bq25050
www.ti.com
SLUSA33 – MARCH 2010
1A, Single-Input, Single Cell Li-Ion Battery Charger with 50-mA LDO, External Power Path
Control, and Single Input Interface
Check for Samples: bq25050
FEATURES
1
•
•
•
•
•
•
•
•
•
•
•
DESCRIPTION
30V input Rating, With 10.5V Over-Voltage
Protection (OVP)
FET Controller for External Battery FET for
External Power Path Control (BGATE)
Input Voltage Dynamic Power Management
50mA integrated Low Dropout Linear
Regulator (LDO)
Programmable Charge Current Through Single
Input Interface (CTRL)
0.5% Battery Voltage Regulation Accuracy
7% Charge Current Regulation Accuracy
Thermal Regulation and Protection
Battery NTC Monitoring During Charge and
Discharge
Status Indication – Charging/Done and
Temperature Faults
Available in small 2mm × 3mm 10 Pin SON
Package
The bq25050 is a highly integrated Li-Ion linear
battery charger targeted at space-limited portable
applications. It operates from either a USB port or AC
Adapter and charges a single-cell Li-Ion battery with
up to 1A of charge current. The 30V input voltage
range with input over-voltage protections supports
low-cost unregulated adapters.
The bq25050 has a single power output that charges
the battery. The system load is connected to OUT.
The low-battery system startup circuitry maintains
OUT greater than 3.4V whenever an input source is
connected. This allows the system to start-up and run
whenever an input source is connected regardless of
the battery voltage. The charge current is
programmable up to 1A using the CTRL input.
Additionally, a 4.9V 50mA LDO is integrated into the
IC for supplying low power external circuitry.
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 an internal temperature threshold is exceeded. The
charger power stage and charge current sense
functions are fully integrated. The charger function
has high accuracy current and voltage regulation
loops, charge status display, and charge termination.
APPLICATIONS
•
•
•
•
Smart Phones
Mobile Phones
Portable Media Players
Low Power Handheld Devices
TYPICAL APPLICATION CIRCUIT
VGPIO
VGPIO
bq25050
USB or Adaptor
VBUS
D+
DGND
1
R2
100kΩ
CHG
8
OUT
10
STATUS
IN
C1
0.1uF
VDD
C2
1uF
QBAT
BGATE 9
7
CTRL
BAT
HOST
6
PACK+
2
IMON
3
VSS
TS
5
LDO
4
TEMP
C4
0.1uF
R1
1 kΩ
PACK -
VLDO
C3
0.1uF
ISENSE
GPIO
1
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.
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 © 2010, Texas Instruments Incorporated
bq25050
SLUSA33 – MARCH 2010
www.ti.com
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
ORDERING INFORMATION
PART NO.
MARKING
MEDIUM
QUANTITY
bq25050DQCR
DAM
Tape and Reel
3000
bq25050DQCT
DAM
Tape and Reel
250
PACKAGE DISSIPATION RATINGS TABLE
PACKAGE
RqJA
RqJC
TA < 25°C POWER
RATING
DERATING FACTOR
ABOVE TA = 25°C
10 Pin 2mm × 3mm SON (1)
58.7°C/W (2)
3.9°C/W
1.70W
0.017W/°C
(1)
(2)
Maximum power dissipation is a function of TJ(max), RqJA, and TA. The maximum allowable power dissipation at any allowable ambient
temperature is PD = [TJ(max) - TA]/RqJA.
This data is based on using the JEDEC High-K board and the exposed die pad is connected to a Cu pad on the board. The pad is
connected to the ground plane by a 2×3 via matrix.
ABSOLUTE MAXIMUM RATINGS (1)
over operating free-air temperature range (unless otherwise noted)
VALUE / UNIT
IN (with respect to VSS)
–0.3 to 30 V
CTRL, TS, CHG, BGATE (with respect to VSS)
–0.3 to 7 V
Output Voltage
BAT, OUT, LDO, CHG, BGATE, IMON (with respect to VSS)
–0.3 to 7 V
Input Current (Continuous)
IN
1.2 A
Output Current (Continuous)
BAT
1.2 A
Output Current (Continuous)
LDO
100 mA
Output Sink Current
CHG
Input Voltage
5 mA
Junction temperature, TJ
–40°C to 150°C
Storage temperature, TSTG
–65°C to 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.
