MP8862
2.8V-22V VIN, 2A IOUT, 4-Switch,
Integrated Buck-Boost Converter
with I2C Interface
DESCRIPTION
FEATURES
The MP8862 is a synchronous, 4-switch,
integrated buck-boost converter capable of
regulating the output voltage across a 2.8V to
22V wide input voltage range with high
efficiency.
The MP8862 uses constant-on-time (COT)
control in buck mode and constant-off-time
control in boost mode, providing fast load
transient response and smooth buck-boost
mode transient. The MP8862 provides auto
PFM/PWM or forced PWM switching modes,
and programmable output constant current (CC)
current limit, which support flexible design for
different applications.
Full protection features include over-current
protection (OCP), over-voltage protection
(OVP),
under-voltage
protection
(UVP),
programmable soft start, and thermal shutdown.
The MP8862 is available in a 16-pin QFN
(3mmx3mm) package.
Wide 2.8V to 22V Operating Input Voltage
Range
1V (1) to 20.47V Output Voltage Range (5V
Default) with 10mV Resolution through I2C
2A Output Current or 4A Input Current
Four Low RDS(ON) Internal Buck Power
MOSFETs
Adjustable Accurate CC Output Current
Limit with Internal Sensing MOSFET via I2C
500kHz (1) Switching Frequency
Output Over-Voltage Protection (OVP)
Hiccup
Output Short-Circuit Protection (SCP) with
Hiccup Mode
Over-Temperature Warning and Shutdown
I2C Interface with ALT Pin
Four Programmable I2C Addresses
One-Time Programmable (OTP) NonVolatile Memory
I2C Programmable Line Drop Compensation,
PFM/PWM Mode, Soft Start, and OCP, etc.
EN Shutdown Discharge Programmable
Available in a QFN-16 (3mmx3mm)
Package
APPLICATIONS
Buck-Boost Bus Supplies
Industrial Systems
Personal Medical Products
DSLR Cameras
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 registered trademarks of
Monolithic Power Systems, Inc. or its subsidiaries.
Note:
1)
MP8862 Rev 1.0
5/30/2019
For VOUT < 3V applications, the switching frequency decreases.
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1
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
TYPICAL APPLICATION
C4
Efficiency
100nF
L1
VIN
12V
BST1
SW1
IN
C1A
22µF
C1
100µF
BST2
95
VOUT
OUT
C2A
10µFx2
MP8862
C7
22nF
R4
499kΩ
ADD
R5
301kΩ
100nF
SW2
R3
499kΩ
EN
VCC
100
C5
ALT
SCL
I C slave
SDA
VCC
2
C3
1µF
AGND
GND
R1
21.5kΩ
+
C2
100µF
EFFICIENCY (%)
+
VIN = 12V, VOUT = 5V to 20V, L = 4.7µH,
RDC = 19.5mΩ, forced PWM mode
4.7µH
90
85
80
75
Vo=12V
Vo=20V
Vo=9V
Vo=5V
70
65
OC
C6
22nF
60
0.01
0.1
1
10
OUTPUT CURRENT (A)
MP8862 Rev 1.0
5/30/2019
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© 2019 MPS. All Rights Reserved.
2
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
ORDERING INFORMATION
Part Number*
MP8862GQ-xxxx**
MP8862GQ-0000
EVKT-MP8862
Package
QFN-16 (3mmx3mm)
QFN-16 (3mmx3mm)
Evaluation kit
Top Marking
See Below
See Below
* For Tape & Reel, add suffix –Z (e.g. MP8862GQ-XXXX–Z).
** “xxxx” is the configuration code identifier for the register setting stored in the OTP. The default number is “0000”.
Each “x” can be a hexadecimal value between 0 and F. Please work with an MPS FAE to create this unique
number, even if ordering the “0000” code. MP8862GQ-0000 is the default version.
TOP MARKING
BJT: Product code of MP8862GQ
Y: Year code
LLL: Lot number
EVALUATION KIT EVKT-MP8862
EVKT-MP8862 kit contents (items below can be ordered separately):
#
Part Number
Item
Quantity
1
EV8862-Q-00A
MP8862GQ-0000 evaluation board
1
2
EVKT-USBI2C-02
Includes one USB to I2C communication interface, one
USB cable, and one ribbon cable
1
Order directly from MonolithicPower.com or our distributors.
