MP26101
2A, 24V Input, 1.1MHz, 1- or 2- Cell
4.1V/Cell Switching Li-Ion Battery Charger
The Future of Analog IC Technology
DESCRIPTION
FEATURES
The MP26101 is a monolithic switching charger
for 1- or 2-cell Li-Ion battery packs. It has a
built-in internal power MOSFET, and can output
up to 2A of charge current with current mode
control for fast loop response and easy
compensation. The charge current can be
programmed through an accurate sense
resistor.
MP26101 regulates the charge current and
charge voltage using two control loops to
realize high-accuracy for both constant-current
charge and constant-voltage charge.
Fault condition protection includes cycle-by-cycle
current limiting and thermal shutdown. Other
safety features include battery temperature
monitoring, a charge status indicator, and a
programmable timer to halt the charging cycle.
The MP26101 requires a minimal number of
readily-available external components.
The MP26101 is available in 4mm×4mm 16-pin
QFN package.
Charges 1- or 2-cell Li-Ion battery packs
4.1V/Cell Charge Full Voltage
3.9V/Cell Auto-recharge Threshold
Wide 5V to 24V Operating Input Range
Up to 2A Programmable Charging Current
±0.75% VBATT Accuracy
0.2Ω Internal Power MOSFET
Up to 90% Efficiency
Fixed 1.1MHz Frequency
Preconditioning for Fully-Depleted Batteries
Charging Status Indicator
Input Supply and Battery Fault Indicator
Thermal Shutdown
Cycle-by-Cycle Over-Current Protection
Battery Temperature Monitor and Protection
APPLICATIONS
Distributed Power Systems
Chargers for 1-Cell or 2-Cell Li-Ion Batteries
Smartphones
Portable DVD Player
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“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of
Monolithic Power Systems, Inc.
TYPICAL APPLICATION
MP26101 Rev. 1.01
www.MonolithicPower.com
8/4/2020
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© 2020 MPS. All Rights Reserved.
1
MP26101 – 2A, 24V INPUT, 1.1MHz 1- OR 2- CELL SWITCHING LI-ION BATTERY CHARGER
ORDERING INFORMATION
Part Number*
Package
Top Marking
MP26101DR
QFN16 (4×4mm)
M26101
* For Tape & Reel, add suffix-z (e.g. MP26101DR-Z);
For RoHS Compliant packaging, add suffix-LF (e.g. MP26101DR-LF-Z)
PACKAGE REFERENCE
TOP VIEW
VIN
SW
BST
TMR
PIN 1 ID
16
15
14
13
ACOK
2
11
CSP
CHGOK
3
10
BATT
VREF33
4
9
COMPI
EXPOSED PAD
ON BACKSIDE
5
6
7
8
COMPV
GND
CELLS
12
EN
1
VREF25
NTC
ABSOLUTE MAXIMUM RATINGS (1)
Thermal Resistance (4)
Supply Voltage VIN ........................................ 26V
VSW ...................................... -0.3V to (VIN + 0.3V)
VBST........................................................ VSW + 6V
VCSP, VBATT, ................................... -0.3V to +18V
All Other Pins .................................. -0.3V to +6V
Continuous Power Dissipation (TA = 25°C) (2)
............................................................... 2.7W
Junction Temperature ............................... 150°C
Lead Temperature .................................... 260°C
Storage Temperature ................-65°C to +150°C
QFN16 (4×4mm) ..................... 46 ....... 10 ... °C/W
Recommended Operating Conditions (3)
θJA
θJC
Notes:
1) Exceeding these ratings may damage the device.
2) The maximum allowable power dissipation is a function of the
maximum junction temperature TJ(MAX), the junction-toambient 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.
3) The device is not guaranteed to function outside of its
operating conditions.
4) Measured on JESD51-7 4-layer board.
