MP2615AGQ [MPS]
2 A, 1- or 2- Cell Li-Ion Battery Charger in 3mm x 3mm Package;
| 型号： | MP2615AGQ |
| 厂家： | 
MONOLITHIC POWER SYSTEMS |
| 描述： | 2 A, 1- or 2- Cell Li-Ion Battery Charger in 3mm x 3mm Package 电池 |
| 文件： | 总21页 (文件大小：1764K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MP2615A
2 A, 1- or 2- Cell Li-Ion Battery Charger
in 3mm x 3mm Package
The Future of Analog IC Technology
DESCRIPTION
FEATURES
The MP2615A is a high-efficiency, switch mode
battery charger suitable for 1- or 2- cell lithium-
ion or lithium-polymer applications. The
MP2615A is capable of delivering 2 A of charge
current programmable via an accurate sense
resistor over the entire input range.
•
•
•
•
•
4.75 V to 18 V Operating Input Voltage
Up to 99% Duty Cycle Operation
Up to 2 A Programmable Charging Current
±0.75% Full Battery Voltage Accuracy
4.2 V/Cell and 4.35 V/Cell Selection for Full
Battery Voltage
•
•
•
Fully Integrated Power Switches
Internal Loop Compensation
No External Reverse-Blocking Diode
Required
The MP2615A regulates the charge current and
full battery voltage using two control loops to
achieve high-accuracy constant current (CC)
charge and constant voltage (CV) charge.
•
•
•
•
•
•
Preconditioning for Fully Depleted Battery
Charging Operation Indicator
Programmable Safety Timer
Thermal Shutdown Protection
Cycle-by-Cycle Over-Current Protection
Battery Temperature Monitor and Protection
Constant-off-time
(COT)
control
allows
operation at up to 99% duty cycle when the
battery voltage is close to the input voltage,
ensuring the charge current always remains at
a relatively high level.
The battery temperature and charging status
are always monitored during each charging
cycle. Two status monitor output pins are
provided to indicate the battery charging status
and input power status. Also, the MP2615A
features internal reverse-blocking protection.
APPLICATIONS
•
•
•
Smart Phones
Portable Hand-Held Solutions
Portable Media Players
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.
The MP2615A is available in a 3mm × 3mm
16-pin QFN package.
Analog digital adaptive modulation (ADAM) and advanced asynchronous
modulation (AAM) are trademarks of Monolithic Power Systems, Inc.
TYPICAL APPLICATION
Efficiency
100
95
90
85
VIN=5V,1CELL,4.35V/CELL
80
75
70
VIN=18V,2CELL,4.2V/CELL
65
60
0
0.5
1
1.5
(A)
2
2.5
I
BATT
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
1
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
ORDERING INFORMATION
Part Number*
Package
Top Marking
MP2615AGQ
QFN-16 (3mm × 3mm)
See Below
* For Tape & Reel, add suffix –Z (e.g. MP2615AGQ–Z).
TOP MARKING
ANK: Product code of MP2615A
Y: Year code
LLL: Lot number
PACKAGE REFERENCE
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
2
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
ABSOLUTE MAXIMUM RATINGS (1)
VSW...............................................–0.3 V to 23 V
VIN, VACOK, VCHGOK.........................................–0.3 V to 23 V
Thermal Resistance (4)
QFN-16 (3mm x 3mm)............50...... 12... °C/W
θJA
θJC
NOTES:
V
V
BATT,VCSP………………………… –0.3 V to 12 V
BST .....................................................VSW + 6 V
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.
All other pins ..................................–0.3 V to 6 V
Junction temperature ................................150°C
Lead temperature......................................260°C
(2)
Continuous power dissipation (TA = +25°C)
............................................................ 2.5 W
Operating temperature.............. –40°C to +85°C
3) The device is not guaranteed to function outside of its
operating conditions.
4) Measured on JESD51-7, 4-layer PCB.
