2010 www.ti.com
Figure 12. Battery Detect Timing Diagram
Battery Detection Example
In order to detect a no battery condition during the discharge and wake tests, the maximum output capacitance
should not exceed the following:
a. Discharge (I
DISCHRG1
= 400 mA, t
DISCHRG1
= 1s, V
SHORT
= 2V)
(10)
b. Wake (I
WAKE
= 2 mA, t
WAKE
= 0.5 s, V
OREG
– V
RCH
= 4.1V)
(11)
Based on these calculations the recommended maximum output capacitance to ensure proper operation of the
battery detection scheme is 100 mF which will allow for process and temperature variations.
Figure 13 shows the battery detection scheme when a battery is inserted. Channel 3 is the output signal and
Channel 4 is the output current. The output signal switches between V
OREG
and GND until a battery is inserted.
Once the battery is detected, the output current increases from 0A to 1.3A, which is the programmed charge
current for this application.
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