Supply Voltage VIN .............................. 5V to 24V
Maximum Junction Temp. (TJ) ................ 125°C
MP26101 Rev. 1.01
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MP26101 – 2A, 24V INPUT, 1.1MHz 1- OR 2- CELL SWITCHING LI-ION BATTERY CHARGER
ELECTRICAL CHARACTERISTICS
VIN = 19V, TA = 25°C, CELLS=0V, unless otherwise noted.
Parameters
Symbol Condition
Terminal Battery Voltage
VBATT
CSP,BATT Current
CELLS=0V
CELLS= VREF33
Min
Typ
Max
Units
4.069
8.139
4.1
8.2
4.131
8.262
V
ICSP,IBATT Charging disabled
Switch On Resistance
RDS(ON)
Switch Leakage
CC current
ICC
Trickle charge current
1
IBF
Oscillator Frequency
fSW
Fold-back Frequency
Maximum Duty Cycle
Maximum current Sense Voltage
(CSP to BATT)
Minimum On Time (5)
Trickle Mode
1.75
A
RS1= 100mΩ
1.8
2.0
2.2
10%
ICC
2.87
V
CELLS=3.3V
5.74
V
5%
CELLS=0V,
VBATT =3.5V
VBATT =0V
170
VSENSE
tON
3
VDRAIN =0.3V
In trickle mode CTMR=0.1μF
Termination delay
Time after
CTMR=0.1μF
NTC Low Temp Rising Threshold
NTC High Temp Falling Threshold
(reverse
mV/cell
15%
IBF
reached
VRECHG
RNTC=NCP18XH103 (0°C)
Recovery Hysteresis
RNTC=NCP18XH103 (50°C)
Recovery Hysteresis
VIN - VBATT
ICC
1.1
MHz
350
kHz
%
200
230
mV
ns
3.2
3.4
V
200
1000
mV
5
Dead-battery indicator
Recharge threshold at VBATT
Recharge Hysteresis
10%
100
Under Voltage Lockout Threshold
Rising
Under Voltage Lockout Threshold
Hysteresis
Open-drain sink current ( ACOK ),
A
CELLS=0V
87
( CHGOK )
μA
A
350
Termination current threshold
head-room
Ω
3.8
Trickle charge hysteresis
VIN min
blocking)
0.2
CC Mode(5)
ITRICKLE
Trickle charge voltage threshold
µA
0
EN = 4V, VSW = 0V
Peak Current Limit
1
mA
30
min
1
min
3.9
100
V/cell
mV/Cell
70.5
73.5
76.5
27.5
3
29.5
2
%of
VREF33
31.5
%of
VREF33
180
MP26101 Rev. 1.01
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8/4/2020
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© 2020 MPS. All Rights Reserved.
mV
3
MP26101 – 2A, 24V INPUT, 1.1MHz 1- OR 2- CELL SWITCHING LI-ION BATTERY CHARGER
ELECTRICAL CHARACTERISTICS (continued)
VIN = 19V, TA = 25°C, CELLS=0V, unless otherwise noted.
Parameters
Symbol Condition
Min
Typ
Max
Units
EN =4V
0.16
mA
Supply Current (Shutdown)
EN =4V,
Consider VREF33 pin output current.
R3=10k, RNTC=10k
0.32
mA
Supply Current (Quiescent)
EN =0V, CELLS=0V
EN Input Low Voltage
1.8
EN Input High Voltage
EN Input Current
Thermal Shutdown
VREF25 output voltage
VREF33 output voltage
VREF33 load regulation
2.0
mA
0.4
V
V
EN =4V
4
EN =0V
0.2
ILOAD =0 to 10mA
150
2.5
3.3
30
μA
°C
V
V
mV
Notes:
5) Guaranteed by design.
MP26101 Rev. 1.01
www.MonolithicPower.com
8/4/2020
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4
MP26101 – 2A, 24V INPUT, 1.1MHz 1- OR 2- CELL SWITCHING LI-ION BATTERY CHARGER
PIN FUNCTIONS
Pin #
Name
Description
1
NTC
2
ACOK
3
CHGOK
4
VREF33
5
VREF25
6
EN
7
CELLS
8
COMPV
Command Input. Sets the number of li-ion cells. Connect this pin to VREF33 for 2-cell
operation or ground the pin for 1-cell operation. Do not leave this pin floating.
