bq24270
bq24271
www.ti.com
SLUSB10 – JUNE 2012
1.5A, Singe Input, Single Cell Switchmode Li-Ion Battery Charger with Power Path
Management and I2C Interface
Check for Samples: bq24270, bq24271
FEATURES
1
•
23
•
•
•
•
High-Efficiency Switch Mode Charger with
Separate Power Path Control
– Make a GSM Call with a Deeply Discharged
Battery or No Battery
– Instantly Start up the System from a Deeply
Discharged Battery or No Battery
Highly Integrated Battery N-Channel MOSFET
Controller for Power Path Management
– 20 V input rating, with 6.5 V Overvoltage
Protection (OVP)
– Integrated FETs for Up to 1.5 A Charge
Rate
Safe and Accurate Battery Management
Functions
– 0.5% Battery Regulation Accuracy
– 10% Charge Current Accuracy
Charge Parameters Programmed Using I2C
™Interface
– Charge Voltage, Current, Termination
Threshold, Input Current Limit, VINDPM
Threshold
Voltage-based, NTC Monitoring Input
– JEITA Compatible
•
Thermal Regulation Protection for Output
Current Control
BAT Short-Circuit Protection
Soft-Start Feature to Reduce Inrush Current
Thermal Shutdown and Protection
Available in Small 2.8 mm x 2.8 mm 49-ball
WCSP or 4 mm x 4 mm QFN-24 Packages
•
•
•
•
APPLICATIONS
•
•
•
•
Handheld Products
Portable Media Players
Portable Equipment
Netbook and Portable Internet Devices
APPLICATION SCHEMATIC
USB
SW
VBUS
D+
D-
System
Load
GND
PMID
`
USB PHY
BOOT
PSEL
`
SYS
SCL
SDA
CD
HOST
INT
BAT
BYP
bq24271
PGND
STAT
TS
DRV
PACK+
TEMP
PACK-
DESCRIPTION
The bq24270 and bq24271 are highly integrated single cell Li-Ion battery charger and system power path
management devices targeted for space-limited, portable applications with high capacity batteries. The single cell
charger has several input current limits which allow operation from either a USB port or higher power input
supply (i.e. AC adapter or wireless charging input) for a versatile solution.
1
2
3
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
NanoFree is a trademark of Texas Instruments.
I2C is a trademark of NXP B.V. Corporation.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2012, Texas Instruments Incorporated
bq24270
bq24271
SLUSB10 – JUNE 2012
www.ti.com
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
DESCRIPTION (CONTINUED)
The power path management feature allows the bq24270 and bq24271 to power the system from a high
efficiency DC to DC converter while simultaneously and independently charging the battery. The charger
monitors the battery current at all times and reduces the charge current when the system load requires current
above the input current limit. This allows for proper charge termination and timer operation. The system voltage
is regulated to the battery voltage but will not drop below 3.5 V. This minimum system voltage support enables
the system to run with a defective or absent battery pack and enables instant system turn-on even with a totally
discharged battery or no battery. The power-path management architecture also permits the battery to
supplement the system current requirements when the adapter cannot deliver the peak system currents. This
enables the use of a smaller adapter. The charge parameters are programmable using the I2C interface
The battery is charged in three phases: precharge, fast charge constant current and constant voltage. In all
charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if
the internal temperature threshold is exceeded. Additionally, a voltage-based battery pack thermistor monitoring
input (TS) is included that monitors battery temperature for safe charging The TS function for bq24270 and
bq24271 are JEITA compatible.
ORDERING INFORMATION
PART
NUMBER (1)
USB OVP
CE bit Default
USB Detection
Safety and WD
Timers
NTC Monitoring
VBATSHRT or
IBATSHRT
Package
bq24270YFFR
6.5 V
0 (Charge
Enabled)
D+, D-
Yes
JEITA
3V
50 mA
WCSP
bq24270YFFT
6.5 V
0 (Charge
Enabled)
D+, D-
Yes
JEITA
3V
50 mA
WCSP
bq24270RGER
6.5 V
0 (Charge
Enabled)
D+, D-
Yes
JEITA
3V
50 mA
RGE
bq24270RGET
6.5 V
0 (Charge
Enabled)
D+, D-
Yes
JEITA
3V
50 mA
RGE
bq24271YFFR
6.5 V
0 (Charge
Enabled)
PSEL
Yes
JEITA
3V
50 mA
WCSP
bq24271YFFT
6.5 V
0 (Charge
Enabled)
PSEL
Yes
JEITA
3V
50 mA
WCSP
bq24271RGER
6.5 V
0 (Charge
Enabled)
PSEL
Yes
JEITA
3V
50 mA
RGE
bq24271RGET
6.5 V
0 (Charge
Enabled)
PSEL
Yes
JEITA
3V
50 mA
RGE
(1)
(2)
2
(2)
The YFF and RGE packages are available in the following options:
R - taped and reeled in quantities of 3,000 devices per reel.
T - taped and reeled in quantities of 250 devices per reel
This product is RoHS compatible, including a lead concentration that does not exceed 0.1% of total product weight, and is suitable for
use in specified lead-free soldering processes. In addition, this product uses package materials that do not contain halogens, including
bromine (Br) or antimony (Sb) above 0.1% of total product weight
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Product Folder Link(s): bq24270 bq24271
bq24270
bq24271
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SLUSB10 – JUNE 2012
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted) (1)
USB
Pin voltage range (with respect to VSS)
MIN
MAX
–2
20
V
PMID, BYP, BOOT
–0.3
20
V
SW
–0.7
12
V
SDA, SCL, SYS, BAT, STAT, BGATE, DRV, TS, D+, D-, INT,
PSEL, CD
–0.3
7
V
BOOT to SW
–0.3
7
V
4.5
A
SYS
3.5
A
USB
1.75
SW
Output current (continuous)
Input current (continuous)
STAT
Output sink current
UNIT
A
10
mA
1
mA
INT
Operating free-air temperature range
-40
85
°C
Junction temperature, TJ
-40
125
°C
Storage temperature, TSTG
–65
150
°C
(1)
Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltage
values are with respect to the network ground terminal unless otherwise noted.
THERMAL INFORMATION
THERMAL METRIC (1)
bq24270 and bq24721
YFF (48 PINS)
RGE (24 PINS)
θJA
Junction-to-ambient thermal resistance
49.8
32.6
θJCtop
Junction-to-case (top) thermal resistance
0.2
30.5
θJB
Junction-to-board thermal resistance
1.1
3.3
ψJT
Junction-to-top characterization parameter
1.1
0.4
ψJB
Junction-to-board characterization parameter
6.6
9.3
θJCbot
Junction-to-case (bottom) thermal resistance
N/A
2.6
UNITS
°C/W
spacer
(1)
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
RECOMMENDED OPERATING CONDITIONS
PARAMETER (1)
VUSB
MIN
MAX
USB voltage range
4.2
18
USB operating range
4.2
6
IUSB
Input current USB input
ISYS
Output Current from SW, DC
IBAT
TJ
(1)
A
3
A
1.5
Discharging, using internal battery FET
2.5
0
V
1.5
Charging
Operating junction temperature range
UNITS
125
A
ºC
The inherent switching noise voltage spikes should not exceed the absolute maximum rating on either the BOOT or SW pins. A tight
layout minimizes switching noise.
