MP2678
The Future of Analog IC Technology
Single-Cell, Li-Ion Battery Charger
Protection Circuit with Low-Dropout Mode
DESCRIPTION
FEATURES
The MP2678 is a high-performance, single-cell
Li-ion and Li-polymer battery charger protection
circuit with low-dropout mode. Its integrated
high-voltage input protection allows the IC to
tolerate input surges up to 30V.
The device operates similar to a linear regulator,
and maintains a regulated 5V output at input
voltages up to the over-voltage protection (OVP)
threshold (10.4V).
Full protection features include input OVP,
MPS’s proprietary battery OVP, and overcurrent protection (OCP). If a fault event occurs,
the internal N-channel MOSFET turns off to
disconnect the charging circuit from the input.
Fault indication is also provided to indicate
when a fault event occurs.
Input Surge Up to 30V
5V Regulated Output
Input Over-Voltage Protection (OVP)
MPS Proprietary Battery OVP
Output Short-Circuit Protection (SCP)
Soft-Stop to Prevent Voltage Spikes
Up to 1.7A Load Current
Thermal Monitoring
Thermal Shutdown
Enable (EN) Function
Fault Indication
Available in a QFN-8 (2mmx2mm) Package
APPLICATIONS
Thermal monitoring and thermal shutdown are
provided to guarantee safe operation. The
MP2678 monitors the internal temperature. If
the die temperature exceeds the thermal
shutdown threshold (typically 140°C), then the
N-channel MOSFET bridging the input and
output turns off.
Cell Phones
Smartphones
Personal Digital Assistants (PDAs)
MP3 Players
Digital Cameras
Low-Power Handheld Devices
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”, the MPS logo, and “Simple, Easy Solutions” are
trademarks of Monolithic Power Systems, Inc. or its subsidiaries.
The MP2678 requires a minimal number of
standard, external components, and is available
in a QFN-8 (2mmx2mm) package.
TYPICAL APPLICATION CIRCUIT
VIN
VIN
OUT
MP2678
VIN
On Off
CE
COUT
VB
RVB
GND
FLT
Battery
Pack
+
3.3V~VOVP
LINEAR
BATTERY
CHARGER
RFLT
MP2678 Rev. 1.1
7/19/2021
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1
MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
ORDERING INFORMATION
Part Number* OVP Voltage
Package
Top Marking Free Air Temperature (TA)
MP2678EG
10.4V
QFN-8 (2mmx2mm)
AK
-20C to +85C
For Tape & Reel, add suffix -Z (e.g. MP2678EG-Z).
For RoHS-compliant packaging, add suffix -LF-Z (e.g. MP2678EG-LF-Z).
PACKAGE REFERENCE
TOP VIEW
VIN
1
8
OUT
GND
2
7
NC
NC
3
6
VB
FLT
4
5
CE
QFN-8 (2mmx2mm)
MP2678 Rev. 1.1
7/19/2021
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MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
PIN FUNCTIONS
Pin #
1
2
3, 7
4
Name
VIN
GND
Exposed Pad
NC
FLT
5
CE
6
VB
8
OUT
Description
Input power source. The VIN pin can withstand up to a 30V input.
System ground. Connect the exposed pad to the GND plane for optimized thermal
performance.
No connect. Float NC.
Open-drain output. If a fault event occurs, the FLT pin goes low.
Active-low enable (EN). Pull the CE pin below 0.4V to turn the IC on; pull CE above
1.5V to turn it off.
Battery voltage (VBATT) monitoring input. Connect the VB pin to the battery pack’s
positive terminal via an isolation resistor.
Output. The OUT pin is the input pin of the protected charger.
ABSOLUTE MAXIMUM RATINGS (1)
Thermal Resistance (5)
VIN to GND .................................... -0.3V to +30V
VOUT to GND .................................... -0.3V to +7V
All other pins to GND ...................... -0.3V to +7V
Continuous power dissipation (TA = 25°C) (2)…...
