MP2637 [MPS]
2.5A Single Cell Switch Mode Battery Charger with Power Path Management (PPM) and 2.4A Boost Current with Trickle Timer;型号: | MP2637 |
厂家: | MONOLITHIC POWER SYSTEMS |
描述: | 2.5A Single Cell Switch Mode Battery Charger with Power Path Management (PPM) and 2.4A Boost Current with Trickle Timer 电池 |
文件: | 总36页 (文件大小:1862K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
MP2637
2.5A Single Cell Switch Mode Battery Charger
with Power Path Management (PPM)
and 2.4A Boost Current with Trickle Timer
DESCRIPTION
FEATURES
Up to 16V Sustainable Input Voltage
4.5V-to-6V Operating Input Voltage Range
Power Management function, Integrated
The MP2637 is a highly-integrated, flexible,
switch-mode battery charger with system power
path management, designed for single-cell Li-
ion or Li-Polymer batteries used in a wide range
of applications.
Input-Current
Regulation
Limit,
Input
Voltage
Up to 2.5A Programmable Charge Current
Trickle-Charge Function
Selectable 4.2V/ 4.35V Charge Voltage with
0.5% Accuracy
The MP2637 can operate in both charge mode
and boost mode to allow full system and battery
power management.
When input power is present, the device
operates in charge mode. It automatically
detects the battery voltage and charges the
battery in three phases: trickle current, constant
current and constant voltage. Other features
include charge termination and auto-recharge.
This device also integrates both input current
limit and input voltage regulation in order to
manage input power and meet the priority of the
system power demand.
Negative Temperature Coefficient Pin for
Battery Temperature Monitoring
Programmable Timer Back-Up Protection
Thermal Regulation and Thermal Shutdown
Internal Battery Reverse Leakage Blocking
Integrated Over Voltage Protection and
Over Current Protection for Pass-Through
Path
Reverse Boost Operation Mode for System
Power
Up to 2.4A Programmable Output Current
Limit for Boost Mode
In the absence of an input source, the MP2637
switches to boost mode through the MODE pin
to power the SYS pins from the battery. The
OLIM pin programs the output current limit in
boost mode. The MP2637 also allows for output
short circuit protection to completely disconnect
the battery from the load in the event of a short
circuit fault. Normal operation will recover as
soon as the short circuit fault is removed. The
MP2637 provides full operating status indication
to distinguish charge mode from boost mode.
Integrated Short Circuit Protection and
Output Over Voltage Protection for Boost
Mode
APPLICATIONS
Sub-Battery Applications
Power-Bank Applications for Smart-Phone
Tablet and Other Portable Devices
All MPS parts are lead-free, halogen free, and adhere to the RoHS directive. For
MPS green status, please visit MPS website under Quality Assurance.
To guarantee safe operation, the MP2637 limits
the die temperature to a preset value of 120oC.
Other safety features include input over-voltage
protection, battery over-voltage protection,
“MPS” and “The Future of Analog IC Technology” are Registered Trademarks
of Monolithic Power Systems, Inc.
thermal
shutdown,
battery
temperature
monitoring, and a programmable timer to
prevent prolonged charging of a dead battery.
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
1
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
TYPICAL APPLICATION
To 5V System
C2
R1
R2
ROLIM*
CSYS
*
SYS
Q1
FB
OLIM
SW
RS1
L1*
5V Input
ICHG
VBATT
IBATT
VIN
Q2
Q3
R4
R6
R3
R5
CBATT
CSP
Battery
CIN
REG
Q4
BATT
VSYS
PWIN
NTC
VB
Battery Voltage
Program
GND: 4.35V
High/Float: 4.2V
MP2637
CHG
VCC
ACOK
C4*
EN
VCC
BOOST
ISET
MODE
ILIM
TMR
AGND
PGND
RILIM
CTMR RISET
*Note:
1. ROLIM CANNOT be lower than 47.5kΩ. ROLIM is for the boost output current loop setting, and please refer to
the APPLICATION INFORMATION section for details.
2. CSYS should be put as close to the SYS pin and PGND as possible. At least 22μF is recommended, and
CSYS+C2 should not be less than 44μF, the ceramic is preferred and E-cap is not recommended.
3. VCC cap should not exceed 100nF. Recommend 47nF or 100nF.
4. Inductor should not exceed 2.2μH. Recommend 1.5μH or 2.2μH.
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
2
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
Table 1: Operation Mode
Power Source
__________
Operating
MODE
EN
Q1,Q2
Q3
Q4
ACOK
Mode
VIN
PWIN
Only Pass
Through Mode
Low
On
On
Off
Off
VIN> VBATT+300mV 0.8V<PWIN<1.15V
X
Low
High
Charging Mode
SW
SW
PWIN<0.8V or
PWIN >1.15V
X
Boost Discharge
Mode
High
X
High
Off
SW
SW
VIN <VBATT+300mV
X
PWIN<0.8V or
PWIN >1.15V
SYS Force-off
Mode
X
Low
Low
X
X
High
High
Off
Off
Off
Off
Off
Off
VIN<2V
X
Sleep Mode
X=Don’t Care.
On = Fully Turn On
Off = Fully Off
SW = Switching
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
3
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
ORDERING INFORMATION
Part Number*
Package
Top Marking
MP2637GR
QFN-24 (4mm×4mm)
See Below
* For Tape & Reel, add suffix –Z (e.g. MP2637GR–Z);
TOP MARKING
MPS: MPS prefix;
Y: year code;
WW: week code:
MP2637: first six digits of the part number;
LLLLLL: lot number;
PACKAGE REFERENCE
TOP View
24
23
22
21
20
19
18
EN
1
2
3
4
5
6
PGND
____
CHG
17
16
15
14
13
VB
______
BOOST
VCC
ILIM
PWIN
CSP
BATT
AGND
TMR
7
8
9
10
11
12
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
4
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
ABSOLUTE MAXIMUM RATINGS (1)
VIN.................................................–0.3V to 20V
SYS...............................................–0.3V to 6.5V
SW…………….. .................................................
–0.3V (-2V for <20ns) to 6.5V (8.5V for <20ns)
Thermal Resistance (4)
QFN-24 (4mm×4mm) ............. 42........9 ... °C/W
θJA
θJC
Notes:
1) Exceeding these ratings may damage the device.