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bq24271
SLUSB10 – JUNE 2012
www.ti.com
ELECTRICAL CHARACTERISTICS
Circuit of Figure 3, V(UVLO) < V(USB) < V(OVP) AND V(USB) > V(BAT)+V(SLP), TJ = 0°C–125°C and TJ = 25°C for typical values
(unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
V(UVLO) < V(USB) < V(OVP) AND V(USB) > V(BAT) + V(SLP) PWM switching
I(USB)
Supply current for control
TYP
5
0°C < TJ < 85°C, High-Z Mode
I(BAT)
0°C< TJ < 85°C, V(BAT) = 4.2 V, V(USB) = 0 V
Battery discharge current in High
Impedance mode (BAT, SW, SYS)
0°C< TJ < 85°C, V(BAT) = 4.2 V, V(USB) = 5 V or 0 V, SCL, SDA = 0 V or
1.8 V,
High-Z Mode
UNIT
mA
V(UVLO) < V(USB) < V(OVP) AND V(USB) > V(BAT)+V(SLP) PWM NOT switching
Leakage current from BAT to the
supply
MAX
15
175
μA
5
μA
55
μA
POWER PATH MANAGEMENT
V(BAT) < V(MINSYS)
VSYS(REG)
System regulation voltage
V(MINSYS)
Minimum system regulation voltage
Battery FET turned off
V(BSUP1)
Enter supplement mode threshold
V(BAT) < V(MINSYS), Input current limit or V(INDPM) active
3.6
3.7
3.82
VBATREG +
1.5%
VBATREG +
3%
VBATREG +
4.17%
V
3.5
3.62
V
3.4
V(BAT) > 2.5 V
VBAT –
30mV
V
VBAT –
10mV
V
7
A
250
μs
60
ms
V(BSUP2)
Exit supplement mode threshold
V(BAT) > 2.5 V
ILIM
Current limit, discharge or
supplement mode
Current monitored in internal FET only
tDGL(SC1)
Deglitch time, SYS short circuit
during discharge or supplement
mode
Measured from (V(BAT) – V(SYS)) = 300 mV to
BAT = high-impedance
tREC(SC1)
Recovery time, SYS short circuit
during discharge or supplement
mode
Battery range for BGATE and
supplement mode operation
2.5
4.5
V
BATTERY CHARGER
RON(BAT-SYS)
V(BATREG)
YFF pkg
37
57
RGE pkg
50
70
Internal battery charger MOSFET
on-resistance
Measured from BAT to SYS,
V(BAT) = 4.2 V
Charge voltage
Operating in voltage regulation, Programmable Range
Voltage regulation accuracy
mΩ
TA = 25°C
3.5
4.44
-0.5%
.5%
-1%
1%
550
1500
-10%
10%
Fast charge current range
V(BATHSRT) ≤ V(BAT) < VBAT(REG) programmable range
Fast charge current accuracy
0°C to 125°C
V(BATSHRT)
Battery short circuit threshold
100 mV hysteresis
I(BATSHRT)
Battery short circuit current
V(BAT) < V(BATSHRT)
tDGL(BATSHRT)
Deglitch time for battery short to
fast charge transition
ITERM
Termination charge current
tDGL(TERM)
Deglitch time for charge
termination
Both rising and falling, 2-mV over-drive,
tRISE, tFALL = 100 ns
V(RCH)
Recharge threshold voltage
Below V(BATREG)
tDGL(RCH)
Deglitch time
V(BAT) falling below V(RCH), tFALL = 100 ns
During battery detection source cycle
3.3
I(CHARGE)
2.9
3
3.1
V
mA
V
50.0
mA
32
ms
I(TERM) = 50 mA
-35%
35%
I(TERM) ≥ 100 mA
-15%
15%
32
ms
120
mV
32
ms
V(DETECT)
Battery detection voltage
I(DETECT)
Battery detection current before
charge done (sink current)
Termination enabled (EN_TERM = 1)
2.5
mA
t(DETECT)
Battery detection time
Termination enabled (EN_TERM = 1)
250
ms
VIH
PSEL, CD input high logic level
VIL
PSEL, CD input low logic level
4
V
During battery detection sink cycle
3
1.3
V
0.4
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Copyright © 2012, Texas Instruments Incorporated
Product Folder Link(s): bq24270 bq24271
bq24270
bq24271
www.ti.com
SLUSB10 – JUNE 2012
ELECTRICAL CHARACTERISTICS (continued)
Circuit of Figure 3, V(UVLO) < V(USB) < V(OVP) AND V(USB) > V(BAT)+V(SLP), TJ = 0°C–125°C and TJ = 25°C for typical values
(unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
INPUT CURRENT LIMITING
I(USBLIM)
Input current limit threshold (USB
input)
USB charge mode, V(USB) = 5 V, DC Current
pulled from SW
I(USBLIM) = USB100
90
95
100
I(USBLIM) = USB500
400
475
500
I(USBLIM) = USB150
135
142.5
150
I(USBLIM)= USB900
800
850
900
I(USBLIM) = USB800
I(USBLIM)= 1.5A
V(IN_DPM)
Input based DPM threshold range
Charge mode, programmable via I2C
V(IN_DPM) threshold Accuracy
mA
700
750
800
1250
1400
1500
4.2
4.76
–2%
2%
V
VDRV BIAS REGULATOR
V(DRV)
Internal bias regulator voltage
I(DRV)
DRV Output current
V(DO_DRV)
DRV Dropout voltage (V(USB) –
V(DRV))
V(USB) > 5.45 V
5
5.2
5.45
V
10
mA
I(USB) = 1A, V(USB) = 5 V, I(DRV) = 10 mA
450
0.4
mV
STATUS OUTPUT (STAT, INT)
VOL
Low-level output saturation voltage
IO = 10 mA, sink current
IIH
High-level leakage current
VCHG = VPG = 5 V
V(UVLO)
IC active threshold voltage
V(USB) rising
3.6
3.8
VUVLO(HYS)
IC active hysteresis
V(USB) falling from above V(UVLO)
120
150
V(SLP)
Sleep-mode entry threshold, VUSBVBAT
2 V ≤ V(BAT) ≤ V(BATREG), VUSB falling
V(SLP_EXIT)
Sleep-mode exit hysteresis
2 V ≤ V(BAT) ≤ V(BATREG)
Deglitch time for supply rising
above VSLP + VSLP_EXIT
Rising voltage, 2-mV over drive, tRISE = 100 ns
V
1
mA
PROTECTION
0
40
100
mV
100
175
mV
30
ms
VIN_DPM –
80 mV
Deglitch on bad source detection
V
32
VOVP
Input supply OVP threshold voltage
USB, V(USB) Rising
VOVP(HYS)
VOVP hysteresis
Supply falling from V(OVP)
V(BOVP)
Battery OVP threshold voltage
V(BAT) threshold over V(OREG) to turn off charger during charge
VBOVP hysteresis
Lower limit for V(BAT) falling from above V(BOVP)
VBAT(UVLO)
Battery UVLO threshold voltage
V(BAT) rising, 100 mV hysteresis
ILIMIT
Cycle by Cycle current limit
V(SYS) shorted
TSHUTDWN
Thermal trip
6.3
1.025 ×
VBATREG
ms
6.7
V
1.05 ×
VBATREG
mV
1.075 ×
VBATREG
V
% of
VBATREG
1
2.5
4.1
Charge current begins to cut off
Safety timer accuracy
6.5
100
Thermal hysteresis
Thermal regulation threshold
V
mV
40
Bad source detection threshold
TREG
4
4.9
V
5.6
A
165
°C
10
°C
120
–20%
°C
20%
PWM
Internal top reverse blocking
MOSFET on-resistance
I(IN_LIMIT) = 500 mA, Measured from V(USB) to PMIDU
Internal top N-channel Switching
MOSFET on-resistance
Internal bottom N-channel
MOSFET on-resistance
fOSC
Oscillator frequency
DMAX
Maximum duty cycle
DMIN
Minimum duty cycle
95
175
mΩ
Measured from PMIDU to SW
100
175
mΩ
Measured from SW to PGND
65
115
mΩ
1.50
1.65
MHz
1.35
95%
0%
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SLUSB10 – JUNE 2012
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ELECTRICAL CHARACTERISTICS (continued)
Circuit of Figure 3, V(UVLO) < V(USB) < V(OVP) AND V(USB) > V(BAT)+V(SLP), TJ = 0°C–125°C and TJ = 25°C for typical values
(unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
29.7
30
30.5
UNIT
BATTERY-PACK NTC MONITOR
VHOT
High temperature threshold
V(TS) falling
VHOT(HYS)
Hysteresis on high threshold
V(TS) rising
VWARM
High temperature threshold
V(TS) falling
VWARM(HYS)
Hysteresis on high threshold
V(TS) rising
VCOOL
Low temperature threshold
V(TS) rising
VCOOL(HYS)
Hysteresis on low threshold
V(TS) falling
VCOLD
Low temperature threshold
V(TS) rising
VCOLD(HYS)
Hysteresis on low threshold
V(TS) falling
TSOFF
TS Disable threshold
V(TS) rising, 2% V(DRV) Hysteresis
tDGL(TS)
Deglitch time on TS change
%VDRV
1
37.9
38.3
39.6
%VDRV
1
56
56.5
56.9
%VDRV
1
59.5
60
60.4
%VDRV
1
70
73
50
%VDRV
ms
D+/D- Detection (bq24270)
VD+_SRC
D+ Voltage Source
ID+_SRC
D+ Connection Check Current
Source
ID-_SINK
D- Current Sink
0.5
0.6
0.7
V
14
µA
100
150
µA
7
50
D-, switch open
–1
1
µA
D+, switch open
–1
1
µA
ID_LKG
Leakage Current into D+/D-
VD+_LOW
D+ Low Comparator Threshold
0.8
VD-_LOW
D- Low Comparator Threshold
250
400
mV
RD-_DWN
D- Pulldown for Connection Check
14.25
24.8
kΩ
V
BATGD Operation
VBATGD
Good Battery threshold
Deglitch for good battery threshold
3.6
V(BAT) rising to HIGH-Z mode, DEFAULT Mode Only
3.8
3.9
32
V
ms
I2C Compatible Interface
VIH
Input high threshold level
V(PULL-UP) = 1.8 V, SDA and SCL
VIL
Input low threshold level
V(PULL-UP) = 1.8 V, SDA and SCL
0.4
VOL
Output low threshold level
IL = 10 mA, sink current
0.4
V
IBIAS
High-Level leakage current
V(PULL-UP) = 1.8 V, SDA and SCL
1
µA
tWATCHDOG
Watchdog Timer timeout
6
1.3
30
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bq24271
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SLUSB10 – JUNE 2012
BLOCK DIAGRAM
PMID
BYP
5.2V
Reference
DRV
USB
5A
+
BOOT
CbC Current
Limit
USB IUSBLIM
Q1
USB VINDPM
DC-DC CONVERTER PWM LOGIC,
COMPENSATION AND BATTERY
FET CONTROL
VSYS(REG)
IBAT(REG)
VBAT(REG)
SW
DIE Temp
Regulation
Q2
PGND
SYS
References
Termination
Reference
+
OVP
Comparator
+
VUSB
VUSBOVP
Termination
Comparator
Q3
IBAT
BAT
Recharge Comparator
VUSB
VBAT+VSLP
Start Recharge
Cycle
+
VBATREG – 0.12V
VBAT
Hi-Impedance Mode
Sleep
Comparator
Enable Linear
Charge
Hi-Z
Mode
CD
+
Good Battery
Circuit
VSYSREG Comparator
+
VSYS
BGATE
VMINSYS
+
VBAT
VBATGD
VBATSC Comparator
SDA
Enable
IBATSHRT
I2C
Interface
SCL
+
VBAT
VBATSHRT
Supplement COMPARATOR
+
D+
D-
VSYS
VBAT
bq24270
USB
Adapter
Detection
Circuitry
VBSUP
VDRV
VBOVP Comparator
+
1.5A /
USB100
VBAT
VBATOVP
+
DISABLE
bq24271
TS COLD
PSEL
1C/
0.5C
+
TS COOL
+
VBATREG
– 0.14V
STAT
TS WARM
+
DISABLE
INT
CHARGE
CONTROLLER
TS HOT
TS
w/ Timers
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PIN CONFIGURATION
Spacer
49-Ball 2.78 mm x 2.78 mm WCSP
bq24270 (Top View)
A
B
C
D
E
1
2
3
AGND
AGND
AGND
BYP
BYP
SW
PGND
SW
PGND
PGND
SYS
D+
4
BYP
SW
USB
PMID
SW
PGND
SYS
USB
USB
SCL
BGATE
1
2
3
4
5
6
7
A
AGND
AGND
AGND
AGND
USB
USB
USB
B
BYP
BYP
BYP
BYP
PMIDU
PMIDU
PMIDU
C
SW
SW
SW
SW
SW
SW
SW
D
PGND
PGND
PGND
PGND
PGND
PGND
PGND
E
PGND
PSEL
N.C.