Input Power
Supply
Input
GUI
USB Cable
USB to I2C
Communication
Interface
Ribbon Cable
EV8862-Q-00A
Output
Load
Figure 1: EVKT-MP8862 Evaluation Kit Set-Up
MP8862 Rev 1.0
5/30/2019
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3
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
PACKAGE REFERENCE
TOP VIEW
BST1 SW1
16
IN
SW2
BST2
OUT
1
GND
GND
AGND
EN
VCC
ADD
SCL
SDA
OC
ALT
QFN-16 (3mmx3mm)
PIN FUNCTIONS
Pin #
Name
1
IN
2, 11
GND
3
EN
4
ADD
5
6
7
8
9
10
12
SCL
SDA
OC
ALT
VCC
AGND
OUT
13
BST2
14
SW2
15
SW1
16
BST1
MP8862 Rev 1.0
5/30/2019
Description
Supply voltage. IN is the drain of the internal power device and provides power to the
entire chip. The MP8862 operates from a 2.8V to 22V input voltage. A capacitor (CIN) is
required to prevent large voltage spikes from appearing at the input. Place CIN as close to
the IC as possible.
Power ground. GND is the reference ground of the regulated output voltage. GND
requires extra care during PCB layout. Connect GND with copper traces and vias.
On/off control for entire chip. Drive EN high to turn on the chip. Drive EN low or float
EN to turn off the device. EN has an internal 2MΩ pull-down resistor to ground.
I2C slave addresses program pin. Connect a resistor divider from VCC to ADD to set
four different I2C slave addresses.
Clock pin of the I2C interface. SCL can support an I2C clock up to 3.4MHz.
Data pin of the I2C interface.
Output constant current limit set pin.
Alert output. ALT pulling to logic low indicates that a fault or warning has occurred.
Internal 3.65V LDO regulator output. Decouple VCC with a 1µF capacitor.
Analog ground. Connect AGND to GND.
Output power pin. Place the output capacitor close to OUT and GND.
Bootstrap. Connect a 0.1µF capacitor between SW2 and BST2 to form a floating supply
across the high-side switch driver.
Switching node of the second half-bridge. Connect one end of the inductor to SW2 for
the current to run through the bridge.
Switching node of the first half-bridge. Connect one end of the inductor to SW1 for the
current to run through the bridge.
Bootstrap. Connect a 0.1µF capacitor between SW1 and BST1 to form a floating supply
across the high-side switch driver.
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4
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
θJA
θJC
ABSOLUTE MAXIMUM RATINGS (2)
Thermal Resistance
Supply voltage (VIN, VOUT) ........................... 24V
VSW1, SW2 ............................ -0.3V (-7V for VOUT)
When the input voltage is significantly higher
than the output voltage, the MP8862 works in
buck mode. In buck mode, SWA and SWB
switch for buck regulation. SWC is off, and
SWD remains on to conduct the inductor
current.
SWA works with COT control logic, and SWB
turns on as a complement to SWA. In each
cycle, SWB turns on to conduct the inductor
current. When the inductor current drops to the
COMP voltage (VCOMP), SWB turns off, and
MP8862 Rev 1.0
5/30/2019
Figure 6: Boost Waveform
Buck-Boost Mode (VIN ≈ VOUT)
When VIN is close to VOUT, the converter may be
unable to provide enough energy to operate in
buck mode due to SWA’s minimum off time, or
the converter may supply too much power to
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19
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
VOUT in boost mode due to SWC’s minimum on
time. The MP8862 uses buck-boost control to
regulate the output in these conditions.
In buck mode, if VIN falls and the SWA off
period is close to the buck minimum off time,
buck-boost mode is engaged. When the next
cycle starts after the SWA and SWD on period
(buck high-side MOSFET (HS-FET) on period),
boost starts with SWA and SWC on (boost lowside MOSFET (LS-FET) on). SWA and SWD
turn on again for the rest of the boost period
(boost HS-FET on). After the boost period
elapses, the buck period starts, and SWB and
SWD remain on until the inductor current drops
to VCOMP. Then SWA and SWD turn on until the
next boost period begins. Buck and boost
switching work with a one-interval period. This
is called buck-boost mode.
In boost mode, if VIN rises and the SWC on
period is close to the boost minimum on time,
buck-boost mode is engaged. After the boost
constant-off-time period (SWA and SWD on),
SWB and SWD remain on until the inductor
current signal drops to VCOMP, just like a buck off
period control. After the inductor current signal
triggers VCOMP, SWA and SWD turn on for the
buck on time, which is followed by a boost
switching (SWA and SWC on). Buck and boost
switching work with a one-interval period.
