MP2612ER-Z [MPS]
Power Supply Support Circuit, Fixed, 1 Channel, 4 X 4 MM, MO-220VGGC, QFN-16;
| 型号： | MP2612ER-Z |
| 厂家： | 
MONOLITHIC POWER SYSTEMS |
| 描述： | Power Supply Support Circuit, Fixed, 1 Channel, 4 X 4 MM, MO-220VGGC, QFN-16 |
| 文件： | 总20页 (文件大小：582K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MP2612
2A,24V Input, 600kHz
2-3 Cells Switching Li-Ion Battery Charger
The Future of Analog IC Technology
DESCRIPTION
FEATURES
Charges 2-3 Cells Series Li-Ion Battery
Packs
Wide Operating Input Range
Up to 2 A Programmable Charging Current
±0.75% VBATT Accuracy
0.2Ω Internal Power MOSFET Switch
Up to 90% Efficiency
The MP2612 is a monolithic switching charger
for 2-3 cells series Li-Ion cells battery with a
built-in internal power MOSFET. It achieves up
to 2A charge current with current mode control
for fast loop response and easy compensation.
The charge current can be programmed by
sensing the current through an accurate sense
resistor.
Fixed 600kHz Frequency
Preconditioning for Fully Depleted Batteries
Charging Operation Indicator
Input Supply and Battery Fault Indicator
Thermal Shutdown
Cycle-by-Cycle Over Current Protection
Battery Temperature Monitor and Protection
MP2612 regulates the charge current and
charge voltage using two control loops to
realize high accuracy CC charge and CV
charge.
Fault condition protection includes cycle- by-
cycle current limiting and thermal shutdown.
Other safety features include battery temperature
monitoring, charge status indication and
programmable timer to finish the charging cycle.
APPLICATIONS
Distributed Power Systems
Chargers for 2-Cell or 3-Cell Li-Ion Batteries
Pre-Regulator for Linear Regulators
Smart Phones
The MP2612 requires a minimum number of
readily available standard external components.
Net-book
The MP2612 is available in 16-pin 4mm x 4mm
QFN package.
For MPS green status, please visit MPS website under Quality Assurance.
“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of
Monolithic Power Systems, Inc.
TYPICAL APPLICATION
Figure 1—Standalone Switching Charger
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
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© 2011 MPS. All Rights Reserved.
1
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
D1
VSYS
RS2 20m
VIN
9V to 24V
(9V min for 2-cell)
RG1
RG2
M2
C8
22uF
RG2
RG1MP8110
NC
VCC
SHDN
GND
OUT2
OUT1
M3
C1
4.7uF
L
RS1
VIN
SW
4.7uH
VREF33
C7
100m
C3
0.1uF
2-3 cells
battery
1uF
R1
R2
VREF25
CHGOK
BST
C2
D2
22uF
CSP
MP2612
ACOK
BATT
R3
R5 750
R4 2.5k
10k
CELLS
COMPI
COMPV
TMR
NTC
EN
GND
RNTC
10k
ON
OFF
C6
0.1uF
C4
C5
2.2nF
2.2nF
(1)
Figure 2—Switching Charger with Power Path Management
Notes:
1) ACOK should be pulled up to VIN in the power path management application.
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
2
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
ORDERING INFORMATION
Part Number*
Package
Top Marking
Free Air Temperature (TA)
MP2612ER
4mm x 4mm QFN16
2612ER
-20C to +85C
*For Tape & Reel, add suffix –Z (eg. MP2612ER–Z);
For RoHS compliant packaging, add suffix –LF (eg. MP MP2612ER–LF–Z)
PACKAGE REFERENCE
TOP VIEW
PIN 1 ID
16
15
14
13
NTC
ACOK
1
2
3
4
12 GND
11
CSP
CHGOK
VREF33
10 BATT
9
COMPI
5
6
7
8
EXPOSED PAD
ON BACKSIDE
ABSOLUTE MAXIMUM RATINGS (2)
Thermal Resistance (5)
4x4 QFN16 .............................46...... 10... C/W
θJA
θJC
Supply Voltage VIN ....................................... 26V
V
V
SW........................................-0.3V to VIN + 0.3V
BST ...................................................... VSW + 6V
Notes:
2) Exceeding these ratings may damage the device.
