MP157
Smallest Energy Efficient Off-line
Regulator with Extended Power Range
The Future of Analog IC Technology
DESCRIPTION
FEATURES
MP157 is a primary side regulator providing
accurate constant voltage (CV) regulation
without the Opto-coupler. It supports Buck,
Buck-Boost, Boost and Flyback topologies. A
500V MOSFET is integrated in the regulator, so
very simple structure and low cost can be
achieved. These features make MP157 an ideal
solution for off-line low power applications.
Typical applications include home appliance,
standby power and industrial control.
MP157 is a green mode operation regulator.
When the load decreases, the peak current and
the switching frequency decrease with the load.
As a result, it still offers excellent efficiency
performance at light load, thus better average
efficiency is achieved.
MP157 features various protections like
Thermal Shutdown (TSD), VCC under Voltage
Lockout (UVLO), Over Load Protection (OLP),
Short Circuit Protection (SCP), Open Loop
Protection.
MP157 is available in the TSOT23-5 and
SOIC8 packages.
Primary side constant voltage (CV) control,
supporting Buck, Buck-Boost, Boost and
Flyback topologies
Integrated 500V/10Ω MOSFET
< 100mW No-load power consumption
Up to 6W output power
Maximum discontinuous conduction mode
(DCM) output current less than 225mA,
maximum continuous conduction mode
(CCM) output current less than 360mA
Low Vcc Operating Current
Frequency Foldback
Limited maximum frequency
Peak Current Compression
Internal High Voltage Current Source
Internal 400ns Leading Edge Blanking
Thermal Shutdown (auto restart)
VCC Under Voltage Lockout with Hysteresis
(UVLO)
Timer based Over Load Protection
Short Circuit Protection
Open Loop Protection
APPLICATIONS
Home Appliances, White Goods and
Consumer Electronics
Industrial Controls
Standby Power
All MPS parts are lead-free, halogen free, and adhere to the RoHS
directive. 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.
MP157 Rev. 1.04
6/27/2016
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
TYPICAL APPLICATION
MP157 Rev. 1.04
6/27/2016
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
ORDERING INFORMATION
Part Number*
MP157GJ
MP157GS
Package
TSOT23-5
SOIC-8
Top Marking
See Below
See Below
* For Tape & Reel, add suffix –Z (e.g. MP157GJ–Z);
* For Tape & Reel, add suffix –Z (e.g. MP157GS–Z);
TOP MARKING (MP157GJ)
AFC: product code of MP157GJ;
Y: year code;
TOP MARKING (MP157GS)
MP157: product code of MP157GS;
MPS: MPS prefix:
Y: year code;
WW: week code:
LLLLLLLL: lot number;
MP157 Rev. 1.04
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
PACKAGE REFERENCE
TOP VIEW
VCC
1
FB
2
SOURCE
3
TOP VIEW
5
4
DRAIN
SOURCE
TSOT23-5
VCC
1
8
N/C
FB
2
7
DRAIN
SOURCE
3
6
N/C
SOURCE
4
5
N/C
SOIC-8
ABSOLUTE MAXIMUM RATINGS (1)
Thermal Resistance
Drain to SOURCE .........................-0.3V to 500V
All the other Pin .............................-0.3V to 6.5V
(2)
Continuous Power Dissipation (TA = +25°C)
TSOT23-5 ..................................................... 1W
SOIC8 ........................................................... 1W
Junction Temperature ...............................150C
Lead Temperature ....................................260C
Storage Temperature............... -60C to +150C
ESD Capability Human Body Mode .......... 2.0kV
ESD Capability Machine Mode .................. 200V
TSOT23-5.............................. 100 ..... 55... °C/W
SOIC-8.................................... 96 ...... 45... °C/W
Recommended Operating Conditions
(3)
Operating Junction Temp. (TJ). -40°C to +125°C
Operating VCC range ...................4.45V to 4.6V
MP157 Rev. 1.04
6/27/2016
(4)
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 PCB.
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
ELECTRICAL CHARACTERISTICS
VCC = 5V, TA = 25C, unless otherwise noted.