Recommended Operating Conditions (3)
VIN ................................................4.75 V to 18 V
VBATT.................................................2 V to 8.7 V
Operating junction temp. (TJ).. –40°C to +125°C
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
3
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
ELECTRICAL CHARACTERISTICS
VIN = 12 V, VCELL = 0 V, VSEL = 0 V, C1 = 22 µF, C2 = 22 µF, TA = 25°C, unless otherwise noted.
Parameter
Symbol Condition
Min
Typ
Max
Units
Input voltage and current
VCELL = 4 V
VIN
4.5
5
18
18
Input voltage
V
V
CELL = 0 V
8.75
12
Under-voltage lockout
threshold rising
VUVLO
3.55
3.75
225
3.95
V
Under-voltage lockout
threshold hysteresis
mV
mA
ISHDN
IQ
0.27
1.1
= 4 V, Shutdown current
= 0 V, Quiescent current
EN
EN
Supply current
Power MOS
High-side switch on
resistance
RH_DS(ON) Measured from VIN to SW
RL_DS(ON)
110
mΩ
Low-side switch on
resistance
110
0
mΩ
μA
Switch leakage
1
= 4 V, VSW = 0 V
EN
Frequency and time parameter
Switching frequency
Foldback frequency
Minimum off time (5)
Charging parameter
FSW
VBATT = 7.5 V
VBATT = 0 V
VBATT = 9 V
760
160
200
kHz
kHz
ns
TOFF
VSEL = 0 V
4.328
4.168
4.35
4.2
4.386
4.252
Terminal battery voltage VBATT_FULL
V/Cell
VSEL = 4 V
VSEL = 0 V
VCELL = 0 V
8.62
8.34
4.3
8.99
8.71
4.49
4.36
9.36
9.08
4.67
4.54
VSEL=4 V
VCELL = 0 V
Battery
threshold
over-voltage
VBOVP
V
VSEL=0 V
VCELL = 4 V
VSEL = 4 V
4.17
VCELL = 4 V
VSEL = 0 V
4.1
4.0
150
3.1
3.0
Recharge threshold at
VBATT
VRECH
V/Cell
VSEL = 4 V
Recharge hysteresis
mV/Cell
V/Cell
VSEL = 0 V
SEL = 4 V
Trickle charge voltage
threshold
VTC
V
Trickle
hysteresis
charge
225
mV/Cell
A
CC
3.2
Peak current limit
Trickle
2.2
2
CC current
ICC
ITC
RS1 = 50 mΩ
1.8
5%
2.2
A
Trickle charge current
10%
15%
ICC
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
4
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
ELECTRICAL CHARACTERISTICS (continued)
VIN = 12 V, VCELL = 0 V, VSEL = 0 V, C1 = 22 µF, C2 = 22 µF, TA = 25°C, unless otherwise noted.
Parameter
Symbol Condition
Min
Typ
Max
Units
Termination
threshold
current
IBF
5%
10%
15%
ICC
VIN minimum head-room
(reverse blocking)
VIN − VBATT
300
100
mV
Maximum
current-sense
VSENSE
90
110
3
mV
µA
voltage (CSP to BATT)
CSP, BATT current
ICSP, IBATT Charging disabled
VDRAIN = 0.3 V
ACOK/CHGOK open-drain
sink current
5
mA
VCC regulator output
VCC output voltage
VCC load regulation
EN control
VCC
4.25
4.5
4.75
10
V
∆VCC
ILOAD= 0 to 10 mA
mV
0.4
V
V
EN input low voltage
EN input high voltage
1.8
4
= 4 V
= 0 V
EN
EN
IEN
μA
EN input current
0.2
Timer protection
Trickle charge time
CC/CV charge time
NTC protection
tTrickle_tmr CTMR = 0.47 μF
tTotal_tmr CTMR = 0.47 μF
30
Mins
165
NTC
threshold
NTC low
low
temp
rising
rising
72
28
73.3
2
74.6
30.6
RNTC = NCP18 x 103, 0°C
temp
threshold hysteresis
%VCC
NTC high temp falling
threshold
29.3
2
RNTC = NCP18 x 103, 50°C
NTC low temp falling
threshold hysteresis
Thermal protection
Thermal shutdown(5)
TSHDN
150
20
°C
°C
Thermal
shutdown
hysteresis(5)
Reverse leakage blocking
VCELL = 0 V
CELL = 4 V
3
µA
µA
Battery reverse leakage
current
ILEAKAGE
V
0.5
NOTES:
5) Guaranteed by design.
