MP2639A [MPS]
2-Cell Li-Ion or Li-Polymer Switching Charger Compatible with 5V Input and Integrated, Bidirectional Charge/Discharge;
| 型号： | MP2639A |
| 厂家： | 
MONOLITHIC POWER SYSTEMS |
| 描述： | 2-Cell Li-Ion or Li-Polymer Switching Charger Compatible with 5V Input and Integrated, Bidirectional Charge/Discharge |
| 文件： | 总35页 (文件大小：2002K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MP2639A
2-Cell Li-Ion or Li-Polymer Switching Charger
Compatible with 5V Input and
Integrated, Bidirectional Charge/Discharge
DESCRIPTION
FEATURES
The MP2639A is a highly integrated, flexible,
switch-mode, battery-charging management
device for 2-cell series Li-ion and Li-polymer
batteries used in a wide range of portable
applications.
4.0V to 5.75V Input Voltage Range
Charge 2-Cell Batteries with 5V Input
USB-Compliant Charger
Integrates Input Current-Based and Input
Voltage-Based Power Management
Functions
Programmable Input Current and Input
Voltage Limit
Up to 2.5A Programmable Charge Current
for 2-Cell Applications
8.4V Charge Voltage with 0.5% Accuracy
Up to 5.0A Programmable Discharge
Current
Negative Temperature Coefficient Pin for
Temperature Monitoring
The MP2639A is able to charge a 2-cell battery
from a 5V adapter or USB input. The MP2639A
can work in three modes: charge mode,
discharge mode, and sleep mode.
In 2-cell applications, the 5V input charges the
2-cell battery via the MP2639A operating in
step-up mode. When the 5V input is absent, the
2-cell battery voltage is discharged to the 5V
output via the MP2639A working in step-down
mode.
No Load Shutdown and Push Button Turn-
On in Discharge Mode
For the charging function, the MP2639A detects
the battery voltage automatically and charges
the battery in three phases: trickle current,
constant current, and constant voltage. Other
features include charge termination and auto-
recharge.
Programmable Timer Back-Up Protection
Discharge Mode Load Trace Compensation
Thermal Regulation and Thermal Shutdown
Internal Battery Reverse Leakage Blocking
Integrated Short-Circuit Protection (SCP) for
Both Charge and Discharge Mode
Four LED Battery Level and Status
Indicators
To guarantee safe operation, the MP2639A
limits the die temperature to a preset value of
120°C. Other safety features include input over-
voltage protection (OVP), battery over-voltage
protection (OVP), thermal shutdown, battery
temperature monitoring, and a programmable
timer to prevent prolonged charging of a dead
battery.
Available in a QFN-26 (4mmx4mm)
Package
APPLICATIONS
Power Station Applications
Power Bank Applications for Smart Phones,
Tablets, and Other Portable Devices
Mobile Internet Devices
The MP2639A is available in a QFN-26
(4mmx4mm) package.
All MPS parts are lead-free, halogen-free, and adhere to the RoHS
directive. For MPS green status, please visit the MPS website under
Quality Assurance. “MPS” and “The Future of Analog IC Technology” are
registered trademarks of Monolithic Power Systems, Inc.
MP2639A Rev. 1.0
6/6/2017
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
1
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
TYPICAL APPLICATION
2-Cell Application – Charge Mode
VL
L1
R2
R1
FB
BST
SW
LX
QRB
Q1
5V Input
VH
VBATT
VL
CVH
Q2
MID
R3 CVL
Battery
ACOK
VLIM
VCC
MID
NTC
VNTC
PB
MODE
IB
MP2639A
OLIM
ILIM
ISET
TMR
LED1
LED2
LED3
LED4
CTMR RISET RILIM ROLIM CVCC R4
CHGOK
AGND PGND
2-Cell Application – Discharge Mode
VL
L1
R2
R1
FB
BST
SW
LX
QRB
Q1
5V Output
VH
VBATT
VL
CVH
Q2
MID
R3 CVL
Battery
ACOK
VLIM
VCC
MID
NTC
VNTC
PB
MP2639A
OLIM
MODE
IB
ILIM
ISET
TMR
LED1
LED2
LED3
LED4
CTMR RISET RIILIM ROLIM CVCC R4
CHGOK
AGND PGND
Adapter
Term
BATT
Term
Active
SW
MODE
CHG/DSG
Topology
High
Low
DSG
CHG
Q1
Q2
Step-down
Step-up
VL
VH
MP2639A Rev. 1.0
6/6/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
2
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
ORDERING INFORMATION
Part Number*
Package
Top Marking
MP2639AGR
QFN-26 (4mmx4mm)
See Below
* For Tape & Reel, add suffix –Z (e.g. MP2639AGR–Z)
TOP MARKING
MPS: MPS prefix
Y: Year code
WW: Week code
M2639A: Product code of MP2639AGR
LLLLLL: Lot number
PACKAGE REFERENCE
TOP VIEW
CHG ACOK ILIM ISET OLIM IB
NTC
26
25
24
23
22
21
20
19
18
17
16
15
14
13
VNTC
VLIM
FB
1
2
3
4
5
VL
LX
VH
LED4
LED3
LED2
LED1
SW
PGND
6
7
8
9
10
11
12
BST
PB MODE VCC AGNDTMR MID
QFN-26 (4mmx4mm)
MP2639A Rev. 1.0
6/6/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
3
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
ABSOLUTE MAXIMUM RATINGS (1)
VH ............................................... -0.3V to +20V
SW.........................-0.3V (-2V for 50ns) to +20V
VL................................................ -0.3V to +16V
MID.............................................. -0.3V to +12V
BST to SW.................................. -0.3V to +5.5V
All other pins to GND.................. -0.3V to +5.5V
Thermal Resistance (4) θJA
QFN-26 (4mmx4mm) ............ 42........9.... °C/W
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 produces an excessive die temperature, causing
the regulator to go into thermal shutdown. Internal thermal
shutdown circuitry protects the device from permanent
damage.
(2)
Continuous power dissipation (TA = +25°C)
................................................................2.97W
Junction temperature...............................150°C
Lead temperature (solder) .......................260°C
Storage temperature................-65°C to +150°C
3) The device is not guaranteed to function outside of its
operating conditions.
Recommended Operating Conditions (3)
VL to GND ........................................ 4V to 5.5V
VH to GND........................................ 6V to 8.7V
Operating junction temp. (TJ) ...-40°C to +125°C
4) Measured on JESD51-7, 4-layer PCB.
MP2639A Rev. 1.0
6/6/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
4
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
ELECTRICAL CHARACTERISTICS
VIN = VL = 5V, TA = 25°C, unless otherwise noted.