V-LOOP Compensation. Connect this pin to GND with a capacitor and a resistor.
9
COMPI
I-LOOP Compensation. Connect this pin to GND with a capacitor and a resistor.
10
BATT
11
CSP
12
GND,
Exposed
Pad
13
TMR
14
BST
15
SW
16
VIN
Thermistor Input. Connect a resistor from this pin to the pin VREF33 and the Thermistor
from this pin to ground.
Valid Input Supply Indicator. A logic LOW indicates the presence of a valid input supply.
Charging Completion Indicator. A logic LOW indicates charging operation. The pin will
become an open drain once charging has completed or suspended.
Internal Linear Regulator 3.3V Reference Output. Bypass to GND with a 1μF ceramic
capacitor.
Internal Linear Regulator 2.5V Reference Output. PLEASE KEEP THIS PIN FLOATING
On/Off Control Input.
Positive Battery Terminal.
Battery Current Sense Positive Input. Connect a resistor RS1 between CSP and BATT. The
200mV
full charge current is: ICHG A
.
RS1mΩ
Ground. This pin is the voltage reference for the regulated output voltage, and requires
special layout considerations. 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. Connect exposed pad to ground plane for optional thermal performance.
Set Time Constant. 0.1μA current charges and discharges the external cap.
Bootstrap. Use a capacitor connected between BST and SW to drive the power switch’s
gate above the supply voltage..
Switch Output.
Supply Voltage. The MP26101 operates from a 5V to 24V unregulated input to charge a 1or 2-cell li-ion battery. Requires a capacitor to prevent large voltage spikes from appearing
at the input.
MP26101 Rev. 1.01
www.MonolithicPower.com
8/4/2020
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© 2020 MPS. All Rights Reserved.
5
MP26101 – 2A, 24V INPUT, 1.1MHz 1- OR 2- CELL SWITCHING LI-ION BATTERY CHARGER
TYPICAL PERFORMANCE CHARACTERISTICS
VIN=19V, C1=4.7μF, C2=22μF, L=4.7μH, RS1=100mΩ, Real Battery Load, TA=25°C, unless
otherwise noted.
2.5
1.5
3.9
1
IBATT
3.85
0.5
3.8
3.75
0
CHARGE CURRENT(A)
4
3.95
BATTERY CURRENT(A)
BATTERY VOLTAGE(V)
2
VBATT
20 30
40
TIMES(MIN)
50
VIN=19V
2
VIN=24V
1
0.5
VIN=12V
0
0
60
2-cell Charge Current
vs. Battery Voltage
VNTC(V)
1
0.5
1
0
10
VIN=12V
90
VBATT(V)
VIN=24V
70
0.4
0.8
1.2
ICHG(A)
1.6
2
VIN=24V
60
8
12
16
20
VIN (V)
24
28
50
0
4.0
92
3.0
89
2.0
86
5
10
15
VIN (V)
20
25
0.8
1.2
ICHG(A)
1.6
2
2-Cell, VBATT=7.4V, CC Load
95
1Cell Battery
0.4
Efficiency vs. VIN
5.0
0
50
VIN=19V
High Temp Off
1.0
60
0
200
VIN=12V
70
BATT Float Voltage vs. VIN
2-Cell, VBATT=8.2V, CC Load
VIN=19V
100
150
TIMES(MIN)
80
High Temp On
Efficiency vs. ICHG
80
50
90
1.5
BATTERY VOLTAGE(V)
100
0
0
Efficiency vs. ICHG
0.5
VIN=12V
8
0.5
IBATT
7.2
Low Temp On
2
6
7.4
5
Low Temp Off
2.5
1.5
4
1
100
VIN=24V
2
7.6
1-Cell, VBATT=4.1V, CC Load
VIN=19 V
0
0
1.5
7.8
7.0
1
2
3
4
BATTERY VOLTAGE(V)
3
2
2
VBATT
8
NTC Control Window
2.5
CHARGE CURRENT(A)
8.2
1.5
0
10
2.5
8.4
2.5
4.1
4.05
2-Cell Battery Charge Curve
BATTERY VOLTAGE(V)
4.15
1-cell Charge Current
vs. Battery Voltage
BATTERY CURRENT(A)
1-Cell Battery Charge Curve
83
80
5
10
15
VIN (V)
MP26101 Rev. 1.01
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8/4/2020
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20
25
6
MP26101 – 2A, 24V INPUT, 1.1MHz 1- OR 2- CELL 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=25°C, unless
otherwise noted.
