BQ24725A_17 Datasheet, PDF (28/47 Pages) Texas Instruments – 1-4 Cell Li+ Battery SMBus Charge Controller with N-Channel Power MOSFET Selector and Advanced Circuit Protection

bq24725A
SLUSAL0A – SEPTEMBER 2011 – REVISED AUGUST 2014
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9 Application and Implementation
9.1 Application Information
The bq24725AEVM-710 evaluation module (EVM) is a complete charger module for evaluating the bq24725A.
The application curves were taken using the bq24725AEVM-710. Refer to the EVM user's guide (SLUU507) for
EVM information.
9.2 Typical Application
Adapter +
Adapter -
Ri _*
2?
Ci _*
2.2µF
Reverse
Input
R12
Protection ^1M
Q1 (ACFET)
FDS6680A
C17
2200pF
C16
0.1µF
Q6
BSS138W
R13
3.01M
Q2 (RBFET)
FDS6680A ^{RAC 10m?}
C1
0.1µF
C3
0.1µF
R10
4.02 kW
R11
4.02 kW
C2
0.1µF
ACN
ACP
VCC
BATDRV
R1
430 kW
R2
66.5 kW
+3.3V
HOST SMBus
Dig I/O
R3
10 kW
CMSRC
REGN
ACDRV
ACDET
BTST
R8
100 kW
ILIM
R7
316 kW
HIDRV
U1
bq24725A ^PHASE
R4
10 kW
R5
10 kW
SDA
LODRV
GND
SCL
ACOK
SRP
ADC
Dig I/O
EN
C4
100 pF
IOUT
PowerPad
SRN
EN
D2
BAT54C
R9
10 Ω
C5
1µF
R6
4.02 kW
C6
1µF
D1
BAT54
C7
0.047µF
U2
IMD2A
Total
Csys _*
220µF
SYSTEM
C15
0.01µF
Q5 (BATFET)
FDS6680A
C8
10uF
Q3
Sis412DN
C9
10uF
RSR
10m?
L1
4.7µH
Q4
Sis412DN
C10 C11
10µF 10µF
Pack +
Pack -
R14 _*
10 Ω
R15 _*
7.5 W
C13
0.1µF
C14
0.1µF
F_s = 750kHz, I_ADPT = 4.096A, I_CHRG = 2.944A, I_LIM = 4A, V_CHRG = 12.592V, 90W adapter and 3S2P battery pack
Use 0Ω for better current sensing accuracy, use 10Ω/7.5Ω resistor for reversely battery connection protection. See
application information about negative output voltage protection for hard shorts on battery to ground or battery
reversely connection.
The total Csys is the lump sum of system capacitance. It is not required by charger IC. Use Ri and Ci for adapter hot
plug-in voltage spike damping. See application information about input filter design.
Figure 18. Typical System Schematic with Two NMOS Selector
28
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