Parameter
Symbol Condition
Min
Typ
Max
Units
DC/DC Parameter
LV side input over-voltage
threshold
VL rising until the switching
is off
5.75
V
VLOVP
LV side input over-voltage
threshold hysteresis
200
4.5
4.5
mV
V
MODE = high, VH = 7.6V
4.4
4.6
VCC LDO output
VCC
MODE = low, VH = 0V,
VL = 5V
V
VL rising
3.9
3.6
19
19
24
24
10
10
Input power good threshold
VUVLO
Q1_ON
Q2_ON
QBR_ON
V
VL falling
TA = 25°C
High-side NMOS on
resistance
mΩ
mΩ
TA = -40°C to +85°C
TA = 25°C
29
36
Low-side NMOS on resistance
TA = -40°C to +85°C
TA = 25°C
Reverse blocking NMOS on
resistance
mΩ
TA = -40°C to +125°C
15
10
Peak current limit for high-side
NMOS
Step-down mode
6
8
A
Step-up CC mode
Step-up TC mode
7
3
9
4
A
A
Peak current limit for low-side
NMOS
Operating frequency
FSW
1300
kHz
Charging Operation
Battery float, charging is
enabled
Input quiescent current
Trickle charge threshold
IIN
2.5
mA
V
VBATT_TC VBATT rising
VBATT falling
ITC
5.9
Trickle charge threshold
hysteresis
240
mV
Trickle input current
300
992
2.46
10
mA
mA
A
RISET = 215kΩ
ICC
794
2.2
1191
2.7
Constant fast charge current
RISET = 86.6kΩ
As the percentage of ICC
2.5
17.5
%
Termination charge current
IBF
If 10% * ICC < 167mA
38
150
1.2
mA
V
Input voltage clamp reference VIN_ClAMP
1.18
400
720
2.56
1.22
500
900
3
RILIM = 475kΩ
RILIM = 261kΩ
RILIM = 78.7kΩ
449
817
2.71
mA
mA
A
Input current limit
IIN_LMT
Termination charge voltage
Auto-recharge threshold
VBATT_FULL
8.35
8.38
8.00
8.41
V
V
As the percentage of
VBATT_FULL
Battery over-voltage threshold VBATT_OV
101
103.3
105
%
MP2639A Rev. 1.0
www.MonolithicPower.com
5
6/6/2017
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© 2017 MPS. All Rights Reserved.
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
ELECTRICAL CHARACTERISTICS (continued)
VIN = VL = 5V, TA = 25°C, unless otherwise noted.
Parameter
Symbol Condition
Min
Typ
Max
Units
Discharge Operation
Output voltage range
Feedback voltage
IOUT = 0A
4.5
5.5
1.22
300
6.0
V
V
1.18
1.2
Feedback input current
Output over-voltage threshold
VFB = 1.2V
nA
V
5.6
5.75
160
Output over-voltage threshold
hysteresis
mV
Shutdown current
Discharging is disabled
20
μA
ROLIM = 86.6kΩ
IOUT_LIMIT ROLIM = 71.5kΩ
ROLIM = 44.2kΩ
2.2
2.46
2.98
4.83
6.28
5.75
2.7
Programmable output current
limit
2.77
4.49
3.19
5.17
A
Rising
VBATTUV
V
V
Battery UV threshold
Falling
-------------
----------------
ACOK, CHG output low
voltage
Sinking 1.5mA
400
1
mV
-------------
----------------
Connected to 5V
µA
Hz
ACOK, CHG leakage current
LED blinking frequency
CTMR = 0.1μF, ICHG = 1A
1
EN, MODE input logic low
voltage
0.4
V
EN, MODE input high voltage
1.4
V
V
V
ICHG = 1A in charge mode
IDIS = 1A in discharge mode
0.38
0.42
IB voltage output
CTMR = 0.1µF, stay in TC
mode, IL = 1A
Trickle charge time
30
mins
Total current charge time
CTMR = 0.1µF, IL = 1A
5.4
hours
MP2639A Rev. 1.0
www.MonolithicPower.com
6
6/6/2017
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© 2017 MPS. All Rights Reserved.
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
ELECTRICAL CHARACTERISTICS (continued)
VIN = VL = 5V, TA = 25°C, unless otherwise noted.
Parameter
Symbol Condition
Min
Typ
Max
Units
Protection
NTC low temp rising threshold
VCOLD
As percentage of VVREF
As percentage of VVREF
69.3
69.9
0.8
70.5
%
%
NTC low temp rising threshold
hysteresis
NTC cool temp rising
threshold
VCOOL As percentage of VVREF
As percentage of VVREF
67.2
67.8
1.2
68.4
%
%
%
NTC cool temp rising
threshold hysteresis
NTC warm temp falling
threshold
VWARM As percentage of VVREF
As percentage of VVREF
54.7
46.9
55.3
55.9
47.9
NTC warm temp falling
threshold hysteresis
1.5
47.4
1.5
20
%
%
NTC hot temp falling threshold
VHOT
As percentage of VVREF
As percentage of VVREF
NTC hot temp falling threshold
hysteresis
%
No load shutdown delay time
tNOLOAD
INOLOAD
s
No load shutdown current
threshold
50
mA
Threshold between long and
short touch
2.5
5
s
s
LED auto-off timer delay
Voltage-Based Fuel Gauge
Charge Mode
First level of battery voltage
threshold
Battery voltage rising
Battery voltage rising
Battery voltage rising
7.35
400
7.75
400
8.15
400
V
mV
V
Hysteresis
Second level of battery voltage
threshold
Hysteresis
mV
V
Third level of battery voltage
threshold
Hysteresis
mV
MP2639A Rev. 1.0
www.MonolithicPower.com
7
6/6/2017
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© 2017 MPS. All Rights Reserved.
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
ELECTRICAL CHARACTERISTICS (continued)
VIN = VL = 5V, TA = 25°C, unless otherwise noted.
Parameter
Symbol Condition
Min
Typ
Max
Units
Discharge Mode
Fourth level of battery voltage
threshold
Battery voltage falling
8
V
mV
V
Hysteresis
400
7.6
400
7.2
Third level of battery voltage
threshold
Battery voltage falling
Hysteresis
mV
V
Second level of battery
voltage
Battery voltage falling
Battery voltage falling
Hysteresis
400
6
mV
V
First level of battery voltage
Hysteresis
400
mV
Cell Balancing
HS
LS
6
6
Discharge MOSFET on
resistance
Ω
Cell balance start voltage
Balance threshold
VCBST
ΔVCELL
3.4
3.5
65
30
3.6
V
mV
Balance threshold hysteresis
mV
(5)
NOTE:
5) Guaranteed by design.
MP2639A Rev. 1.0
www.MonolithicPower.com
8
6/6/2017
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© 2017 MPS. All Rights Reserved.
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = VL= 5V, VBATT = VH = 7.4V, CVL = CVH = 22µF, L1 = 2.2µH, CTMR = 0.1µF, R1 = 76.8kΩ, R2 =
24.3kΩ, R3 = 27.4kΩ, R4 = 10kΩ, battery simulator, unless otherwise noted.
MP2639A Rev. 1.0
6/6/2017
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
9
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = VL = 5V, VBATT = VH = 7.4V, CVL = CVH = 22µF, L1 = 2.2µH, CTMR = 0.1µF, R1 = 76.8kΩ, R2 =
24.3kΩ, R3 = 27.4kΩ, R4 = 10kΩ, battery simulator, unless otherwise noted.
Battery Charge
Curve
VBATT_FULL = 8.4V, RILIM = 0Ω,
RISET = 86.6kΩ
Auto-Recharge
VBATT_FULL = 8.4V, RILIM = 0Ω,
RISET = 86.6kΩ
LED Indication
during Charging
VBATT_FULL = 8.4V, RILIM = 0Ω,
RISET = 86.6kΩ, VBATT_OFFSET = 6V
CH1: LED1
2V/div.
CH2: VIN
2V/div.
CH2: VIN
2V/div.
CH3:
CHGOK
2V/div.
CH3:
CHGOK
2V/div.
CH2: LED2
2V/div.
CH3: LED3
2V/div.
CH1: VBATT
2V/div.
CH1: VBATT
2V/div.
CHR1: VBATT
500mV/div.
CH4: IBATT
1A/div.
CH4: IBATT
1A/div.
CH4:LED4
2V/div.
4s/div.
4s/div.
4s/div.
Battery Charge
TC Charge
TC Charge Steady
Curve
Steady State
State @ VH = VL - 1V
VBATT = 4.0V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
VBATT_FULL = 8.4V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
VBATT = 5.0V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
CH1: VIN
2V/div.