Steady State Waveform
Steady State Waveform
Steady State Waveform
Trickle Change
1-Cell, VBATT=2.5V, CV Load
CV Change
1-Cell, VBATT=4.1V, CV Load
CC Change
1-Cell, VBATT=3.8V, CV Load
VIN
10V/div
VBATT
2V/div
VIN
10V/div
VBATT
2V/div
VIN
10V/div
VBATT
2V/div
VSW
10V/div
VSW
10V/div
VSW
10V/div
IBATT
200mA/div
IBATT
2A/div
IBATT
500mA/div
2us/div
Power On Waveform
Power Off Waveform
1-Cell, ICHG=2A,VBATT=4V
VSW
10V/div
IBATT
1A/div
EN Off Waveform
NTC Control
1-Cell, ICHG=2A,VBATT=4V
VBATT
2V/div
VTMR
500mV/div
IBATT
2A/div
VSW
10V/div
IBATT
2A/div
1ms/div
1-Cell, VBATT=3.8V, CV Load, CTMR=1nF
VIN
10V/div
VBATT
2V/div
IBATT
1A/div
Time Out
1-Cell, VBATT=3.8V, CV Load
VNTC
2V/div
VSW
10V/div
1ms/div
40ms/div
4ms/div
VEN
5V/div
VBATT
2V/div
1-Cell, ICHG=2A,VBATT=4V
VEN
5V/div
VBATT
2V/div
IBATT
1A/div
IBATT
2A/div
EN On Waveform
1-Cell, ICHG=2A,VBATT=4V
VBATT
2V/div
VIN
10V/div
VSW
10V/div
VBATT
2V/div
VIN
10V/div
VSW
10V/div
1us/div
1us/div
2s/div
1ms/div
MP26101 Rev. 1.01
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8/4/2020
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© 2020 MPS. All Rights Reserved.
7
MP26101 – 2A, 24V INPUT, 1.1MHz 1- OR 2- CELL SWITCHING LI-ION BATTERY CHARGER
FUNCTIONAL BLOCK DIAGRAM
Figure 1—Functional Block Diagram
MP26101 Rev. 1.01
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8
MP26101 – 2A, 24V INPUT, 1.1MHz 1- OR 2- CELL SWITCHING LI-ION BATTERY CHARGER
OPERATION
The MP26101 is a peak-current–mode controlled
switching charger for 1- or 2-cell Li-Ion batteries.
Figure 1 shows the block diagram. At the
beginning of a cycle, M1 is off. The COMP voltage
is higher than the output of the current sense
amplifier (A1) and the PWM comparator’s output
is low. The rising edge of the 1.1MHz CLK signal
sets the RS flip-flop. Its output turns on M1 to
connect the SW pin and inductor to the input
supply.
A1 senses and amplifies the inductor current: The
PWM comparator then compares the sum of this
signal and the ramp compensator signal against
the COMP signal. When the sum of the A1 output
and the ramp compensator exceeds the COMP
voltage, the RS flip-flop reset and turns M1 off.
The external switching diode (D2) then conducts
the inductor current. If the sum of the A1 output
and the ramp compensator does not exceed the
COMP voltage, then the falling edge of the CLK
resets the flip-flop.