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
5
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
PIN FUNCTIONS
Package
Pin #
Name Description
1
2
SW
VIN
Switch output.
Power supply voltage.
Coarse regulator output. Internally generated 4.5 V. Bypass with a 1 µF capacitor to
AGND. Used as low-side switch driver and pull-up bias voltage NTC resistivor divider. Do
NOT connect an external load to VCC.
3
4
5
VCC
CELL
SEL
Command input for the number of li-ion cells. Connect CELL to VCC for 1-cell
application; short CELL to AGND for 2-cell application.
Input pin for setting terminal battery voltage:
SEL = Low-level: VBATT = 4.35 V/cell.
SEL = High-level: VBATT =4.2 V/cell.
6
7
On/off control input. ENis pulled to GND with a 1 M internal resistor.
No connection. Please leave NC floating.
EN
NC
8
AGND Analog ground.
9
BATT Positive battery terminal.
10
CSP
Battery current sense positive input. Connect a resistor (RS1) between CSP and BATT.
Charging complete indicator. A logic low indicates a charging operation. CHGOK will
become an open drain once the charge is completed or suspended.
11
CHGOK
Valid input supply indicator. A logic low on
power supply.
indicates the presence of a valid input
ACOK
12
13
14
ACOK
NTC
Thermistor input. Connect a resistor from NTC to VCC and the thermistor from NTC to
ground.
Internal safety timer control. Connect a capacitor from this node to AGND to set the
timer. The timer can be disabled by connecting TMR to AGND directly.
TMR
Bootstrap. A capacitor is needed to drive the power switch’s gate above the supply
voltage. It is connected between SW and BST to form a floating supply across the power
switch driver.
15
16
BST
PGND Power ground.
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
6
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 5 V/9 V, C1 = C2 = 22 µF, SEL = Low/High, CELL = Low/High, L = 6.8 µH, RS1 = 50 mΩ,
battery simulator, TA = 25°C, unless otherwise noted.
Charge Current vs.
Battery Voltage
Charge Current vs.
Battery Voltage
Battery Full Voltage vs.
Temperature
1 cell
V
=5V,1 cell
V
=9V,2 cell
IN
IN
2.5
2
4.38
4.36
4.34
4.32
4.3
2.5
2
V
V
=4.35V
=4.2V
BATT_FULL
1.5
1
1.5
1
4.28
4.26
4.24
4.22
4.2
BATT_FULL
0.5
0
0.5
0
4.18
0
1
2
3
4
5
0
2
4
6
8
10
-50
0
50
100
150
BATTERY VOLTAGE(V)
BATTERY VOLTAGE(V)
Battery Full Voltage vs.
Temperature
2 cell
8.8
8.75
8.7
230
220
210
200
190
180
170
160
2.09
2.07
2.05
2.03
2.01
1.99
1.97
1.95
8.65
8.6
V
=8.7V
BATT_FULL
8.55
8.5
V
=8.4V
BATT_FULL
8.45
8.4
8.35
-50
0
50
100
150
-50
0
50
100
150
-50
0
50
100
150
VCC Output vs.