CH1: VSW
2V/div.
CH3: VBATT
2V/div.
CH1: VSW
2V/div.
CH2: VBATT
2V/div.
CH3: VBATT
2V/div.
CH3:
CHGOK
1V/div.
CH2: IL
CH2: IL
500mA/div.
500mA/div.
CH4: IBATT
CH4: IBATT
500mA/div.
500mA/div.
CH4: IBATT
1A/div.
4s/div.
2µs/div.
1µs/div.
CC Charge
CV Charge
Steady State
Steady State
VBATT = 6.6V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
VBATT = 8.4V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
CH3: VBATT
2V/div.
CH3: VBATT
2V/div.
CH1: VSW
5V/div.
CH2: IL
1A/div.
CH2: IL
1A/div.
CH4: IBATT
500mA/div.
CH1: VSW
5V/div.
CH4: IBATT
1A/div.
1µs/div.
1µs/div.
MP2639A Rev. 1.0
6/6/2017
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
10
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = VL = 5V, VBATT = VH = 7.4V, CVL = CVH = 22µF, L1 = 2.2µH, CTMR = 0.1µF, R1 = 76.8kΩ, R2 =
24.3kΩ, R3 = 27.4kΩ, R4 = 10kΩ, battery simulator, unless otherwise noted.
Power On,
Power On,
Power Off,
TC Charge Mode
VBATT = 4.0V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
CC Charge Mode
VBATT = 6.6V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
CC Charge Mode
VBATT = 6.6V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
CH2: VBATT
2V/div.
CH2: VBATT
2V/div.
CH2: VBATT
2V/div.
CH1: VIN
2V/div.
CH1: VIN
2V/div.
CH1: VIN
2V/div.
CH4: IL
500mA/div.
CH4: IL
1A/div.
CH4: IL
1A/div.
CH3: VSW
2V/div.
CH3: VSW
5V/div.
CH3: VSW
5V/div.
2ms/div.
2ms/div.
40ms/div.
Input Current Limit
VIN = 5.0V, RILIM = 75kΩ,
RISET = 100kΩ
Input Voltage
Mode On, CC Mode
VBATT = 6.6V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
Regulation
VIN = 5.0V/4A, VIN_REG = 4.49V
CH1: VBATT
2V/div.
CH2: VBATT
2V/div.
CH3: VBATT
2V/div.
CH4: IIN
1A/div.
CH1: VIN
2V/div.
CH1: VMODE
2V/div.
CH3: IBATT
1A/div.
CH4: IIN
1A/div.
CH2: VSW
5V/div.
CH3: IBATT
1A/div.
CH2: VIN
CH4: IBATT
2A/div.
200mV/div.
2s/div.
2s/div.
Mode Off, CC Mode
VBATT = 6.6V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
Mode On, CV Mode
VBATT = 8.4V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
CH3: VBATT
2V/div.
CH3: VBATT
2V/div.
CH1: VMODE
2V/div.
CH1: VMODE
2V/div.
CH2: VSW
2V/div.
CH2: VSW
5V/div.
CH4: IBATT
2A/div.
CH4: IBATT
1A/div.
400µs/div.
400µs/div.
MP2639A Rev. 1.0
6/6/2017
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
11
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = VL = 5V, VBATT = VH = 7.4V, CVL = CVH = 22µF, L1 = 2.2µH, CTMR = 0.1µF, R1 = 76.8kΩ, R2 =
24.3kΩ, R3 = 27.4kΩ, R4 = 10kΩ, battery simulator, unless otherwise noted.
NTC Protection,
NTC Protection,
NTC Protection,
TC Mode
VBATT = 5.6V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
CC Mode
VBATT = 7.4V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
CC Mode
VBATT = 8.15V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
CH2: VBATT
2V/div.
CH2: VBATT
2V/div.
CH2: VBATT
2V/div.
CH1: VNTC
1V/div.
CH1: VNTC
1V/div.
CH1: VNTC
1V/div.
CH4: IBATT
CH4: IBATT
1A/div.
CH4: IBATT
1A/div.
200mA/div.
CH3: VSW
5V/div.
CH3: VSW
5V/div.
CH3: VSW
5V/div.
10ms/div.
10ms/div.
10ms/div.
Timer Out Protection
VBATT = 7.4V, RILIM = 73.2kΩ,
RISET = 86.6kΩ, CTMR = 220pF
Recovery from
Timer Period
VBATT = 7.4V, RILIM = 73.2kΩ,
RISET = 86.6kΩ, CTMR = 220pF
Timer Out
VBATT = 7.4V, RILIM = 73.2kΩ,
RISET = 86.6kΩ, CTMR = 220pF
CH1: VTMR
1V/div.
CH1: VTMR
1V/div.
CH1: VTMR
1V/div.
CH2: VBATT
2V/div.
CH2: VBATT
2V/div.
CH2: VBATT
2V/div.
CH3:
CHGOK
2V/div.
CH3:
CHGOK
2V/div.
CH3:
CHGOK
2V/div.
CH4: IBATT
1A/div.
CH4: IBATT
1A/div.
CH4: IBATT
1A/div.
100µs/div.
1ms/div.
4s/div.
Indication
Indication
Indication
@ BATT OVP
VBATT = 9.0V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
@ Charge Mode Off
VBATT = 7.4V, RILIM = 73.2kΩ,
RISET = 86.6kΩ
@ NTC Fault
VBATT = 3.7V, RILIM = 14.7kΩ,
RISET = 49.9kΩ
CH1: VBATT
2V/div.
CH1: VMODE
2V/div.
CH1: VNTC
2V/div.
CH2: ACOK
2V/div.
CH2: ACOK
2V/div.
CH2: ACOK
2V/div.
CH3:
CHGOK
2V/div.
CH3:
CHGOK
2V/div.
CH3:
CHGOK
2V/div.
CH4: IBATT
1A/div.
CH4: IL
2A/div.
CH4: IL
2A/div.
1ms/div.
1ms/div.
400ms/div.
MP2639A Rev. 1.0
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12
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = VL = 5V, VBATT = VH = 7.4V, CVL = CVH = 22µF, L1 = 2.2µH, CTMR = 0.1µF, R1 = 76.8kΩ, R2 =
24.3kΩ, R3 = 27.4kΩ, R4 = 10kΩ, battery simulator, unless otherwise noted.
Discharge Mode
Steady State
VBATT = 7.4V, ILOAD = 5A
No Load Shutdown,
Discharge Mode
VBATT = 7.4V, ILOAD = 0A
Weak Battery
Protection,
Discharge Mode
ILOAD = 1.5A, VBATT_OFFSET = 5V
CH1: VBATT
2V/div.
CH1: VBATT
2V/div.
CH1: VBATT
500mV/div.
CH2: VL
2V/div.
CH2: VL
2V/div.
CH2: VL
2V/div.
CH3: VSW
5V/div.
CH4: ILOAD
20mA/div.
CH4: ILOAD
1A/div.
CH3: VSW
10V/div.
CH3: VSW
5V/div.
CH4: IL
1A/div.
1µs/div.
4s/div.
4s/div.
Discharge Output
Load Transient,
Power Off by PB,
Current Limit
Discharge Mode
VBATT = 8.0V, load transient
from 0.5A to 2.5A
Discharge Mode
VBATT = 6.6V, ROLIM = 100kΩ
VBATT = 8.0V, ILOAD = 5A
CH1: VBATT
2V/div.
CH1: VBATT
2V/div.
CH3: VBATT
2V/div.
CH2: VL
2V/div.
CH2: VL
CH1: VPB
2V/div.
500mV/div.
CH3: VSW
10V/div.
CH3: VSW
5V/div.