3) 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.
VCSP, VBATT, ...................................-0.3V to +18V
ACOK, VCHGOK, ..............................-0.3V to +26V
V
All Other Pins..................................-0.3V to +6V
Continuous Power Dissipation (TA=+25C) (3)
............................................................. 2.7W
Junction Temperature...............................150C
Lead Temperature ....................................260C
Storage Temperature............... -65C to +150C
Recommended Operating Conditions (4)
Supply Voltage VIN ..............................9V to 24V
Maximum Junction Temp. (TJ) ............. +125C
4) The device is not guaranteed to function outside of its
operating conditions.
5) Measured on JESD51-7 4-layer board.
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
3
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
ELECTRICAL CHARACTERISTICS (6)
VIN = 19V, TA = +25C, CELLS=0V, unless otherwise noted.
Parameters
Symbol Condition
Min
8.337
12.505
Typ
8.4
12.6
1
Max
8.463
12.695
Units
CELLS=0V
VBATT
Terminal Battery Voltage
V
CELLS= VREF33
CSP，BATT Current
ICSP,IBATT Charging disabled
RDS(ON)
µA
Switch On Resistance
0.2
Ω
Switch Leakage
0
10
μA
EN= 4V, VSW = 0V
CC(6)
4.1
A
Peak Current Limit
Trickle
2
A
A
CC current
ICC
RS1=100mΩ
1.8
5%
2.0
2.2
Trickle charge current
Trickle charge voltage threshold
Trickle charge hysteresis
Termination current threshold
ITRICKLE
10%
2.8
ICC
V/cell
mV
ICC
350
10%
IBF
15%
CELLS=0V,
VBATT =4.5V
Oscillator Frequency
fSW
600
190
kHz
Fold-back Frequency
Maximum Duty Cycle
VBATT =0V
kHz
%
90
Maximum current Sense Voltage
(CSP to BATT)
Minimum On Time (6)
VSENSE
tON
170
200
100
3.2
230
3.4
mV
ns
V
CELLS=0V, VBATT =5V
Under Voltage Lockout Threshold
Rising
3
5
Under Voltage Lockout Threshold
Hysteresis
200
mV
mA
min
Open-drain sink current
VDRAIN =0.3V
Stay at trickle mode
Dead-battery indication
30
1
C
TMR=0.1μF
Time after IBF reached,
TMR=0.1μF
Termination delay
min
C
Recharge threshold at VBATT
Recharge Hysteresis
VRECHG
4.0
V/cell
mV
100
NTC Low Temp Rising Threshold
RNTC=NCP18XH103(0°C)
73
%VREF33
NTC High Temp Falling Threshold
RNTC=NCP18XH103(50°C)
VIN-VBATT
30
%VREF33
mV
VIN min head-room (reverse blocking)
180
0.4
V
V
EN Input Low Voltage
EN Input High Voltage
1.8
4
EN
EN
=4V
=0V
μA
EN Input Current
0.2
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
4
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
ELECTRICAL CHARACTERISTICS (continued)
VIN = 19V, TA = +25C, CELLS=0V, unless otherwise noted.
Parameters
Symbol Condition
Min
Typ
Max
Units
0.16
mA
EN=4V
EN=4V,
Consider
pin output current,
R3=10k,RNTC=10k
Supply Current (Shutdown)
VREF33
0.32
mA
mA
Supply Current (Quiescent)
2.0
EN=0V, CELLS=0V
Thermal Shutdown (6)
VREF25 output voltage
VREF33 output voltage
VREF33 load regulation
150
2.5
3.3
30
°C
V
V
ILOAD =0 to 10mA
mV
Notes:
6) Guaranteed by design.
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
5
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
TYPICAL PERFORMANCE CHARACTERISTICS
VIN=19V, C1=4.7μF, C2=22μF, L=4.7μH, RS1=100mΩ, Real Battery Load, TA=25ºC, unless
otherwise noted.