2) The maximum allowable power dissipation is a function of the
maximum junction temperature TJ (MAX), the junction-to-
ambient thermal resistance θJA, and the ambient temperature
TA. The maximum allowable continuous power dissipation at
any ambient temperature is calculated by PD (MAX) = (TJ
(MAX)-TA)/θJA. Exceeding the maximum allowable power
dissipation will cause excessive die temperature, and the
regulator will go into thermal shutdown. Internal thermal
shutdown circuitry protects the device from permanent
damage.
BATT.............................................–0.3V to 6.5V
----------------- ------------- ---------------------
ACOK, CHG, BOOST ...................–0.3V to 6.5V
All Other Pins................................–0.3V to 6.5V
Junction Temperature...............................150°C
Lead Temperature ....................................260°C
(2)
Continuous Power Dissipation (TA = +25°C)
3) The device is not guaranteed to function outside of its
operating conditions.
4) Measured on JESD51-7, 4-layer PCB.
........................................................... 2.97W
Junction Temperature...............................150°C
Storage Temperature.............. –65°C to +150°C
Recommended Operating Conditions (3)
Supply Voltage VVIN............................4.5V to 6V
Battery Voltage VBATT ....................2.5V to 4.35V
Operating Junction Temp. (TJ).−40°C to +125°C
MP2637 Rev. 1.04
8/3/2017
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© 2017 MPS. All Rights Reserved.
5
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
ELECTRICAL CHARACTERISTICS
VIN = 5.0V, TA = 25°C, unless otherwise noted.
Parameter
Symbol Condition
RIN to SYS VCC=5V,
Min
Typ
65
Max Units
IN to SYS NMOS ON Resistance
High-side PMOS ON Resistance
Low-side NMOS ON Resistance
mΩ
mΩ
mΩ
RH_DS
RL_DS
VCC=5V,
VCC=5V,
30
30
CC Charge Mode/ Boost
Mode
6.5
A
High-Side PMOS Peak Current
Limit
IPEAK_HS
TC Charge Mode
3.2
6.3
600
2.2
100
0.8
50
A
A
Low-Side NMOS Peak Current Limit IPEAK_LS
Switching Frequency*
VCC UVLO
fsw
490
2
700
2.4
kHz
V
VCC_UVLO
VCC UVLO Hysteresis
PWIN Lower Threshold
Lower Threshold Hysteresis
PWIN Upper Threshold
Upper Threshold Hysteresis
Charge Mode
mV
V
VPWIN_L
VPWIN_H
0.75
1.1
0.85
1.2
mV
V
1.15
50
mV
EN = 5V, Battery Float
EN = 0
2.5
1.5
mA
mA
Input Quiescent Current
IIN
RlLIM = 100k
RlLIM = 56k
400
720
450
810
2700
4.2
500
900
3000
Input Current Limit
IIN_LIMIT
mA
RlLIM = 16.5k
2400
Input Over-Current Threshold
IIN(OCP)
τINOCBLK
τINRECVR
A
Input Over-Current Blanking Time(5)
Input Over-Current Recover Time(5)
120
100
4.35
µs
ms
Connect VB to GND
4.328
4.179
4.09
4.372
4.221
4.21
Terminal Battery Voltage
Recharge Threshold
VBATT_FULL
Leave VB floating or
connect to logic HIGH
4.2
4.15
V
Connect to VB to GND
VRECH
Leave VB floating or
connect to logic HIGH
3.95
4.01
4.07
V
Recharge Threshold Hysteresis
Battery Over Voltage Threshold
200
mV
As percentage of the
VBATT_FULL
VBATT_
FULL
103.3%
RS1 = 20mΩ, RISET = 120k
850
1000
1987
2525
250
1150
2250
2825
Constant Charge (CC) Current
ICC
ITC
RS1 = 20mΩ, RISET = 60.4k 1725
RS1 = 20mΩ, RISET = 47.5k 2225
125
mA
mA
Trickle Charge Current
* Reserve 1200kHz Option
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
6
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
ELECTRICAL CHARACTERISTICS (continued)
VIN = 5.0V, TA = 25°C, unless otherwise noted.
Parameter
Symbol Condition
Min
Typ
Max Units
Connect to VB to GND
3.0
3.1
3.2
Trickle Charge Voltage Threshold
VBATT_TC
V
Leave VB floating or
connect to high logic
2.9
3
3.1
Trickle Charge Hysteresis
Termination Charge Current
200
10%
10%
mV
RS1 = 20mΩ, RISET=60.4k
RS1 = 20mΩ, RISET=47.5k
2.5%
2.5%
17.5%
17.5%
ICC
ICC
IBF
Input-Voltage-Regulation
Reference
VREG
1.18
1.2
1.22
V
Boost Mode
SYS Voltage Range
Feedback Voltage
Feedback Input Current
4.2
6
V
V
1.18
1.2
1.22
200
VFB=1V
nA
Threshold over VSYS to turn
off the converter during
boost mode
Boost SYS Over-Voltage
Protection Threshold
VSYS(OVP
)
5.6
5.75
125
5.9
V
SYS Over Voltage Protection
Threshold Hysteresis
VSYS falling from VSYS(OVP)
mV
mA
Boost Quiescent Current
ISYS = 0, MODE = 5V
1.4
RS1 = 20mΩ, ROLIM
57.6k
=
1.875
2.1
2.083
2.290
Programmable Boost Output
Current Limit Accuracy
IOLIM
A
RS1 = 20mΩ, ROLIM = 51k
SYS Over-Current Blanking
Time(5)
τSYSOCBLK
τSYSRECVR
VBATT(LOW)
120
1
µs
SYS Over-Current Recover
Time(5)
ms
During boosting
2.5
2.9
V
V
Weak-Battery Threshold
Before Boost starts
3.05
30
Sleep Mode
VBATT = 4.2V, SYS Float,
VIN = 0V, MODE = 0V
Battery Leakage Current
ILEAKAGE
15
μA
Indication and Logic
-------------
----------------
-------------------
ACOK, CHG, BOOST pin output
low voltage
Sinking 1.5mA
400
1
mV
-------------
----------------
-------------------
ACOK, CHG, BOOST pin leakage
current
Connected to 5V
μA
NTC and Time-out Fault Blinking
Frequency(5)
CTMR = 0.1μF, ICHG = 1A
12.5
Hz
EN Input Logic Low Voltage
EN Input High Voltage
0.4
0.4
V
V
V
V
1.4
1.4
Mode Input Logic Low Voltage
Mode Input Logic High Voltage
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
7
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
ELECTRICAL CHARACTERISTICS (continued)
VIN = 5.0V, TA = 25°C, unless otherwise noted.