Temparature
Auto-Recharge Threshold
vs. Temperature
1 cell
4.5
4.49
4.48
4.47
4.46
4.45
4.44
220
210
200
190
180
170
160
4.15
4.1
4.05
4
4.35V/cell
3.95
3.9
4.2V/cell
50
150
-50
0
50
100
150
-50
0
50
100
150
-50
0
100
150
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
7
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 5 V/9 V, C1 = C2 = 22 µF, SEL = Low/High, CELL = Low/High, L = 6.8 µH, RS1 = 50 mΩ,
battery simulator, TA = 25°C, unless otherwise noted.
Battery Charge Curve
Auto-Recharge
Battery Charge Curve
V
=5V, V
IN
=4.35V,1 Cell
BATT_FULL
V
=5V, V
IN
=4.35V,1 Cell
BATT_FULL
V
=9V, 2 Cell,4.2V/cell
IN
V
IN
V
V
IN
IN
2V/div.
1V/div.
1V/div.
V
BATT
1V/div.
V
V
BATT
BATT
1V/div.
1V/div.
V
V
V
CHGOK
5V/div.
CHGOK
2V/div.
CHGOK
2V/div.
I
I
I
BATT
BATT
BATT
1A/div.
1A/div.
1A/div.
Battery Charge Curve
TC Steady State
TC Steady State
V
=18V, V
=4.35V,1 Cell
V
=5V, 1 Cell, V
IN
=1.5V
BATT
V
=18V, 1 Cell, V
IN
=2.9V
BATT
IN BATT_FULL
V
IN
5V/div.
V
BATT
2V/div.
V
BATT
V
IN
2V/div.
2V/div.
V
IN
V
BATT
5V/div.
1V/div.
V
V
CHGOK
5V/div.
SW
V
SW
2V/div.
10V/div.
I
I
I
BATT
BATT
BATT
1A/div.
200mA/div.
200mA/div.
TC Steady State
CC Steady State
CC Steady State
V
=9V, 2 Cell, V
=5.8V
BATT
V
=5V, 1Cell, V
=3.6V
BATT
V
=18V, 1Cell, V
IN
=3.6V
BATT
IN
IN
V
V
IN
IN
10V/div.
2V/div.
V
BATT
V
V
BATT
BATT
2V/div.
2V/div.
2V/div.
V
IN
2V/div.
V
V
SW
SW
10V/div.
2V/div.
V
SW
5V/div.
I
I
I
BATT
BATT
BATT
1A/div.
200mA/div.
1A/div.
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
8
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 5 V/9 V, C1 = C2 = 22 µF, SEL = Low/High, CELL = Low/High, L = 6.8 µH, RS1 = 50 mΩ,
battery simulator, TA = 25°C, unless otherwise noted.
CC Steady State
CC Steady State
CC Steady State (COT)
V
=18V, 2Cell, V
=8.0V
BATT
V
=12V, 2Cell, V
IN
=6V
BATT
V
V
=4.75V, 1Cell,4.35V/cell,
IN
IN
=4.1V
BATT
V
V
IN
IN
10V/div.
5V/div.
V
IN
V
2V/div.
V
BATT
BATT
5V/div.
5V/div.
V
V
SW
V
SW
SW
2V/div.
10V/div.
5V/div.
V
BATT
1V/div.
I
I
BATT
I
BATT
BATT
1A/div.
1A/div.
1A/div.
CC Steady State
(BST Refresh)
CV Steady State
CV Steady State
V
=5V, 1Cell, V
IN
=4.35V
BATT
V
=18V, 1Cell, V
IN
=4.2V
BATT
V
=9.0V, 2Cell,4.35V/cell, V
=8.67V
BATT
IN
V
IN
V
IN
5V/div.
V
2V/div.
IN
5V/div.
V
BATT
2V/div.
V
V
SW
SW
10V/div.
5V/div.
V
SW
V
V
BATT
BATT
2V/div.
1V/div.
2V/div.
I
I
I
BATT
BATT
BATT
500mA/div.
500mA/div.
