Data Sheet

V
CHG
I
BAT
2V/div
400 ms/div
V
BAT
1 A/div
5V/div
ChargingInitiated
BatteryDetectionMode
BatteryInserted
V
IN
500mV/div
4ms/div
5V/div
I
BAT
V
PGOOD
5V/div
V
4.4V
OUT
V
3.6V
BAT
500mA/div
bq24072 , bq24073 , bq24074 , bq24075 , bq24079
www.ti.com SLUS810K –SEPTEMBER 2008–REVISED MARCH 2015
Typical Application (continued)
10.2.2.3 TS Function
Use a 10-kΩ NTC thermistor in the battery pack (103AT-2). For applications that do not require the TS
monitoring function, connect a 10-kΩ resistor from TS to VSS to set the TS voltage at a valid level and maintain
charging.
10.2.2.4 CHG and PGOOD
LED Status: Connect a 1.5-kΩ resistor in series with a LED between OUT and CHG to indicate charging status.
Connect a 1.5-kΩ resistor in series with a LED between OUT and PGOOD to indicate when a valid input source
is connected.
Processor Monitoring Status: Connect a pullup resistor (on the order of 100 kΩ) between the power rail of the
processor and CHG and PGOOD.
10.2.2.5 Selecting IN, OUT, and BAT Pin Capacitors
In most applications, all that is needed is a high-frequency decoupling capacitor (ceramic) on the power pin,
input, output and battery pins. Using the values shown on the application diagram, is recommended. After
evaluation of these voltage signals with real system operational conditions, one can determine if capacitance
values can be adjusted toward the minimum recommended values (DC load application) or higher values for fast
high amplitude pulsed load applications. Note if designed high input voltage sources (bad adaptors or wrong
adaptors), the capacitor needs to be rated appropriately. Ceramic capacitors are tested to 2x their rated values
so a 16-V capacitor may be adequate for a 30-V transient (verify tested rating with capacitor manufacturer).
10.2.3 Application Curves
R
LOAD
= 10 Ω
Figure 31. Adapter Plug-In
Figure 32. Battery Detection
Battery Connected
Battery Inserted
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