RECOMMENDED OPERATING CONDITIONS
over operating free-air temperature range (unless otherwise noted)
IN voltage range
VIN
IN operating voltage range
MIN
MAX
3.55
28
4.4
10.2
UNITS
V
IIN
Input current, IN
1
A
IOUT
Ouput Current in charge mode, OUT
1
A
TJ
Junction Temperature
125
°C
0
ELECTRICAL CHARACTERISTICS
Over junction temperature range 0°C ≤ TJ ≤ 125°C and VIN = 5V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
3.25
3.30
3.55
UNITS
INPUT
VUVLO
Under-voltage lock-out
VIN: 0V → 4V
VHYS-UVLO
Hysteresis on UVLO
VIN: 4V → 0V
2
Submit Documentation Feedback
250
V
mV
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
bq25050
www.ti.com
SLUSA33 – MARCH 2010
ELECTRICAL CHARACTERISTICS (continued)
Over junction temperature range 0°C ≤ TJ ≤ 125°C and VIN = 5V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
1.95
2.05
2.15
UNITS
VBATUVLO
Battery UVLO
VBAT rising
VHYS-BUVLO
Hysteresis on BAT UVLO
VBAT falling
VIN-SLP
Valid input source threshold VIN-SLP above
VBAT
Input power good if VIN > VBAT + VIN–SLP
VBAT = 3.6V, VIN: 3.5V → 4V
VHYS-INSLP
Hysteresis on VIN-SLP
VBAT = 3.6V, VIN: 4V → 3.5V
32
mV
tDGL(NO-IN)
Deglitch time, input power loss to charger
turn-off
Time measured from VIN: 5V → 2.5V 1µs
fall-time
32
ms
VOVP
Input over-voltage protection threshold
VIN: 5 V → 11 V
VHYS-OVP
Hysteresis on OVP
VIN: 11 V → 5 V
tDGL(OVP)
Input over-voltage deglitch time
tREC(OVP)
Input over-voltage recovery time
Time measured from VIN: 11V → 5V 1µs
fall-time to LDO = HI, VBAT = 3.5V
VIN_DPM
Input DPM threshold
VIN Falling, VIN-DPM enabled with CTRL
125
30
10.2
4.2
75
10.5
V
mV
150
10.8
mV
V
100
mV
100
µs
100
µs
4.30
4.4
V
120
150
µA
6
µA
QUIESCENT CURRENT
IBAT(PDWN)
Battery current into BAT, No input
connected
VIN = 0V, VCHG = High, TS Enabled
IBAT(DONE)
BAT current, charging terminated
VIN = 6V, VBAT > VBAT(REG)
10
µA
IIN(STDBY)
Standby current into IN pin
CTRL = HI, VIN < VOVP
0.5
mA
CTRL = HI, VIN ≥ VOVP
2
ICC
Active supply current, IN pin
VIN = 6V, no load on OUT pin, VBAT >
VBAT(REG), IC enabled
3
VIN = 0V, VCHG = Low, TS Disabled, TJ =
85°C
mA
BATTERY CHARGER FAST-CHARGE
VBAT(REG)
Battery charge regulation voltage
TA = 0°C to 125°C, IOUT = 50 mA
TA = 25°C
IIN(LIM)
Input current limit (selected by CTRL
interface)
4.16
4.20
4.23
4.179
4.200
4.221
4 pulses on CTRL
87
93
100
5 pulses on CTRL
174
187
200
6 pulses on CTRL
261
280
300
7 pulses on CTRL
348
374
400
8 pulses on CTRL
435
467
500
9 pulses on CTRL
608
654
700
10 pulses on CTRL
739
794
850
11 pulses on CTRL
864
935
1000
500
900
VDO(IN-OUT)
VIN – VOUT
VIN = 4.2V, IOUT = 0.75 A
KIMON
Input current monitor ratio
KIMON = IIMON / ICHG, RIMON = 1kΩ,
Current programmed using CTRL
VIMON(MAX)
Maximum IMON voltage
IMON open
IMON Accuracy
25 mA < IIN < 100 mA
–25%
25%
IIN = 100 mA to 1 A
–8.5%
5%
1
1.2
V
mA
mV
mA/A
1.25
V
PRE-CHARGE AND CHARGE DONE
VLOWV
Pre-charge to fast-charge transition
threshold
tDGL1(LOWV)
Deglitch time on pre-charge to fast-charge
transition
25
ms
tDGL2(LOWV)
Deglitch time on fast-charge to pre-charge
transition
25
ms
IPRECHARGE
Precharge current to BAT during precharge
mode
VBAT = 0V to 2.9V, Battery FET connected