CD
SDA
SCL
BOOT
SYS
SYS
SYS
SYS
BGATE
INT
DRV
BAT
BAT
BAT
BAT
TS
STAT
PGND
PMID
SW
PGND
SDA
SYS
7
SW
PGND
CD
6
PMID
SW
PGND
D-
SYS
5
AGND
BYP
bq24271 (Top View)
PGND
BOOT
INT
DRV
F
F
G
BAT
BAT
BAT
BAT
TS
STAT
PGND
G
24-Pin RGE
17 PGND
PSEL
2
17 PGND
16 AGND
SCL
3
20
19
14
6
13
DRV
19
18
5
PGND
20
1
PGND
4
21
N.C.
SW
15
SDA
22
21
BQ24270
23
22
3
24
23
SCL
BOOT
BOOT
2
BYP
BYP
D+
AGND
AGND
18
USB
USB
1
PMID
PMID
D-
CD
CD
SW
16 AGND
BQ24271
15
PGND
5
14
SYS
6
13
SYS
SDA
4
SYS
PGND
SYS
DRV
7
8
9
10
11
12
7
8
9
10
11
12
INT
STAT
TS
BGATE
BAT
BAT
INT
STAT
TS
BGATE
BAT
BAT
8
bq24271 (Top View)
24
bq24270 (Top View)
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SLUSB10 – JUNE 2012
PIN FUNCTIONS
PIN NO.
bq24270
PIN NAME
PIN NO.
bq24271
I/O
DESCRIPTION
YFF
RGE
YFF
RGE
AGND
A1-A4
16, 21
A1-A4
16, 21
I
Ground terminal. Connect to the thermal pad (for QFN only) and the
ground plane of the circuit.
USB
A5-A7
22
A5-A7
22
I
USB Input Power Supply. USB is connected to the external DC supply
(AC adapter or USB port). Bypass USB to PGND with at least a 1 μF
ceramic capacitor.
BYP
B1-B4
20
B1-B4
20
O
Bypass for internal supply. Bypass BYP to GND with at least a 0.1 µF
ceramic capacitor.
PMID
B5-B7
23
B5-B7
23
O
Reverse Blocking MOSFET and High Side MOSFET Connection Point
for USB Input. Bypass PMID to GND with at least a 4.7μF ceramic
capacitor. Use caution when connecting an external load to PMID. The
PMID output is not current limited. Any short on PMID will result in
damage to the IC.
SW
C1-C7
18
C1-C7
18
O
Inductor Connection. Connect to the switched side of the external
inductor.
PGND
D1-D7, E1,
G7
5, 15, 17
D1-D7, E1,
G7
5, 15, 17
–
Ground terminal. Connect to the thermal pad (for QFN only) and the
ground plane of the circuit.
D+
E2
2
–
–
I
D-
E3
1
–
–
I
CD
E4
24
E4
24
I
SDA
E5
4
E5
4
I/O
I2C Interface Data. Connect SDA to the logic rail through a 10 kΩ
resistor.
SCL
E6
3
E6
3
I
I2C Interface Clock. Connect SCL to the logic rail through a 10 kΩ
resistor.
BOOT
E7
19
E7
19
I
High Side MOSFET Gate Driver Supply. Connect a 0.01 µF ceramic
capacitor (voltage rating > 10 V) from BOOT to SW to supply the gate
drive for the high side MOSFETs.
D+ and D- Connections for USB Input Adapter Detection. When a
charge cycle is initiated by the USB input, and a short is detected
between D+ and D-, the USB input current limit is set to 1.5 A. If a
short is not detected, the USB100 mode is selected.
IC Hardware Disable Input. Drive CD high to place the bq24270 and
bq24271 in high-z mode. Drive CD low for normal operation.
PSEL
–
–
E2
2
I
USB Source Detection Input. Drive PSEL high to indicate a USB
source is connected to the USB input. When PSEL is high, the IC starts
up with a 100mA input current limit for USB. Drive PSEL low to indicate
that an AC Adapter is connected to the USB input. When PSEL is low,
the IC starts up with a 1.5 A input current limit for USB.
SYS
F1-F4
13, 14
F1-F4
13,14
I/O
System Voltage Sense and Charger FET Connection. Connect SYS to
the system output at the output bulk capacitors. Bypass SYS locally
with 10 μF.
O
External Discharge MOSFET Gate Connection. BGATE drives an
external P-Channel MOSFET to provide a very low resistance
discharge path. Connect BGATE to the gate of the external MOSFET.
BGATE is low in high impedance mode and when no input is
connected.
O
Status Output. INT is an open-drain output that signals charging status
and fault interrupts. INT pulls low during charging. INT is high
impedance when charging is complete or the charger is disabled.
When a fault occurs, a 128 μs pulse is sent out as an interrupt for the
host. INT is enabled /disabled using the EN_STAT bit in the control
register. Connect INT to a logic rail through a 100 kΩ resistor to
communicate with the host processor.
BGATE
INT
F5
F6
10
7
F5
F6
10
7
DRV
F7
6
F7
6
O
Gate Drive Supply. DRV is the bias supply for the gate drive of the
internal MOSFETs. Bypass DRV to PGND with a 1 μF ceramic
capacitor. DRV may be used to drive external loads up to 10 mA. DRV
is active whenever the input is connected and VUSB > VUVLO and VUSB >
(VBAT + VSLP)
BAT
G1-G4
11, 12
G1-G4
11, 12
I/O
Battery Connection. Connect to the positive terminal of the battery.
Additionally, bypass BAT to GND with a 1μF capacitor.
TS
G5
9
G5
9
I
Battery Pack NTC Monitor. Connect TS to the center tap of a resistor
divider from DRV to GND. The NTC is connected from TS to GND. The
TS function provides 4 thresholds for JEITA compatibility. TS faults are
reported by the I2C interface. See the NTC Monitor section for more
details on operation and selecting the resistor values.
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PIN FUNCTIONS (continued)
PIN NO.
bq24270
PIN NAME
YFF
STAT
PIN NO.
bq24271
RGE
G6
Thermal
PAD
—
YFF
8
G6
Pad
I/O
DESCRIPTION
O
Status Output. STAT is an open-drain output that signals charging
status and fault interrupts. STAT pulls low during charging. STAT is
high impedance when charging is complete or the charger is disabled.
When a fault occurs, a 128 μs pulse is sent out as an interrupt for the
host. STAT is enabled /disabled using the EN_STAT bit in the control
register. Connect STAT to a logic rail using an LED for visual indication
or through a 10 kΩ resistor to communicate with the host processor.
-
There is an internal electrical connection between the exposed thermal
pad and the VSS pin of the device. The thermal pad must be
connected to the same potential as the VSS pin on the printed circuit
board. Do not use the thermal pad as the primary ground input for the
device.