Parameter
Symbol
Condition
Min
Typ
Max
Units
VCC=4V;VDrain=100V
VCC=5V;Vdarin=400V
2.5
-500
3.5
10
--
4.5
25
--
mA
μA
V
4.5
4.6
4.9
V
4.3
4.45
4.7
V
--
230
--
mV
3.2
3.35
3.5
V
2.05
2.35
2.65
V
--
--
500
μA
--
--
165
uA
--
16
--
μA
VBRDSS
500
--
--
V
Ron
--
10
--
Ω
Peak Current Limit
ILimit
500
640
780
mA
Leading edge blanking
TLEB1
--
400
--
ns
SCP point
Leading edge blanking for SCP (5)
Feedback input (FB Pin)
Minimum off time
Feedback Threshold to turn on the
primary MOSFET
Feedback Threshold to trigger the
OLP
Over Load Protection Delay time
Open loop detection
Thermal Shutdown
ISCP
TLEB2
---
900
180
1200
--
mA
ns
Tminoff
10.6
13.1
15.6
us
VFB
2.45
2.55
2.65
V
VFB_OLP
1.6
1.7
1.8
V
---
150
60
---
ms
mV
--
150
--
ºC
Start-up Current Source (Drain Pin)
Internal regulator supply current
Iregulator
Leakage Current from Pin Drain
ILeak
Break Down Voltage
V(BR)DSS
Supply Voltage Management (VCC Pin)
VCC Increasing Level at which the
VCCOFF
internal regulator stops
VCC Decreasing Level at which the
VCCON
internal regulator Turns-On
VCC Regulator on and off Hysteresis
VCC Decreasing level at which the IC
VCCstop
stops working
VCC Decreasing Level at which the
VCCpro
protection Phase Ends
Internal IC Consumption
ICC
Internal IC Consumption (No Switch)
Internal IC Consumption, Latch off
Phase
Internal MOSFET (Drain Pin)
Break Down Voltage
ICC
On-State resistance
ICCLATCH
VCC=4.6V, Fs=45kHz
Duty= 40%
VCC=4.6V
VCC=5V
Internal Current Sense
Thermal shutdown threshold (5)
TOLP
VOLD
Fs=37kHz
Notes:
5) Guarantee by Characterization
MP157 Rev. 1.04
6/27/2016
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
TYPICAL CHARACTERISTICS
Feedback Threshold
vs. Temperature
2.58
2.57
610
1.6
2.56
600
1.4
2.55
590
1.2
2.54
580
1.0
570
0.8
560
0.6
2.51
550
0.4
2.50
540
0.2
2.49
530
-40-25 -10 5 20 35 50 65 80 95 110125
0.0
-40 -25-10 5 20 35 50 65 80 95110 125
2.48
-40 -25-10 5 20 35 50 65 80 95110 125
VCC Increasing Level at
which the internal regulator
stops vs. Temperature
4.62
VFB (V)
1.8
4.86
VCC Decreasing Level at
which the internal regulator
Turns-On vs. Temperature
2.53
2.52
VCC Decreasing Level at
which the protection Phase
Ends vs. Temperature
2.60
4.60
2.55
4.82
4.58
2.50
4.80
4.56
2.45
4.78
4.76
4.74
4.72
VCCPRO (V)
4.84
4.54
4.52
4.50
4.48
2.40
2.35
2.30
2.25
4.70
4.46
2.20
4.68
4.44
2.15
4.66
-40-25 -10 5 20 35 50 65 80 95 110125
4.42
-40-25 -10 5 20 35 50 65 80 95 110125
2.10
-40-25-10 5 20 35 50 65 80 95 110125
Minimum Off Time
vs. Temperature
Peak Current Limit
vs. Temperature
SCP Point vs. Temperature
1200
680
13.7
670
1100
13.6
660
1000
13.5
650
900
640
800
ILIMIT (mA)
13.8
13.4
13.3
13.2
630
620
ISCP (mA)
VCCOFF (V)
2.0
On-State Resistance
vs. Temperature
620
VCCON (V)
VBVDSS (V)
630
Break Down Voltage
vs. Temperature
700
600
13.1
610
500
13.0
600
400
12.9
590
300
12.8
-40-25 -10 5 20 35 50 65 80 95110 125
580
-40-25 -10 5 20 35 50 65 80 95110125
200
-40-25-10 5 20 35 50 65 80 95110125
MP157 Rev. 1.04
6/27/2016
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 265VAC, VOUT = 12V, IOUT = 350mA, L = 1.2mH, COUT = 100μF, TA = +25°C, unless otherwise
noted.