Default termination current threshold
VIN = 5V, ICHARGE = 100 mA to 1 A
ITERM
External power path control disabled,
BGATE = VSS
2.4
2.5
2.6
External power path control enabled
2.8
2.9
3.0
VBAT = 0V to 2.5V, BGATE = VSS, Input
current limit regulated to IPRECHARGE
28
37
45
41.5
45
48.5
7.5
10.5
13.5
VBAT(REG)
–0.13V
VBAT(REG)
–0.1V
VBAT(REG)
–0.065V
V
mA
%ICHG
RECHARGE OR REFRESH
VRCH
Recharge detection threshold
VBAT falling
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
V
3
bq25050
SLUSA33 – MARCH 2010
www.ti.com
ELECTRICAL CHARACTERISTICS (continued)
Over junction temperature range 0°C ≤ TJ ≤ 125°C and VIN = 5V (unless otherwise noted)
PARAMETER
tDGL(RCH)
TEST CONDITIONS
MIN
Deglitch time, recharge threshold detected
TYP
MAX
25
UNITS
ms
EXTERNAL POWER PATH CONTROL
VOUT(REG)
Output regulation voltage
VBAT ≤ 2.9 V
2.9 V < VBAT ≤ 3.6V
VBAT > 3.6 V
3.4
3.5
3.6
V
3.44
3.59
3.75
V
VBAT + Vdrop(QBAT)
V
VSUPP1
Enter supplement mode threshold
VBAT = 3.4 V, VOUT Falling
VOUT ≤
VBAT
-60mV
V
VSUPP2
Exit supplement mode threshold
VBAT = 3.4 V, VOUT Rising
VOUT ≥
VBAT-20mV
V
VLDO
LDO Output Voltage
VIN = 5.5V, ILDO = 0mA to 50mA
ILDO
Maximum LDO Output Current
VDO
Dropout Voltage
LDO
4.
4.9
5.1
60
VIN = 4.5V, ILDO = 50mA
V
mA
200
300
mV
CTRL INTERFACE
tCTRL-DGL
CTRL Deglitch timer
5
tCTRL-LATCH
CTRL Latch timer
2
ms
tCTRL-HIGH
High Duration on CTRL
50
1000
tCTRL-LOW
Low Time Duration on CTRL
50
1000
RPULLDOWN
CTRL Pulldown Resistor
ms
260
ms
µs
kΩ
LOGIC LEVELS ON CTRL, CHG, BGATE
VIL
Logic LOW input voltage
VIH
Logic HIGH input voltage
0.4
1.4
V
V
BATTERY-PACK NTC MONITOR (TS)
VTS_CLAMP
Maximum TS Voltage
ITS-0C
Current source for 0°C TS sensing
1.5
V
3.75
4
4.25
µA
ITS
Current source for 45°C and 60°C TS
sensing
19
20
21
µA
VCOLD
TS Cold Threshold, when BGATE is
disabled
VTS < VCOLD to begin charge
(Corresponds to 0°C, 2°C, 4°C (1)
0.55
0.575
0.600
V
VCUTOFF_0
TS Cold Cutoff Threshold
Temp falling (Corresponds to –1°C, 1°C,
3°C (1) (2))
0.575
0.600
0.625
V
VHOT_45
TS Hot Threshold (0°C to 45°C), when
BGATE is disabled
VTS > VHOT_45 to begin charge, 0°C to
45°C thresholds selected. (Corresponds to
40°C, 42°C, 44°C (1) (2))
0.44
0.45
0.46
V
VCUTOFF_45
TS Hot Cutoff Threshold (0°C to 45°C)
Temp rising (Corresponds to 45°C, 47°C,
49°C (1) (2))
0.365
0.375
0.385
V
VHOT_60
TS Hot Threshold (0°C to 60°C), when
BGATE is disabled
VTS > VHOT_60 to begin charge, 0°C to
60°C thresholds selected, Temp rising
(Corresponds to 54.5°C, 57°C, 60°C (1)
0.240
0.250
0.258
V
VCUTOFF_60
TS Hot Cutoff Threshold (0°C to 60°C)
Temp rising. (Corresponds to 58.5°C,
61.5°C, 64°C (1) (2))
0.204
0.213
0.223
V
V-20
–20°C TS Voltage
See
(1)
0.968
V80
+80°C TS Voltage
See
(1)
0.110
tdgl(TS)
Deglitch for TS Fault
Fault detected on TS to stop charge
VOL
Output LOW voltage
ISINK = 5 mA
IIH
Leakage current
V/CHG = 5 V
tFLSH(TS)
TS fault flash period
50% Duty Cycle, TS out of valid range
100
ms
(2)
)
(2)
)
V
V
25
ms
CHG OUTPUT
0.45
V
1
µA
THERMAL REGULATION
TJ(REG)
Temperature Regulation Limit
TJ rising
125
°C
TJ(OFF)
Thermal shutdown temperature
TJ rising
155
°C
(1)
(2)
4
Information is based on using the NCP15WB473F NTC thermistor.