The MP26101 has two linear regulators, VREF33
and VREF25, that power the internal circuit. The
3.3V reference can power external circuitry as
long as the current does not exceed 50mA. Add a
1μF bypass capacitor from VREF33 to GND to
ensure stability. By comparison, the 2.5V
reference regulator can not carry any significant
load,.
For most applications, leave VREF25 floating
without a bypass capacitor. Otherwise, connect a
capacitor with a value less than 100pF.
Charge Cycle (Mode Change: Trickle
Constant Current Constant Voltage)
The MP26101 senses battery current through the
amplified voltage drop across RS1 (Figure 1). The
charging starts in trickle-charge mode (10% of the
RS1-programmed current ICC) until the battery
voltage reaches 2.87V/cell. If the charge stays in
trickle-charging mode until the trickle-charge time
limit, the device shuts down. Otherwise, the
MP26101 operates in constant-current (CC) mode
and regulates the output current to a level set by
RS1. The COMPI voltage (regulated by the
amplifier GMI) determines the switching duty
cycle .
When the battery voltage reaches the constant
voltage (CV) mode threshold, the amplifier GMV
regulates the COMPV pin and the duty cycle.
Automatic Recharge
The charger will cease charging and the CHGOK
pin becomes an open drain output if the battery
charging current drops below the termination
threshold for more than one minute. If the battery
voltage drops to 3.9V/Cell, the MP26101
automatically begins recharging the battery.
Charger Status Indication
MP26101 has two open-drain status outputs,
CHGOK and ACOK . The ACOK pin pulls low
when an input voltage is 300mV over the battery
voltage and over the under voltage lockout
threshold. CHGOK indicates the status of the
charge cycle. Table 1 describes the status of the
charge cycle based on the CHGOK and ACOK
outputs.
Table 1―Charging Status Indication
ACOK
low
low
CHGOK
low
high
high
high
Charger status
In charging
End of charge
Vin < UVLO, thermal
shutdown, timer out, EN
disable
Timer Operation
MP26101 uses an internal timer to terminate
charging. An external capacitor programs timer
duration at the TMR pin.
The trickle mode charge time is:
t TICKLE _ TMR 30min s
CTMR
0.1F
The total charge time is:
t TOTAL _ TMR 3hours
CTMR
0.1F
MP26101 Rev. 1.01
www.MonolithicPower.com
8/4/2020
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© 2020 MPS. All Rights Reserved.
9
MP26101 – 2A, 24V INPUT, 1.1MHz 1- OR 2- CELL SWITCHING LI-ION BATTERY CHARGER
Negative Thermal Coefficient (NTC)
Thermistor
The MP26101 has a built-in NTC resistance
window comparator that allows MP26101 to
measure the temperature through a thermistor in
the battery pack that ensures that the battery
operates
under
recommended
conditions.
Connect an appropriate resistor from VREF33 to
the NTC pin, and connect the thermistor from the
NTC pin to GND. The voltage on the NTC pin is
determined by the temperature-sensitive resistor
divider. When the NTC voltage falls out of NTC
window range, MP26101 will stop the charging.
The charger will restart if the temperature goes
back into NTC window range.
Figure 2—Li-Ion Battery Charge Profile
MP26101 Rev. 1.01
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8/4/2020
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10
MP26101 – 2A, 24V INPUT, 1.1MHz 1- OR 2- CELL SWITCHING LI-ION BATTERY CHARGER
POR
No
VUVLOVBATT+0.3V?
Yes
No
RCHG
Set up
Charging
Set up?
Yes
CELLS Voltage?
CELLS= VREF33
CELLS= 0V
VBATT_TC = 5.74V
VBATT_FULL=8.2V
VBATT_RECHG=7.8V
VBATT_TC = 2.87V
VBATT_FULL=4.1V
VBATT_RECHG=3.9V
Normal Operation
Charge On,
ACOK&
CHGOK low
Charge Mode?
VBATT>VBATT_FULL
VBATT_TC