Figure 7 shows the buck-boost waveform for
both VIN > VOUT and VIN < VOUT.
SW1
tBoo st-Min
SW2
Buck Min Off Time
IL
COMP
Buck Buck-Boo st
tBuck-Boo st
Buck to Buck-Boost Transient
SW1
tBuck-Min
SW2
Boo st Min On Time
COMP
IL
Boo st Buck-Boo st
tBuck-Boo st
Boost to Buck-Boost Transient
Figure 7: Buck-Boost Waveform
In buck-boost mode, if VIN exceeds 130% of
VOUT, the MP8862 switches from buck-boost
mode to buck mode. If VIN is below 20% of VIN,
it switches from buck-boost mode to boost
mode.
Working Mode Selection
The MP8862 works with a fixed frequency in
heavy-load condition. When the load current
decreases, the MP8862 can work in forced
continuous conduction mode (FCCM) or pulseskip mode (PSM) based on the MODE register
setting.
FCCM (or Forced PWM)
In FCCM condition, the buck on time and boost
off time are determined by the internal circuit to
achieve a fixed frequency based on the VIN/VOUT
ratio. When the load decreases, the average
input current drops, and the inductor current
may go negative from VOUT to VIN during the off
time (SWD on). This forces the inductor current
to work in continuous mode with a fixed
frequency, producing a lower VOUT ripple than in
PSM mode.
PSM (Auto PFM/PWM Mode)
In PSM condition, once the inductor current
drops to 0A, SWD turns off to prevent the
current from flowing from VOUT to VIN, forcing the
inductor current to work in discontinuous
conduction mode (DCM). Simultaneously, the
internal off-time clock stretches once the
MP8862 enters DCM mode. The frequency
drops when the inductor current conduction
period decreases, helping to save power loss
and reduce the VOUT ripple.
If VCOMP drops to the PSM threshold, even if the
IC stretches the frequency, the MP8862 stops
switching to decrease switching power loss.
MP8862 Rev 1.0
5/30/2019
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20
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
The MP8862 recovers switching once VCOMP
rises above the PSM threshold. The switching
pulse skips based on VCOMP in very light-load
condition. PSM has a much higher efficiency
than FCCM mode in light load, but the VOUT
ripple may be higher due to the group switching
pulse.
Internal VCC Regulator
The 3.65V internal regulator powers most of the
internal circuitries. This regulator takes VIN and
operates in the full VIN range. When VIN
exceeds 3.65V, the output of the regulator is in
full regulation. If VIN is less than 3.65V, the
output decreases with VIN. VCC requires an
external 1µF ceramic capacitor for decoupling.
Enable Control (EN)
The MP8862 has an enable control pin (EN).
Pull EN high to enable the IC. Pull EN low or
float EN to disable the IC.
If EN is pulled down when the output discharge
function is enabled, the MP8862 completely
shuts down after 55ms. The MP8862’s I2C
register value is reset to default only after the
MP8862 completely shuts down. If EN is pulled
high within 55ms, the I2C register is not reset,
and the MP8862 enables the output with
previous register setting.
If the output discharge function is disabled, the
MP8862 completely shuts down once EN is
pulled down for more than 100µs, and the
MP8862 I2C register is reset after a 100µs
delay.
VOUT = 12V (I2C Setting)
VOUT = 12V (I2C Setting)
VOUT = 5V (I2C Reset)
EN
EN Off
< 55ms
EN Off > 55ms
Figure 8: EN On/Off Logic for I2C Register Reset
Under-Voltage Lockout (UVLO)
Under-voltage lockout (UVLO) protects the chip
from operating at an insufficient supply voltage.
The UVLO comparator monitors the input
voltage and enables or disables the entire IC.
MP8862 Rev 1.0
5/30/2019
Internal Soft Start (SS)
Soft start (SS) prevents the converter output
voltage from overshooting during start-up.
When the chip starts up, the internal circuitry
generates a SS voltage that ramps up from 0V
to 3.6V. When SS is lower than VREF, the error
amplifier uses SS as the reference. When SS is
higher than VREF, the error amplifier uses VREF
as the reference.
If the output of the MP8862 is pre-biased to a
certain voltage during start-up, the IC disables
the switching of both the high-side and low-side
switches until the voltage on the internal SS
capacitor exceeds the internal feedback voltage
(see Figure 9).