Temperature references give design guidance only, actual absolute temperatures are not guaranteed.
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
bq25050
www.ti.com
SLUSA33 – MARCH 2010
ELECTRICAL CHARACTERISTICS (continued)
Over junction temperature range 0°C ≤ TJ ≤ 125°C and VIN = 5V (unless otherwise noted)
PARAMETER
TJ(OFF-HYS)
Thermal shutdown hysteresis
TEST CONDITIONS
TJ falling
MIN
TYP
MAX
20
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
UNITS
°C
5
bq25050
SLUSA33 – MARCH 2010
www.ti.com
DEVICE INFORMATION
SIMPLIFIED BLOCK DIAGRAM
LDO
+
Q1
Q2
OUT
VIN
Precharge
Current Source
+
IMON
+
125C
TJ
Charge
Pump
1.5V
+
IIN(REG)
External Power
Path Control
Mode
2.9V
BAT
VOUT(REG)
+
VIN_DPM
+
Charge
Pump
VOUT(MIN)
ILIM
TERMINATION
COMPARATOR
BGATE
+
VREF
+
VOUTMIN
150mV
VIN-DPM
Enable
External Power Path
Control Mode
Sleep Comparator
75mV
VBAT
+
CTRL
Digital
Decode
CHARGE
CONTROL
260k
OVP Comparator
+
VIN
VOUTMIN Enable
Comparator
VBAT
3.5V
+
VOVP
V IN
TS Current
VREF
Source Control
STATUS
OUTPUT
DISABLE
+
VREF
+
/CHG
TS COLD
TS HOT
TS
VSS
6
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
bq25050
www.ti.com
SLUSA33 – MARCH 2010
PIN CONFIGURATION
IN
1
10
IMON
2
9
BGATE
VSS
3
8
CHG
OUT
bq 25050
LDO
4
7
CTRL
TS
5
6
BAT
10-pin 2mm x 3mm SON
PIN FUNCTIONS
PIN
NAME
NO.
I/O
DESCRIPTION
IN
1
I
Input power supply. IN is connected to the external DC supply (AC adapter or USB port). Bypass IN to VSS with
at least a 0.1µF ceramic capacitor.
IMON
2
O
Current monitoring output. Connect a 1kΩ resistor from IMON to VSS to monitor the input current. The voltage at
IMON ranges from 0V to 1V which corresponds to an input current from 0A to 1A.
VSS
3
–
Ground terminal. Connect to the thermal pad and the ground plane of the circuit.
LDO
4
O
LDO output. LDO is regulated to 4.9V and drives up to 50mA. Bypass LDO to VSS with a 0.1µF ceramic
capacitor. LDO is enabled when VUVLO < VIN < VOVP.
TS
5
I
Battery pack NTC monitoring input. Connect the battery pack 47-kΩ NTC from TS to VSS to monitor battery pack
temperature. The default pack temperature range is 0°C to 45°C thresholds.
CTRL
7
I
Single-input interface Input. Drive CTRL with pulses to enable/disable the device, enable/disable VIN-DPM, select
battery temperature range and select current limits. See the interface section for details on using the CTRL
interface.