CH2: VL
2V/div.
CH4: ILOAD
1A/div.
CH4: ILOAD
2A/div.
CH4: IL
2A/div.
2s/div.
400µs/div.
1s/div.
Short Protection,
Short Recovery,
LED Indication
Discharge Mode
VBATT = 8.0V, ILOAD = 5A,
VL short to GND
Discharge Mode
VBATT = 8.0V, ILOAD = 5A,
VL short to GND
Discharge Mode
VBATT_OFFSET = 5V
CH1: VBATT
2V/div.
CH1: VBATT
2V/div.
CHR1: VBATT
500mV/div.
CH2: VL
2V/div.
CH2: VL
2V/div.
CH4:LED4
2V/div.
CH3: VSW
10V/div.
CH3: VSW
10V/div.
CH3: LED3
2V/div.
CH4: IL
5A/div.
CH4: IL
5A/div.
CH2: LED2
2V/div.
CH1: LED1
2V/div.
400µs/div.
4ms/div
2s/div.
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
PIN FUNCTIONS
Pin #
Name
Type Description
1
2
3
4
5
6
VL
Power Low-voltage terminal. Attach a 5V input to VL.
Power Connection node between the induction and internal block switch.
Power High-voltage terminal. Attach a 2-cell battery to VH.
Power Switching node.
LX
VH
SW
PGND
BST
Power Power ground. Connect the exposed pad and GND to the same ground plane.
Power Bootstrap. Connect a 100 - 500nF BST capacitor between the BST and SW node.
- - - - -
Push button input. Connect a push button from PB to AGND pulled up internally by
- - - - -
a resistor. When PB is pushed for less than 2.5s, the discharge function is enabled
- - - - -
- - - - -
7
8
I
PB
and latched when MODE is high. If discharging is enabled, push PB for more than
2.5s to disable the discharge. Otherwise, discharging remains, and LED1-4 are
enabled for 5s.
Charge or discharge mode selection. Pull MODE to low logic to make the
MP2639A work in charge mode. Pull MODE to logic high to make the MP2639A
work in discharge mode.
MODE
I
Internal circuit power supply. Bypass VCC to AGND with a 1μF ceramic
capacitor. VCC cannot float or carry an external load higher than 50mA.
VCC
AGND
TMR
I/O
I/O
I
9
10
Analog ground.
Oscillator period timer. Connect a timing capacitor between TMR and AGND to
set the oscillator period. Short TMR to AGND to disable the timer function.
11
12
13
14
15
16
Middle point of the 2-cell battery. MID is used to detect the voltage of each cell in
a 2-cell application. Connect MID to GND if it is not being used.
MID
I
Fuel gauge indication. LED1 works with LED2, LED3, and LED4 to achieve the
voltage-based fuel gauge.
LED1
LED2
LED3
LED4
O
O
O
O
Fuel gauge indication. LED2 works with LED1, LED3, and LED4 to achieve the
voltage-based fuel gauge.
Fuel gauge indication. LED3 works with LED1, LED2, and LED4 to achieve the
voltage-based fuel gauge.
Fuel gauge indication. LED4 works with LED1, LED2, and LED3 to achieve the
voltage-based fuel gauge.
17
18
FB
I
I
Voltage feedback input in discharge mode.
Input voltage limit setting in charge mode.
VLIM
Pull-up bias voltage of both the NTC resistive dividers. VNTC is connected to
VCC by an internal switch, which is turned on only in charge mode. Do not connect
any capacitors to VNTC.
19
20
VNTC
NTC
O
I
Negative temperature coefficient (NTC) thermistor.
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
PIN FUNCTIONS (continued)
Pin #
Name
Type Description
Current output for the battery current monitor. IB is proportional to the real
battery current. Connect an R-C filter from IB to AGND.
21
IB
O
I
Discharge output current limit setting. Connect an external resistor from OLIM to
AGND to program the system current.
22
OLIM
Charge current set. Connect an external resistor from ISET to AGND to program
the charge current.
23
24
ISET
ILIM
I
I
Input current limit setting in charge mode.
----------------
----------------
----------------
Valid input supply indicator. ACOK is an open-drain output. ACOK is pulled low
25
26
O
O
ACOK
when the input voltage is recognized as a good source.
-------------
-------------
-------------
Charging completion indicator. CHG at logic low indicates charge mode. CHG
becomes an open drain once the charging has completed or is suspended.
CHG
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
BLOCK DIAGRAM
Figure 1: Block Diagram for 2-Cell Charge Mode
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
BLOCK DIAGRAM (continued)
Figure 2: Block Diagram for 2-Cell Discharge Mode
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
FLOW CHART
Figure 3: Input Power Start-Up Flow Chart
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
FLOW CHART (continued)
Figure 4: Three-Phase Trickle Charge
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
The sense gain can be programmed by the
OPERATION
external resistor (RIB) connected from IB to
GND. For example, for a 40kΩ RIB, a 0.3V IB
value represents a 1A battery current.
The MP2639A is a highly integrated, switch-
mode battery charger with a sophisticated
control strategy to charge 2-cell series Lithium-
ion or Lithium-polymer batteries from a 5V
adapter or USB input.
CHARGE MODE
Input Power Start-Up
MODE Control
As shown in Figure 3, once VCC exceeds the
UVLO threshold, the MP2639A qualifies both
the LV side and HV side voltage according to
the MODE status.
When MODE is low, the MP2639A works in
charging mode to charge a 2-cell series battery
from 5V. The MP2639A operates in step-up
mode at this time, and Q2 works as the active
switch, while Q1 works as the synchronous
switch.
In charging mode, VL is the input power
terminal. Once VOVLO > VLV > VUVLO and no fault
occurs, the MP2639A is ready for charging.
When MODE is high, the MP2639A is
configured to discharge mode. Once discharge
mode is enabled, the MP2639A operates in
reverse to achieve a 5V output from a 2-cell
battery via step-down mode (see Table 1).
As shown in Figure 4, depending on VH, the
MP2639A operates in three different trickle-
current charge modes: linear down mode,
switch down mode, and switch TC mode (see
Table 2).
Table 1: Operation MODE Table
1. Linear Down Mode: When VH < VL - 1V,
the QRB MOSFET works linearly to charge
the battery with the trickle charge current. At
this time, the pulse-width modulation (PWM)
block delivers the Q2 off signal and Q1 on
signal. The BST refresh block is still
disabled, so the Q1 MOSFET cannot be on.
When VH > VL - 1V, a 2.8μs BST refresh
window launches. In this window, the low-
side Q2 MOSFET is turned on for 100ns
each cycle (1.3MHz). Whenever Q1 is set to
be on for 270μs, the 2.8μs BST refresh
window is launched again.
Adapter BATT
Active
SW
MODE CHG/DIS
Topology
Term
Term
High
Low
DSG
CHG
Q1
Q2
Step-down
Step-up
VL
VH
Internal Power Supply
The VCC output is used to power the internal
circuit and the MOSFET driver. This output is
supplied by the higher terminal voltage value of
VL or VH. After VL is set, the internal reference
voltage is set up during charge mode. In
discharge mode, VH is always higher than the
output voltage, so VCC is always comes from
VH when VH is higher than the under-voltage
lockout (UVLO).
2. Switch Down Mode: When VH > VL -
114mV, QRB is fully on, Q1 is turned off, Q2
is switching, and FSW is lowered to 280kHz.
Connect an external capacitor from VCC to
AGND. The VCC output current limit is 50mA.
Figure 3 shows the MODE selection and power
start-up flow chart in each mode.
3. Switch TC Mode: When VH > VL + 400mV,
QRB remains fully on, Q1 is turned off, Q2 is
switching, and FSW recovers to 1.3MHz.