Start Up
Normal Operation
SCP
VDS
100V/div.
VDS
100V/div.
VDS
100V/div.
IL
200mA/div.
IL
200mA/div.
IL
200mA/div.
Open Loop
VDS
100V/div.
IL
200mA/div.
MP157 Rev. 1.04
6/27/2016
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 230VAC, VOUT = 12V, IOUT = 350mA, L = 1.2mH, COUT = 100μF, TA = +25°C, unless otherwise
noted.
Input Power Start Up
Input Power Shut Down
SCP Entry
VDS
100V/div.
VDS
100V/div.
VDS
100V/div.
IL
200mA/div.
IL
200mA/div.
IL
200mA/div.
SCP Recovery
Open Loop Entry
Open Loop Recovery
VDS
100V/div.
VDS
100V/div.
VDS
100V/div.
IL
200mA/div.
IL
200mA/div.
IL
200mA/div.
Output Voltage Ripple
VRIPPLE
50mV/div.
Load Transient
VRIPPLE
100mV/div.
IOUT
200mA/div.
MP157 Rev. 1.04
6/27/2016
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
PIN FUNCTIONS
Pin #
TSOT23-5
1
2
3,4
5
MP157 Rev. 1.04
6/27/2016
Pin#
Name
SOIC8
1
VCC
2
FB
3,4
SOURCE
7
DRAIN
5,6,8
N/C
Description
Power supply of all the control circuit.
Feedback of the regulator.
Source of internal power MOSFET. Ground reference for VCC and FB pins.
Drain of internal power MOSFET. Input of high voltage current source.
Not connected.
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
FUNCTIONAL BLOCK DIAGRAM
Vcc
Drain
Start up unit
Power
Management
Driving Signal
Management
Feedback control
Peak current
Limitation
FB
Protection Unit
Source
Figure 1: Functional Block Diagram
MP157 Rev. 1.04
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
OPERATION
MP157 is a green mode operation regulator. With
the load decreasing, the peak current and the
switching frequency will both decreasing with the
load. As a result, it still offers excellent efficiency
performance at light load, thus better average
efficiency is achieved. As shown in the typical
application diagram, the regulator is designed to
operate with a minimum number of external
components. It incorporates the following
features as described in the following sections.
Start-up and Under Voltage Lock-out
The internal high voltage regulator self-supplies
the IC from the Drain pin. The IC starts switching
and the internal high voltage regulator turns off
as soon as the voltage on pin VCC reaches
VCCOFF (4.6V, typical). the internal high voltage
regulator turns on to charge the external Vcc
capacitor When the Vcc voltage decreases below
VCCON (4.45V, typical). So a small capacitor
such as several uF capacitor is enough to hold
on the voltage of Vcc and this can lower the cost
by decreasing the value of the capacitor.
When the voltage on Pin Vcc drops blow VCCstop
(3.3V, typical), the IC stops working, then the
internal high voltage regulator charges the Vcc
capacitor again.
When fault conditions happen, such as OLP,
SCP, and OTP, the IC stops working and an
internal current source, around 16uA, will
discharge the Vcc capacitor, before the Vcc
drops below VCCpro (2.4V, typical), the internal
high voltage regulator will not start to charge the
Vcc capacitor again. So when the fault conditions
happen, the restart time can be calculated by the
following equation,
t restart C VCC
VCC
VCCOFF=4.6V
VCCON =4.45V
VCCStop=3.3V
ON
Internal
Current
Source
OFF
Driving
Signal
Figure 2: VCC Under-Voltage Lock Out
Constant Voltage Operation
MP157 is a fully integrated regulator when used
in the Buck solution, as shown in the typical
application on page2.
At the beginning of each cycle, the integrated
MOSFET is turned ON when the feedback
voltage is below the reference voltage — 2.5V,
which indicates insufficient output voltage. The
ON period is determined by the peak current limit.