CHG
8
I/O Charge status indicator open-drain output. CHG is pulled low while the device is charging the battery. CHG goes
high impedance when the battery is fully charged and does not indicate subsequent recharge cycles. CHG pulses
to indicate TS faults.
BAT
6
O
BGATE
9
I/O Battery P-Channel FET gate drive output. Connect BGATE to the gate of the external P-Channel FET that
connects the battery to OUT. Connect BGATE to VSS if the external FET is not used. No external capacitor is
recommended from BGATE to GND.
OUT
10
O
System output connection. OUT supplies the system with a minimum voltage of 3.4V (min.) to ensure system
operation whenever an input adapter is connected regardless of the battery voltage. Bypass OUT to VSS with a
1µF ceramic capacitor.
Pad
–
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. VSS pin must be connected to ground at all times.
Thermal
PAD
Battery connection output. BAT is the sense input for the battery as well as the precharge current output. Connect
BAT to the battery and bypass BAT to VSS with a 0.1µF ceramic capacitor.
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
7
bq25050
SLUSA33 – MARCH 2010
www.ti.com
APPLICATION CIRCUITS
VGPIO
VGPIO
bq25050
USB or Adaptor
VBUS
D+
DGND
1
R2
100kΩ
CHG
8
OUT
10
STATUS
IN
C1
0.1uF
VDD
C2
1uF
QBAT
BGATE 9
7
CTRL
BAT
6
TS
5
HOST
PACK+
2
TEMP
C4
0.1uF
IMON
R1
1 kΩ
PACK -
3
VSS
LDO
4
VLDO
C3
0.1uF
ISENSE
GPIO
Figure 1. Typical Application Circuit Using the External Power Path Control Feature
VGPIO
VGPIO
bq25050
USB or Adaptor
VBUS
D+
DGND
1
R2
100kΩ
CHG
8
OUT
10
STATUS
IN
C1
0.1uF
VDD
C2
1uF
7
CTRL
BGATE
9
BAT
6
TS
5
HOST
PACK+
2
TEMP
IMON
R1
1 kΩ
PACK -
3
VSS
LDO
4
VLDO
C3
0.1uF
ISENSE
GPIO
Figure 2. Typical Application Circuit Disabling the External Power Path Control Feature
8
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
bq25050
www.ti.com
SLUSA33 – MARCH 2010
TYPICAL CHARACTERISTICS
Using circuit in Figure 1, TA = 25°C, unless otherwise specified
ADAPTER INSERTION
ENABLE USING CTRL
CTRL
2 V/div
VIN = 0 V - 5 V, VBAT = 3.3 V, ICHG = 280 mA
VIN = 5 V, VBAT = 3 V, ICHG = 280 mA
CHG
2 V/div
VIN
5 V/div
BGATE
2 V/div
BGATE
2 V/div
LDO
2 V/div
ICHG
0.5 A/div
IIN
100 mA/div
20 ms/div
10 ms/div
Figure 3.
Figure 4.
DISABLE USING CTRL
CONTROL CURRENT LIMIT - STEP UP
CTRL
2 V/div
LDO
2 V/div
CTRL
2 V/div
VIN = 5 V, VBAT = 3.4 V, ICHG = 280 mA
VIN = 5 V, VBAT = 3.4 V, ICHG = 93 mA to 935 mA
BGATE
2 V/div
IMON
500 mV/div
BGATE
2 V/div
IBAT
0.5 A/div
IIN
2 mA/div
1 ms/div
5 ms/div
Figure 5.
Figure 6.
CONTROL CURRENT LIMIT - STEP DOWN
BGATE FORCED ON
CTRL
2 V/div
VIN = 5 V, VBAT = 3.4 V, ICHG = 935 mA to 93 mA
CTRL
2 V/div
VBAT
2 V/div
Offset 4.1 V
VOUT
2 V/div
Offset 4.1 V
BGATE
2 V/div
BGATE
2 V/div
IMON
500 MV/div
IBAT
500 mA/div
VIN = 5 V, VBAT = 4.18 V, VBAT(REG) = 4.2 V
5 ms/div
1 ms/div
Figure 7.
Figure 8.