Battery Current Monitor
The MP2639A has an IB pin to represent the
real battery current in both charge and
discharge mode. The current flowing out from
IB is proportional to the real battery current. An
external, precise, sense resistor can convert the
current signal to a voltage signal. Calculate the
IB voltage with Equation (1):
3IBATT
400k
V
RIB
IB
(1)
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
Table 2: Operation Mode
VBATT Rising, Quit Linear
3. Phase 3 (constant-voltage charge): When
the battery voltage rises to the charge-full
voltage (VBATT_FULL), the charge current
begins to taper off. The charge cycle is
considered complete when the CV loop is
dominated, and the charge current reaches
the battery-full termination threshold. A
500μs force charge time is designed for
each charge cycle. After the 500μs force
charge time expires, the charge full signal is
allowed to assert.
Down Mode
(enter switch down mode)
VH > VL - 114mV
VH < VL - 342mV
VH > VL + 400mV
VH < VL + 114mV
VBATT Falling, Enter Linear
Down Mode
(quit switch down mode)
VBATT Rising, Quit Switch
Down Mode
(enter normal switch mode)
VBATT Falling, Enter Switch
Down Mode
If IBF is not reached before the safety charge
timer expires, the charge cycle is ceased,
and the corresponding timeout fault signal is
asserted. See the Safety Timer section for
more detail.
(quit normal switch mode)
Battery Charge Profile
The MP2639A provides three main charging
phases: trickle-current, constant-current charge,
and constant-voltage charge (see Figure 5).
A new charge cycle starts when the following
conditions are valid:
VBATT_FULL
Battery Voltage
The input power is re-plugged.
MODE is toggled from high to low.
No thermistor fault at NTC.
No safety timer fault.
ICC
Charge Current
VBATT_LOW
No battery over-voltage.
ITC
IBF
Automatic Recharge
When the battery is fully charged and the
charging is terminated, the battery may be
discharged for system consumption or self-
discharge. The MP2639A starts a new charging
cycle automatically without requiring a manual
restart of a charging cycle.
Trickle charge CC Fast Charge Constant Voltage Charge
Charge Full
Figure 5: Battery Charge Profile
1. Phase 1 (trickle-current charge): When the
battery voltage is lower than VBATT_LOW, the
MP2639A applies a safe trickle-charge
current (ITC) to the deeply depleted battery
until the battery voltage reaches trickle
charge to the fast charge threshold
(VBATT_LOW). If VBATT_LOW is not reached
before the trickle-charge timer expires, the
Charge Current Setting
ISET is used to program the charge current.
The setting formula is shown in Equation (2):
640(k)
3RISET
ICHG
(A)
charge
cycle
is
ceased,
and
a
(2)
corresponding timeout fault signal is
asserted. See the Safety Timer section on
page 21 for more detail.
Battery Over-Voltage Protection (OVP)
The MP2639A is designed with a built-in battery
over-voltage limit of 103.3% of VBATT_FULL. When
a battery over-voltage event occurs, the
MP2639A suspends the charging immediately.
2. Phase 2 (constant-current charge): When
the battery voltage exceeds VBATT_LOW, the
MP2639A stops the trickle-current charge
phase and enters constant-current charge
(fast charge) phase with a soft start. The
fast charge current can be programmed via
ISET.
Non-Sync Mode
When the input current at the VL side is lower
than 330mA, the MP2639A turns off Q1 and
switches to non-sync operation.
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
Safety Timer
Negative Temperature Coefficient (NTC)
Thermistor
The MP2639A uses an internal timer to
terminate the charging. The timer remains
active during the charging process. An external
capacitor between TMR and AGND programs
the charge cycle duration. An internal current
source charges and discharges the external
capacitor alternatively. When the voltage across
CTMR is lower than 0.7V, the internal current
source charges CTMR. Once the voltage
exceeds 1.5V, the internal current source
begins to discharge CTMR. As a result, the
voltage across CTMR oscillates between 0.7V
and 1.5V periodically, like a triangle wave.
There are two counter limits for the trickle
charge and total charge processes: 45056 for
trickle charge and 3407872 for CC and CV
charge. Once the counter reaches the
corresponding limit, the timer expires, and the
charging is suspended (see Figure 6).
“Thermistor” is the generic name given to
thermally sensitive resistors. negative
A
temperature coefficient thermistor is called a
thermistor, typically. Depending on the
manufacturing method and the structure, there
are many shapes and characteristics available
for various purposes. The thermistor resistance
values, unless otherwise specified, are
classified at a standard temperature of 25°C.
The resistance of a temperature is solely a
function of its absolute temperature.
The relationship between the resistance and
the absolute temperature of a thermistor is
shown in Equation (5):
1
1
R1 R2 e
T1 T2
(5)
Where R1 is the resistance at absolute
temperature T1, R2 is the resistance at
absolute temperature T2, and β is a constant
that depends on the material of the thermistor.
1.5V
TR = 0.8V/ISRC
TF = 0.8V/ISNK
0.7V
The
MP2639A
monitors
the
battery’s
Figure 6: Voltage Profile of TMR
temperature continuously by measuring the
voltage at NTC during charge mode. This
voltage is determined by the resistor divider,
whose ratio is produced by different resistances
of the NTC thermistor under different ambient
temperatures of the battery.
In trickle-charge mode, the input trickle-charge
current is fixed at 300mA. The trickle-charge
time (τTC_TMR) is set using Equation (3):
CTMR(F)
0.1F
TRICKLE_TMR 33.7mins
The MP2639A sets a pre-determined upper and
lower bound of the range internally. If the
voltage at NTC goes out of this range, then the
temperature is outside of the safe operating
limit. At this time, charging stops unless the
operating temperature returns to the safe range.
(3)
In CC and CV mode, the internal IOSC is
proportional to the reference of the inductor
current and is independent of the input current.
The total charge time (τTOTAL_TMR) is set using
Equation (4):
To satisfy the JEITA requirement, the MP2639A
monitors four temperature thresholds: 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). For a given
NTC thermistor, these temperatures correspond
CTMR(F)
0.1F
1A
TOTAL_TMR 6.05Hours
IL (A) 0.08
(4)
In the event of an NTC hot and cold fault, the
charging timer should be suspended. Once the
NTC fault is removed, the timer continues
counting from the value before an NTC fault.
to VCOLD, VCOOL, VWARM, and VHOT. When VNTC
<
VHOT or VNTC > VCOLD, charging and the timers
are suspended. When VHOT < VNTC < VWARM, the
charge-full voltage (VBATT_FULL) is reduced by
140mV from the programmable threshold.
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
When VCOOL < VNTC < VCOLD, the charging
current is reduced to half of the programmed
charge current (see Figure 7).
Input Voltage-Based and Input Current-
Based Power Management
To meet the USB maximum current limit
specification and avoid overloading the adapter,
the MP2639A features both input current- and
input voltage-based power management by
monitoring the input current and input voltage
continuously. The total input current limit can be
programmed to prevent the input source from
overloading. When the input current reaches its
limit, the charge current tapers off to keep the
input current from increasing further. The input
current limit can be calculated with Equation (6):
Maximum Charge Current 1C
0.5C
Maximum Charge Voltage : 4.25V
(4.2V Typical)
4.15V Maximum
4.10V Maximum
640(k)
3RILIM
I
(A)
ILIM
Cold
Cool
Normal
Warm
T4
Hot
T5
(6)
T1
T2
T3
If the preset input current limit is higher than the
rating at the adapter, the back-up input voltage-
based power management also works to
prevent the input source from being overloaded.
When the input voltage falls below the input
voltage limit due to an overload, the charge
current is reduced to keep the input voltage
from dropping further.