EN
90%
VOUT
tDELA Y
Figure 9: EN On to VOUT > 90% Delay
Output Constant Current Limit (OCP)
The MP8862 has a constant-current limit
control loop to limit the output average current.
The current information is sensed from switches
A, B, C, and D. Then an average algorithm is
used to calculate the output current.
When the output current exceeds the currentlimit threshold, the output voltage starts to drop.
If VOUT drops below the under-voltage (UV)
threshold (typically 50% below the reference),
the MP8862 enters hiccup mode or latch-off
mode, according to the I2C setting.
In hiccup mode, the MP8862 stops switching
and recovers automatically with 12.5% duty
cycles. In latch-off mode, the MP8862 stops
switching until the IC restarts (VIN, EN, or EN bit
toggle).
Over-Voltage Protection (OVP)
The MP8862 monitors a resistor-divided
feedback voltage to detect output over-voltage.
When the feedback voltage exceeds 160% of
the target voltage, the over-voltage protection
(OVP) comparator output goes high, and the
output-to-ground discharge resistor turns on.
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21
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
The OUT pin has an absolute OVP function.
Once VOUT is higher than the absolute OVP
threshold (23V), the MP8862 stops switching
and turns on the OUT-to-ground discharge
resistor.
Start-Up and Shutdown
If both VIN and EN exceed their respective
thresholds, the chip is enabled. The reference
block starts first, generating a stable reference
voltage and current, and then the internal
regulator is enabled. The regulator provides a
stable supply for the remaining circuitries.
Three events can shut down the chip: EN low,
VIN low, and thermal shutdown. During
shutdown, the signaling path is blocked to avoid
any fault triggering. Then VCOMP and the internal
supply rail are pulled down. The floating driver
is not subject to this shutdown command.
Output Discharge
The MP8862 has an output discharge function
that provides a resistive discharge path for the
external output capacitor. The function is active
when the part is disabled (input voltage is under
UVLO or EN is off), and the discharge path is
turned off when VOUT < 50mV or the 50ms
maximum timer passes. This function can also
be disabled via the I2C.
Over-Temperature Warning (OTW) and
Thermal Shutdown (TSD)
Thermal warning and thermal shutdown prevent
the part from operating at exceedingly high
temperatures. When the silicon die temperature
exceeds 120°C, the MP8862 sets the OTW
bit[D5] to 1. When the temperature falls below
its lower threshold (typically 100°C), the OTW
bit[D5] is 0.
When the silicon die temperature exceeds
150°C, the entire chip shuts down. When the
temperature falls below its lower threshold
(typically 130°C), the chip is enabled. This is a
non-latch protection.
I2C INTERFACE
I2C Serial Interface Description
The I2C is a 2-wire, bidirectional, serial interface
consisting of a data line (SDA) and a clock line
(SCL). The lines are pulled to a bus voltage
externally when they are idle. When connecting
to the line, a master device generates the SCL
signal and device address, and arranges the
communication sequence.
The MP8862
interface is an I2C slave that supports fast mode
(400kHz) and high-speed mode (3.4MHz). The
I2C interface adds flexibility to the power supply
solution. The output voltage, transition slew
rate, and other parameters can be controlled
via the I2C interface. When the master sends
the address as an 8-bit value, the 7-bit address
should be followed by a 0 or 1 to indicate a
write or read operation.
Start and Stop Conditions
The start and stop conditions are signaled by
the master device, which signifies the beginning
and end of an I2C transfer. The start condition is
defined as the SDA signal transitioning from
high to low while the SCL is high. The stop
condition is defined as the SDA signal
transitioning from low to high while the SCL is
high (see Figure 10). The master then
generates the SCL clocks and transmits the
device address and read/write direction bit
(R/W) on the SDA line.
Transfer Data
Data is transferred in 8-bit bytes by an SDA
line. Each byte is followed by an acknowledge
bit.
I2C Update Sequence
The MP8862 requires a start condition, a valid
I2C address, a register address byte, and a data
byte for a single data update. The MP8862
acknowledges the receipt of each byte by
pulling the SDA line low during the high period
of a single clock pulse. A valid I2C address
selects the part. It performs an update on the
falling edge of the LSB byte. Page 23 shows
examples of an I2C write and read sequence.
I2C Start-Up Timing
The I2C function is enabled when VIN > UVLO
and EN is active. The function continues to
work during OCP, OVP, and thermal shutdown.