....................................................…..........1.25W
Junction temperature ................-20°C to +150°C
Storage temperature .................-65°C to +150°C
QFN-8 (2mmx2mm) ................ 80 ....... 60 ... °C/W
ESD Ratings (3)
HBM (human-body model) ..........................2kV
MM (machine model) ................................ 200V
Recommended Operating Conditions (4)
Supply input voltage (VIN) ............... 3.3V to VOVP
Output current (IOUT) ..................................... 1.5A
Maximum junction temp (TJ) ..................... 125°C
MP2678 Rev. 1.1
7/19/2021
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 can cause excessive die temperature, and the
device may go into thermal shutdown. Internal thermal
shutdown circuitry protects the device from permanent
damage.
3) Devices
are
ESD
sensitive.
Handling
precaution
recommended.
4) The device is not guaranteed to function outside of its
operating conditions.
5) Measured on JESD51-7, 4-layer PCB.
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MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
ELECTRICAL CHARACTERISTICS
VIN = 5.5V, TJ = -20°C to +125°C, unless otherwise noted.
Parameter
Power-On Reset
Output voltage
VIN rising threshold
POR hysteresis
Supply current
Symbol
VOUT
VPOR
Min
Typ
Max
Units
5.5V < VIN < VOVP, IOUT = 1mA
4.6
2.4
5
5.4
2.8
V
V
mV
µA
150
IIN
Input power-on blanking time
Protection
Input over-voltage protection
(OVP)
Input OVP hysteresis
Input OVP propagation delay (6)
Input OVP recovery time
Over-current protection (OCP)
OCP blanking time
OCP recovery time
Battery OVP threshold
Battery OVP hysteresis
Battery OVP blanking time
VB Leakage Current
Over-Temperature Protection
(OTP) Rising Threshold
OTP Falling Threshold
Logic
Condition
TREC(Vout)
VOVP
TREC(OVP)
IOCP
BTOCP
TREC(OCP)
VBOVP
600
CE is low, VIN = 5V, no load
CE is high, VIN = 5.5V
VIN rising to VOUT rising
MP2678EG
3V < VIN < VOVP
9.9
1.2
4.23
BTBOVP
10.4
150
1
8
1.5
170
50
4.35
150
176
TJ = 25°C
140
5mA sink current
FLT output logic low
100
µA
ms
10.8
V
8
100
mV
µs
ms
A
µs
ms
V
mV
µs
nA
150
C
1.7
4.5
20
C
0.2
V
FLT output logic high leakage
current
10
µA
0.4
V
CE logic low threshold
VIH
CE logic high threshold
Input to Output Characteristics
VIL
Dropout voltage
VDO
VIN = VOUT(NOM) - 0.1V,
IOUT = 1A
330
mV
Q1 off-state leakage current
IOFF
CE is high, VIN = 5.5V
10
µA
1.5
V
Note:
6) Guarantee by design.
MP2678 Rev. 1.1
7/19/2021
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MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 6V, VBATT = GND, RVB = 10kΩ, RFLT = 6.04kΩ, CIN = 1μF, COUT = 1μF, TA = 25°C, unless
otherwise noted.
Supply Current vs.VIN
Breakdown Voltage
800
16
250
600
12
225
400
8
200
200
4
175
0
0
1
2
3
4
5 6
7
8
0
10
9 10
INPUT VOLTAGE(V)
14
18
22
26
30
34
38
150
0.2
0.4
0.6
0.8
1.0
1.2
OUTPUT CURRENT(A)
INPUT VOLTAGE(V)
Line Regulation
ACIN to OUT On
Resistance vs. IOUT
Load Regulation
No Load
5.00
OUTPUT VOLTAGE(V)
OUTPUT VOLTAGE(V)
5.00
4.95
4.90
4.85
4.80
5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0
4.90
4.80
4.70
4.60
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5
INPUT VOLTAGE(V)
OUTPUT CURRENT(A)
VIN
2V/div.