Parameter
Protection
Symbol Condition
Min
Typ
Max
Units
CTMR=0.1µF, remains in TC
Mode, ITC= 100mA test
mode
Trickle Charge Time
26
Min
Min
Total Charge Time
CTMR=0.1µF, ICHG= 1A
336
NTC Low Temp, Rising Threshold
65.6% 66.6% 67.6%
RNTC=NCP18XH103(0ºC)
NTC Low Temp, Rising Threshold
Hysteresis
1%
VSYS
NTC High Temp, Rising
Threshold
34%
35%
1%
36%
RNTC=NCP18XH103(50ºC)
Charge Mode
NTC High Temp, Rising
Threshold Hysteresis
Charging Current Foldback
120
150
°C
°C
Threshold(5)
Thermal Shutdown Threshold(5)
Notes:
5) Guaranteed by design.
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
8
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
TYPICAL CHARACTERISTICS
CIN = CBATT = CSYS = C2 = 22µF, L1 = 2.2µH, RS1 = 20mΩ, C4 = CTMR = 0.1µF, Battery Simulator,
unless otherwise noted.
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
9
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
TYPICAL CHARACTERISTICS (continued)
CIN = CBATT = CSYS = C2 = 22µF, L1 = 2.2µH, RS1 = 20mΩ, C4 = CTMR = 0.1µF, Battery Simulator,
unless otherwise noted.
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
10
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
TYPICAL PERFORMANCE CHARACTERISTICS
For Charge Mode: VIN = 5V, ICHG = 2.5A, LIN_LIM = 2.7A, ISYS = 0A
For Boost Mode:
VBATT = 3.7V, VSYS_SET = 5V, IOLIM = 2.1A
CIN = CBATT = CSYS = C2 = 22µF, L1 = 2.2µH, RS1 = 20mΩ, C4 = CTMR = 0.1µF, Battery Simulator,
unless otherwise noted.
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
11
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
For Charge Mode: VIN = 5V, ICHG = 2.5A, LIN_LIM = 2.7A, ISYS = 0A
For Boost Mode:
VBATT = 3.7V, VSYS_SET = 5V, IOLIM = 2.1A
CIN = CBATT = CSYS = C2 = 22µF, L1 = 2.2µH, RS1 = 20mΩ, C4 = CTMR = 0.1µF, Battery Simulator,
unless otherwise noted.
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
12
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
For Charge Mode: VIN = 5V, ICHG = 2.5A, LIN_LIM = 2.7A, ISYS = 0A
For Boost Mode:
VBATT = 3.7V, VSYS_SET = 5V, IOLIM = 2.1A
CIN = CBATT = CSYS = C2 = 22µF, L1 = 2.2µH, RS1 = 20mΩ, C4 = CTMR = 0.1µF, Battery Simulator,
unless otherwise noted.
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
13
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
For Charge Mode: VIN = 5V, ICHG = 2.5A, LIN_LIM = 2.7A, ISYS = 0A
For Boost Mode:
VBATT = 3.7V, VSYS_SET = 5V, IOLIM = 2.1A
CIN = CBATT = CSYS = C2 = 22µF, L1 = 2.2µH, RS1 = 20mΩ, C4 = CTMR = 0.1µF, Battery Simulator,
unless otherwise noted.
MP2637 Rev. 1.04
8/3/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
14
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
PIN FUCTIONS
Pin #
Name
Description
1, 23, 24
PGND
------------
Power Ground.
Charge Completion Indicator. Logic LOW indicates charge mode. This is an open drain
pin during charge complete or suspended
Boost Mode indicator. Logic LOW indicates boost mode in operation. This is an open
drain pin during charge mode or sleep mode operation.
2
3
CHG
-------------------
BOOST
4
5
6
CSP
BATT
AGND
Battery Charge Current Sense Positive Input.
Positive Battery Terminal / Battery Charge Current Sense Negative Input.
Analog Ground
Programmable Output-Current Limit for boost mode. Connect an external resistor to GND
to program the system current in boost mode. The ROLIM CANNOT be lower than 47.5kΩ.
Programmable Charge Current Pin. Connect an external resistor to GND to program the
charge current.
7
8
OLIM
ISET
9
10
NTC
FB
Negative Temperature Coefficient (NTC) Thermistor.
System voltage feedback input.
----------------
Valid Input Supply Indicator. Logic LOW on this pin indicates the presence of a valid
power supply.
11
12
ACOK
Input Voltage Feedback for input voltage regulation loop. Connect to tap of an external
resistor divider from VIN to GND to program the input voltage regulation. Once the voltage
at REG pin drops to the inner threshold, the charge current is reduced to maintain the
input voltage at the regulation value.
REG
Oscillator Period Timer. Connect a timing capacitor between this pin and GND to set the
oscillator period. Short to GND to disable the Timer function.
Input pin to detect the presence of valid input power. Pulling this pin to GND will turn off
the IN-to-SYS pass through MOSFET
Input Current Set. Connect to GND with an external resistor to program input current limit
in charge mode.
Internal Circuit Power Supply. Bypass this pin to GND with a ceramic capacitor not higher
than 100nF. This pin CANNOT carry external load higher than 5mA.
Programmable Battery-Full Voltage. Leave floating or connect to logic HIGH for 4.2V,
while connect to GND for 4.35V.
13
14
15
16
17
TMR
PWIN
ILIM
VCC
VB
Charge Control Input. Logic HIGH enables charging. Logic LOW disables charging. Active
__________
18
19
EN
only when ACOK is low (input power is OK).
Mode Select. Logic HIGH→boost mode. Logic LOW→sleep mode. Active only when
__________
MODE
ACOK is HIGH (input power is not available).
Adapter Input. Place a bypass capacitor close to this pin to prevent large input voltage
spikes.