MP8862 Rev 1.0
5/30/2019
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22
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
Figure 10: Start and Stop Condition
8 bits
8 bits
S Slave Address
8 bits
WR A Register Address K A Write Data A P
Master to Slave
A = Acknowledge (SDA = LOW)
S = Start Condition
WR Write = 0
Slave to Master
NA = NOT Acknowledge (SDA = HIGH)
P = Stop Condition
RD Read = 1
I2C Write Example – Write Single Register
8 bits
8 bits
8 bits
S Slave Address WR A Register Address K A Write Data K A Write Data K+1 A
Write Data K+N A P
Multi-byte write executed from current register location
(the read-only register will be skipped)
Master to Slave
A = Acknowledge (SDA = LOW)
S = Start Condition
WR Write = 0
Slave to Master
NA = NOT Acknowledge (SDA = HIGH)
P = Stop Condition
RD Read = 1
I2C Write Example – Write Multi Register
8 bits
S Slave Address
8 bits
WR A Register Address K A Sr
Register address to read specified
8 bits
8 bits
Slave Address
RD
A Read Data K NA P
Read register data from current register location
Master to Slave
A = Acknowledge (SDA = LOW)
S = Start Condition
Slave to Master
NA = NOT Acknowledge (SDA = HIGH)
P = Stop Condition
Sr = Repeat
Start Condition
WR Write = 0
RD Read = 1
I2C Read Example – Read Single Register
MP8862 Rev 1.0
5/30/2019
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23
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
I2C REGISTER MAP
ADD
(HEX)
NAME
R/W
00
VOUT_L
R/W
01
VOUT_H
R/W
02
VOUT_GO
R/W
03
IOUT_LIM
R/W
04
CTL1
R/W
05
06
07
08
09
CTL2
RESERVED
RESERVED
RESERVED
Status
R/W
R
R
R
R
0A
Interrupt
W1C
0B
Mask
R/W
0C
27
28
29
ID1
MFR_ID
DEV_ID
IC_REV
R
R
R
R
D7
D6
D5
D4
D3
Reserved
D2
D1
D0
VOUT DATA BIT LOW [2:0]*
VOUT DATA BIT HIGH [10:3]*
PG_
GO_
DELAY_
BIT
EN*
OUTPUT CURRENT LIMIT THRESHOLD (0A-4A/50mA STEP FOR 21.5K OC
Reserved
RESISTOR)*
HICCUP
DISCHG
EN*
MODE*
FREQ
Reserved
OCP_OVP*
_EN*
LINE DROP COMP*
SS*
Reserved
Reserved, ALL “0”
Reserved
Reserved
Reserved
PG
OTP
OTW
CC_CV
Reserved
OT
OT
PG_
OTEMPP_
OC_
OC_
UVP_
OTEMP
WARNING_
WARNING
RISING
ENTER
ENTER
RECOVER
FALLING
P_EXIT
ENTER
_EXIT
RESERVED
OTWMSK*
OC_
UVP_
PG_
OTPMSK*
MSK*
MSK*
MSK*
OTP configure code. "0x00" means standard MP8862, “0x01” means MP8862-0001 part number*
MANUFACTURER ID: b ‘0000 1001’
DEVICE ID: b ‘0101 1000’
IC REVISION: b ‘0000 0001’
RESERVED
Note:
* These items have one-time programmable (OTP) non-volatile memory. The OTP is reloaded to the I2C register during VIN > UVLO or EN
shutdown.
MP8862 Rev 1.0
5/30/2019
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24
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
REGISTER DESCRIPTION
I2C Bus Slave Address
A resistor-divider from VCC to GND can achieve an accurate reference voltage. Connect ADD to this
reference voltage to set different I2C addresses. The internal circuit changes the I2C address
accordingly. Table 1 shows the four voltage thresholds for the four I2C addresses, and recommended
resistor settings.
Table 1: I2C Address Setting via ADD Voltage
ADD Voltage
ADD Upper
Resistor R4
(kΩ)
ADD Lower
Resistor R5
(kΩ)
Binary
Hex
75% VCC
100
No connection
1101 111
6FH
I2C Address
VOUT Setting
The registers VOUT_L and VOUT_H set the output voltage and follow the 11-bit direct format below.