RGE
8
—
Pad
TYPICAL APPLICATION CIRCUIT
USB
SW
VBUS
D+
PMID
D-
1uF
System
Load
0.01uF
GND
4.7uF
BOOT
SYS
10uF
BYP
PGND
0.1uF
AGND
BGATE
DRV
BAT
VDRV
1uF
1uF
STAT
PACK+
TS
TEMP
VSYS
(1.8V)
D+
DPACK-
bq24270
INT
HOST
GPIO1
SDA
SDA
SCL
SCL
Figure 1. Typical Application Circuit– bq24270, Shown with No External Discharge FET
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USB
VBUS
SW
D+
PMIDU
DGND
1uF
System
Load
0.01uF
4.7uF
BOOT
SYS
BYP
10uF
PGND
0.1uF
AGND
BGATE
DRV
BAT
VDRV
1uF
1uF
STAT
PACK+
TS
TEMP
VSYS
(1.8V)
USB PHY
PSEL
PACK-
bq24271
INT
HOST
GPIO1
SDA
SDA
SCL
SCL
Figure 2. Typical Application Circuit – bq24271, Shown with External Discharge FET
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DETAILED DESCRIPTION
The bq24270 and bq24271 are highly integrated single cell Li-Ion battery chargers and system power path
management devices targeted for space-limited, portable applications with high capacity batteries. The singleinput, single cell charger operates from either a USB port or alternate power source (i.e. wall adapter or wireless
power input) for a versatile solution.
The power path management feature allows the bq24270 and bq24271 to power the system from a high
efficiency DC to DC converter while simultaneously and independently charging the battery. The charger
monitors the battery current at all times and reduces the charge current when the system load requires current
above the input current limit. This allows for proper charge termination and enables the system to run with a
defective or absent battery pack. Additionally, this enables instant system turn-on even with a totally discharged
battery or no battery. The power-path management architecture also permits the battery to supplement the
system current requirements when the adapter cannot deliver the peak system currents. This enables the use of
a smaller adapter. The charge parameters are programmable using the I2C interface.
The battery is charged in three phases: conditioning, constant current and constant voltage. In all charge phases,
an internal control loop monitors the IC junction temperature and reduces the charge current if the internal
temperature threshold is exceeded.
Charge Mode Operation
Charge Profile
The internal battery MOSFET is used to charge the battery. When the battery is above the MINSYS voltage, the
internal FET is on to maximize efficiency and the PWM converter regulates the charge current into the battery.
When battery is less than MINSYS, the SYS is regulated to VSYS(REG) and battery is charged using the battery
FET to regulate the charge current. There are 5 loops that influence the charge current:
• Constant current loop (CC)
• Constant voltage loop (CV)
• Thermal-regulation loop
• Minimum system-voltage loop (MINSYS)
• Input-voltage dynamic power-management loop (V(IN-DPM))
During the charging process, all five loops are enabled and the one that is dominant takes control. The bq24270
supports a precision Li-Ion or Li-Polymer charging system for single-cell applications. The Dynamic Power Path
Management (DPPM) feature regulates the system voltage to a minimum of VMINSYS, so that startup is enabled
even for a missing or deeply discharged battery. Figure 3shows a typical charge profile including the minimum
system output voltage feature.
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Current Regulation
Phase
Precharge
Phase
Voltage Regulation
Phase
Regulation
voltage
Charge Current
Regulation
Threshold
System Voltage
VSYS
(3.7 V)
VBATSHRT
(3 V)
Battery
Voltage
Charge Current
Termination
Current
Threshold
IBATSHRT
50mA Precharge to
Close Pack Protector
Linear Charge
to Maintain
Minimum
System
Voltage
Battery
FET
is OFF
Battery FET is ON
Figure 3. Typical Charging Profile of bq24270 and bq24271
PWM Controller in Charge Mode
The bq24270 and bq24271 provide an integrated, fixed-frequency 1.5 MHz voltage-mode controller to power the
system and supply the charge current. The voltage loop is internally compensated and provides enough phase
margin for stable operation, allowing the use of small ceramic capacitors with low ESR. The input scheme for the
devices prevents battery discharge when the supply voltages are lower than VBAT. The high-side N-MOSFET
(Q1) switches to control the power delivered to the output. The DRV LDO provides a supply for the gate drive for
the low side MOSFET, while a bootstrap circuit (BST) with an external bootstrap capacitor is used to boost up
the gate drive voltage for Q1.
The input is protected by a cycle-by-cycle current limit that is sensed through the internal sense MOSFETs for
Q1. The threshold for the current limit is set to a nominal 5-A peak current. The input also uses an input current
limit that limits the current from the power source
Battery Charging Process
When the battery is deeply discharged or shorted (V(BAT) < V(BATSHRT)) the bq24270 and bq24271 apply IBATSHRT
to close the pack protector switch and bring the battery voltage up to acceptable charging levels. During this
time, the battery FET is linearly regulated and the system output is regulated to VSYS(REG). Once the battery rises
above V(BATSHRT), the charge current is regulated to the value set in the I2C register. The battery FET is linearly
regulated to maintain the system voltage at VSYS(REG). Under normal conditions, the time spent in this region is a
short percentage of the total charging time, so the linear regulation of the charge current does not affect the
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overall charging efficiency for long. If the die temperature does heat up, the thermal regulation circuit reduces the
charge current to maintain a die temperature less than 125°C. If the current limit for the SYS output is reached
(limited by the input current limit, or V(IN_DPM)), the SYS output drops to the V(MINSYS) output voltage. When this
happens, the current is reduced to provide the system with all the current that is needed while maintaining the
minimum system voltage. If the charge current is reduced to 0 mA, pulling further current from SYS causes the
output to fall to the battery voltage and enter supplement mode (see the Dynamic Power Path Management
section for more details
Once the battery is charged enough to where the system voltage begins to rise above VSYS(REG) (approximately
3.5 V), the battery FET is turned on fully and the battery is charged with the full programmed charge current set
by the I2C interface, I(CHARGE). The slew rate for fast charge current is controlled to minimize the current and
voltage over-shoot during transient. The charge current is regulated to I(CHARGE) until the battery is charged to the
regulation voltage. Once the battery voltage is close to the regulation voltage, V(BATREG), the charge current is
tapered down as shown in Figure 3 while the SYS output remains connected to the battery. The voltage
regulation feedback occurs by monitoring the battery-pack voltage between the BAT and PGND pins. The
V(BATREG) is targeted for single-cell voltage batteries and has an adjustable regulation voltage (3.5 V to 4.44 V)
programmed using the I2C interface
The devices monitor the charging current during the voltage regulation phase. Once the termination threshold,
I(TERM), is detected and the battery voltage is above the recharge threshold, the devices terminate charge and
turn off the battery charging FET and enters battery detection. If a battery is detection (See the Battery Detection
section), the devices enter charge done. The system output is regulated to the VSYS(REG) and supports the full
current available from the input and the battery supplement mode is available (see the Dynamic Power Path
Management section for more details). The termination current level is programmable. To disable the charge
current termination, the host sets the charge termination bit (TE) of charge control register to 0, see the to I2C
section for details.
1. The battery voltage falls below the V(BATREG)- V(RCH) threshold.
2. V(USB) toggle
3. CE bit toggle or RESET bit is set
4. Hi-Z bit toggle
Battery Detection
When termination conditions are met, a battery detection cycle is started. During battery detection, I(DETECT) is
pulled from V(BAT) for t(DETECT) to verify there is a battery. If the battery voltage remains above V(DETECT) for the full
duration of t(DETECT), a battery is determined to present and the IC enters “Charge Done”. If V(BAT) falls below
V(DETECT), a “Battery Not Present” fault is signaled and battery detection continues. The next cycle of battery
detection, the bq24270 and bq24271 turn on I(BATSHRT) for t(DETECT). If V(BAT) rises to V(DETECT), the current source
is turned off and after t(DETECT), the battery detection continues through another current sink cycle. Battery
detection continues until charge is disabled or a battery is detected. Once a battery is detected, the fault status
clears and a new charge cycle begins. Battery detection is not run when termination is disabled.
Dynamic Power Path Management
The bq24270 and bq24271 feature a SYS output that powers the external system load connected to the battery.
This output is active whenever a source is connected to USB or BAT. The following sections discuss the
behavior of SYS with a source connected to the supply or a battery source only.
Input Source Connected
When a valid input source is connected, the buck converter turns on to power the load on SYS. The STAT/INT
show an interrupt with 128 µs pulse to tell the host that something has changed. The FAULT bits read normal,
and the Supply Status register shows that a new supply is connected. The CE bit (bit 1) in the control register
(0x02) determines whether a charge cycle is initiated. By default, the bq24270 and bq24271 (CE = 0) enable a
charge cycle when a valid input source is connected. When the CE bit is 1 and a valid input source is connected,
the battery FET is turned off and the SYS output is regulated to the VSYS(REG) programmed by the V(BATREG)
threshold in the I2C register. A charge cycle is initiated when the CE bit is written to a 0.
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When the CE bit is a 0 and a valid source is connected to USB, the buck converter starts up and a charge cycle
is initiated. When V(BAT) is high enough that V(SYS) is > VSYS(REG), the battery FET is turned on and the SYS
output is connected to BAT. If the SYS voltage falls to VSYS(REG), it is regulated to that point to maintain the
system output even with a deeply discharged or absent battery. In this mode, the SYS output voltage is regulated
by the buck converter and the battery FET linearly regulates the charge current into the battery. The current from
the supply is shared between charging the battery and powering the system load at SYS. The dynamic power
path management (DPPM) circuitry of the devices monitor the current limits continuously and if the SYS voltage
falls to the V(MINSYS) voltage, it adjusts charge current to maintain the minimum system voltage and supply the
load on SYS. If the charge current is reduced to zero and the load increases further, the devices enter battery
supplement mode. During supplement mode, the battery FET is turned on and the battery supplements the
system load.
