MP4050AGS [MPS]
Non-Isolated, High-Brightness LED Driver with Enhanced Thermal Feature;
| 型号： | MP4050AGS |
| 厂家： | 
MONOLITHIC POWER SYSTEMS |
| 描述： | Non-Isolated, High-Brightness LED Driver with Enhanced Thermal Feature |
| 文件： | 总21页 (文件大小：557K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MP4050A
Non-Isolated, High-Brightness LED Driver
with Enhanced Thermal Feature
The Future of Analog IC Technology
DESCRIPTION
FEATURES
The MP4050A is a constant current LED driver
with an integrated 500V MOSFET. It is
designed specifically for energy efficient and
low-cost LED bulb replacement applications.
Constant Current LED Driver
Integrated 500V/8Ω MOSFET
Low VCC Operating Current
Maximum Frequency Limit
Audible Noise Restrain
The MP4050A is designed to drive high-
brightness LEDs from a universal AC grid input
or DC input. The accurate output LED current
is achieved by an averaging internal current
feedback loop. Constant LED current is
delivered quietly by switching the internal
MOSFET at a frequency regulated above
22kHz.
Internal High-Voltage Current Source
Internal 200ns Leading Edge Blanking
Integrated Thermal Current Foldback
Thermal Shutdown (Auto Re-Start with
Hysteresis)
VCC Under-Voltage Lockout with Hysteresis
Open LED Protection
Short-Circuit Protection
The MP4050A can be powered directly by the
high input voltage. An internal high-voltage
current source regulates supply voltage without
external circuitry.
Auto-Restart Function
Available in TSOT23-5/SOIC-8 Packages
APPLICATIONS
Full protections features include integrated
thermal current foldback, VCC under-voltage
lockout (UVLO), open LED protection (OLP),
short-circuit protection (SCP), and over-
temperature protection (OTP). These features
make the MP4050A an ideal solution for simple,
off-line, and non-isolated LED applications.
AC/DC or DC/DC LED Driver Application
General Illumination
Industrial Lighting
Automotive/Decorative LED Lighting
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” and “The Future of Analog IC Technology” are registered
trademarks of Monolithic Power Systems, Inc.
TYPICAL APPLICATION
MP4050A Rev. 1.01
1/14/2016
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1
MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
ORDERING INFORMATION
Part Number
MP4050AGJ*
MP4050AGS**
Package
TSOT23-5
SOIC-8
Top Marking
See Below
* For Tape & Reel, add suffix –Z (e.g. MP4050AGJ–Z);
** For Tape & Reel, add suffix –Z (e.g. MP4050AGS–Z).
TOP MARKING (TSOT23-5)
ANV: Product Code of MP4050AGJ;
Y: Year Code.
TOP MARKING (SOIC-8)
MP4050A: Product Code of MP4050AGS;
LLLLLLLL: Lot Number;
MPS: MPS Prefix;
Y: Year Code;
WW: Week Code.
MP4050A Rev. 1.01
1/14/2016
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2
MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
PACKAGE REFERENCE
TOP VIEW
TOP VIEW
VCC
PRO
GND
1
2
3
5
DRAIN
VCC
PRO
1
2
3
4
8
7
6
5
N.C
DRAIN
N.C
GND
4
SOURCE
SOURCE
N.C
TSOT23-5
SOIC-8
Thermal Resistance (4)
TSOT23-5..............................100..... 55... C/W
SOIC-8....................................96...... 45... C/W
θJA
θJC
ABSOLUTE MAXIMUM RATINGS (1)
DRAIN to SOURCE ......................-0.3V to 500V
VCC, SOURCE to GND.................-0.3V to 6.5V
PRO to GND..................................-0.7V to 6.5V
Source Current on PRO ............................. 4mA
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-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 produces an excessive die temperature, causing
the regulator to go into thermal shutdown. Internal thermal
shutdown circuitry protects the device from permanent
damage.
(2)
Continuous Power Dissipation (TA = +25°C)
TSOT23-5................................................ 1.25W
SOIC-8....................................................... 1.3W
Lead Temperature ....................................260C
Storage Temperature............... -60C to +150C
ESD Capability Human Body Mode.......... 2.0kV
CDM ESD Capability................................. 2.0kV
3) The device is not guaranteed to function outside of its
operating conditions.
4) Measured on JESD51-7, 4-layer PCB.
Recommended Operating Conditions (3)
Supply Voltage VCC Range............4.1V to 5.0V
MP4050A Rev. 1.01
1/14/2016
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
ELECTRICAL CHARACTERISTICS
Typical values are VCC =5V, TJ = 25C, unless otherwise noted.
Minimum and maximum values are at VCC =5V, TJ = -40C to +125C, unless otherwise noted,
guaranteed by characterization.