500mA/div.
CV Steady State (COT)
Power On
Power Off
V
=9V, 2Cell, V
=8.4V
BATT
V
=9V, 1Cell, V
=3.6V
BATT
V
=5V, 1Cell, V
IN
=3.6V
BATT
IN
IN
V
IN
5V/div.
V
V
IN
IN
5V/div.
5V/div.
V
BATT
2V/div.
V
BATT
2V/div.
V
SW
V
SW
V
5V/div.
SW
10V/div.
10V/div.
V
BATT
2V/div.
I
I
I
BATT
BATT
BATT
1A/div.
1A/div.
1A/div.
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
9
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 5 V/9 V, C1 = C2 = 22 µF, SEL = Low/High, CELL = Low/High, L = 6.8 µH, RS1 = 50 mΩ,
battery simulator, TA = 25°C, unless otherwise noted.
V
BATT
2V/div.
V
V
IN
IN
5V/div.
5V/div.
V
SW
10V/div.
V
SW
V
10V/div.
BATT
2V/div.
SW
V
IN
V
10V/div.
5V/div.
V
BATT
1V/div.
I
I
BATT
1A/div.
BATT
500mA/div.
I
BATT
500mA/div.
V
V
V
EN
EN
EN
5V/div.
5V/div.
5V/div.
V
BATT
2V/div.
V
V
SW
SW
V
SW
5V/div.
10V/div.
10V/div.
V
V
BATT
BATT
2V/div.
1V/div.
I
500mA/div.
I
BATT
BATT
I
BATT
500mA/div.
1A/div.
V
TMR
1V/div.
V
ACOK
V
BATT
5V/div.
V
NTC
2V/div.
2V/div.
V
SW
V
CHGOK
5V/div.
10V/div.
V
TMR
V
SW
2V/div.
5V/div.
V
BATT
2V/div.
BATT
1A/div.
I
I
BATT
1A/div.
I
BATT
1A/div.
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
10
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
FUNCTIONAL BLOCK DIAGRAM
Figure 1—Functional block diagram
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
11
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
OPERATION
The MP2615A is a peak current mode controlled
switching charger for 1- or 2- cell lithium-ion and
a trickle-charge current (ITC) until the battery
voltage reaches VTC. If the charger stays in the
trickle-charge mode until the trickle-charge timer
is triggered, charging will be terminated.
lithium-polymer
batteries.
The
MP2615A
integrates both the high-side and low-side
switches of the synchronous buck converter to
provide high efficiency and save space on the
PCB.
The MP2615A enters constant-current charge
mode once the battery voltage rises higher than
VTC. In this mode, the charge current increases
from ITC to ICC to fast charge the battery.
Charge Cycle (Mode Change: TCÆ CCÆ CV)
The MP2615A regulates the charge current (ICHG
)
When the battery voltage rises over the full
battery voltage (VBATT_FULL), the charger enters
constant-voltage mode. In constant-voltage mode,
the battery voltage is regulated at VBATT_FULL
precisely, and the charge current decreases
naturally due to the existing equivalent internal
resistance of the battery. For the operation flow
chart, please refer to Figure 4.
and battery voltage (VBATT) using two control
loops. This achieves highly-accurate constant
current (CC) charge and constant voltage (CV)
charge.
As shown in Figure 2, when the VBATT < VTC, the
MP2615A stays in trickle-charge mode, and the
output of the charge current loop (COMPI)
dominates the control. The battery is charged by
Figure 2—Li-ion battery charge profile
MP2615A Rev. 1.0
4/22/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
12
MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
Charge Full Termination and Auto-Recharge
Safety Timer Operation
The MP2615A has an internal safety timer to
terminate charging during time out. The capacitor
(CTMR) connected between TMR and GND is
used to set the internal oscillator period. See
Equation (1):
When the charge current drops below the
termination threshold (IBF) during the CV charge
phase, the charger stops charging and CHGOK
becomes an open drain. Also, the timer is re-set
and turns off. Once the battery voltage decreases
below the recharge threshold (VRECH), recharging
kicks in automatically, and the timer re-starts a
new charge cycle.