(0DegC) (10DegC)
(45DegC) (50DegC) (60DegC)
Figure 7: JEITA-Compatible NTC Window
VNTC Output
VNTC is an input pin used to pull up both the
internal and external resistor dividers to the
same point (see Figure 8). VNTC is connected
to VCC via an internal switch. In charging mode,
the switch is turned on, and VNTC is connected
to VCC. In discharge mode, the switch is off,
and VNTC is bridged off from VCC.
The input voltage clamp threshold can be
programmed by VLIM. The internal reference of
the input voltage loop is 1.2V, so the input
voltage clamp limit can be calculated with
Equation (7):
Charge/
Discharge?
R3 R4
V
1.2V
VNTC
VCC
IN_REG
R4
(7)
Indication
Cold
The MP2639A integrates indicators for the
conditions shown in Table 3.
Cool
NTC
Table 3: Indication in Difference Cases
NTC Control
Block
Charging State
In Charging
ACOK
CHGOK
Warm
Low
Low
Charging
complete, sleep
mode, charge
disable, battery
OVP
Hot
Low
High
Mode is
low
AGND
Blinking
at fixed
1Hz
NTC fault, timer
fault,
Low
Figure 8: NTC Protection Circuit
Mode is
high
Discharging
High
High
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
- - - - -
DISCHARGE MODE
2) During t0, PB is pulled low, and the 2.5s
- - - - -
Discharge Control
timer is reset. PB is released to high before
the 2.5s timer expires, so a short push is
detected. PBDIS remains high, and
discharging continues.
When MODE is configured high, discharge
mode is enabled. However, discharging can
only be enabled or disabled when the push
- - - - -
- - - - -
button pin (PB ) is configured properly.
3) During t1, PB is pulled low again, and the
- - - - -
- - - - -
2.5s timer is reset. PB remains low until the
2.5s timer expires, so a long push is
detected. PBDIS is pulled low, and
A short push is defined as PB being pulled low
- - - - -
for less than 2.5s. A long push is defined as PB
being pulled low for longer than 2.5s.
discharging ceased. Then PBDIS rises high
- - - - -
In the MP2639A, discharging is enabled only
when MODE is high and a short push is
detected. Discharging is disabled once MODE
is pulled low or a long push is detected.
once PB goes high.
4) At the moment of t2, another long push is
detected. Discharging is still disabled.
5) At the moment of t3, a short push is
detected, and PDBIS remains high.
Discharging is enabled.
Figure 9 shows the steps below.
1) Before t0, MODE is high, and discharging
has already been enabled. PBDIS is the
enable signal of the discharging. If PBDIS is
high, discharging is enabled. If PBDIS is
low, discharging is disabled.
PB
2.5s
MODE
2.5s
TMR
2.5s
PBDIS
2.5s
2.5s
2.5s
2.5s
On
T0(1st push)
On
T1(2nd push)
Off
T2(3rd push)
Off
On
T4(5thpush)
T3(4th push)
Figure 9: Push Button Detection Profile
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
- - - - -
Output Over-Current Limit (OCL)
Since the MP2639A is in sleep mode, if PB is
The MP2639A features an output over-current
limit (OCL), which can be programmed by the
resistor connected from OLIM to AGND. When
the output current flowing out from the VL node
exceeds the output over-current limit, the
MP2639A regulates the duty cycle to maintain
the output current at this limit, so the output
voltage drops accordingly. The output current
limit can be set using Equation (8):
pulled down to AGND for less than 2.5s (short
push), the IC enters discharge mode, and the
LEDs display the battery capacity. After 5s, the
LED pins switch to open drain automatically to
minimize the battery quiescent current. For the
LED to display the battery capacity, short push
- - - - -
PB .
No-Load Automatic Shutdown
In discharge mode, the MP2639A monitors the
discharge current continuously. When the
discharge current (IBATT) is lower than 50mA,
discharging can be shut down after 20s
automatically (see Figure 10).
640(k)
3ROLIM
IOLIM
(A)
(8)
Output Short-Circuit Protection (SCP)
The MP2639A monitors the VL voltage
continuously. If VL drops below 3.9V, an event
of the output short circuit is detected. The
MP2639A works in hiccup mode with 1.2ms
intervals, and the peak current limit of the high-
side switch is cut by half (see Figure 11).
EN DSG
No
SS Done?
EN DSG
Yes
Reset 20s Timer
No
SS Done?
Yes
No
No
Normal
Operation
IBATT < 50mA?
No
VL<2.1V?
VL<3.9V?
No
Yes
No
Yes
Yes
Cut Q1 PK
current by half
20s timer expires?
Yes
Yes
Yes
PK current limit is hit?
No Load
Shutdown
Yes
Start 1.2ms
Timer
Figure 10: No-Load Shutdown Detection
Output Over-Voltage Protection (OVP)
Disable
Discharging
The MP2639A has an internal, output, over-
voltage protection (OVP). If the voltage at the
VL node is higher than 5.75V, and an external,
abnormal voltage is added or FB is pulled to
GND falsely, then the MP2639A disables the
discharge and turns off the QRB MOSFET.
When the output voltage returns to a safe level,
the MP2639A restarts the discharging.
No
1.2ms expires?
Figure 11: Output Short-Circuit Protection
MP2639A Rev. 1.0
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25
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
Over-Discharge Control
1. The balance block is only active when a
valid power source is present and charging
is enabled.(6)
The MP2639A has a battery over-discharge
control scheme to avoid over-discharging.
During discharging, the MP2639A shuts down
automatically when the battery voltage declines
to 5.75V, and the MP2639A recovers to
discharge when the battery voltage is over
6.28V.
2. At least one of the cell voltages is higher
than the balance starting voltage (typical
3.5V).
3. The voltage difference between the cells is
higher than the balance threshold (65mV).
Battery Cell Balance and Protection
NOTE:
6) The balance block is valid only while the charge function is
applied. If both the charge and discharge functions are
enabled, disable the balance block by connecting MID to
GND.
The MP2639A provides battery cell balance
and protection for 2-cell applications. The
MP2639A senses the voltage across each cell.
If the two cell voltages are too different, the
balance function begins, and the internal
discharge circuit is turned on to decrease the
charge current of the cell with the higher
voltage. If the voltage across one of the cells
exceeds the battery OVP threshold, the
charging stops. If the two cell voltages are still
too different, the cell with the higher voltage
discharges to balance until the two cell voltages
match or the part recovers from OVP (120mV
lower than the OVP threshold) and recharges.
The MP2639A detects the cell with the lower
voltage (VCMIN
)
and checks the voltage
difference between each cell. If the differential
voltage is higher than the balance threshold
(65mV), the related balance MOSFET is turned
on, and the charge current of the cell with the
higher voltage is decreased.
The balancing action is suppressed if the higher
cell voltage is less than the cell-balance start
voltage (VCBST) or the cell-voltage measurement
is active.
The MP2639A integrates the balance MOSFET
and control circuit (see Figure 12).
In each balance cycle, the cell voltage
measures for about 200µs and balances for
about 200ms. Cell measurements are frozen
when the balance is ongoing.
VH
The cell balance flow chart is shown in Figure
13.
Balance &
Protection
Start
MID
No
Any Cell > VCBST
?
PGND
Yes
Find the Cell with minimum
voltage (VCMIN
)
Figure 12: Block Diagram of the Battery Balance
The balance current (less than 200mA)
depends on the external resistor from MID to
the middle of the 2-cell battery. If a larger
balance current is needed, then refer to the
external balance circuit in Figure 18.