VBAT
5V/div.
VIN
2V/div.
VBAT
5V/div.
VOUT
2V/div.
VOUT
2V/div.
IOUT
500mA/div.
IOUT
500mA/div.
MP2678 Rev. 1.1
7/19/2021
VEN
2V/div.
VBAT
500mV/div.
VOUT
2V/div.
IOUT
500mA/div.
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MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 6V, VBATT = GND, RVB = 10kΩ, RFLT = 6.04kΩ, CIN = 1μF, COUT = 1μF, TA = 25°C, unless
otherwise noted.
VEN
2V/div.
VBAT
500mV/div.
VIN
10V/div.
VOUT
5V/div.
VIN
10V/div.
VOUT
5V/div.
VOUT
2V/div.
IOUT
500mA/div.
IOUT
500mA/div.
IOUT
500mA/div.
VFLT
5V/div.
VFLT
5V/div.
OCP
Increase IOUT to OCP point
after input start up
VBAT
50mV/div.
VIN
5V/div.
VOUT
5V/div.
VIN
2V/div.
VBAT
2V/div.
VOUT
5V/div.
IOUT
500mA/div.
VOUT
2V/div.
VIN
1V/div.
IOUT
500mA/div.
VFLT
5V/div.
VFLT
5V/div.
SCP
SCP Recovery
Short the OUT to GND
Remove the short wire
VOUT
5V/div.
VIN
2V/div.
IOUT
2A/div.
VFLT
5V/div.
MP2678 Rev. 1.1
7/19/2021
VOUT
5V/div.
VIN
2V/div.
VOUT
5V/div.
VIN
2V/div.
IOUT
500mA/div.
IOUT
2A/div.
VFLT
5V/div.
VFLT
5V/div.
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MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
FUNCTIONAL BLOCK DIAGRAM
Q1
VIN
OUT
Regulating Amplifier
1.23V
RA
PRE-REG
REF
OOC
Charge
Pump
1.23V
Q2
Output OVP Comparator
Q3
RLIM
CP
1.23V
POR
1.23V
OVP
OCP
Logic
1.23V
Q5
Battery
OVP
VB
Q4
FLT
GND
CE
Figure 1: Functional Block Diagram
MP2678 Rev. 1.1
7/19/2021
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7
MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
OPERATION
The MP2678 is a high-performance, single-cell
Li-ion and Li-polymer battery charger protection
IC. Its integrated high-voltage input protection
allows the IC to tolerate input surges up to 30V.
The device operates similar to a linear regulator,
and maintains a regulated 5V output at input
voltages up to the over-voltage protection (OVP)
threshold (10.4V).
Full protection features include input OVP, MPS
proprietary battery OVP, and over-current
protection (OCP). If a fault event occurs, the
internal N-channel MOSFET turns off to
disconnect the charging circuit from the input.
Fault indication is also provided to indicate
when a fault event occurs.
Thermal monitoring and thermal shutdown are
provided to guarantee safe operation. The
MP2678 monitors the internal temperature. If
the die temperature exceeds the thermal
shutdown threshold (typically 140°C), then the
N-channel MOSFET bridging the input and
output turns off.
For guaranteed safe operation, the MP2678
monitors its internal temperature and turns off
the N-MOSFET bridging VIN and OUT when
the die temperature exceeds 140ºC.
Power-On Reset
The MP2678 has a power-on reset (POR)
threshold of 2.8V, with a built-in hysteresis of
150mV. If the input voltage (VIN) drops below
the POR threshold, then the internal N-channel
MOSFET turns off. The IC resets itself and is
followed by an 8ms delay. If VIN and battery
voltage (VBATT) are at safe levels, then the Nchannel MOSFET turns on again. During a hot
insertion of the power supply, the 8ms delay
allows any transient to settle before the IC
resumes normal operation.