TP(seconds) = 0.46×CTMR(uF)
(1)
This timer limits the maxium trickle charge time to
8192 internal oscillating periods. If the charger
stays in trickle-charge mode for longer than the
maximum oscillating periods, it is terminated.
COT Charge Mode
The MP2615A uses the floating ground method
to drive the high-side MOSFET (HS-FET) of the
buck converter. During the HS-FET off time, the
BST capacitor is recharged, and the voltage
across the BST capacitor is used as the HS-FET
gate drive. Thus a minimum off-time (200ns) is
required to maintain sufficient voltage at the BST
capacitor.
When the 200ns minimum off-time is achieved,
due to a large duty cycle, the MP2615A enters
constant off-time (COT) charge mode. In this
mode of operation, the switching frequency is
decreased slightly in order to achieve a 99% duty
cycle.
CHGOK becomes an open drain to indicate the
timer-out fault. If the charge cycle goes through
the trickle charge successfully within the allowed
time limit, it enters CC charge mode, and the
timer continues to count the oscillating periods.
When the battery is fully charged, the timer turns
off and clears the counter, waiting for the auto-
recharge to re-start.
If the charge time during the CC/CV modes
exceed 49152 oscillating periods, and the battery
full has not been qualified, the charger is
terminated, and a timer-out fault is indicated by
floating CHGOK . The charger exits the timer-out
fault state, and the on-chip safety timer re-starts
counting when the following conditions occur:
Charge Status Indication
The MP2615A has two open-drain status outputs:
CHGOK and ACOK . ACOK goes low when the
input voltage is 300 mV larger than the battery
voltage, and it rises above the under-voltage
•
The battery voltage falls below the auto-
recharge threshold (VRECH);
•
•
a power-on-reset (POR) event occurs;
EN is toggled.
lockout threshold.CHGOK indicates the status of
the charge cycle. Table 1 summarizes the
operation of both CHGOK and ACOK according
to the charging status.
The timer can be disabled by pulling TMR to
AGND.
Table 1—Charging status indication
Thus, the trickle mode charge time is calculated
using Equation (2):
Charger Status
ACOK
Low
CHGOK
Low
In charging
End of charge
NTC fault
tTrickle_tmr (minutes) = 62.8×CTMR(uF)
(2)
If a CTMR (0.47uF) is connected, the trickle charge
time is about 30 minutes.
High
impedance
Timer out
Low
EN disable
The CC/CV mode charge time is calculated with
Equation (3):
Thermal shutdown
VIN absent
High
High
tTotal_tmr (hours) = 6.28×CTMR(uF)
(3)
impedance impedance
VIN − VBATT < 0.3 V
If a CTMR (0.47 uF) is connected, the CC/CV
charge time is 2.95 hours.
MP2615A Rev. 1.0
4/22/2015
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MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
Negative
Thermal
Coefficient
(NTC)
Thermistor
NTC allows the MP2615A to sense the battery
temperature using an negative thermal coefficient
(NTC) resistor. This resistor is available in the
battery pack to ensure a safe operating
environment for the battery. A resistor with an
appropriate value should be connected from VCC
to NTC, and the thermistor should be connected
from NTC to AGND. The voltage on NTC is
determined by the resistor divider whose divide-
ratio depends on the battery temperature. When
the voltage at NTC falls out of the NTC window
range, the charging will pause until the battery
temperature goes back to normal operating
conditions.
As a result, the MP2615A stops charging and
reports this condition to the status pins. Charging
resumes automatically after the temperature falls
back within safe range.