Name
Format
Register Name
Bit
Access
Function
Default Value
(5V)
VOUT
Direct, unsigned binary integer
VOUT_H D[7:0]
N/A
15
14
13
N/A
N/A
12
11
VOUT_L D[2:0]
10
9
8
7
6
5
4
3
2
1
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Data bit high
N/A
Data bit low
500 integer
The output voltage can be calculated with Equation (1):
VOUT (V) = V / 100
(1)
Where V is an 11-bit unsigned binary integer of VOUT[10:0], and V ranges from 0 to 2047. The VOUT
resolution is 10mV/LSB.
Inside the MP8862, there is a feedback resistor network from OUT to the internal FB reference voltage.
The feedback resistor ratio is VOUT / VFB = 12.5. The output voltage change slew rate is fixed at 1mV/µs.
Refer to the GO_BIT bit when implementing the output voltage change.
VOUT_GO Register
GO_BIT D[0]
The MP8862 can be controlled when to VOUT begins to change. Set GO_BIT to 1 to start the output
change based on the VOUT register. When the VOUT change is complete (internal VREF steps to the goal
of VREF), GO_BIT auto-resets to 0. This prevents a false operation of the VOUT scaling.
Write the output voltage (0x00 and 0x01 registers) first, and then write GO_BIT = 1. VOUT changes
based on the new register setting. GO_BIT resets to 0 when VOUT reaches a new value. The host can
read GO_BIT to determine if the VOUT scaling is finished or not.
The VOUT-to-ground discharge function is enabled when GO_BIT is 1. This can help ramp VOUT from
high to low in light-load condition.
When GO_BIT is 0, VOUT will not change. When GO_BIT is 1, VOUT changes based on the VOUT register
setting. After VOUT scaling finishes, GO_BIT is reset to 0 automatically.
MP8862 Rev 1.0
5/30/2019
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MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
PG_DELAY_EN D[1]
When PG_DELAY_EN D[1] is 0, there is no delay on PG. When PG_DELAY_EN D[1] is 1, PG
experiences a 100µs rising delay. The default value is 0.
IOUT_LIM Register
Set the output current limit threshold.
Name
IOUT_LIM
Format
Direct, unsigned binary integer
Bit
7
6
5
4
3
2
1
0
Access
N/A
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Default Value (3A)
N/A
60 integer
IOUT_OC can be calculated with Equation (2):
IOUT_OC (A) = IOUT_LIM * 0.05
(2)
Where IOUT_LIM is a 7-bit unsigned binary integer of IOUT_LIM D[6:0]. The IOUT_OC resolution is
50mA/LSB (maximum value is 4A or 0x50).
The OC pin-to-ground resistor should be 21.5kΩ when using the above IOUT_LIM register. A 22nF
(C6) filter capacitor should be added on OC to keep the CC loop stable. The MP8862 directly supports
the I2C setting IOUT_LIM. If the CC threshold needs to be changed dynamically after the MP8862 has
already entered the CC limit operation state, it is recommended to change the CC threshold step-bystep (e.g. 50mA per step) instead of changing the current value directly to the final value.
CTL1 Register
NAME
BITS
DEFAULT
DESCRIPTION
I2C-controlled, turns the part on or off. When the external EN pin is low, the
converter is off, and the I2C shuts down. When EN is high, the EN bit takes over.
EN
D[7]
1
HICCUP
OCP_OVP
D[6]
1
1: Hiccup mode
0: Latch-off mode
Output discharge enable bit.
DISCHG_EN
D[5]
1
1: Output discharge function during EN or VIN shutdown
0: No discharge output during shutdown
Default is PWM mode for light load.
MODE
D[4]
1
0: Enables auto PFM/PWM mode
1: Sets forced PWM mode
Sets the switching frequency.
FREQ
D[3:2]
00
MP8862 Rev 1.0
5/30/2019
1: Part is turned on. Default
0: Part is turned off. I2C register does not reset
Over-current and over-voltage protection mode selection.
00: 500kHz
01, 10, 11: Reserved
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MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
CTL2 Register
NAME
BITS
DEFAULT
DESCRIPTION
Sets the output voltage compensation vs. the load feature.
LINE
DROP
COMP
D[7:6]
00
00: No compensation
01: VOUT compensates 100mV @ 2A IOUT
10: VOUT compensates 200mV @ 2A IOUT
11: VOUT compensates 400mV @ 2A IOUT
The above compensation amplitude is fixed for any output voltage. Line drop
compensation is only enabled for VOUT ≥ 5V.
Sets the output start-up soft-start timer (from 0 to 100%). For 5V output voltage:
SS
D[5:4]
11
00: 300µs
01: 500µs
10: 700µs
11: 900µs
The SS slew rate is constant, but changes for different VOUT values.