Input Over-Voltage Protection (OVP)
The IC’s internal comparator monitors VIN
continuously. If the input voltage exceeds the
OVP threshold (VOVP), then the internal Nchannel MOSFET turns off within 1µs,
MP2678 Rev. 1.1
7/19/2021
preventing the high VIN from damaging the
electronics in the handheld system. Input OVP
has a typical threshold of 10.4V. Once the overvoltage (OV) condition is removed, then the Nchannel MOSFET turns on again. Due to the
8ms delay, the output is not enabled during a
fault condition where VIN quickly exceeds VOVP.
Battery Over-Voltage Protection (OVP)
The battery OVP threshold (VBOVP) is set
internally to 4.35V. The threshold has an
integrated 150mV hysteresis. The VB pin
monitors VBATT. If VBATT exceeds VBOVP, then VB
issues an OV signal to turn off the N-channel
MOSFET. The internal comparator has a builtin blanking time (176µs) to prevent any
transient voltage from triggering an OV fault. If
the OV condition is still present after the
blanking time, then the power MOSFET turns
off.
Over-Current Protection (OCP)
The internal N-channel MOSFET’s current is
limited. This prevents charging the battery with
an excessive current. The OCP threshold is set
to 1.5A by default. If an over-current (OC)
condition occurs, the FLT pin is pulled low and
the timer (tREC(OCP)) begins. Once tREC(OCP)
expires, FLT is pulled high, and the part
restarts again after an 8ms delay.
Thermal Shutdown
The MP2678 monitors its die temperature to
prevent any thermal failure. When the internal
temperature reaches 140°C, the internal Nchannel MOSFET is turned off and the FLT pin
is pulled low. The IC does not resume operation
until the internal temperature drops below
120°C.
Enable (EN) Function
The MP2678 has an active-low CE pin that
enables and disables the IC. Pull CE high to
turn the internal N-channel MOSFET off; pull
CE low to turn it on and begin the start-up
sequence. CE has an internal pull-down
resistor that can remain unconnected.
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MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
Fault Indication
The FLT pin is an open-drain output that
indicates a low signal when any of the following
fault events occur:
1. Output short-circuit condition
2. Input OV condition
3. Battery OV condition
4. Thermal shutdown
If CE goes high, then FLT is pulled high.
MP2678 Rev. 1.1
7/19/2021
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MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
APPLICATION INFORMATION
For safe and effective charging, certain
requirements have to be satisfied while
charging Li-Ion batteries, such as a high,
precise power source (4.2V ±50mV). For
charging, the accuracy should be above 1%.
For highly used capacity, VBATT should not be
charged to above 4.2V; otherwise, the
performance and battery life can suffer from
over-charging.
Linear battery chargers require pre-charge for
depleted batteries, charge voltage, charge
current, temperature monitoring, and thermal
shutdown. The typical output of an MPS linear
charger has an I-V curve, which provides OCP,
battery OVP, input OVP, and over-temperature
protection (OTP). The function of the MP2678 is
to add a redundant protection layer such that,
under any fault condition, the charging system
output does not exceed the I-V limits required
by the battery.
Additionally, the MP2678 provides full
protection features for chargers that do not
have complete protection (particularly for those
without input surge voltage sustainability). The
MP2678 guarantees the charge system’s safety
with its full protection features, including OVP,
battery OVP, OCP, and OTP.
An internal N-channel MOSFET regulates the
output voltage (VOUT) at 5V while VIN reaches
VOVP.
The MP2678 requires a minimal number of
standard, external components, in addition to
the linear charger circuit as shown in the
Typical Application Circuit on page 1.
Selecting the Input Capacitor (CIN) and
Output Capacitor (COUT)
The input capacitor (CIN) is used for decoupling.
A higher CIN capacitance reduces the voltage
drop and the overshoot during transients. The
AC adapter is inserted live (i.e. hot insertion).