2000mA
1800mA
ISYS
800mA
0mA
1500mA
USB
~850mA
0mA
1A
IBAT
0mA
-200mA
3.75V
3.55V
DPPM loop active
VOUT
~3.1V
Supplement
Mode
Figure 4. Example DPPM Response (V(Supply) = 5 V, V(BAT) = 3.1 V, 1.5 A Input Current Limit)
VBAT(REG) should never be programmed less than V(BAT). If the battery is ever 5% above the regulation threshold,
the battery OVP circuit shuts the PWM converter off and the battery FET is turned on to discharge the battery to
safe operating levels. Battery OVP errors are shown in the I2C status registers.
Battery Only Connected
When a battery voltage > V(BATUVLO) is connected with no input source, the battery FET is turned on similar to
supplement mode. In this mode, the current is not regulated; however, there is a short circuit current limit. If the
short circuit limit is reached, the battery FET is turned off for the deglitch time. After the deglitch time, the battery
FET is turned on to test and determine if the short has been removed. If it has not, the FET turns off and the
process repeats until the short is removed. This process is to protect the internal FET from over current. If an
external FET is used for discharge, the body diode prevents the load on SYS from being disconnected from the
battery. If the battery voltage is less than V(BATUVLO), the battery FET (Q3) remains off and BAT is highimpedance. This prevents further discharging deeply discharged batteries.
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Battery Discharge FET (BGATE)
The bq24270 and bq24271 contain a MOSFET driver to drive an external discharge FET between the battery
and the system output. This external FET provides a low impedance path when supplying the system from the
battery. Connect BGATE to the gate of the external discharge MOSFET. BGATE is on under the following
conditions:
1. No valid input supply connected.
2. 2. HZ_MODE = 1
DEFAULT Mode
DEFAULT mode is used when I2C communication is not available. DEFAULT mode is entered in the following
situations:
1. When the charger is enabled and V(BAT) < 3.6 V before I2C communication is established.
2. When the watchdog timer expires without a reset from the I2C interface and the safety timer has not expired.
3. When the devices comes out of any fault condition (sleep mode, OVP, faulty adapter mode, etc.) before I2C
communication is established.
In default mode, the I2C registers are reset to the default values. The 27 min safety timer is reset and starts when
DEFAULT mode is entered. The default value for V(BATREG) is 3.6V, and the default value for I(CHARGE) is 1 A. The
input current limit for the USB input is determined by the D+ and D- detection (bq24270) or PSEL (bq24271).
Default mode is exited by programming the I2C interface. Once I2C communication is established, PSEL has no
effect on the USB input. Note that if termination is enabled and charging has terminated, a new charge cycle is
NOT initiated when entering DEFAULT mode.
Safety Timer and Watchdog Timer
At the beginning of charging process, the bq24270 and bq24271 start the safety timer. This timer is active during
the entire charging process. If charging has not terminated before the safety timer expires, charging is halted and
the CE bit is written to a “1”. The length of the safety timer is selectable using the I2C interface. A single 128 μs
pulse is sent on the STAT and INT outputs and the STATx bits of the status registers are updated in the I2C. The
CE bit must be toggled in order to clear the safety timer fault. The safety timer duration is selectable using the
TMR_X bits in the Safety Timer Register/ NTC Monitor register. Changing the safety timer duration resets the
safety timer. If the safety timer expires, charging is disabled (CE changed to a “1”). This function prevents
continuous charging of a defective battery if the host fails to reset the safety timer.
In addition to the safety timer, the devices contain a watchdog timer that monitors the host through the I2C
interface. Once a read/write is performed on the I2C interface, a 30-second timer (tWATCHDOG) is started. The 30second timer is reset by the host using the I2C interface. This is done by writing a “1” to the reset bit (TMR_RST)
in the control register. The TMR_RST bit is automatically set to “0” when the 30-second timer is reset. This
process continues until battery is fully charged or the safety timer expires. If the 30-second timer expires, the IC
enters DEFAULT mode where the default register values are loaded, the safety timer restarts at 27 minutes and
charging continues. The I2C may be accessed again to reinitialize the desired values and restart the watchdog
timer as long as the 27 minute safety timer has not expired. The watchdog timer flow chart is shown in Figure 5.
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Start Safety Timer
Safety timer expired?
Yes
Safety timer
fault
No
Charge Done?
ICHG < ITERM
Yes
STAT = Hi
Update STAT
bits
Yes
STAT = Hi
Update STAT
bits
Charging suspended
Enter suspended
mode
Fault indicated in
STAT registers
No
No
I2C Read/Write
performed?
Yes
Start 30 second
watchdog timer
Charge Done?
ICHG < ITERM
Reset 30 second
watchdog timer
No
Yes
Safety timer
fault
Safety timer expired?
No
Charging suspended
Fault indicated in
STAT registers
No
30s timer expired?
Yes
Yes
Received SW watchdog
RESET?
No
Reset to default
values in I2C
register
Restart 27min
safety timer
Figure 5. The Watchdog Timer Flow Chart for bq24270 and bq24271
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D+ and D- Based Adapter Detection for the USB Input (D+ and D-, bq24270)
The bq24270 contains a D+ and D– based adapter detection circuit that is used to program the input current limit
for the USB input during DEFAULT mode. D+ and D– detection is only performed in DEFAULT mode unless
forced by the D+ and D– EN bit in host mode.
By default the USB input current limit is set to 100 mA. When USB is asserted the bq24270 performs a charger
source identification to determine if it is connected to an SDP (USB port) or CDP and DCP (dedicated charger).
When the detection is initiated, the first step is the connection detection as described in BC1.2. This step detects
when the D+ and D- lines are connected to the bq24270. Once this connection is made, the circuit moves to the
Primary Detection. If the connection detection has not completed within 500 ms, the D+ and D- detection selects
100 mA for the unknown input source. The primary detection complies with the method described in BC1.2.
During primary detection, the D+ and D- lines are tested to determine if the port is an SDP or CDP and DCP. If a
CDP and DCP is detected the input current limit is increased to 1.5 A, if an SDP is detected the current limit
remains at 100 mA, until changed via the I2C interface. Secondary detection is not performed.
Automatic detection is performed only if V(D+) and V(D–) are less than 0.6 V to avoid interfering with the USB
transceiver which may also perform D+ and D- detection when the system is running normally. However, D+ and
D– can be initiated at any time by the host by setting the D+ and D– EN bit in the Control/Battery Voltage
Register to 1. After detection is complete the D+ and D– EN bit is automatically reset to 0 and the detection
circuitry is disconnected from the D+ and D- pins to avoid interference with USB data transfer. When a command
is written to change the input current limit in the I2C, this overrides the current limit selected by D+/D- detection.
USB Input Current Limit Selector Input (PSEL, bq24271)
The bq24271 contains a PSEL input that is used to program the input current limit for USB during DEFAULT
mode. Drive PSEL high to indicate a USB source is connected to the USB input and program the 500 mA current
limit for USB. Drive PSEL low to indicate that an AC Adapter is connected to the )USB input. When PSEL is low,
the IC starts up with a 1.5 A current limit for USB. Once an I2C write is done, PSEL has no effect on the input
current limit until the watchdog timer expires.
Hardware Chip Disable Input (CD)
The bq24270 and bq24271 contain a CD input that is used to disable the IC and place the devices into highimpedance mode. Drive CD low to enable charge and enter normal operation. Drive CD high to disable charge
and place the devices into high-impedance mode. Driving CD resets the safety timer.
LDO Output (DRV)
The bq24270 and bq24271 contain a linear regulator (DRV) that is used to supply the internal MOSFET drivers
and other circuitry. Additionally, DRV supplies up to 10mA external loads to power the STAT LED or the USB
transceiver circuitry. The maximum value of the DRV output is 5.45 V so it ideal for protecting voltage sensitive
USB circuits from high voltage fluctuations in the supply. The LDO is on whenever a supply is connected to the
USB input of the bq24270 and bq24271. The DRV is disabled under the following conditions:
1. V(USB) < UVLO
2. V(USB) < VSLP
3. Thermal Shutdown
4. OTG_LOCK bit set to '1'
External NTC Monitoring (TS)
The I2C interface allows the user to implement the JEITA standard for systems where the battery pack thermistor
is monitored by the host. Additionally, the bq24270 and bq24271 provide a flexible, voltage based TS input for
monitoring the battery pack NTC thermistor. The voltage at TS is monitored to determine that the battery is at a
safe temperature during charging. The devices enable the user to implement the JEITA. The JEITA specification
is shown in Figure 6.
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1.0C
0.5C
Portion of spec not covered by TS
Implementation on bq2427x
4.25V
4.15V
4.1V
T1
(0ºC)
T2
(10ºC)
T3
(45ºC)
T4
(50ºC)
T5
(60ºC)
Figure 6. Charge Current/Voltage During TS Conditions
To satisfy the JEITA requirements, four temperature thresholds are monitored; the cold battery threshold (TNTC <
0°C), the cool battery threshold (0°C < TNTC < 10°C) the warm battery threshold (45°C < TNTC < 60°C) and the
hot battery threshold (TNTC > 60°C). ). These temperatures correspond to the VCOLD, VCOOL, VWARM, and VHOT
thresholds. Charging is suspended and timers are suspended when VTS < VHOT or VTS > VCOLD. When VHOT <
VTS , VWARM the battery regulation voltage is reduced by 140 mV from the programmed regulation threshold.