System Output. A minimum of 22uF ceramic cap is required to be placed as close as
possible to the SYS and PGND pins. Total capacitance should not be lower than 44uF
Switch Output Node. It is recommended not to place Via's on the SW plane during PCB
layout
20
21
22
VIN
SYS
SW
MP2637 Rev. 1.04
8/3/2017
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15
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
BLOCK DIAGRAM
SYS
FB
SW
Q1
Q2
HSMOS
VIN
Buffer
Current
Sense
LSMOS
A1
CSP
VCC
Driver
BATT
K1*ICHG
VBATT
PWM Signal
Charge
Pump
PGND
ACOK
VBATT
PWIN
0.8V
Mode Control
PWM Controller
1.15V
VCC
VCC
VCC
Control Logic&
Mode Selection
BATT+
300mV
NTC
TRef
MODE
EN
GMT
TJ
VB
VBATT_Ref
ACOK
Thermal
Shutdown
GMV
VBATT
CHG
REG
BOOST
GMINV
Indication&
Timer
MIN
VREG_Ref
GMI
ICHG_Ref
K1*ICHG
ISET
ILIM
IIN_Ref
Current Setting
GMINI
TMR
K2*IIN
OLIM
AGND
Figure 1: Functional Block Diagram in Charge Mode
MP2637 Rev. 1.04
8/3/2017
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
SYS
FB
SW
Q1
Q2
HSMOS
VIN
A1
CSP
VCC
LSMOS
Driver
BATT
Charge
Pump
VBATT
PWM Signal
Integration
ACOK
PGND
To Current
Setting
VBATT
PWIN
0.8V
Mode Control
PWM Controller
1.15V
VCC
Control Logic&
Mode Selection
BATT+
300mV
NTC
MODE
EN
VB
VSYS_Ref
ACOK
CHG
Thermal
Shutdown
GMV
VFB
REG
BOOST
Indication&
Timer
ISET
ILIM
IOLIM_Ref
Current Setting
GMINI
TMR
K3*ISYS
OLIM
AGND
Figure 2: Functional Block Diagram in Boost Mode
MP2637 Rev. 1.04
8/3/2017
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17
MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
OPERATION FLOW CHART
POR
Yes
VCC<VCC_UVLO
No
VPWIN_L<VPWIN<VPWIN_H
&VIN>VBATT+300mV
Yes
No
/ACOK is Low, System
Powered By IN
MODE High?
No
EN High?
Yes
Yes
No
Charge Mode
/CHG Low
Boost Mode
/BOOST Low
Sleep Mode
Figure 3: Mode Selection Flow Chart
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
OPERATION FLOW CHART (continued)
Normal Operation
Charge Mode
/CHG Low
Charge Mode?
VBATT>VBATT_FULL
VBATT_TC<VBATT<VBATT_FULL
VBATT<VBATT_TC
C.V.C
C.C.C
T.C.C
No
No
No
ICHG<IBF
Battery Full
VBATT>VBATT_FULL
VBATT>VBATT_TC
Yes
Yes
Yes
Charger “Off”,
/CHG is high
Yes
No
VBATT< VRECH
?
No
No
No
Timer Out ?
Yes
NTC Fault?
TJ ≥120oC?
Yes
Yes
Charge
Termination, /CHG
is high
Charge Suspend,
/CHG is high
Decrease ICHG to
maintain TJ at 120oC
No
No
No
Reset
Timer?
NTC OK?
TJ ≥150oC?
Yes
Yes
Yes
Charge Recovery,
Return to Normal
Operation
Thermal
Shutdown, /CHG is
high
No
TJ ≤120oC?
Yes
Fault Protection
Figure 4: Normal Operation and Fault Protection in Charge Mode
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
OPERATION FLOW CHART (continued)
Power Path Management
SYS Output
Current Increase
VPWIN touch the VREG
?
IIN hit the IIN_LIMIT?
No
No
Yes
Yes
Charge Current
Decrease
ICHG=0?
Yes
No
IIN >7A?
No
Normal Operation
IIN exceeds I
?
IN(OCP)
No
Yes
Regulate the I at
IN
IIN(OCP)
No
Yes
TINOCBLK reaches?
Yes
Yes
IN to SYS MOSFET
turns Off
No
TINRECVR reaches?
Figure 5: Power-path Management in Charge Mode
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
OPERATION FLOW CHART (continued)
Boost Mode
Normal Boost
/BOOST Low
Operation
No
No
No
ISYS > IOLIM
?
VBATT >2.9V?
Yes
Yes
Output current loop
works, VSYS decreases
No
Mode High?
Yes
VSYS < VBATT
?
Yes
Normal Boost
Operation
VSYS < 2V?
Yes
No
Yes
No
VBATT<2.5V?
Yes
Down mode
No
IL hits the
current limit
TSYSBLK Reaches?
Yes
Boost Turns Off
Yes
Boost Shutdown
No
TSYSRECVR
Reaches?
Figure 6: Operation Flow Chart in Boost Mode
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
START UP TIME FLOW IN CHARGE MODE
Condition: EN = 5V, Mode = 0V, /ACOK and /CHG are always pulled up to an external 5V.
VPWIN > 0.8V
0V
&
VIN
VIN > VBATT+ 300mV
5V
0V
0V
EN
Mode
VCC
VCC follows VIN
2.2V
Band
Gap
0V
5V
ACOK
0V
VSYS > VBATT + 50mV
VSYS
5V
0V
CHG
SS
400μs
400μs
150μs
150μs
Force
Charge
ICC
10%ICC
Charge
Current
0A
IBF
Comparator
VBATT_FULL
Battery
Voltage
Auto-recharge threshold
Assume vBATT > VBATT_TC
Auto-
recharge
Figure 7: Input Power Start-Up Time Flow in Charge Mode
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
START UP TIME FLOW IN CHARGE MODE
Condition: EN = 5V, Mode = 0V, /ACOK and /CHG are always pulled up to an external 5V.
0V
VIN
5V
0V
EN
0V
Mode
VCC
2.2V
Band
Gap
0V
5V
ACOK
0V
VSYS
5V
0V
CHG
SS
400μs
400μs
400μs
150μs
150μs
150μs
Force
Charge
ICC
10%ICC
0A
Charge
Current
IBF
Comparator
VBATT_FULL
Battery
Voltage
Assume vBATT > VBATT_TC
Auto-
recharge
Figure 8: EN Start-Up Time Flow in Charge Mode
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
START UP TIME FLOW IN BOOST MODE
Condition: VIN = 0V, Mode = 5V, /Boost is always pulled up to an external constant 5V.
2.5V
2.9V
0V
0V
VCC follows VSYS
VBATT
VCC follows
VBATT
2.2V
VCC
MODE
Band
Gap
5V
0V
BOOST
1.2ms
Boost
SS
Down
Mode
VSYS>VBATT+300mV
0V
VSYS
Figure 9: Battery Power Start-Up Time Flow in Boost Mode
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
START UP TIME FLOW IN BOOST MODE
Condition: VIN = 0V, /Boost is always pulled up to an external constant 5V.