After the ON period elapses, the integrated
MOSFET is turned OFF. The Freewheeling diode
(D1) will not be turned ON until inductor (L1)
charges the voltage of the sampling capacitor
(C3) to equal the output voltage. The sampling
capacitor voltage changes along with the output
voltage. The sampling capacitor can sample and
hold the output voltage to keep the output voltage
regulated. The voltage of the sampling capacitor
will decrease when the current of inductor is
smaller than the output current. When the
feedback voltage falls below the internal
reference voltage — 2.5V, another switching
cycle begins. The detail operation in CCM is
shown as Figure 3.
VCC 2.4V
4.6V 2.4V
CVCC
16uA
3.5mA
Figure 2 shows the typical waveform with VCC
under voltage lock out.
MP157 Rev. 1.04
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
Minimum off time limitation
A minimum off time limitation is implemented.
During the normal operation, the minimum off
time limit is 13.1s, and during the start up
period, the minimum off time limit is shorten
gradually from 52.4s, 26.2s to 13.1s
(Shown as Figure 4). Each minimum off time
retains 128 switching cycle. This soft start
function provides safe start-up.
MOS
Diode
IL
Ipeak
Io
Vo
V FB
2.5V
Driver
Thus by monitoring the sampling capacitor, the
output voltage can be regulated, and the output
voltage is determined by the following equation:
Vout 2.5V
R1 R2
R2
Frequency Foldback
At the light load or no load conditions, the
output drops very slowly. This makes the
MOSFET OFF time increase. The frequency
decreases as the load decreases. So MP157
can maintain a high efficiency under light load
condition by reducing the switching frequency
automatically.
52.4us
13.1us
26.2us
128 Switching cycle 128 Switching cycle
Figure 4: tminoff at start-up
EA Compensation
FB
Comparator
+
EA
VFB
+
+
M
Figure 3: VFB Vs Vout
Vramp
+
Vramp
The switching frequency can be obtained as:
fs
(Vin Vo ) Vo
, For CCM
2L(Ipeak Io ) Vin
fs
2(Vin VO ) Io Vo
, for DCM
LI2peak
Vin
At the same time, the peak current limit starts to
decrease from 640mA as the off-time increases.
At standby mode, the frequency and the peak
current are both minimum, so smaller dummy
load could be added. As a result, peak current
compression function helps to save no load
consumption. The peak current limit can be
calculated by the following equation (Toff is the
off time of the power module):
Ipeak 640mA (3mA / s) (Toff 13.1s)
MP157 Rev. 1.04
6/27/2016
+
-
Vref
2.5V
Ipeak
Figure 5: EA and Ramp Compensation
To obtain a better load regulation, MP157
features EA (Error Amplifier) Compensation
function (Shown as Figure 5). After 6s delay of
MOSFET turning off, MP157 samples the
feedback
voltage.
So
with
the
EA
Compensation, the reference voltage— 2.5V
can be regulated with the load. This can make
better regulation of power module.
Ramp Compensation
To maintain the precise output voltage, an
internal ramp compensation circuit is added --an exponential voltage sinking source will be
added to pull down the reference voltage of the
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
feedback comparator which is also shown in
Figure 5. The ramp compensation is related
with the load conditions. At the full load
conditions, the compensation is about the
3mV/s. With the load decreases, the
compensation increases exponentially.
Over Load Protection (OLP)
As the load increases, the peak current and the
switching frequency both increase. When
switching frequency and peak current reaches
the maximum, output voltage decreases if the
load continues to increase. So FB voltage drops
below OLP point.
By continuously monitoring the FB voltage,
when FB voltage drops below 1.7V which is
considered as an error flag, the timer starts
counting. If the error flag removes, the timer
resets. If the timer reaches its completion when
it has counted to 150ms (Fs=37kHz), OLP
takes place. This timer duration avoids
triggering OLP function when the power supply
is at start up or load transition phase. So power
supply should start up in less than 150ms
(Fs=37kHz). Different switching frequency (fs)
leads to different over load protection delay
time, as shown following equation:
TDealy 150ms
Open Loop Detection
If the FB voltage is lower than 60mV, IC will
stop working and a re-start cycle will begin.