2 Cells Battery Charge Curve
2 Cells Charge Current vs.
Battery Voltage
CV Load
3 Cells Battery Charge Curve
2.5
2
8.5
2.5
2
12.8
2.5
2
8.4
8.3
8.2
8.1
8
12.6
12.4
12.2
12
V
V
BATT
BATT
1.5
1
1.5
1
1.5
1
11.8
11.6
11.4
11.2
11
7.9
7.8
7.7
7.6
7.5
V
=19V
IN
V
=24V
4
IN
I
I
BATT
60
BATT
0.5
0
0.5
0.5
V
6
=12V
8
IN
0
0
150
0
2
10
0
20
40
80 100 120
0
50
100
BATTERY VOLTAGE(V)
T IME S (MIN)
T IME S (MIN)
3 Cells Charge Current vs.
Battery Voltage
CV Load
NTC Control Window
2.5
3
2.5
2
2.5
2
V
=19V
IN
Low Temp Off
Low Temp On
2
1.5
1
V
=24V
IN
1.5
1
1.5
1
High Temp On
High Temp Off
0.5
0.5
0
0.5
0
0
0
2
4
6
8
10 12 14
0
0.5
1
1.5
(A)
2
2.5
8
12
16
20
24
28
BATTERY VOLTAGE(V)
I
V
(V)
IN
SYS
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
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© 2011 MPS. All Rights Reserved.
6
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN=19V, C1=4.7μF, C2=22μF, L=4.7μH, RS1=100mΩ, Real Battery Load, TA=25ºC, unless
otherwise noted.
Efficiency vs. I
Efficiency vs. I
Efficiency vs. V
IN
CHG
CHG
2 Cells, V
=8.4V
3 Cells, V
=12.6V
2 Cells, V
=7.4V
BATT
BATT
BATT
100
90
95
92
89
86
83
80
100
90
V
=15V
IN
V
=19V
IN
V
=12V
V
=15V
IN
IN
V
=24V
IN
V
=19V
IN
V
=24V
80
70
60
IN
80
70
60
0
0.4
0.8
I
1.2
(A)
1.6
2
5
10
15
20
25
0
0.4
0.8
1.2
(A)
1.6
2
V
(V)
IN
I
CHG
CHG
BATT Float Voltage vs. V
2 Cells
BATT Float Voltage vs.
Temperature
2 Cells
Charge Current vs.
Temperature
IN
2 Cells, V
=7.4V
BATT
8.5
8.4
8.3
8.2
8.1
8
2.2
8.5
8.4
8.3
8.2
8.1
8
2
1.8
1.6
1.4
1.2
8
13
18
(V)
23
28
-20
0
20
40
60
80
-20
0
20
40
60
80
V
IN
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
7
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN=19V, C1=4.7μF, C2=22μF, L=4.7μH, RS1=100mΩ, Real Battery Load, TA=25ºC, unless
otherwise noted.
Steady State Waveform
Steady State Waveform
Steady State Waveform
Trickle Charge
2 Cells, V =5V
CC Charge
2 Cells, V
CV Charge
2 Cells, V
=7.4V
BATT
=8.4V
BATT
BATT
V
IN
V
V
IN
IN
10V/div.
10V/div.
BATT
5V/div.
10V/div.
BATT
5V/div.
V
V
BATT
5V/div.
V
V
SW
10V/div.
V
SW
V
10V/div.
SW
10V/div.
I
BATT
I
BATT
200mA/div.
500mA/div.
I
BATT
1A/div.
Power On Waveform
Power Off Waveform
EN On Waveform
2 Cells, I
=2A,V
=8V
2 Cells, I
=2A,V
=8V
2 Cells, I
CHG
=2A,V =8V
BATT
CHG
BATT
CHG
BATT
V
EN
5V/div.
V
V
IN
IN
10V/div.
10V/div.
V
V
V
BATT
BATT
BATT
5V/div.
5V/div.
5V/div.
V
V
SW
SW
V
SW
10V/div.
10V/div.
10V/div.
I
I
I
BATT
BATT
BATT
2A/div.
2A/div.
2A/div.