The sudden step down of the current may
cause VIN to overshoot. During an input OV
condition, the N-channel MOSFET turns off in
less than 1µs, which can to significant
overshooting. A higher CIN capacitance reduces
this type of overshoot. However, overshoot
caused by a hot insertion is not entirely
dependent on the decoupling capacitance.
MP2678 Rev. 1.1
7/19/2021
It is recommended that CIN be a dielectric
ceramic capacitor between 1µF to 4.7µF.
The MP2678 output and charging circuit input
typically share one decoupling output capacitor
(COUT). The selection of COUT is predominately
determined by the charging circuit requirement.
When using the MP2602 family chargers, it is
recommended that COUT be a 1µF to 4.7uF
ceramic capacitor.
Selecting the VB Resistor (RVB)
RVB limits the current from the VB pin to the
battery terminal in case the MP2678 fails. It is
recommended that the RVB resistance be
between 200kΩ to 1MΩ. For example, during a
failure operation, the worst-case scenario for
the current flowing from VB to the charger
output can be calculated with Equation (1):
(VVB - VBATT) / RVB = 130µA
(1)
Where RVB is 200kΩ, the VB pin voltage (VVB) is
30V, and VBATT is 4.2V.
Such small currents can be absorbed easily by
the bias current of other components. A largervalue resistor reduces the worst-case scenario
current. However, a larger-value resistor can
increase the error of the battery’s OVP
threshold (4.35V).
The typical VB leakage current is 20nA. the
error of VBOVP can be calculated with Equation
(2):
4.35V + 20nA x RVB
(2)
With a 200kΩ resistor, the worst-case scenario
for the additional error is 4mV. With a 1MΩ
resistor, the worst-case additional error is 20mV.
Selecting the
Resistor (RFLT)
pin is pulled
If a fault events occurs, the
low and the pull-up resistor (RFLT) limits the sink
current (ISINK). The maximum ISINK should not
exceed 5mA during the worst-case scenario,
which means that VIN should be 30V. Then the
RFLT can be calculated with Equation (3):
RFLT > 30V / 5mA = 6kΩ
(3)
It is recommended that RFLT be between 6kΩ to
200kΩ. When using an LED driver to indicate
the status, select a smaller-value resistor (e.g.
6.04kΩ) to drive the LED.
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10
MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
PACKAGE INFORMATION
QFN-8 (2mmx2mm)
PIN 1 ID
MARKING
1.90
2.10
0.25
0.45
0.18
0.30
1.90
2.10
PIN 1 ID
INDEX AREA
PIN 1 ID
SEE DETAIL A
0.45
0.65
8
1
1.05
1.25
0.50
BSC
5
TOP VIEW
4
BOTTOM VIEW
0.80
1.00
PIN 1 ID OPTION A
0.30x45º TYP.
PIN 1 ID OPTION B
R0.20 TYP.
0.20 REF
0.00
0.05
SIDE VIEW
DETAIL A
NOTE:
1.90
0.70
0.60
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) DRAWING CONFORMS TO JEDEC MO-229, VARIATION VCCD-3.
5) DRAWING IS NOT TO SCALE.
0.25
1.20
0.50
RECOMMENDED LAND PATTERN
MP2678 Rev. 1.1
7/19/2021
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MP2678 – LI-ION BATTERY CHARGER PROTECTION IC WITH LOW-DROPOUT MODE
REVISION HISTORY
Revision # Revision Date Description
Pages Updated
1.0
1/6/2011
Initial Release
Updated the Description section; updated the footnote below the
1
Applications section
Updated the part number from “MP2678EG-104–LF–Z” to
“MP2678EG-LF-Z”; removed “–XXX” suffix option; added the
2
1.1
7/19/2021
package information to the Package Reference section
Added equation numbers
10
Grammatical, formatting, and clerical updates; updated headers
All
and footers; updated pagination
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.
MP2678 Rev. 1.1
7/19/2021
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