VBATT
2.9V
VCC follows VSYS
VCC follows VBATT
2.2V
VCC
5V
0V
MODE
5V
Band
Gap
0V
5V
0V
BOOST
1.2ms
Boost
Down
Mode
SS
VSYS>VBATT+300mV
0V
VSYS
Figure 10: Mode Start-Up Time Flow in Boost Mode
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
OPERATION
INTRODUCTION
The MP2637 is a highly-integrated, flexible,
switch-mode battery charger with system power
path management, designed for single-cell Li-ion
or Li-Polymer batteries used in a wide range of
applications. Depending on the status of the
Input, the MP2637 can operate in three different
modes: Charge Mode; Boost Mode; Sleep Mode.
In charge mode the MP2637 can work with a
single cell Li-ion or Li-polymer battery. In boost
mode the MP2637 boosts the battery voltage to
VSYS_SET to power higher voltage system rails. In
sleep mode both charging and boost operations
are disabled and the device enters a power
saving mode to help reduce the overall power
consumption. The MP2637 monitors VIN to allow
smooth transition between different modes of
operation.
CHARGE MODE OPERATION
Charge
Cycle
(Trickle
ChargeCC
ChargeCV Charge)
In charge mode, the MP2637 has five control
loops to regulate the input current, input voltage,
charge current, charge voltage, and device
junction temperature. The MP2637 charges the
battery in three phases: trickle current (TC),
constant current (CC), and constant voltage (CV).
While charge operation is enabled, all five loops
are active but only one determines the IC
behavior. A typical battery charge profile is
depicted in Figure11 (a). The charger stays in TC
charge mode until the battery voltage reaches a
TC-to-CC threshold. Otherwise the charger
enters CC charge mode. When the battery
voltage rises to the CV-mode threshold, the
charger operates in constant voltage mode.
Figure (b) shows a typical charge profile when
the input-current-limit loop dominates during the
CC charge mode, and in this case the charger
maximizes the charging current due to the
switching-mode charging solution, resulting in
faster charging than a traditional linear solution.
Figure 11: Typical Battery Charge Profile
Auto-recharge
Once the battery charge cycle is completed, the
charger remains off. During this time, the system
load may consume battery power, or the battery
may self discharge. To ensure the battery will not
go into depletion,
a
new charge cycle
automatically begins when the battery voltage
falls below the auto-recharge threshold and the
input power is present. The timer is reset when
the auto-recharge cycle begins.
During the off state after the battery is fully
charged, if the input power re-starts or the EN
signal refreshes, the charge cycle will start and
the timer will reset no matter what the battery
voltage is.
Battery Over-Voltage Protection
The MP2637 has battery over-voltage protection.
If the battery voltage exceeds the battery over-
voltage threshold, (103.3% of the battery-full
voltage), charging is disabled. Under this
condition, an internal 5kΩ dummy load draws a
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
current from the BATT pin to decrease the
battery voltage and protect the battery.
Input Voltage Regulation in Charge Mode
In charge mode, if the input power source is not
sufficient to support both the charge current and
system load current, the input voltage will
decrease. As the input voltage approaches the
programmed input voltage regulation value,
charge current is reduced to allow priority of
system power and maintain proper regulation of
the input voltage.
Timer Operation in Charge Mode
The MP2637 uses an internal timer to terminate
the charging. The timer remains active during the
charging process. An external capacitor between
TMR and GND programs the charge cycle
duration.
If charging remains in TC mode beyond the
trickle-charge time, τTRICKLE_TMR, charging will
terminate. The following equation determines the
length of the trickle-charge period:
The input voltage can be regulated by a resistor
divider from IN pin to REG pin to AGND
according to the following equation:
R5
4.5104 1.6(V)CTMR(F)
1.25ITC(A)RS1(m) 2(A)
(4)
VREG VIN_R
(V)
(1)
TC_ TMR
(s)
R3 R5
where the VREG is the internal voltage reference,
1.2V, and the VIN_R is the desired regulation
voltage.
The maximum total charge time is:
3.4106 1.6(V)CTMR(F)
1.25ICHG(A)RS1(m) 2(A)
Negative Temperature Coefficient (NTC) Input
for Battery Temperature Monitoring
(2)
TOTAL _ TMR
(s)
Integrated Over Current Protection and Over
Voltage Protection for Pass-through Path
The MP2637 has an integrated IN to SYS pass-
through path to allow direct connection of the
input voltage to the system even if charging is
disabled. Based on the above, the MP2637
continuously monitors both input current and
voltage. In the event of an OCP or OVP charge
current will be reduced to ensure priority of the
system power requirements.
The MP2637 has a built-in NTC resistance
window comparator, which allows the MP2637 to
monitor the battery temperature via the battery-
integrated thermistor. Connect an appropriate
resistor from VSYS to the NTC pin and connect the
thermistor from the NTC pin to GND. The resistor
divider determines the NTC voltage depending
on the battery temperature. If the NTC voltage
falls outside of the NTC window, the MP2637
stops charging. The charger will then restart if the
temperature goes back into NTC window range.
Please refer to Application Information section for
the appropriate resistance selection.
In addition, the MP2637 also features input over
current and voltage protection for the IN to SYS
pass-through path.
Input over-current protection (OCP):
When the total input current exceeds 4.2A, Q2
(Fig 12) is controlled linearly to regulate the
current. If the current continues to exceeds 4.2A
after a 120µs blanking time, Q2 will be turn off. In
the event of input current exceeding 7A Q2 will
be turned off almost instantaneously and without
any blanking time, this to protect both Q1 and Q2.
Input Current Limiting in Charge Mode
The MP2637 has a dedicated pin used to
program the input current limit. The current at
ILIM is a fraction of the input current; the voltage
at ILIM indicates the average input current of the
switching regulator as determined by the resistor
value between ILIM and GND. As the input
current approaches the programmed input
current limit, charge current is reduced to allow
priority to system power.
Input over-voltage protection (OVP):
The MP2637 uses the PWIN pin to sense the
status of input voltage. When the voltage at the
PWIN pin is lower than 0.8V or higher than 1.15V,
an invalid input power source is detected by the
MP2637. At this time the IN to SYS pass-through
path will be turned off. An OVP threshold can be
programmed via PWIN pin to prevent an over
Use the following equation to determine the input
current limit threshold.