EN Off Waveform
NTC Control
,
Timer Out
2 Cells, I
=2A,V
=8V
V
=7.4V
BATT
2 Cells, V
=7.4V, C =1nF
BATT TMR
CHG
BATT
V
EN
V
NTC
5V/div.
V
2V/div.
IN
10V/div.
V
V
BATT
BATT
V
BATT
5V/div.
5V/div.
5V/div.
V
V
TMR
V
SW
SW
500mV/div.
10V/div.
10V/div.
I
BATT
I
BATT
I
2A/div.
BATT
2A/div.
2A/div.
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
8
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN=19V, C1=4.7μF, C2=22μF, L=4.7μH, RS1=110mΩ, RS2=20mΩ, Real Battery Load, TA=25ºC,
unless otherwise noted.
Power Path Management
Current Sharing
Power Path Management
Steady State
2 Cells, I
=2A, V =7.4V
BATT
2 Cells, I
=2A, V
=8V, I =0.8A
SYS
CHG
CHG
BATT
V
IN
V
V
IN
10V/div.
IN
10V/div.
10V/div.
V
V
BATT
SW
5V/div.
10V/div.
V
BATT
5V/div.
I
I
SYS
BATT
1A/div.
1A/div.
V
5V/div.
I
SYS
SYS
I
500mA/div.
BATT
1A/div.
I
BATT
1A/div.
V
IN
10V/div.
V
BATT
5V/div.
I
BATT
1A/div.
V
5V/div.
SYS
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
9
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
PIN FUNCTIONS
Pin #
Name Description
Thermistor Input. Connect a resistor from this pin to the pin VREF33 and the Thermistor
from this pin to ground.
1
NTC
Valid Input Supply Indicator. A logic LOW on this pin indicates the presence of a valid input
supply.
2
3
4
ACOK
CHGOK
VREF33
Charging Completion Indicator. A logic LOW indicates charging operation. The pin will
become an open drain once the charging is complete.
Internal linear regulator 3.3V reference output. Bypass to GND with a 1μF ceramic
capacitor.
5
6
VREF25 Internal linear 2.5V reference circuit. PLEASE KEEP THIS PIN FLOATING.
On/Off Control Input.
EN
Command Input for the number of Li-Ion Cells. Connect this pin to VREF33 for 3-cell
operation or ground the pin for 2-cell operation. DO NOT LEAVE THIS PIN FLOAT.
7
8
CELLS
COMPV V-LOOP Compensation. Decouple this pin with a capacitor and a resistor.
9
COMPI I-LOOP Compensation. Decouple this pin with a capacitor and a resistor.
10
BATT Positive Battery Terminal.
Battery Current Sense Positive Input. Connect a resistor RSEN between CSP and BATT. The
200mV
11
12
CSP
GND
I
CHG
A
full charge current is:
.
RS1
mΩ
Ground. This pin is the voltage reference for the regulated output voltage. For this reason
care must be taken in its layout. This node should be placed outside of the switching diode
(D2) to the input ground path to prevent switching current spikes from inducing voltage
noise into the part.
13
14
15
16
TMR
BST
SW
IN
Set time constant. 0.1uA current charges and discharges the external cap.
Bootstrap. This capacitor is needed to drive the power switch’s gate above the supply
voltage. It is connected between SW and BS pins to form a floating supply across the power
switch driver.
Switch Output.
Supply Voltage. The MP2612 operates from a 9V to 24V unregulated input to charge 2~3
cell li-ion battery. Capacitor is needed to prevent large voltage spikes from appearing at the
input.
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
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© 2011 MPS. All Rights Reserved.
10
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
BLOCK DIAGRAM
Figure 3—Function Block Diagram
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
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© 2011 MPS. All Rights Reserved.
11
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
OPERATION
The MP2612 is a peak current mode controlled
switching charger for use with Li-Ion batteries.
current charging mode.” The duty cycle of the
switcher is determined by the COMPI voltage
that is regulated by the amplifier GMI.