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
9
bq25050
SLUSA33 – MARCH 2010
www.ti.com
TYPICAL CHARACTERISTICS (continued)
Using circuit in Figure 1, TA = 25°C, unless otherwise specified
CANCEL BGATE FORCED ON
INPUT OVP
VIN
10 V/div
CTRL
2 V/div
VIN = 5 V to 29 V, VBAT = 3.8 V
VBAT
2 V/div
Offset 4.1 V
VOUT
2 V/div
Offset 4.1 V
VBAT
2V/div
LDO
2 V/div
BGATE
2 V/div
VIN = 5 V, VBAT = 4.18 V, VBAT(REG) = 4.2 V
IBAT
0.5 A/div
1 ms/div
50 µs/div
Figure 9.
Figure 10.
PRE-CHARGE MODE TO MINIMUM OUTPUT REGULATION
MODE
MINIMUM OUTPUT REGULATION MODE TO CONSTANT
CURRENT (CC) MODE
VIN = 5 V, VBAT = 1.8 V to 3.45 V, ICHG = 467 mA
VIN = 5 V, VBAT = 2.4 V to 3.6 V, ICHG = 467 mA
VBAT
500 V/div
VBAT
500 V/div
IMON
500 mV/div
IMON
500 mV/div
BGATE
2 V/div
BGATE
2 V/div
IBAT
500 mA/div
IBAT
500 mA/div
20 ms/div
20 ms/div
Figure 11.
Figure 12.
PRE-CHARGE TO CONSTANT VOLTAGE (CV) MODE
VIN-DPM
VIN
2 V/div
VBAT
500 mV/div
IMON
500 mV/div
VIN = 5 V, VBAT = 2.8 V to 4.18 V, ICHG = 467 mA
IIN
500 mA/div
IMON
500 mV/div
BGATE
2 V/div
BGATE
2 V/div
IBAT
500 mA/div
20 ms/div
200 µs/div
Figure 13.
10
VIN = 5 V with current limit of 600 mA,
VBAT = 3.2 V, ICHG = 93 mA to 935 mA
Figure 14.
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
bq25050
www.ti.com
SLUSA33 – MARCH 2010
TYPICAL CHARACTERISTICS (continued)
Using circuit in Figure 1, TA = 25°C, unless otherwise specified
SUPPLEMENT MODE
CHARGE CYCLE DEMO
VOUT
2 V/div
IMON
1 V/div
VBAT
2 V/div
BGATE
1 V/div
VIN = 5 V, ICHG = 280 mA,
BGATE =Enabled, CBAT = 2000 µF,
No battery connected,
RDSon from IN to OUT
IIN
100 mA/div
VOUT
2 V/div
IOUT
2 A/div
BGATE
2 V/div
VIN = 5 V, VBAT = 3.2 V,
ICHG = 935 mA, IOUT = 0 A to 2 A
20 ms/div
100 µs/div
Figure 15.
Figure 16.
BATTERY VOLTAGE
vs
CHARGE CURRENT
RDSON (From IN to OUT)
vs
JUNCTION TEMPERATURE
4.24
1.20
CV Mode
Iload = 500 mA
4.23
1.00
4.22
RDSON - W
VBAT - Battery Voltage - V
0.80
4.21
4.20
0.60
4.19
0.40
4.18
0.20
4.17
4.16
0
200
400
600
800
1000
0.00
-50
ICHRG - Charge Current - mA
Figure 17.
0
50
100
TJ - Junction Temperature - °C
150
Figure 18.
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
11
bq25050
SLUSA33 – MARCH 2010
www.ti.com
TYPICAL CHARACTERISTICS (continued)
Using circuit in Figure 1, TA = 25°C, unless otherwise specified
INPUT CURRENT LIMIT
vs
INPUT VOLTAGE
OUTPUT VOLTAGE
vs
CHARGE CURRENT
4.00
1000
VBAT = 3 V
900
3.90
Dropout
Thermal Regulation
3.80
700
VOUT - Output Voltage - V
IINLIM - Input Current Limit - mA
800
600
500
400
300
3.70
3.60
3.50
3.40
3.30
200
3.20
100
3.10
0
4
5
6
7
8
9
10
11
External Power Path Control Mode
VBAT = 3 V
3.00
0.000
VIN - Input Voltage - V
0.200
0.400
0.600
0.800
1.000
ICHRG - Charge Current - mA
Figure 19.