45(k)
RILIM(k)
(3)
I
(A)
ILIM
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
voltage event happening at SYS side when
junction temperature rises to 150°C.
plugging in a wrong adapter.
Non-sync Operation Mode
During charging mode, the MP2637 continuously
monitors the total input current flowing from IN
pin to SYS pin. When the input current is lower
than 170mA, the low side switch operates as a
non-synchronous MOSFET.
SYS
Q1
Q2
IN
Constant-Off-Time Control for Large Duty
Charging Operation
The MP2637 has a built-in 600kHz frequency
oscillator for the switching frequency. Unlike a
traditional fixed frequency, the MP2637 features
a constant off time control to support constant-
current charge even when the input voltage is
very close to battery voltage. As shown in the
Figure 13, the MP2637 continuously compares
the high-side FET sense current with comp level,
if the sense current doesn’t reach the comp level
within the original switching period, the next clock
will be delayed until the sense current reaches
the comp level. As a result the duty cycle is able
to be extended as large as possible.
Charge
Pump
Figure12: Integrated Pass-through Path
Charge Current Setting
The external sense resistors, RS1 and RISET
program the battery charge current, ICHG. Select
RISET based on RS1:
,
2400
ICHG(A)
(5)
RISET(k)RS1(m)
Battery Short Protection
The MP2637 has two current limit thresholds. CC
and CV modes have a peak current limit
threshold of 6.5A, while TC mode has a current
limit threshold of 3.2A. Therefore, the current limit
threshold decreases to 3.2A when the battery
voltage drops below the TC threshold. Moreover,
the switching frequency also decreases when the
BATT voltage drops to 40% of the charge-full
voltage.
Full Operation Indication
The MP2637 integrates indicators for the
following conditions as shown in Table2.
The blinking frequency is:
1(A)
0.8CTMR(F)
F
(6)
Blinking
Table 2: Indicator for Each Operation Mode
----------------
------------
-------------------
Thermal Foldback Function
Operation
ACOK
CHG
BOOST
The MP2637 implements thermal protection to
prevent thermal damage to the IC and the
surrounding components. An internal thermal
sense and feedback loop automatically
decreases the programmed charge current when
the die temperature reaches 120°C. This function
is called the charge-current-thermal foldback. Not
only this function protects against thermal
damage, it can also set the charge current based
on requirements rather than worst-case
conditions while ensuring safe operation.
Furthermore, the part includes thermal shutdown
protection where the ceases charging if the
In Charging
Low
End of Charge,
Charging
disabled,
Battery OVP
NTC Fault,
Timer Out
Charge
Mode
Low
High
High
Blinking
Boost Mode
Sleep Mode
High
High
High
High
Low
High
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
Comp
Slope Compensation
HS Sense Current
Constant Off Time
HS Signal
600kHz
Lower the Fsw to support larger Duty
Figure 13: Constant-Off-Time Operation Profile
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
boost converter restarts again as long as the
MODE pin remains in active status.
BOOST MODE OPERATION
Low-Voltage Start-Up
The minimum battery voltage required to start up
the circuit in boost mode is 2.9V. Initially, when
VSYS < VBATT, the MP2637 works in down mode.
In this mode, the synchronous P-MOSFET stops
switching and its gate connects to VBATT statically.
The P-MOSFET stays off as long as the voltage
Boost Output Current Limiting
The MP2637 integrates a programmable output
current limit function in boost mode. If the boost
output current exceeds this programmable limit,
the output current will be limited at this level and
the SYS voltage will start to drop down. The
OLIM pin programs the current limit threshold up
to 2.4A as per the following equation:
across the parasitic CDS (VSW) is lower than VBATT
.
When the voltage across CDS exceeds VBATT, the
synchronous P-MOSFET enters linear mode
allowing the inductor current to decrease and
flowing into the SYS pin. Once VSYS exceeds
VBATT, the P-MOSFET gate is released and
normal closed-loop PWM operation is initiated. In
boost mode, the battery voltage can drop to as
low as 2.5V without affecting circuit operation.
2400
IOLIM(A)
(7)
ROLIM(k)RS1(m)
SYS Output Over Current Protection
The MP2637 integrates three-phase output over-
current protection.
Phase one (boost mode output current limit):
when the output current exceeds the
programmed output current limit, the output
constant current loop controls the output current,
the output current remains at its limit of IOLIM, and
VSYS decreases.
SYS Disconnect and Inrush Limiting
The MP2637 allows for true output disconnect by
eliminating body diode conduction of the internal
P-MOSFET rectifier. VSYS can go to 0V during
shutdown, drawing no current from the input
source. It also allows for inrush current limiting at
start-up, minimizing surge currents from the input
supply. To optimize the benefits of output
disconnect, avoid connecting an external
Schottky diode between the SW and SYS pins.
Phase two (down mode): when VSYS drops below
VBATT+100mV and the output current loop
remains in control, the boost converter enters
down mode and shutdown after a 120μs blanking
time.
Board layout is extremely critical to minimize
voltage overshoot at the SW pin due to stray
inductance. Keep the output filter capacitor as
close as possible to the SYS pin and use very
low ESR/ESL ceramic capacitors tied to a good
ground plane.
Phase three (short circuit mode): when VSYS
drops below 3.75V (will be 2V during boost soft
start), the boost converter shuts down
immediately once the inductor current hits the
fold-back peak current limit of the low side N-
MOSFET. The boost converter can also recover
automatically after a 1ms deglitch period.
Boost Output Voltage Setting
In boost mode, the MP2637 programs the output
voltage via the external resistor divider at FB pin,
and provides built-in output over-voltage
protection (OVP) to protect the device and other
components against damage when VSYS goes
beyond 6V. Once the output over voltage occurs,
the MP2637 turns off the boost converter. When
the voltage on VSYS drops to a normal level, the
Thermal Shutdown Protection
The thermal shutdown protection is also active in
boost mode. Once the junction temperature rises
higher than 150°C, the MP2637 enters thermal
shutdown. It will not resume normal operation
until the junction temperature drops below 120°C
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
APPLICATION INFORMATION
COMPONENT SELECTION
With the given R6, R4 is then:
Setting the Charge Current in Charge Mode
V V
IN
PWIN R6
(12)
R4
VPWIN
In charge mode, both the external sense resistor,
RS1, and the resistor RISET connect to the ISET
pin to set the charge current (ICHG) of the MP2637
(see the Typical Application circuit).
For a typical application, start with R6=5.1kΩ, R4
is 21.5kΩ.