Status Register
NAME
BITS
DEFAULT
DESCRIPTION
PG
D[7]
X
0: Output power is not good
1: Output power is good
Over-temperature protection indication.
OTP
D[6]
X
0: Normal state
1: Chip is in over-temperature protection state
Over-temperature warning indication.
Output power good indication.
OTW
D[5]
X
CC_
CV
D[4]
X
0: Normal state
1: Chip is in-over temperature warning state
The chip works in constant-current output mode or constantvoltage output mode.
These status bits
indicate instantaneous
value.
0: CV mode
1: CC mode
Interrupt Register
NAME
BITS
OTEMPP_
ENTER
D[7]
OTWARNING_
ENTER
D[6]
OC_ENTER
D[5]
OC_RECOVER
D[4]
UVP_FALLING
D[3]
OTEMPP_EXIT
D[2]
OTWARNING_
EXIT
D[1]
PG_RISING
D[0]
MP8862 Rev 1.0
5/30/2019
DESCRIPTION
Over-temperature protection entry indication. When this bit is high,
the IC enters thermal shutdown. This bit is not masked, even if
OTPMSK = 1. OTPMSK = 1 only masks the interrupt pin’s output
(ALT).
Die temperature early warning entry bit. When this bit is high, the die
temperature is above 120˚C. This bit is not masked, even if
OTWMSK = 1. OTWMSK = 1 only masks the interrupt pin’s output
(ALT).
Entry of OC or CC current-limit mode. The OC_MSK bit can enable
or disable OC_ENTER and OC_RECOVER alert output.
Recovery from CC current-limit mode. Recovering from a hiccup will
not trigger this interrupt signal.
Output voltage is in under-voltage protection.
Over-temperature protection exit. OTPMSK can mask off the ALT of
this bit.
Die temperature early warning exit bit. When the die temperature is
lower than 100°C, this bit is set to 1. This bit is not masked, even if
OTWMSK = 1. OTWMSK = 1 only masks the interrupt pin’s output
(ALT).
Output power good rising edge.
This bit is latched once
triggered.
Write 0xFF to this
register to reset the
interrupt (ALT) pin’s
state.
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MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
MSK Register
NAME
BITS
DEFAULT
OTPMSK
D[4]
0
OTWMSK
OC_MSK
UVP_MSK
D[3]
D[2]
D[1]
0
0
0
PG_MSK
D[0]
0
DESCRIPTION
SET OTPMSK = 1 to mask off the OTP alert. OTPMSK = 1 only masks the interrupt
pin’s output (ALT). This is not the interrupt register, but is similar for other mask bits.
Masks off the over-temperature warning.
Masks off both OC/CC entry and recovery.
Masks off the output UVP interrupt.
Masks off the PG indication function on ALT.
1: ALT pin does not indicate a PG event
0: ALT indicates a PG rising event
OTEMPP_ENTER
OTWARNING_ENTER
OC_ENTER
Event
ALT Pin
Active Low
Write 0xFF to 0A Reg Can
OTEMPP_EXIT
Reset ALT Pin
OTWARNING_EXIT
OC_RECOVER
Event
Figure 11: ALT Behavior of OTP, OT Warning, and OC Recovery
MP8862 Rev 1.0
5/30/2019
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28
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
APPLICATION INFORMATION
Component Selection
Selecting the Inductor
In a buck-boost topology circuit, the inductor
must support buck applications with the
maximum input voltage, and boost applications
with the minimum input voltage. Two critical
inductance values can be determined according
to the buck mode and boost mode current ripple
using Equation (2) and Equation (3):
LMINBUCK
LMINBOOST
VOUT (VIN(MAX) VOUT )
VIN(MAX) fREQ IL
VIN(MIN) (VOUT VIN(MIN) )
VOUT fREQ IL
(2)
(3)
Where fREQ is the switching frequency, and ∆IL
is the peak-to-peak inductor current ripple. As a
rule of thumb, the peak-to-peak ripple can be
set as 0.5A to 1.5A of the inductor current. The
minimum inductor value for the application must
be higher than both the Equation (2) and
Equation (3) results.
Input and Output Capacitor Selection
It is recommended to use ceramic capacitors
plus an electrolytic capacitor for input and
output capacitors, to filter the input and output
ripple current and achieve stable operation.
Since the input capacitor absorbs the input
switching current, it requires sufficient
capacitance. For most applications, a 100µF
electrolytic capacitor plus a 22µF ceramic
capacitor are sufficient.