Short-Circuit Protection
The MP2615A has an internal comparator to
check for a battery short circuit. Once VBATT falls
below 2 V, the device detects a battery-short
status, and the cycle-by-cycle peak current limit
falls to about 2.2 A to limit the current spike
during the battery-short transition. Also, the
switching frequency folds back to minimize the
power loss.
Thermal Shutdown Protection (TSD)
To prevent the chip from overheating during
charging, the MP2615A monitors the junction
temperature (TJ), of the die. Once TJ reaches the
thermal shutdown threshold (TSHTDWN) of 150°C,
the charger converter turns off. Once TJ falls
below 130°C the charging re-starts.
MP2615A Rev. 1.0
4/22/2015
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MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
INPUT POWER-UP, START-UP TIMING FLOW
Figure 3—Input power start-up timing diagram
MP2615A Rev. 1.0
4/22/2015
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MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
OPERATION FLOW CHART
Figure 4—Operation flow chart
MP2615A Rev. 1.0
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MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
APPLICATION INFORMATION
COMPONENT SELECTION
Charge Current Setting
ΔIL_MAX = 30%ICC
(7)
Based on the condition where ICC = 2 A,
VIN = 12 V, VBATT = 6 V, and fs = 760 kHz, the
calculated inductance is 6.6 µH. The inductor
saturation current must exceed at least 2.6 A and
have some tolerance. To optimize efficiency,
chose an inductor with a DC resistance less than
50 mꢀ.
The constant charge current (ICC) of the
MP2615A can be set by the sense resistor RS1
(see Typical Application). The equation to
determine the programmable CC charge current
is expressed in Equation (4):
100mV
(4)
ICC
=
(A)
RS1(mΩ)
NTC Resistor Divider Selection
To get 2 A ICC, a RS1 of 50 mꢀ should be
selected.
Figure 5 shows that an internal resistor divider is
used to set the low temperature threshold at
29.3%·VCC and the high temperature threshold
at 73.3%·VCC, respectively. For a given NTC
thermistor, select the appropriate RT1 and RT2 to
set the NTC window.
Accordingly, the trickle-charge current (ITC) can
be obtained using Equation (5):
10mV
(5)
ITC = 10%ICC
=
(A)
RS1(mΩ)
VCC
Inductor Selection
To select the right inductor, a trade off should be
made between cost, size, and efficiency. An
Low Temp Threshold
RT1
VTH_Low
inductor with
a
lower inductance value
NTC
corresponds with smaller size, but it results in
higher ripple currents, higher magnetic hysteretic
losses, and higher output capacitances.
RNTC
RT2
Conversely,
a
higher inductance value is
High Temp Threshold
VTH_High
beneficial to getting a lower ripple current and
smaller output filter capacitors. However, this
results in higher inductor DC resistance (DCR)
loss. Based on practical experience, the inductor
ripple current should not exceed 30% of the
maximum charge current under worst cases. For
the MP2615A with a typical 12 V input voltage to
charge a 2-cell battery, the maximum inductor
current ripple occurs at the corner point between
the trickle charge and the CC charge
(VBATT = 6 V). Inductance estimations are
calculated with Equation (6):
Figure 5—NTC function block
The thermistor (NCP18XH103) noted above has
the following electrical characteristics:
•
•
At 0°C, RNTC_Cold = 27.445 kꢀ;
At 50°C, RNTC_Hot = 4.1601kꢀ.
Equation (8) and Equation (9) are derived
assuming that the NTC window is between 0°C
and 50°C:
V - VBATT VBATT
IN
(6)
L =
RT2//RNTC_Cold
RT1 +RT2//RNTC_Cold VREF33
RT2//RNTC_Hot
VTH_High
RT1 +RT2//RNTC_Hot VREF33
VTH_Low
ΔIL_MAX V ⋅ fS
IN
(8)
=
=73.3%
Where VIN, VBATT, and fS are the typical input
voltage, the CC charge threshold, and the
switching frequency, respectively. And ΔIL_MAX is
(9)
=
= 29.3%
the maximum inductor ripple current, which is
usually 30% of the CC charge current. See
Equation (7):
Calculate RT1 and RT2 according to Equation (8)
and Equation (9) and the required battery
temperature range.