Figure 3 shows the block diagram. At the
beginning of a cycle, M1 is off. The COMP
voltage is higher than the current sense result
from amplifier A1’s output and the PWM
comparator’s output is low. The rising edge of the
600 kHz CLK signal sets the RS Flip-Flop. Its
output turns on M1 thus connecting the SW pin
and inductor to the input supply.
When the battery voltage reaches the “constant
voltage mode” threshold, the amplifier GMV will
regulate the COMP pin, and then the duty cycle.
The charger will then operate in “constant voltage
mode.”
Automatic Recharge
A programmable time delay after the battery
charging current drops below the termination
threshold, the charger will cease charging and
The increasing inductor current is sensed and
amplified by the Current Sense Amplifier A1.
Ramp compensation is summed to the output of
A1 and compared to COMP by the PWM
comparator.
the CHGOK pin becomes an open drain. If for
some reason, the battery voltage is lowered to
4.0V/Cell, recharge will automatically kick in.
When the sum of A1’s output and the Slope
Compensation signal exceeds the COMP
voltage, the RS Flip-Flop is reset and M1 is
turned off. The external switching diode D2 then
conducts the inductor current.
CTMR
Termination Delay 1min
0.1uF
Charger Status Indication
MP2612 has two open-drain status outputs:
If the sum of A1’s output and the Slope
Compensation signal does not exceed the COMP
voltage, then the falling edge of the CLK resets
the Flip-Flop.
CHGOK and ACOK . The ACOK pin pulls low
when an input voltage is greater than battery
voltage 300mV and over the under voltage
lockout threshold. CHGOK is used to indicate the
status of the charge cycle. Table 1 describes the
status of the charge cycle based on the
The MP2612 have two internal linear regulators
power internal circuit, VREF33 and VREF25. The
output of 3.3V reference voltage can also power
external circuitry as long as the maximum current
(50mA) is not exceeded. A 1μF bypass capacitor
is required from VREF33 to GND to ensure
stability. The output of 2.5V reference voltage
can not carry any load.
CHGOK and ACOK outputs.
Table 1―Charging Status Indication
Charger status
ACOK
CHGOK
low
low
low
high
In charging
End of charge,
Vin<UVLO, timer out,
In typical application, VREF25 should be float
and no capacitor is required. It can only connect
to a capacitor which is smaller than 100pF.
high
high
thermal shutdown EN
disable
Timer Operation
Charge Cycle (Mode change: Trickle CC
CV)
MP2612 uses internal timer to terminate the
charge if the timer times out. The timer duration
is programmed by an external capacitor at the
TMR pin.
The battery current is sensed via RS1 (Figure 3)
and amplified by A2. The charge will start in
“trickle charging mode” (10% of the RSEN
programmed current ICC) until the battery voltage
reaches 2.8V/cell. If the charge stays in the
“trickle charging mode” till “timer out” condition is
triggered, the charge is terminated. Otherwise,
the output of A2 is then regulated to the level set
by RS1. The charger is operating at “constant
The trickle mode charge time is:
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
12
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
Power Path Management
CTMR
TTICKLE_TMR 30mins
Using MP8110 together with MP2612 can
implement a switching charger circuit with power
path management function, which realizes the
current sharing of the charger and system load
(Figure 2). In another word, MP8110 senses the
system current and feeds back to MP2612 and
MP2612 reduces charge current according to the
increase of the system current.
0.1uF
The total charge time is:
TTOTAL_TMR 3hours
CTMR
0.1uF
Coefficient
Negative
Thermal
(NTC)
Thermistor
The MP2612 has a built-in NTC resistance
window comparator, which allows MP2612 to
sense the battery temperature via the thermistor
packed internally in the battery pack to ensure a
safe operating environment of the battery. A
resistor with appropriate value should be
connected from VREF33 to NTC pin and the
thermistor is connected from NTC pin to GND.
The voltage on NTC pin is determined by the
resistor divider whose divide ratio depends on
the battery temperature. When the voltage of pin
NTC falls out of NTC window range, MP2612 will
stop the charging. The charger will restart if the
temperature goes back into NTC window range.
However, after the charge current decrease to 0,
the system current can only be limited by the
adapter.