When VCOOL < VTS < VCOLD, the charging current is reduced to half of the programmed charge current.
The TS function is voltage based for maximum flexibility. Connect a resistor divider from DRV to GND with TS
connected to the center tap to set the threshold. The connections are shown in Figure 7. The resistor values are
calculated using the following equations:
é
1
1 ùú
V
× RCOLD × RHOT × ê
êV
ú
DRV
V
HOT û
ë COLD
RLO =
éV
ù
é V
ù
RHOT × ê DRV - 1ú - RCOLD × ê DRV -1 ú
êV
ú
êV
ú
ë HOT
û
ë COLD
û
(1)
V
DRV -1
V
COLD
RHI =
1 +
1
RLO RCOLD
(2)
Where:
VCOLD = 0.6 x VDRV
VHOT = 0.3 v VDRV
Where RHOT is the NTC resistance at the hot temperature and RCOLD is the NTC resistance at cold
temperature.
For the bq24270 and bq24271, the WARM and COOL thresholds are not independently programmable. The
COOL and WARM NTC resistances for a selected resistor divider are calculated using the following equations:
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RLO × 0.564 × RHI
RLO - RLO × 0.564 - RHI × 0.564
RLO × 0.383 × RHI
RWARM =
RLO - RLO × 0.383 - RHI × 0.383
RCOOL =
DISABLE
VBAT(REG)
– 140mV
1 x Charge/
0.5 x Charge
TS COLD
TS COOL
TS WARM
(3)
(4)
VDRV
+
+
+
VDRV
TS HOT
RHI
+
TS
PACK+
TEMP
bq2427x
RLO
PACK-
Figure 7. TS Circuit
If the TS function is not used, connect TS to DRV directly to disable the feature. Additionally, the TS function can
be disabled in the I2C by writing to the EN_TS bit. When the TS is disabled, the status registers always read
“Normal”.
Thermal Regulation and Protection
During the charging process, to prevent the IC from overheating, bq24270 and bq24271 monitor the junction
temperature, TJ, of the die and begins to taper down the charge current once TJ reaches the thermal regulation
threshold, TREG. The charge current is reduced to zero when the junction temperature increases about 10°C
above TREG. Once the charge current is reduced, the system current is reduced while the battery supplements
the load to supply the system. This may cause a thermal shutdown of the devices if the die temperature rises too
high. At any state, if TJ exceeds TSHTDWN, the devices suspend charging and disables the buck converter. During
thermal shutdown mode, PWM is turned off, and the timers are suspended, and a single 128 μs pulse is sent on
the STAT and INT outputs and the STATx and FAULT_x bits of the status registers are updated in the I2C. A
new charging cycle begins when TJ falls below TSHTDWN by approximately 10°C.
Input Voltage Protection in Charge Mode
Sleep Mode
The bq24270 and bq24271 enter the low-power sleep mode if the voltage on V(USB) falls below sleep-mode
entry threshold, V(BAT) + V(SLP), and V(VBUS) is higher than the undervoltage lockout threshold, VUVLO. This
feature prevents draining the battery during the absence of V(USB). When V(USB) < V(BAT) + V(SLP), the devices
turn off the PWM converter, turn on the battery FET, drive BGATE to GND, send a single 128 μs pulse on
the STAT and INT outputs, and update the STATx and FAULT_x bits in the status registers. Once V(USB) >
V(BAT)+ V(SLP), the STATx and FAULT_x bits are cleared and the devices initiate a new charge cycle.
20
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Input Voltage Based DPM
During normal charging process, if the input power source is not able to support the programmed or default
charging current, the supply voltage deceases. Once the supply drops to VIN_DPM (default 4.2 V), the input
current limit is reduced down to prevent further supply droop. When the IC enters this mode, the charge
current is lower than the set value and the DPM_STATUS bit is set (Bit 5 in Register 05H). This feature
ensures IC compatibility with adapters with different current capabilities without a hardware change. Figure 8
shows the VIN-DPM behavior to a current limited source. In this figure, the input source has a 750 mA current
limit and the charging is set to 750 mA. The SYS load is then increased to 1.2 A.
Figure 8. bq24270 VIN-DPM
Bad Source Detection
When a source is connected to USB, the bq24270 and bq24271 run a Bad Source Detection procedure to
determine if the source is strong enough to provide some current to charge the battery. A current sink is
turned on (30 mA) for 32 ms. If the source is valid after the 32 ms (V(BAD_SOURCE) < V(USB) < V(OVP)), the buck
converter starts up and normal operation continues. If the supply voltage falls below V(BAD_SOURCE) during the
detection, the current sink shuts off for 2s and then retries. The detection circuits retries, a single 128 μs
pulse is sent on the STAT and INT outputs, and the STATx and FAULT_x bits of the status registers and the
battery/supply status registers are updated in the I2C. The detection circuits retries continuously until either a
new source is connected to the other input or a valid source is detected after the detection time. If during
normal operation the source falls to V(BAD_SOURCE), the devices turn off the PWM converter, turn on the
battery FET and BGATE, send a single 128 μs pulse on the STAT and INT outputs, and the STATx and
FAULT_x bits of the status registers and the battery/supply status registers are updated in the I2C. Once a
good source is detected, the STATx and FAULT_x bits are cleared and the devices return to normal
operation
Input Overvoltage Protection
The bq24270 and bq24271 provide overvoltage protection on the input that protects downstream circuitry.
The built-in input overvoltage protection to protect the devices and other components against damage from
overvoltage on the input supply (Voltage from V(USB) or VIN to PGND). During normal operation, if V(USB) >
V(OVP), the devices turn off the PWM converter, turns the battery FET and BGATE on, sends a single 128 μs
pulse is sent on the STAT and INT outputs and the STATx and FAULT_x bits of the status registers and the
battery and supply status registers are updated in the I2C. Once the OVP fault is removed, the STATx and
FAULT_x bits are cleared and the devices return to normal operation.
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Charge Status Outputs (STAT, INT)
The STAT output is used to indicate operation conditions for bq24270 and bq24271. STAT is pulled low during
charging when EN_STAT bit in the control register (0x02h) is set to “1”. When charge is complete or disabled,
STAT is high impedance. When a fault occurs, a 128-µs pulse (interrupt) is sent out to notify the host. The status
of STAT during different operation conditions is summarized in Table 1. STAT drives an LED for visual indication
or can be connected to the logic rail for host communication. The EN_STAT bit in the control register (00H) is
used to enable/disable the charge status for STAT. The interrupt pulses are unaffected by EN_STAT and will
always be shown. The INT output is identical to STAT and is used to interface with a low voltage host processor
Table 1. STAT Pin Summary
Charge State
STAT and INT behavior
Charge in progress and EN_STAT=1
Low
Other normal conditions
High-Impedance
Status Changes: Supply Status Change (plug in or
removal), safety timer fault, watchdog expiration,
sleep mode, battery temperature fault (TS), battery
fault (OVP or absent), thermal shutdown
128-µs pulse, then High Impedance
The bq24270 and bq24271 contain a good battery monitor circuit that places the devices into high-z mode if the
battery voltage is above the BATGD threshold while in DEFAULT mode. This function is used to enable
compliance to the battery charging standard that prevents charging from an un-enumerated USB host while the
battery is above the good battery threshold. If the devices are in HOST mode, it is assumed that USB host has
been enumerated and the good battery circuit has no effect on charging.
SERIAL INTERFACE DESCRIPTION
The bq24270 and bq24271 use an I2C compatible interface to program charge parameters. I2C is a 2-wire serial
interface developed by Philips Semiconductor (see I2C-Bus Specification, Version 2.1, January 2000). The bus
consists of a data line (SDA) and a clock line (SCL) with pull-up structures. When the bus is idle, both SDA and
SCL lines are pulled high. All the I2C compatible devices connect to the I2C bus through open drain I/O pins,
SDA and SCL. A master device, usually a microcontroller or a digital signal processor, controls the bus. The
master is responsible for generating the SCL signal and device addresses. The master also generates specific
conditions that indicate the START and STOP of data transfer. A slave device receives and/or transmits data on
the bus under control of the master device.
The devices work as a slave and support the following data transfer modes, as defined in the I2C Bus
Specification: standard mode (100 kbps) and fast mode (400 kbps). The interface adds flexibility to the battery
charging solution, enabling most functions to be programmed to new values depending on the instantaneous
application requirements. Register contents remain intact as long as battery voltage remains above 2.5 V
(typical). The I2C circuitry is powered from V(BUS) when a supply is connected. If the V(BUS) supply is not
connected, the I2C circuitry is powered from the battery through BAT. The battery voltage must stay above 2.5 V
with no input connected in order to maintain proper operation
The data transfer protocol for standard and fast modes is exactly the same; therefore, they are referred to as the
F/S-mode in this document. The devices only support 7-bit addressing. The 7-bit address is defined as ‘1101011’
(6Bh).