Figure 20.
DETAILED FUNCTIONAL DESCRIPTION
The bq25050 is a highly integrated Li-Ion linear battery charger targeted at space-limited portable applications. It
operates from either a USB port or AC Adapter and charges a single-cell Li-Ion battery with up to 1A of charge
current. The 30V input voltage range with input over-voltage protections supports low-cost unregulated adapters.
The bq25050 has a single power output that charges the battery. The system load is connected to OUT. The
low-battery system startup circuitry maintains OUT pin voltage at VOUT(REG) whenever an input source is
connected. This allows the system to start-up and run whenever an input source is connected regardless of the
battery voltage. The charge current is programmable up to 1A using the CTRL input. Additionally, a 4.9V 50mA
LDO is integrated into the IC for supplying low power external circuitry.
External FET Controller (BGATE)
The External Power Path Control feature is implemented using the BGATE output. BGATE is also used to
enable/ disable the External Power Path Control feature. When power is first applied to either VBAT or VIN on the
bq25050, the BGATE output is tested. If the BGATE pin is connected to VSS, the External Power Path Control
feature is disabled. In order to enable the External Power Path Control feature after it has been disabled, the
battery and the input source must be removed and reconnected and BGATE must NOT be connected to VSS.
With External Power Path Control enabled, BGATE is used to drive an external P-channel MOSFET that
connects the battery to the system output. This state of this MOSFET is dependant on the battery voltage and
the IC status. In discharge mode, BGATE is pulled to GND to turn the MOSFET on fully. During discharge mode,
the output is connected directly to the battery. Discharge mode is entered under the following conditions:
1. IC disabled or no input power
2. Supplement mode
3. "Force On" – enabled through CTRL
When not in one of these conditions, the BGATE output is controlled by the bq25050 and changes depending on
which mode is required. See the Charging Operation section for more details.
12
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
bq25050
www.ti.com
SLUSA33 – MARCH 2010
Enable/ Disable External Power Path Control
When power is first applied to the bq25050, either at the IN or BAT input, the bq25050 checks the BGATE
output. The device sources a small current out of BGATE for 32ms and monitors the voltage. If VBGATE is
connected to ground and the voltage does not rise above logic High, the External Power Path Control feature is
disabled and VLOWV is set to 2.5V. If the BGATE voltage rises above logic High, the External Power Path
Control feature is enabled and VLOWV is set to 2.9V. The bq25050 only does this check when power is initially
applied. Power must removed from IN and BAT and then reapplied to initiate another check. Figure 21 illustrates
the startup check procedure.
No Input Source or
Battery Connected
Input source OR
Battery connected?
NO
YES
Source Current to
BGATE
BGATE =
VSS?
YES
External
Power Path
Control
Disabled
V LOWV = 2.5V
NO
External
Power Path
Control
Enabled
VLOWV = 2.9V
Figure 21. BGATE Monitor Sequence
Charging Operation
The bq25050 charges a battery in 3 stages while maintaining a minimum system output. When the bq25050 is
enabled by CTRL, the battery voltage is monitored to verify which stage of charging must be used. The bq25050
charges in precharge mode, minimum output regulation mode, or normal CC/CV mode based on the battery
voltage.
Submit Documentation Feedback
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): bq25050
13
bq25050
SLUSA33 – MARCH 2010
www.ti.com
Charger Operation with External Power Path Control Mode Enabled
PRECHARGE
4.2V
CC FAST CHARGE
Maximum
Charge Current
(ILIM )
CV TAPER
System Voltage
IFASTCHG
3.5V
VLOWV
Battery Voltage
IPRECHG
CHG = Hi -Z
ITERM
Figure 22. Typical Charging Cycle with External Power Path Control Enabled
Precharge Mode (VBAT ≤ VLOWV)
The bq25050 enters precharge mode when VBAT ≤ VLOWV. Upon entering precharge mode, the battery is charged
with a 40mA current source and /CHG goes low. During precharge mode, VOUT is regulated to 3.5V and the
battery is charged from the internal fixed 40mA current source connected to the BAT output. With BGATE
connected to GND, the system output is connected to the battery and therefore the system voltage is equal to
the battery voltage.
Minimum Output Regulation Mode (2.9V
工商网监
湘ICP备2023018690号