The output capacitor stabilizes the DC output
voltage. Low-ESR capacitors and a sufficient
capacitor value are recommended to limit the
output voltage ripple. Considering the ceramic
DC voltage derating, if the output voltage is less
than 12V, the minimum COUT should be 22µFx5
ceramic. If the output voltage is greater than
12V, use a 100µF low-ESR (≤80mΩ) aluminum
electrolytic or polymer capacitor and two 10µF
ceramic capacitors.
The input and output ceramic capacitors must
be placed as close as possible to the device.
In addition to the inductance value, to avoid
saturation, the inductor must support the peak
current based on Equation (4) and Equation (5):
IPEAK BUCK IOUT
IPEAK BOOST
VOUT (VIN(MAX) VOUT )
2 VIN(MAX) fREQ L
(4)
VOUT IOUT VIN(MIN) (VOUT VIN(MIN) )
(5)
VIN(MIN)
2 VOUT fREQ L
Where η is the estimated efficiency of the
MP8862.
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1. Place the ceramic CIN and COUT capacitors
close to the IC’s VIN-to-GND and OUT-toGND pins, respectively.
L1
SW2
PCB Layout Guidelines (9)
Efficient PCB layout is critical for stable
operation and thermal dissipation. For best
results, refer to Figure 12 and follow the
guidelines below:
SW1
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
OUT
VIN
2. Use a large copper plane for PGND.
GND
3. Add multiple vias to improve thermal
dissipation.
4. Connect AGND to PGND.
5. Use short, direct, and wide traces to
connect OUT.
Top Layer
6. Add vias under the IC and routing the OUT
trace on both PCB layers (highly
recommended).
SW1
8. Place the VCC decoupling capacitor as
close to VCC as possible.
Notes:
9)
The recommended layout is
Application Circuits on page 31.
based
on
the
Typical
VIN
SW2
L1
7. Use a large copper plane for SW1 and SW2.
OUT
GND
Close-Up of Layout
Figure 12: Recommended Layout
MP8862 Rev 1.0
5/30/2019
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MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
TYPICAL APPLICATION CIRCUITS
0 R6
C4
100nF
16
VIN
2.8V-22V
1
C1
100µF
+
C1B
22µF
IN
BST2
C1A
0.1µF
SW2
OUT
R3
499kΩ
3
4.7µH
0 R7
13
VOUT
1V-20V
C5
100nF
14
12
EN
C2A
0.1µF
MP8862
C7
22nF
VCC
L1
15
SW1
BST1
C2B
10µF
C2C
10µF
+ C2
100µF
EMZJ350ARA101MHA
1.8V
R4
499kΩ
4
ADD
9
R5
301kΩ
VCC
C3
1µF
AGND
10
R1
100kΩ
8
5
6
ALT
I2C Slave SCL
SDA
OC
GND
2, 11
7
C6
22nF
R2
21.5kΩ
Figure 13: Typical Application Circuit for 1V-20VOUT
Note: Refer to the recommended maximum IOUT vs. VIN and VOUT with 120μF low-ESR COUT capacitor curve on page 9.
0 R6
C1
100µF
100nF
16
VIN
2.8V-22V
+
C4
1
C1B
22µF
BST1
SW1
IN
BST2
C1A
0.1µF
SW2
OUT
R3
499kΩ
3
13
4.7µH
0 R7
VOUT
1-12V
C5
100nF
14
12
EN
C2A
0.1µF
MP8862
C7
22nF
VCC
L1
15
C2B
22µF
C2C
22µF
C2D
22µF
C2E
22µF
C2F
22µF
1.8V
R4
499kΩ
R5
301kΩ
4
9
ADD
ALT
I2C Slave SCL
SDA
VCC
C3
1µF
AGND
10
GND
2, 11
R2
21.5kΩ
8
5
6
R1
100kΩ
OC
7
C6
22nF
Figure 14: Typical Application Circuit for 1V-12VOUT
Note: Refer to the recommended maximum IOUT vs. VIN and VOUT with 22μFx5 ceramic COUT capacitor curve on page 9.
MP8862 Rev 1.0
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31
MP8862 – 22V VIN, 2A IOUT, INTEGRATED BUCK-BOOST WITH I2C INTERFACE
PACKAGE INFORMATION
QFN-16 (3mmx3mm)
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.
MP8862 Rev. 1.0
5/30/2019
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