F/S Mode Protocol
The master initiates data transfer by generating a start condition. The start condition is when a high-to-low
transition occurs on the SDA line while SCL is high, as shown in Figure 9. All I2C - compatible devices should
recognize a start condition.
22
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Figure 9. START and STOP Condition
The master then generates the SCL pulses, and transmits the 8-bit address and the read/write direction bit R/W
on the SDA line. During all transmissions, the master ensures that data is valid. A valid data condition requires
the SDA line to be stable during the entire high period of the clock pulse (see Figure 10). All devices recognize
the address sent by the master and compare it to their internal fixed addresses. Only the slave device with a
matching address generates an acknowledge (see Figure 11) by pulling the SDA line low during the entire high
period of the ninth SCL cycle. Upon detecting this acknowledge, the master knows that communication link with a
slave has been established.
Figure 10. Bit Transfer on the Serial Interface
The master generates further SCL cycles to either transmit data to the slave (R/W bit 1) or receive data from the
slave (R/W bit 0). In either case, the receiver needs to acknowledge the data sent by the transmitter. So an
acknowledge signal can either be generated by the master or by the slave, depending on which one is the
receiver. The 9-bit valid data sequences consisting of 8-bit data and 1-bit acknowledge can continue as long as
necessary. To signal the end of the data transfer, the master generates a stop condition by pulling the SDA line
from low to high while the SCL line is high (see Figure 12). This releases the bus and stops the communication
link with the addressed slave. All I2C compatible devices must recognize the stop condition. Upon the receipt of a
stop condition, all devices know that the bus is released, and wait for a start condition followed by a matching
address. If a transaction is terminated prematurely, the master needs sending a STOP condition to prevent the
slave I2C logic from remaining in an incorrect state. Attempting to read data from register addresses not listed in
this section result in FFh being read out.
Figure 11. Acknowledge on the I2C Bus
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Figure 12. Bus Protocol
REGISTER DESCRIPTION
Status and Control Register (READ/WRITE)
Memory location: 00, Reset state: 0xxx 0xxx
BIT
NAME
Read/Write
FUNCTION
B7(MSB)
TMR_RST
Read/Write
Write: TMR_RST function, write “1” to reset the watchdog timer (auto clear)
Read: Always 0
B6
STAT_2
Read only
B5
STAT_1
Read only
B4
STAT_0
Read only
B3
NA
Read/Write
NA
B2
FAULT_2
Read only
B1
FAULT_1
Read only
B0(LSB)
FAULT_0
Read only
000-Normal
001- Thermal Shutdown
010- Battery Temperature Fault
011- Watchdog Timer Expired (bq24270/1 only)
100- Safety Timer Expired (bq24270/1 only)
101- NA
110- USB Supply Fault
111- Battery Fault
24
000- No Valid Source Detected
001- NA
010- USB Ready
011-NA
100- Charging from USB
101- Charge Done
110- NA
111- Fault
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Battery and Supply Status Register (READ/WRITE)
Memory location: 01, Reset state: xxxx 0xxx
BIT
NAME
Read/Write
FUNCTION
B7(MSB)
NA
Read Only
NA
B6
NA
Read Only
NA
B5
USBSTAT1
Read Only
B4
USBSTAT0
Read Only
00-Normal
01-Supply OVP
01-Weak Source Connected (No Charging)
11- VUSB < VUVLO
B3
OTG_LOCK
Read/Write
B2
BATSTAT1
Read Only
B1
BATSTAT0
Read Only
B0 (LSB)
EN_NOBATOP
Read/ Write
0 – No OTG supply present. Use USB input as normal.
1 – OTG supply present. Lockout USB input for charging.
(default 0)
00-Battery Present and Normal
01-Battery OVP
10-Battery Not Present
11- NA
0-Normal Operation
1-Enables No Battery Operation when termination is disabled
(default 0)
OTG_LOCK Bit (USB Lockout)
The OTG_LOCK bit is used to prevent any charging from USB. For systems using OTG supplies, it is not
desirable to charge from an OTG source. Doing so would mean draining the battery by allowing it to effectively
charge itself. Write a “1” to OTG_LOCK to lock out the USB input. Write a “0” to OTG_LOCK to return to normal
operation. The watchdog timer must be reset while in USB_LOCK to maintain the USB lockout state. This
prevents the USB input from being permanently locked out for cases where the host loses I2C communication
with OTG_LOCK set (i.e. discharged battery from OTG operation). See the Safety Timer and Watchdog Timer
section for more details.
EN_NOBATOP (No Battery Operation with Termination Disabled
The EN_NOBATOP bit is used to enable operation when termination is disabled and no battery is connected.
This is useful for cases where the PA is connected to the BAT pin and it desired to do a calibration in the factory.
For this application, the TE bit (Bit 2 in Register 0x02h) should be set to a “0” to disable termination and the
EN_NOBATOP should be set to a “1”. This feature should not be used during normal operation as it disables the
BATOVP and the reverse boost protection circuits.
Control Register (READ/WRITE)
Memory location: 02, Reset state: 1000 1100
BIT
NAME
Read/Write
FUNCTION
B7(MSB)
RESET
Write only
Write: 1-Reset all registers to default values
0-No effect
Read: always get “1”
B6
IUSB_LIMIT_2
Read/Write
B5
IUSB_LIMIT_1
Read/Write
B4
IUSB_LIMIT _0
Read/Write
B3
EN_STAT
Read/Write
1-Enable STAT output to show charge status,
0-Disable STAT output for charge status. Fault interrupts are still show even
when EN_STAT = 0. (default 1)
B2
TE
Read/Write
1-Enable charge current termination, 0-Disable charge current termination
(default 1)
B1
CE
Read/Write
1-Charger is disabled
0-Charger enabled (default 0)
000-USB2.0 host with 100mA current limit
001-USB3.0 host with 150mA current limit
010 – USB2.0 host with 500mA current limit
011 – USB host/charger with 800mA current limit
100 – USB3.0 host with 900mA current limit
101 – USB host/charger with 1500mA current limit
110 -111 – NA (default 000(1))
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BIT
NAME
Read/Write
FUNCTION
B0 (LSB)
HZ_MODE
Read/Write
1-High impedance mode
0-Not high impedance mode (default 0)
RESET Bit
The RESET bit in the control register (0x02h) is used to reset all the charge parameters. Write “1” to RESET bit
to reset all the registers to default values and place the bq24270 and bq24271 into DEFAULT mode and turn off
the watchdog timer. The RESET bit is automatically cleared to zero once the devices enter DEFAULT mode.
CE Bit (Charge Enable
The CE bit in the control register (0x02h) is used to disable or enable the charge process. A low logic level (0) on
this bit enables the charge and a high logic level (1) disables the charge. When charge is disabled, the SYS
output regulates to VSYS(REG) and battery is disconnected from the SYS. Supplement mode is still available if
the system load demands cannot be met by the supply. BGATE is high impedance when CE is high.
HZ_MODE Bit (High Impedance Mode Enable
The HZ_MODE bit in the control register (0x02h) is used to disable or enable the high impedance mode. A low
logic level (0) on this bit enables the IC and a high logic level (1) puts the IC in a low quiescent current state
called high impedance mode. When in high impedance mode, the converter is off and the battery FET and
BGATE are on. The load on SYS is supplied by the battery.
Control/Battery Voltage Register (READ/WRITE)
Memory location: 03, Reset state: 0001 0100
BIT
NAME
Read/Write
FUNCTION
B7(MSB)
VBREG5
Read/Write
Battery Regulation Voltage: 640mV (default 0)
B6
VBREG4
Read/Write
Battery Regulation Voltage: 320mV (default 0)
B5
VBREG3
Read/Write
Battery Regulation Voltage: 160mV (default 0)
B4
VBREG2
Read/Write
Battery Regulation Voltage: 80mV (default 1)
B3
VBREG1
Read/Write
Battery Regulation Voltage: 40mV (default 0)
B2
VBREG0
Read/Write
Battery Regulation Voltage: 20mV (default 1)
B1
NA
Read/Write
NA
B0(LSB)
D+/D-_EN
Read/Write
0—Normal state, D+/D- Detection done
1—Force D+/D- Detection. Returns to “0” after detection is done. (default 0)
Charge voltage range is 3.5 V—4.44 V with the offset of 3.5V and step of 20mV (default 3.6V).