No
Any
VCELL-VCMIN > 65mV
Yes
The
balancing
algorithm
will
enable
Related Balance
MOSFET is on
automatically when the following conditions are
true:
Figure 13: Flow Chart of the Battery Balance
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
Voltage-Based Fuel Gauge
The MP2639A integrates four comparators and
an open-drain circuit to indicate the fuel gauge
via four LEDs during both charge and discharge
mode (see Figure 14). The MP2639A compares
the battery voltage with four voltage references
to reveal the capacity of the battery, with four
options of 25%, 50%, 75%, and 100%.
VH_fb or VL_fb
LED1
Vref4
Bias Voltage
LED2
LED3
Vref3
Vref2
Vref1
LED4
The indication plan is shown in Table 4.
Figure 14: Block Diagram of Fuel Gauge
Table 4: Voltage-Based Fuel Gauge Indication
-------------
2-Cell Charge
LED1
LED2
LED3
LED4
CHG
Done
8.4V
On
On
On
On
On
On
On
On
Off
On
Blinking
at 1Hz
8.2V<VBATT<8.4V
7.8V<VBATT<8.2V
7.4V< VBATT<7.8V
VBATT<7.4V
On
On
On
On
On
On
On
On
On
On
Blinking
at 1Hz
Off
Off
Off
Blinking
at 1Hz
Off
Off
Blinking
at 1Hz
Off
-------------
2-Cell Discharge
LED1
LED2
LED3
LED4
CHG
8V<VBATT
On
On
On
On
On
On
On
Off
On
On
Off
Off
On
Off
Off
Off
Off
Off
Off
Off
7.6V<VBATT<8V
7.2V<VBATT<7.6V
6V<VBATT<7.2V
Blinking
at 1Hz
VBATT<6V
Off
Off
Off
Off
During discharge mode, to minimize the power
consumption of the gauge indication, the
indication control is designed in the MP2639A
- - - - -
- - - - -
achieved by PB . When PB is short pushed,
the gauge indication is enabled and disabled
after 5s automatically.
MP2639A Rev. 1.0
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27
MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
Discharge Line Drop Compensation
The MP2639A integrates a discharge line
compensation function to compensate for the
voltage drop across the USB cable
automatically.
The output voltage is compensated by feeding
the output current to the top feedback
resistance (R1) (see Figure 15).
RTRACE1
VOUT
RLoad
R1
FB
RTRACE2
R2
RTRACE = RTRACE1+RTRACE2
IOUT (Real Output Current)
Sensing
Gain KSNS
VIOUT (Final Voltage Signal)
COMP
10M
10pF
Rx
Figure 15: Block Diagram of Line Drop Compensation
If the trace to the load is long, there is a voltage
The output voltage after compensation is shown
in Equation (11):
drop between VOUT and VLOAD. The voltage at
the output terminator (VOUT) is not equal to the
voltage at the load (VLOAD). The voltage drop is
described in Equation (9):
R1R2
IOUT K
VOUT
VFB
SNS R1
R2
Rx
(11)
Ensure that VLOAD is always equal to the output
setting voltage with Equation (12):
VLOAD VOUT IOUT RTRACE
(9)
Where RTRACE is the resistance of the cable.
R1R2
V
VFB
LOAD
To maintain an accurate and constant load
voltage, output line drop compensation is
R2
(12)
To solve Equation (11) and Equation (12), use
the value calculated from Equation (13):
necessary.
The
MP2639A
offers
a
compensation method by adjusting the FB
voltage (VFB) slightly according to the load
current. The relation between VOUT and VFB is
described in Equation (10):
IOUT K
SNS R1 IOUT RTRACE
Rx
(13)
Given a tested RTRACE, R1 should be selected
according Equation (14):
V
VOUT VFB VFB
I
OUT
R1
R2
Rx
(10)
RTRACE Rx
R1
Where VIOUT is the voltage signal representing
the real output current.
KSNS
(14)
Where RX is 150kΩ, and KSNS is 0.3. In practice,
RTRACE ranges from 120 - 200mΩ.
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
Calculate R2 with Equation (15):
VFB
LOAD VFB
R2 (
)R1
V
(15)
Where VLOAD is equal to the regulation voltage,
and VFB is 1.2V.
For example, given an RTRACE of 200mΩ,
calculate R1 with Equation (16):
RTRACE Rx 0.2150k
R1
100k
KSNS
0.3
(16)
Where R2 is 31.6kΩ for a 5V regulation.
Given an RTRACE of 120mΩ, calculate R1 with
Equation (17):
RTRACE Rx 0.12150k
R1
60k
KSNS
0.3
(17)
Where R2 is 18.9kΩ for a 5V regulation.
Additionally, no matter how much the drop
compensation is, the maximum compensation
limit is 300mV. Given a 5V output application,
the maximum regulation voltage at VL is 5.3V.
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
VVLIM is 1.2V. For a preset input voltage
regulation value (i.e.: 4.675V), start with R4 =
10kΩ and R3 = 27.4kΩ.
APPLICATION INFORMATION
Setting the Input Current Limit in Charge
Mode
Setting the Output Current Limit in
Discharge Mode
The input current limit setting is set according to
the input power source capability. The input
current limit can be set through ILIM. Connect a
resistor from ILIM to AGND to program the
input current limit. The relationship is calculated
using Equation (18):
In discharge mode, connect a resistor from
OLIM to AGND to program the output current
limit. The relationship between the output
current limit and setting resistor is shown in
Equation (22):
640(k)
3RILIM
(18)
I
(A)
ILIM
640(k)
3ROLIM
IOLIM
(A)
(22)
To set the input current limit to 3A, choose RILIM
to be 71.5kΩ. To set the input current limit to
500mA according to the USB input request,
choose RILIM to be 432kΩ. If RILIM is 0Ω, then
there is no limit on the input current.
The output current limit of the boost can be
programmed up to 5.0A.
The expected ROLIM for typical output current
limits is shown in Table 5.
Setting the Charge Current
Table 5: Discharge Current Setting Table
The charge current of the MP2639A can be set
by an external resistor (RISET) according to
Equation (19):
ROLIM (kΩ)
215
Charge Current (A)
1.0
1.5
2.0
2.5
143
107
84.5
640(k)
ICHG
(A)
(19)
3RISET
Setting the Output Voltage in Discharge
Mode
The charge current can be programmed to 2.5A.
The expected RISET for a typical charge current
is shown in Table 4.
The MP2639A can regulate the output voltage
on VL during discharge mode by adding voltage
compensation to VLOAD, which is the voltage
powering the load. The setting formula for VLOAD
is shown in Equation (23):
Table 4: Charge Current Setting Table
RISET (kΩ)
215
Charge Current (A)
1.0
1.5
2.0
2.5
143
107
84.5
R1R2
V
1.2V
(V)
LOAD
(23)
R2
The IC implements internal line drop
compensation by feeding the output current to
the top feedback resistance (R1). The selection
of R1 must satisfy Equation (24):
Setting the Input Voltage Regulation in
Charge Mode
In charge mode, connect a resistor divider from
VL to AGND tapped to VLIM to program the
input voltage regulation using Equation (20):
RTRACE Rx
(24)
R1
KSNS
R3 R4
(20)
V
1.2V
(V)
INLMT
R4
Where Rx is 150kΩ, KSNS is 0, and RTRACE is the
line resistance of the trace from the output of
the IC to the load of the system.
With the given R4, R3 can be calculated with
Equation (21):
V
1.2V
1.2V
INLMT
(21)
R3
R4(V)
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
According to different evaluations on RTRACE
,
The following equation calculations are derived
assuming that the NTC window is between 0°C
and 50°C. According to Equation (25) and
choose an R1 value for correct compensation
using Table 6. Suppose VLOAD is required to
regulate at 5V.