MP2615A Rev. 1.0
4/22/2015
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MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
For VIN_MAX = 18 V, VCC_MIN = VTC =6 V, L = 6.8 µH,
fS = 760 kHz, ∆rO_MAX = 0.1%, the output
capacitor can be calculated using Equation (12):
Input Capacitor Selection
The input capacitor C1 from the typical
application circuit absorbs the maximum ripple
current from the buck converter, which is given
by Equation (10):
VTC
1-
V
IN_MAX
(12)
CO =
= 21.3μF
8fs2LΔrO_MAX
VTC (V
− VTC )
IN_MAX
IRMS_MAX = ICC
(10)
V
IN_MAX
We can then approximate this value and choose
a 22 µF ceramic capacitor.
For a given ICC = 2 A, and VTC = 6 V when
VIN_MAX = 12 V (the duty is 0.5), the maximum
ripple current is 1 A. Select the input capacitors
so that the temperature rise due to the ripple
current does not exceed 10°C. Use ceramic
capacitors with X5R or X7R dielectrics because
of their low ESR and small temperature
coefficients. For most applications, use a 22 µF
capacitor. A small, high-quality ceramic capacitor
(i.e. 1.0 μF) should be placed as close to the IC
as possible from VIN to PGND.
PCB Layout Guidelines
Efficient PCB layout is critical to meet specified
noise, efficiency, and stability requirements. For
optimum performance, refer to Figure 6 and
follow the design considerations below:
1) Route the power stage adjacent to the
grounds. Aim to minimize the high-side
switching node (SW, inductor), trace
lengths in the high-current paths, and the
current-sense resistor trace. Keep the
switching node short and far away from
the feedback network.
Output Capacitor Selection
The output capacitor C2 (see the typical
application circuit) is in parallel with the battery.
C2 absorbs the high-frequency switching ripple
current and smoothes the output voltage. Its
impedance must be much less than that of the
battery to ensure it absorbs the ripple current.
Use a ceramic capacitor because it has a lower
ESR and smaller size. The output voltage ripple
is given by Equation (11):
2) Connect the charge current-sense resistor
to CSP (pin 10) and BATT (pin 9).
Minimize the length and area of this circuit
loop.
3) Place the input capacitor as close as
possible to VIN and PGND. Place the
output inductor close to the IC and
connect the output capacitor between the
inductor and PGND of the IC. This
minimizes the current path loop area from
SW through the LC filter and back to
PGND.
VO
1-
ΔVO
VO
V
IN
(11)
ΔrO =
=
2
8COfS L
In order to guarantee ±0.5% full battery voltage
accuracy, the maximum output voltage ripple
must not exceed 0.5% (e.g., 0.1%). The
maximum output voltage ripple occurs at the
minimum battery voltage of the CC charge and
the maximum input voltage.
4) Connect AGND and PGND at a single
point.
MP2615A Rev. 1.0
4/22/2015
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MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
Figure 6—Recommneded PCB layout
MP2615A Rev. 1.0
4/22/2015
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MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
TYPICAL APPLICATION CIRCUITS
Figure 7—Typical application circuit to charge a 2-cell battery with 12 VIN.
MP2615A Rev. 1.0
4/22/2015
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MP2615A – 2 A, 1- CELL OR 2- CELL LI-ION BATTERY CHARGER
QFN-16 (3mm x 3mm)
PACKAGE INFORMATION
PIN 1 ID
MARKING
PIN 1 ID
0.10x45° TYP.
PIN 1 ID
INDEX AREA
TOP VIEW
BOTTOM VIEW
SIDE VIEW
NOTE:
0.10x45°
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. 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.
MP2615A Rev. 1.0
4/22/2015
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21
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