Vender, Part, Revision Register (READ only)
Memory location: 04, Reset state: 0100 0000
BIT
NAME
Read/Write
FUNCTION
B7(MSB)
Vender2
Read only
Vender Code: bit 2 (default 0)
B6
Vender1
Read only
Vender Code: bit 1 (default 1)
B5
Vender0
Read only
Vender Code: bit 0 (default 0)
B4
PN1
Read only
B3
PN0
Read only
For I2C Address 6Bh:
00: bq24270 and bq24271
01 – 11: Future product spins
B2
Revision2
Read only
B1
Revision1
Read only
B0(LSB)
Revision0
Read only
26
000: Revision 1.0
001:Revision 1.1
010: Revision 2.0
011:Revision 2.1
100:Revision 2.2
101: Revision 2.3
110-111: Future Revisions
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Battery Termination and Fast Charge Current Register (READ/WRITE)
Memory location: 05, Reset state: 0011 0010
BIT
NAME
Read/Write
FUNCTION
B7(MSB)
NA
Read/Write
NA
B6
ICHRG3
Read/Write
Charge current: 600 mA— (default 0)
B5
ICHRG2
Read/Write
Charge current: 300 mA—(default 1)
B4
ICHRG1
Read/Write
Charge current: 150 mA— (default 1)
B3
ICHRG0
Read/Write
Charge current: 75 mA (default 0)
B2
ITERM2
Read/Write
Termination current sense voltage: 200 mA (default 0)
B1
ITERM1
Read/Write
Termination current sense voltage: 100 mA (default 1)
B0(LSB)
ITERM0
Read/Write
Termination current sense voltage: 50 mA (default 0)
Charge current sense offset is 550 mA and default charge current is 1000 mA
Termination threshold offset is 50 mA and default termination current is 150 mA
VIN-DPM Voltage and DPPM Status Register
Memory location: 06, Reset state: xx00 0000
BIT
NAME
Read/Write
FUNCTION
B7(MSB)
MINSYS_STATUS
Read Only
1—Minimum System Voltage mode is active (low battery condition)
0—Minimum System Voltage mode is not active
B6
DPM_STATUS
Read Only
1—VIN-DPM mode is active
0—VIN-DPM mode is not active
B5
VINDPM2(USB)
Read/Write
USB input VIN-DPM voltage: 320mV (default 0)
B4
VINDPM1(USB)
Read/Write
USB input VIN-DPM voltage: 160mV (default 0)
B3
VINDPM0(USB)
Read/Write
USB input VIN-DPM voltage: 80mV (default 0)
B2
NA
Read/Write
NA
B1
NA
Read/Write
NA
B0(LSB)
NA
Read/Write
NA
VIN-DPM voltage offset is 4.20 V and default VIN-DPM threshold is 4.20 V
Safety Timer and NTC Monitor Register (READ/WRITE)
Memory location: 07, Reset state: 1001 1xxx
BIT
NAME
Read/Write
FUNCTION
B7(MSB)
2XTMR_EN
Read/Write
1 – Timer slowed by 2x when in thermal regulation, input current limit, VIN_DPM
or DPPM
0 – Timer not slowed at any time (default 0)
B6
TMR_1
Read/Write
B5
TMR_2
Read/Write
B4
NA
Read/Write
NA
B3
TS_EN
Read/Write
0 – TS function disabled
1 – TS function enabled (default 1)
B2
TS_FAULT1
Read only
B1
TS_FAULT0
Read only
B0(LSB)
LOW_CHG
Read/ Write
Safety Timer Time Limit –
00 – 27 minute fast charge
01 – 6 hour fast charge
10 – 9 hour fast charge
11 – Disable safety timers (default 00)
TS Fault Mode:
00— Normal, No TS fault
01— TS temp < TCOLD or TS temp > THOT (Charging suspended)
10— TCOOL > TS temp > TCOLD (Charge current reduced by half, bq24270 only)
11— TWARM < TS temp < THOT (Charge voltage reduced by 140 mV, bq24270
only)
0 – Charge current as programmed in Register 0x05
1 – Charge current is half programmed value in Register 0x05 (default 0)
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LOW_CHG Bit (Low Charge Mode Enable)
The LOW_CHG bit is used to reduce the charge current from the programmed value. This feature is used by
systems where battery NTC is monitored by the host and requires a reduced charge current setting or by
systems that need a “preconditioning” current for low battery voltages. Write a “1” to this bit to charge at half of
the programmed charge current. Write a “0” to this bit to charge at the programmed charge current.
APPLICATION INFORMATION
Output Inductor and Capacitor Selection Guidelines
When selecting an inductor, several attributes must be examined to find the right part for the application. First,
the inductance value should be selected. The bq24270 and bq24271 are designed to work with 1.5 µH to 2.2 µH
inductors. The chosen value will have an effect on efficiency and package size. Due to the smaller current ripple,
some efficiency gain is reached using the 2.2 µH inductor, however, due to the physical size of the inductor, this
may not be a viable option. The 1.5 µH inductor provides a good tradeoff between size and efficiency.
Once the inductance has been selected, the peak current must be calculated in order to choose the current
rating of the inductor. Use Equation 5 to calculate the peak current.
%
I
=I
× (1 + RIPPPLE )
PEAK LOAD(MAX)
2
(5)
The inductor selected must have a saturation current rating less than or equal to the calculated IPEAK. Due to the
high currents possible with the devices, a thermal analysis must also be done for the inductor. Many inductors
have 40°C temperature rise rating. This is the DC current that will cause a 40°C temperature rise above the
ambient temperature in the inductor. For this analysis, the typical load current may be used adjusted for the duty
cycle of the load transients. For example, if the application requires a 1.5 A DC load with peaks at 2.5 A 20% of
the time, a Δ40°C temperature rise current must be greater than 1.7 A:
ITEMPRISE = ILOAD + D × (IPEAK – ILOAD) = 1.5 A + 0.2 × (2.5 A – 1.5 A) = 1.7 A
(6)
The devices provide internal loop compensation. Using this scheme, the bq24270 is stable with 10 µF to 200 µF
of local capacitance. The capacitance on the SYS rail can be higher if distributed amongst the rail. To reduce the
output voltage ripple, a ceramic capacitor with the capacitance between 10µF and 47µF is recommended for
local bypass to SYS.
PCB Layout Guidelines
It is important to pay special attention to the PCB layout. Figure 13 provides a sample layout for the high current
paths of the bq24270 and bq24271.
WCSP I2C PART
BYP
AGND
QFN I2C PART
PMID
USB
USB
AGND
BOOT
SW
BOOT
PMID
BYP
PGND
PGND
SW
SW
SYS
PGND
BAT
SYS
SYS
SYS
BAT
Figure 13. Recommended bq24270 and bq24271 PCB Layout
28
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The following provides some guidelines:
• To obtain optimal performance, the power input capacitors, connected from the PMID input to PGND, must be
placed as close as possible to the bq24270 and bq24271
• Place 4.7 µF input capacitor as close to PMID pin and PGND pin as possible to make high frequency current
loop area as small as possible. Place 1µF input capacitor GNDs as close to the respective PMID cap GND
and PGND pins as possible to minimize the ground difference between the input and PMID.
• The local bypass capacitor from SYS to GND should be connected between the SYS pin and PGND of the
IC. The intent is to minimize the current path loop area from the SW pin through the LC filter and back to the
PGND pin.
• Place all decoupling capacitor close to their respective IC pin and as close as to PGND (do not place
components such that routing interrupts power stage currents). All small control signals should be routed
away from the high current paths.
• The PCB should have a ground plane (return) connected directly to the return of all components through vias
(two vias per capacitor for power-stage capacitors, one via per capacitor for small-signal components). It is
also recommended to put vias inside the PGND pads for the IC, if possible. A star ground design approach is
typically used to keep circuit block currents isolated (high-power/low-power small-signal) which reduces noisecoupling and ground-bounce issues. A single ground plane for this design gives good results. With this small
layout and a single ground plane, there is no ground-bounce issue, and having the components segregated
minimizes coupling between signals.
• The high-current charge paths into USB, BAT, SYS and from the SW pins must be sized appropriately for the
maximum charge current in order to avoid voltage drops in these traces. The PGND pins should be
connected to the ground plane to return current through the internal low-side FET.
• For high-current applications, the balls for the power paths should be connected to as much copper in the
board as possible. This allows better thermal performance as the board pulls heat away from the IC.
PACKAGE SUMMARY
1
2
3
4
5
6
7
A
AGND
AGND
AGND
AGND
USB
USB
USB
B
BYP
BYP
BYP
BYP
PMID
PMID
PMID
C
SW
SW
SW
SW
SW
SW
SW
D
PGND
PGND
PGND
PGND
PGND
PGND
PGND
E
PGND
D+
D-
CD
SDA
SCL
BOOT
SYS
SYS
SYS
SYS
BGATE
INT
DRV
BAT
BAT
BAT
BAT
TS
STAT
PGND
D
TI YMLLLLS
bq24270
bq24271
F
G
0-Pin A1 Marker, TI-TI Letters, YM-Year Month Date Code,
LLLL-Lot Trace Code, S-Assembly Site Code
CHIP SCALE PACKAGING DIMENSIONS
The devices are available in a 49-bump chip scale package (YFF, NanoFree™). The package dimensions are:
• D – 2.78mm ± 0.05mm
• E – 2.78mm ± 0.05mm
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
Product Folder Link(s): bq24270 bq24271
29
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
BQ24270RGER
ACTIVE
VQFN
RGE
24
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
BQ
24270
BQ24270RGET
ACTIVE
VQFN
RGE
24
250
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
BQ
24270
BQ24270YFFR
ACTIVE
DSBGA
YFF
49
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
BQ24270
BQ24270YFFT
ACTIVE
DSBGA
YFF
49
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
BQ24270
BQ24271RGER
ACTIVE
VQFN
RGE
24
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
BQ
24271
BQ24271RGET
ACTIVE
VQFN
RGE
24
250
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
BQ
24271
BQ24271YFFR
ACTIVE
DSBGA
YFF
49
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
BQ24271
BQ24271YFFT
ACTIVE
DSBGA
YFF
49
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
BQ24271
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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