VTH_High
VTH_Low
Equation (26), use
and
from the
Table 6: R1, R2 Selection Table
VNTC
VNTC
RTRACE
20m
50m
100m
150m
200m
R1 (Ω)
10k
15k
50k
75k
R2 (Ω)
3.16k
4.75k
15.8k
23.7k
31.6k
EC table to calculate RT1 = 2.27kΩ and RT2
6.86kΩ (see Figure 16).
=
VNTC
100k
Low Temp Threshold
RT1
VTL
Note that there is a max compensation voltage
limit on RTRACE which means that the
NTC
,
RNTC
RT2
compensated output voltage of the IC is a
maximum of 0.3V higher than the voltage on
the load side.
High Temp Threshold
VTH
Resistor Selection for the NTC Sensor
Figure 16 shows an internal resistor divider
reference circuit that limits both the high and
low temperature thresholds at VTH_High and
Figure 16: NTC Function Block
Selecting the Inductor
Inductor selection is a trade-off between cost,
size, and efficiency. A lower inductance value
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.
VTH_Low
,
respectively. For
a
given NTC
thermistor, select an appropriate RT1 and RT2
value to set the NTC window using Equation
(25) and Equation (26):
RT2//RNTC_Cold
VTH_Low
VNTC
(25)
RT1 RT2//RNTC_Cold
RT2//RNTC_Hot
VTH_High
VCC
(26)
RT1 RT2//RNTC_Hot
Choose an inductor that does not saturate
under the worst-case load condition.
Where RNTC_Hot is the value of the NTC resistor
at a high temperature (within the required
temperature operating range), and RNTC_Cold is
the value of the NTC resistor at a low
temperature.
When the MP2639A works in charge mode (as
a boost converter), estimate the required
inductance with Equation (27), Equation (28),
and Equation (29):
The two resistors (RT1 and RT2) allow the high
and low temperature limits to be programmed
independently. With this feature, the MP2639A
can fit most types of NTC resistors and different
temperature operating range requirements.
VVL (VVH VVL )
VVH fSW IL _MAX
(27)
(28)
(29)
L
IL _MAX 30%IVL(MAX)
VVH IVH(MAX)
The RT1 and RT2 values depend on the type of
NTC resistor selected.
IVL(MAX)
VVL
For example, for a 103AT thermistor, RNTC_Cold
is 27.28kΩ at 0°C, and RNTC_Hot is 3.02kΩ at
50°C.
Where VVH is the minimum battery voltage, fSW
is the switching frequency, ∆IL_MAX is the peak-
to-peak inductor ripple current (approximately
30% of the maximum input current (IVL(MAX))),
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
IVH(MAX) is the battery current (2.5A), and η is the
efficiency.
Under most application conditions, the charge
current is limited at the input current limit, so
IVL(MAX) is 3A, typically.
Suppose that the maximum VL ripple must not
exceed 1% (e.g.: 0.5%). When VVH_MAX is 8.4V,
VVL is 5V, L is 2.2µH, fSW is 1200kHz, and
∆rVL_AX is 0.5%, then CVL is 3.2µF.
One 4.7µF ceramic capacitor with X7R
dielectrics is sufficient.
In the worst-case scenario with a 8.4V battery
voltage, a 30% inductor current ripple, and a
typical input voltage (VVL = 5V), the inductance
is calculated as 1.9µH.
Selecting the VH Capacitor (CVH)
The 2-cell battery is connected to the VH port,
which is the output of the boost during charge
mode and the input of the buck converter during
discharge mode.
When the MP2639A works in discharge mode
(as a buck converter), estimate the required
inductance with Equation (30):
In discharge mode, the capacitor CVH acts as
the input capacitor of the buck converter. The
input current ripple can be calculated with
Equation (33):
VVH VVL
IL _MAX
VVL
(30)
L
VVH fSW
Where VVH is the output voltage, VIN is the input
voltage, fSW is the switching frequency, and
∆IL_MAX is the maximum peak-to-peak inductor
current (usually 30 - 40% of the discharge
current).
VVL (VVH_MAX VVL )
(33)
IRMS _MAX IVH_MAX
VVH_MAX
In boost mode, the capacitor (CVH) is the output
capacitor of the boost converter. CVH keeps the
VH ripple small (<0.5%) and ensures feedback
loop stability. The VH current ripple is given by
Equation (29).
With a typical 8.4V input voltage (2-cell battery),
a 30% inductor current ripple at the max output
current when VVL is set at the typical 5V value
(VVL = 5V, IVL(max) = 5A), and the inductance is
calculated as 1.2µH.
When IVH_MAX is 2.0A, VVL is 5V, and VVH_MAX is
8.4V, the maximum ripple current is 1A. Select
the system capacitors base on the ripple-
current temperature rise, not to exceed 10°C.
For best results, use X7R dielectric ceramic
capacitors with low ESR and small temperature
coefficients. For most applications, place two
22µF capacitors and one 1µF capacitor as
close to the IC as possible.
For best results, use an inductor with an
inductance of 2.2µH with a DC current rating no
lower than the peak current of the MOSFET.
For higher efficiency, minimize the inductor’s
DC resistance.
Selecting the VL Capacitor (CVL)
Select the VL capacitor (CVL) based on the
demand of the system current ripple.
CVL is the input capacitor of the boost converter
during charge mode and the output capacitor of
the buck converter during discharge mode.
Calculate its values with Equation (31) and
Equation (32):
VVL
VVL
1 VVL / VVH
8CVL fSW2 L
(31)
rVL
1 VVL / VVH_MAX
8 rVL _MAX fSW2 L
(32)
CVL
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
PCB Layout Guidelines
Efficient PCB layout is critical for meeting
specified noise, efficiency, and stability
requirements. For best results, follow the
guidelines below.
1. Route the power stage adjacent to their
grounds.
2. Minimize the length of high-side switching
node (SW, inductor) trace that carries the
high current.
3. Keep the switching node short and away
from all control signals, especially the
feedback network.
4. Place the input capacitor as close to VH and
PGND as possible.
5. Place the local power input capacitors
connected from VL to PGND as close to the
IC as possible.
6. Place the output inductor close to the IC.
7. Connect the output capacitor between the
inductor and PGND of the IC.
8. Connect the power pads for VH, VL, BATT,
and PGND to as many copper planes on the
board as possible for high-current
applications.
This
improves
thermal
performance
because the board conducts heat away
from the IC.
9. Provide a ground plane for the PCB
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.
10. Place the ISET, OLIM and ILIM resistors
very close to their respective IC pins.
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
TYPICAL APPLICATION CIRCUITS
Figure 17: Two-Port Application
L1
BST
LX
SW
QRB
Q1
5 V Input
VH
VBATT
VL
Q2
MID
MP2639A
PGND
Figure 18: Large Balance Current Application
MP2639A Rev. 1.0
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MP2639A – SWITCH-MODE BATTERY CHARGER W/ BIDIRECTIONAL OPERATION
PACKAGE INFORMATION
QFN-26 (4mmx4mm)
PIN 1 ID
0.15x45° TYP.
PIN 1 ID
MARKING
PIN 1 ID
INDEX AREA
TOP VIEW
BOTTOM VIEW
SIDE VIEW
NOTE:
0.15x45°
1) ALL DIMENSIONS ARE IN MILLIMETERS.
2) LEAD COPLANARITY SHALL BE 0.10
MILLIMETERS MAX.
3) DRAWING CONFORMS TO JEDEC MO-220.
4) DRAWING IS NOT TO SCALE.
RECOMMENDED LAND PATTERN
NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications.
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.
MP2639A Rev. 1.0
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35
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