The system current is satisfied first and always. It
chooses the adapter as its power source when
the adapter plugs in, and the battery is the
backup power source when the adapter is
removed.
Figure 4 to 8 shows the charge profile, operation
waveform and flow chart, respectively.
MP2612 Rev. 1.0
9/7/2011
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13
MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
CHARGE PROFILE AND POWER PATH MANAGEMENT FUNCTION
Figure 4—Li-Ion Battery Charge Profile
Figure 5 — Power Path Management Function- Current Sharing
MP2612 Rev. 1.0
9/7/2011
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MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
OPERATION FLOW CHART
Figure 6— Normal Charging Operation Flow Chart
MP2612 Rev. 1.0
9/7/2011
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MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
OPERATION FLOW CHART (continued)
Figure 7— Power Path Management Operation Flow Chart
MP2612 Rev. 1.0
9/7/2011
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MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
OPERATION FLOW CHART (continued)
Normal Operation
Charge On,
ACOK&
CHGOK is 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
Battery Full?
ICHG<IBF
VBATT>VBATT_TC
VBATT>VBATT_FULL
Yes
Yes
Yes
Stop Charge.
ACOK is low,
CHGOK is high
Yes
No
VBATT<VBATT_RECH
?
No
No
No
Timer Out ?
Yes
NTC Fault?
Tj>=150oC?
Yes
Yes
Charge
Termination,
ACOK& CHGOK
are high
Charge Current
Thermal Shutdown,
ACOK& CHGOK
are high
Charge Suspend
No
No
NTC OK?
Yes
Tj<=130oC?
Yes
Charger Recovery,
Return to Normal
Operation
Fault Protection
Figure 8— Fault Protection Flow Chart
MP2612 Rev. 1.0
9/7/2011
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MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
APPLICATION INFORMATION
Setting the Charge Current
1. Standalone Switching Charger
RS1 RGS1
(5)
The charge current of MP2612 is set by the
sense resistor RS1 (Figure1). The charge current
programmable formula is as following:
RGS1/2 causes charge current sense error as it
changes the sense gain of A2, which can be
calculated from:
200mV
12.3
kΩ
ICHG
A
(1)
GA2
(6)
RS1
mΩ
2
kΩ RGS
kΩ
2. Switching Charger with Power Path
Management
The charge current is set as:
1230
GA2 RS1
When MP2612 is applied together with MP8110,
the charge current setting should be calibrated
(Figure2).
ICHG
A
(7)
mΩ
Then the influence of RGS1 to the charge current
is:
Figure 8 shows MP8110 sensing the system
current and feeding back to the MP2612.
2000 RGS
Ω
ICHG
A
(8)
10RS1mΩ
To decrease the power loss of the sensing circuit,
choose RS2 as small as possible, 20m is
recommended. Too small RG1 results in too big
current sense error of MP8110, 50Ω is at least.
Substitute these two values into equation (5),
then the calibrated charge current set formula in
power path application is got from equation (8):
2000 2.5RS1
mΩ
ICHG
A
(9)
10RS1mΩ
Following table is the calculated RS1 and RGS1
value for setting different charge current.
Table2—ICHG Set in Power Path Application
Figure 8— System Current Sensing Circuit
The gain of MP8110 is set as:
RGS1
ICHG(A)
2
1.5
1
0.8
0.5
RGS(Ω)
280
402
665
909
2k
RS1(mΩ)
110
160
260
360
800
Gain
(2)
RG1
The voltage of OUT1 pin, VOUT1 can be calculated
from:
If choose different RS2 and RG1, re-calculated
from equation (5) and equation (8), then get the
different equation (9) and the table.
ISYS RS2RGS1
VOUT1 ISYS RS2Gain
(3)
RG1
When the system current increased ΔISYS, to
satisfy the charge current decreased ΔISYS
accordingly, the relationship should be:
ΔVOUT1 ΔISYS RS2RGS1
ΔIBAT
(4)
RS1
RS1RG1
BecauseΔISYS=ΔIBATT, we can get:
MP2612 Rev. 1.0
9/7/2011
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MP2612 – 2A, 24V INPUT, 600kHz 2-3CELL SWITCHING LI-ION BATTERY CHARGER
Also, any relationship between ΔISYS and ΔIBATT
can be realized by re-calculate equation (4),(5)
and (8).