During the start up, the open loop detection is
blanked for 128 switching cycles.
Leading Edge Blanking
In order to avoid the premature termination of
the switching pulse due to the parasitic
capacitance, an internal leading edge blanking
(LEB) unit is employed between the current
sense resistor inside the IC and the current
comparator input. During the blanking time, the
current comparator is disabled and can not turn
off the external MOSFET. Figure 6 shows the
leading edge blanking.
VLimit
TLEB = 400nS
t
Figure 6: Leading Edge Blanking
37kHz
fs
Short Circuit Protection (SCP)
The MP157 monitors the peak current, and
shuts down when the peak current rises above
900mA, featuring a short circuit protection. As
soon as the fault disappears, the power supply
resumes operation.
Thermal shutdown (TSD)
To prevent from any lethal thermal damage,
MP157 shuts down switching cycle when the
inner temperature exceeds 150C. During the
thermal shutdown (TSD), the VCC will be
discharged to 2.4V, and then be re-charged by
the internal high voltage regulator.
MP157 Rev. 1.04
6/27/2016
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
APPLICATION INFORMATION
Table 1. Common Topologies Using MP157
Topology
High-Side
Buck
Circuit Schematic
Features
1.
2.
3.
4.
No-isolation,
Positive output
Low cost
Direct feedback
1. No-isolation,
2. Negative output
3. Low cost
High-Side
Buck-Boost
Boost
4. Direct feedback
1.
2.
3.
4.
No-isolation,
Positive output
Low cost
Direct feedback
1.
2.
3.
4.
Isolation,
Positive output
Low cost
Indirect feedback
Flyback
MP157 Rev. 1.04
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MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE
Topology Options
MP157 can be used in common topologies, such
as Buck, Buck-Boost, Boost and Flyback. Please
find the Table.1 for more information.
COMPONENT SELECTION
Input Capacitor
The input capacitor is used to supply the DC
input voltage for the converter. Figure 7 shows
the typical DC bus voltage waveform with halfwave rectifier and full-wave rectifier.
VDC(max)
Vin
DC input Voltage
Po max
1 2
1
LIpeak
, for DCM
min off
2
To consider the parameter error of the converter
such as peak current limit, minimum off time and
so on, we can obtain the minimum value Pmin of
the maximum power. The principle of choosing
the inductor is that Pmin should be higher than
the rated power.
Take the output voltage 12V as examples, the
curve of Pmin for 12V is shown as Figure 8,
(Ipeak=0.64A, tminoff=13.1s)
5
4.6
VDC(min)
a) DC input with half-wave rectifier
V DC(max)
Vin
DC input Voltage
PMIN (W)
4.2
3.8
3.4
3
VDC(min)
2.6
0.4
0.5
0.6
0.7
0.8
INDUCTANCE(mH)
0.9
b) DC input with full-wave rectifier
Figure 8: Pmin vs. L at 12V output
Figure 7: Input voltage waveform
For CCM operation, the selection of L should
make the frequency of converter lower than
40kHz to reduce the turn-on switching loss cause
by reverse recovery of free-wheeling diode at
high line input.
When the half-wave rectifier is used, the input
capacitor is usually set as 3uF/W for the
universal input condition. And when the full-wave
rectifier is used, we could choose a smaller
capacitor usually set as 1.5-2uF/W. Avoid the
minimum DC voltage below 70V. Low DC input
voltage will bring the problem of thermal
shutdown. Half-wave rectifier is recommended
for 2W output application.
Inductor
MP157 has a minimum off time limit, and this
decides the maximum power it can output. The
maximum power increases as the inductor
increases. Using a smaller inductor may fail
output the full load. The maximum power can be
obtained as:
Po max Vo (Ipeak
MP157 Rev. 1.04
6/27/2016
Freewheeling Diode
The diode should have a maximum reverse
voltage rating which is greater than the maximum
input voltage, and the current rating of the diode
is determined by the output current.
The reverse recovery of freewheeling diode can
affect the efficiency and the circuit operation. For
CCM operation. ultra fast diode with Trr
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