Setting the Input Voltage Regulation in
Charge Mode
In charge mode, connect a resistor divider from
the IN pin to AGND with tapped to REG pin to
program the input voltage regulation.
Given ICHG and RS1, RISET can be calculated as:
2400
RISET(k)
(8)
ICHG(A)RS1(m)
For example, for ICHG=2.5A, and RS1=20mΩ,
thus: RISET=48kΩ.
R3 R5
(13)
V
VREG
(V)
Setting the Input Current Limiting in Charge
Mode
IN_R
R5
With the given R5, R3 is:
IN_R V
In charge mode, connect a resistor from the ILIM
pin to AGND to program the input current limit.
The relationship between the input current limit
and setting resistor is as following:
45
V
REG R5(V)
(14)
R3
VREG
For a preset input voltage regulation value, say
4.75V, start with R5=5.1kΩ, R3 is 15kΩ.
RILIM
(k)
(9)
IIN_LIM(A)
NTC Function in Charge Mode
where RILIM must exceed 16.5kΩ, so that IIN_LIM is
in the range of 0A to 2.7A.
Figure 14 shows that an internal resistor divider
sets the low temperature threshold (VTL) and high
temperature threshold (VTH) at 66.6%·VSYS and
For most applications, use RILIM = 50kΩ
(IUSB_LIM=900mA) for USB3.0 mode, and use RILIM
= 90kΩ (IUSB_LIM=500mA) for USB2.0 mode.
35%·VSYS
,
respectively. For
a
given NTC
thermistor, select an appropriate RT1 and RT2 to
set the NTC window.
Setting the Input Voltage Range for Different
Operation Modes
RT2//RNTC_Cold
VSYS RT1 RT2//RNTC_Cold
VTL
(15)
TL 66.6%
TH 35%
A resistive voltage divider from the input to PWIN
pin determines the operating mode of MP2637.
RT2//RNTC_Hot
VSYS RT1 RT2//RNTC_Hot
VTH
(16)
R6
(10)
VPWIN V
(V)
IN
R4 R6
Where RNTC_Hot is the value of the NTC resistor at
the upper bound of its operating temperature
range, and RNTC_Cold is its lower bound.
If the voltage on PWIN is between 0.8V and
1.15V, the MP2637 works in the charge mode.
While the voltage on the PWIN pin is not in the
range of 0.8V to 1.15V and VIN > 2V, the
MP2637 works in the boost mode (see Table 1)).
The two resistors, RT1 and RT2, independently
determine the upper and lower temperature limits.
This flexibility allows the MP2637 to operate with
most NTC resistors for different temperature
range requirements. Calculate RT1 and RT2 as
follows:
For a wide operating range, use a maximum
input voltage of 6V as the upper threshold for a
voltage ratio of:
VPWIN 1.15
R6
(11)
V
6
R4 R6
IN
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
RNTC_Hot RNTC_Cold (TL TH)
Setting the Output Current Limit in Boost
Mode
(17)
(18)
RT1
RT2
THTL(RNTC_Cold RNTC_Hot
)
In boost mode, connect a resistor from the OLIM
pin to AGND to program the output current limit.
The relationship between the output current limit
and setting resistor is as follows:
2400
(TL TH)RNTC_Cold RNTC_Hot
(1 TL)THRNTC_Cold-(1-TH)TLRNTC_Hot
For example, the NCP18XH103 thermistor has
the following electrical characteristic:
IOLIM(A)
(21)
ROLIM(k)RS1(m)
At 0°C, RNTC_Cold = 27.445kΩ;
At 50°C, RNTC_Hot = 4.1601kΩ.
The output current limit of the boost can be
programmed up to 2.1A (min). Considering 10%
output current limit accuracy, typical 2.3A output
current limit is required. According to the above
equation, given 20mΩ sense resistor, 52k ROLIM
will get 2.3A output current limit.
Based on equation (17) and equation (18),
RT1=6.65kΩ and RT2 = 25.63kΩ are suitable for
an NTC window between 0°C and 50°C. Chose
approximate values: e.g., RT1=6.65kΩ and
RT2=25.5kΩ.
For safety operation, ROLIM CANNOT be lower
than 47.5kΩ
If no external NTC is available, connect RT1 and
RT2 to keep the voltage on the NTC pin within the
valid NTC window: e.g., RT1 = RT2 = 10kΩ.
Selecting the Inductor
Inductor selection trades off between cost, size,
and efficiency.
A
lower inductance value
SYS
corresponds with smaller size, but results in
higher current ripple, higher magnetic hysteretic
losses, and higher output capacitances. However,
a higher inductance value benefits from lower
ripple current and smaller output filter capacitors,
but results in higher inductor DC resistance (DCR)
loss.
Low Temp Threshold
RT1
VTL
NTC
RNTC
RT2
High Temp Threshold
VTH
Choose an inductor that does not saturate under
the worst-case load condition.
Figure 14: NTC Function Block
For convenience, an NTC thermistor design
spreadsheet is also provided, please inquire if
necessary.
1. In Charge Mode
When MP2637 works in charge mode (as a Buck
Converter), estimate the required inductance as:
Setting the System Voltage in Boost Mode
In the boost mode, the system voltage can be
regulated to the value customer required
between 4.2V to 6V by the resistor divider at FB
pin as R1 and R2 in the typical application circuit.
V VBATT
IL _MAX
VBATT
IN
(22)
L
V fSW
IN
where VIN, VBATT, and fS are the typical input
voltage, the CC charge threshold, and the
switching frequency, respectively. ΔIL_MAX is the
maximum peak-to-peak inductor current, which is
usually designed at 30%-40% of the CC charge
current.
R1R2
VSYS 1.2V
(19)
R2
where 1.2V is the voltage reference of SYS. With
a typical value for R2, 10kΩ, R1 can be
determined by:
With a typical 5V input voltage, 35% inductor
current ripple at the corner point between trickle
charge and CC charge (VBATT=3V, Ichg=2.5A),
the inductance 2.2μH.
VSYS 1.2V
R1 R2
(V)
(20)
1.2V
2. In Boost Mode
For example, for a 5V system voltage, R2 is
10kΩ, and R1 is 31.6kΩ.
MP2637 Rev. 1.04
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
2. Boost Mode
When the MP2637 is in Boost mode (as a Boost
converter), the required inductance value is
calculated as:
The capacitor, CSYS, is the output capacitor of
boost converter. CSYS keeps the system voltage
ripple small and ensures feedback loop stability.