According to equation (12) and equation (13), we
can find that R3 = 9.63k and R6 = 505k.
To be simple in project, making R3=10k and R6
no connect will approximately meet the
specification.
Selecting the Inductor
A 1µH to 10µH inductor is recommended for
most applications. The inductance value can be
derived from the following equation.
VOUT (V VOUT
)
IN
VREF33
L
(10)
V IL fOSC
IN
Low Temp Threshold
Where ΔIL is the inductor ripple current. VOUT is
the 2/3 cell battery voltage.
R3
VTH_Low
NTC
Choose inductor current to be approximately
30% if the maximum charge current, 2A. The
maximum inductor peak current is:
RNTC
R6
High Temp Threshold
IL
2
IL(MAX) ICHG
(11)
VTH_High
Under light load conditions below 100mA, larger
inductance is recommended for improved
efficiency.
Figure 9— NTC function block
Selecting the Input Capacitor
The input capacitor reduces the surge current
drawn from the input and also 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 passing to the input.
Ceramic capacitors with X5R or X7R dielectrics
are highly recommended because of their low
ESR and small temperature coefficients. For
most applications, a 4.7µF capacitor is sufficient.
For optimized efficiency, the inductor DC
resistance is recommended to be less than
200mꢀ.
NTC Function
As Figure 9 shows, the low temperature
threshold and high temperature threshold are
preset internally via a resistive divider, which are
73%·VREF33 and 30%·VREF33. For a given
NTC thermistor, we can select appropriate R3
and R6 to set the NTC window.
Selecting the Output Capacitor
In detail, for the thermistor (NCP18XH103) noted
in above electrical characteristic,
The output capacitor keeps output voltage ripple
small and ensures regulation loop stability. The
output capacitor impedance should be low at the
switching frequency. Ceramic capacitors with
X5R or X7R dielectrics are recommended.
At 0ºC, RNTC_Cold = 27.445k;
At 50ºC, RNTC_Hot = 4.1601k.
Assume that the NTC window is between 0ºC
and 50ºC, the following equations could be
derived:
PC Board Layout
The high frequency and high current paths (GND,
IN and SW) should be placed to the device with
short, direct and wide traces. The input capacitor
needs to be as close as possible to the IN and
GND pins. The external feedback resistors
should be placed next to the FB pin. Keep the
switching node SW short and away from the
feedback network.
R6//RNTC_Cold
VTH_Low
73%
30%
R3 R6//RNTC_Cold VREF33
(12)
(13)
R6//RNTC_Hot
VTH_High
R3 R6//RNTC_Hot VREF33
MP2612 Rev. 1.0
9/7/2011
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19
MP2612 – 2A, 24V INPUT, 600kHz SWITCHING LI-ION BATTERY CHARGER
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION – INTERNAL USE ONLY
PACKAGE INFORMATION
QFN16 (4mm x 4mm)
3.90
4.10
2.15
2.45
PIN 1 ID
SEE DETAIL A
0.50
0.70
13
16
PIN 1 ID
MARKING
0.25
12
1
4
0.35
3.90
4.10
2.15
2.45
0.65
BSC
PIN 1 ID
INDEX AREA
9
8
5
TOP VIEW
BOTTOM VIEW
PIN 1 ID OPTION A
0.45x45º TYP.
PIN 1 ID OPTION B
R0.25 TYP.
0.80
1.00
0.20 REF
0.00
0.05
DETAIL A
SIDE VIEW
3.80
2.30
NOTE:
1) ALL DIMENSIONS ARE IN MILLIMETERS.
2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH.
3) LEAD COPLANARITY SHALL BE 0.10 MILLIMETER MAX.
4) JEDEC REFERENCE IS MO-220, VARIATION VGGC.
5) DRAWING IS NOT TO SCALE.
1.00
0.35
0.65
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.
MP2612 Rev. 1.0
9/7/2011
www.MonolithicPower.com
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© 2011 MPS. All Rights Reserved.
20
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