The system current ripple is given by:
VBATT (VSYS VBATT
VSYS fSW IL _MAX
)
(23)
L
VTC (VSYS _MAX VTC )
(27)
IRMS _MAX ISYS _MAX
(24)
IL _MAX (30% 40%)IBATT(MAX)
VSYS _MAX
VSYS ISYS
VBATT
(25)
Since the input voltage is passes to the system
directly, VIN_MAX=VSYS_MAX, both charge mode and
boost mode have the same system current ripple.
IBATT(MAX)
Where VBATT is the minimum battery voltage, fSW
is the switching frequency, and ∆IL_MAX is the
peak-to-peak inductor ripple current, which is
approximately 30% of the maximum battery
current IBATT(MAX), ISYS(MAX) is the system current
and η is the efficiency.
For ICC_MAX=2A, VTC=3V, VIN_MAX=6V, the
maximum ripple current is 1.25A. Select the
system capacitors base on the ripple-current
temperature rise not exceeding 10°C. For best
results, use ceramic capacitors with X7R
dielectrics with low ESR and small temperature
coefficients. For most applications, use three
22µF capacitors.
In the worst case where the battery voltage is 3V,
a 30% inductor current ripple, and a typical
system voltage (VSYS=5V), the inductance is
1.5µH when the efficiency is 90%.
Selecting the Battery Capacitor CBATT
CBATT is in parallel with the battery to absorb the
high-frequency switching ripple current.
For best results, use an inductor with an
inductance of 2.2uH with a DC current rating that
is not lower than the peak current of MOSFET.
For higher efficiency, minimize the inductor’s DC
resistance.
1. Charge Mode
The capacitor CBATT is the output capacitor of the
buck converter. The output voltage ripple is then:
Selecting the Input Capacitor CIN
The input capacitor CIN reduces both the surge
current drawn from the input and the switching
noise from the device. The input capacitor
impedance at the switching frequency should be
less than the input source impedance to prevent
high-frequency-switching current from passing to
the input. For best results, use ceramic
capacitors with X7R dielectrics because of their
low ESR and small temperature coefficients. For
most applications, a 22µF capacitor will suffice.
VBATT
VBATT
1 VBATT / VSYS
(28)
rBATT
8CBATT fSW2 L
2. Boost Mode
The capacitor CBATT is the input capacitor of the
boost converter. The input voltage ripple is the
same as the output voltage ripple from equation
(28)
Both charge mode and boost mode have the
same battery voltage ripple. The capacitor CBATT
can be calculated as:
Selecting the System Capacitor CSYS
Select CSYS based on the demand of the system
current ripple.
1 VTC / VSYS _MAX
8 rBATT _MAX fSW2 L
(29)
CBATT
1. Charge Mode
The capacitor CSYS acts as the input capacitor of
the buck converter in charge mode. The input
current ripple is:
To guarantee the ±0.5% BATT voltage accuracy,
the maximum BATT voltage ripple must not
exceed 0.5% (e.g. 0.2%). The worst case occurs
at the minimum battery voltage of the CC charge
with the maximum input voltage.
VTC (VIN_MAX VTC )
(26)
IRMS _MAX ISYS _MAX
V
IN_MAX
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
For VSYS_MAX=6V, VCC_MIN=VTC=3V, L=2.2µH,
fSW=600kHz, , CBATT is 39µF .
rBATT _ MAX 0.2%
Two pieces of 22µF ceramic with X7R dielectrics
capacitor in parallel will suffice.
PCB Layout Guide
PCB layout is very important to meet specified
noise, efficiency and stability requirements. The
following design considerations can improve
circuit performance:
1) Route the power stage adjacent to their
grounds. Aim to minimize the high-side switching
node (SW, inductor) trace lengths in the high-
current paths.
Top Layer
Keep the switching node short and away from all
small control signals, especially the feedback
network.
Place the input capacitor as close as possible to
the VIN and PGND pins. The local power input
capacitors, connected from the SYS to PGND,
must be placed as close as possible to the IC.
Place the output inductor close to the IC and
connect the output capacitor between the
inductor and PGND of the IC.
2) For high-current applications, the power pads
for IN, SYS, SW, BATT and PGND should be
connected to as many coppers planes on the
board as possible. This improves thermal
performance because the board conducts heat
away from the IC.
Bottom Layer
Figure 15: PCB Layout Example – board size is
22x25mm
Design Example
Below is a design example following the
application guidelines for the specifications:
3) The PCB should have a ground plane
connected directly to the return of all components
through vias (e.g., two vias per capacitor for
power-stage capacitors, one via per capacitor for
small-signal components). A star ground design
approach is typically used to keep circuit block
currents isolated (power-signal/control-signal),
which reduces noise-coupling and ground-
bounce issues. A single ground plane for this
design gives good results.
Table 3: Design Example
VIN
5V/500mA for USB,
5V/3A for Adapter
3.7V / 2.5A
Charge
Discharge
fSW
5V / 2.1A
600kHz
Figure 16 shows the detailed application
schematic. The Typical Performance
Characteristics section shows the typical
performance and circuit waveforms. For more
possible applications of this device, please refer
to the related Evaluation Board datasheets.
4) Place ISET, OLIM and ILIM resistors very
close to their respective IC pins.
MP2637 Rev. 1.04
8/3/2017
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
TYPICAL APPLICATION CIRCUITS
Figure 16: Typical Application Circuit of MP2637 with USB connectors
MP2637 Rev. 1.04
8/3/2017
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MP2637 –2.5A SINGLE CELL SW MODE BATTERY CHARGER WITH PPM AND 2.4A BOOST
PACKAGE INFORMATION
QFN-24 (4mmx4mm)
PIN 1 ID
PIN 1 ID
MARKING
PIN 1 ID
INDEX AREA
TOP VIEW
BOTTOM VIEW
SIDE VIEW
NOTE:
1) ALL DIMENSIONS ARE IN MILLIMETERS.
2) EXPOSED PADDLE SIZE DOES NOT INCLUDE
MOLD FLASH.
3) LEAD COPLANARITY SHALL BE 0.10
MILLIMETERS MAX.
4) JEDEC REFERENCE IS MO-220.
5) DRAWING IS NOT TO SCALE.
RECOMMENDED LAND PATTERN
NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third
party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not
assume any legal responsibility for any said applications.
MP2637 Rev. 1.04
8/3/2017
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36
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