Parameter
Symbol
Condition
Min
Typ
Max Units
Start-Up Current Source (DRAIN)
Internal Regulator Supply Current
Leakage Current from DRAIN
IREGULATOR VCC=0V, VDRAIN=100V
3.8
5
6.1
22
mA
ID_LKG
VCC=6V, VDRAIN=500V
14
μA
Supply Voltage Management (VCC)
VCC Increasing Level: Internal
Regulator Stops & IC Starts Working
VCCOFF
VCCNOR
VCCON
VCC Rising Edge
Normal Operation
VCC Falling Edge
4.00
3.85
4.35
4.25
4.15
4.70
V
V
V
VCC Normal Level
VCC Decreasing Level: Internal
Regulator Turn-On
4.50
VCC Hysteresis: Regulator On/Off
VCC Decreasing Level: IC Stops
VCCOFF-ON
VCCSTOP
0.11
3
0.20
3.4
0.28
3.8
V
V
VCC Falling Edge
VCC Hysteresis: Regulator Off & IC
Stops Working
VCCOFF-STOP
VCCPRO
ICC
0.93
1.9
1.25
2.35
350
18
1.6
2.8
425
32
V
V
VCC Decreasing Level: Protection
Phase Ends
VCC Falling Edge
VCC=4.3V, fSW=33kHz,
Duty=84%
Internal IC Consumption
μA
μA
Internal IC Consumption at Latch-Off
Phase
ICC_LATCH
Internal MOSFET (DRAIN to SOURCE)
Breakdown Voltage
VBRDSS
RDS(ON)
ID=80μA
500
V
ID=10mA, TJ=25°C
8
8
12
12
ꢀ
DRAIN SOURCE On-State Resistance
VCC=VCCSTOP + 50mV,
ID=10mA, TJ=25°C
ꢀ
Current Sampling Management (SOURCE)
Peak Current Limit at Normal
Operation
VLIMIT
0.4
0.46
200
0.52
310
V
Leading Edge Blanking
tLEB
130
ns
Feedback Threshold: Turn-On High-
Side MOSFET
Regulate the Average
Current
VREF
0.187 0.196 0.205
V
tOFF_MIN
Normal Operation
The 1st 32 Switching
Cycles at Start-Up
3.4
4.7
6.2
μs
μs
tOFF_MIN
×3.5
The 2nd 32 Switching
Cycles at Start-Up
The 3rd 32 Switching
Cycles at Start-Up
tOFF_MIN
×2
Minimum Off-Time Limitation
Maximum On-Time Limitation
MP4050A Rev. 1.01
tOFF_MIN_ST
μs
tOFF_MIN
×1.2
μs
μs
tON_MAX
16
25
37
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1/14/2016
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
ELECTRICAL CHARACTERISTICS (continued)
Typical values are VCC =5V, TJ = 25C, unless otherwise noted.
Minimum and maximum values are at VCC =5V, TJ = -40C to +125C, unless otherwise noted,
guaranteed by characterization.
Parameter
Symbol
Condition
Min
Typ
Max Units
Over-Voltage Protection (PRO)
Over-Voltage Threshold
VOVP
tOVP
1.85
2
2.15
32
V
Time Constraint on OVP Comparator
21
μs
Thermal Protection
Thermal Foldback Threshold (5)
Thermal Shutdown Threshold (5)
TSTART
TSD
145
160
C
C
Thermal Shutdown Recovery
Hysteresis (5)
THYS
50
C
Notes:
5) Guaranteed by characterization.
MP4050A Rev. 1.01
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
TYPICAL CHARACTERISTICS
Internal Regulation
Currentt vs. Junction
Temperature
Leakage Current vs.
Junction Temperature
Breakdown Voltage vs.
Junction Temperature
660
640
620
600
580
560
540
17
16
15
14
13
12
11
6.5
6.0
5.5
5.0
4.5
4.0
3.5
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
VCC Current In Latch
Phase vs. Junction
Temperature
VCC Regulator Off
Threshold vs. Junction
Temperature
VCC Regulator On
Threshold vs. Junction
Temperature
28
25
22
19
16
13
10
4.55
4.50
4.45
4.40
4.35
4.30
4.25
4.80
4.75
4.70
4.65
4.60
4.55
4.50
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
VCC Stop Threshold vs.
Junction Temperature
VCC Protection Threshold
vs. Junction Temperature
Feedback Reference vs.
Junction Temperature
2.6
2.5
2.4
2.3
2.2
2.1
2.0
3.6
3.5
3.4
3.3
3.2
3.1
3.0
0.198
0.197
0.196
0.195
0.194
0.193
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
MP4050A Rev. 1.01
1/14/2016
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
TYPICAL CHARACTERISTICS (continued)
Over-Voltage Protection
Minimum Off Time vs.
Junction Temperature
Maximum On Time vs.
Junction Temperature
Reference vs. Junction
Temperature
5.2
5.0
4.8
4.6
4.4
4.2
4.0
2.06
2.04
2.02
2.00
1.98
1.96
28
27
26
25
24
23
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
On-State Resistance vs.
Junction Temperature
Peak Current Limit vs.
Junction Temperature
0.48
0.47
0.46
0.45
0.44
0.43
16
14
12
10
8
VCC=VCCSTOP+50mV
VCC=5V
6
4
-50 -25
0
25 50 75 100 125 150
-50 -25
0
25 50 75 100 125 150
MP4050A Rev. 1.01
1/14/2016
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 230VAC, 13 LEDs in series, VOUT = 40V, ILED=115mA, L = 4.7mH, COUT=47μF, TA = 25°C,
unless otherwise noted.
Steady State
Turn-On Delay
Input Power Start-Up
V
V
DS
DS
V
BULK
100V/div.
100V/div.
100V/div.
V
OUT
10V/div.
I
I
OUT
L
I
L
50mA/div.
100mA/div.
100mA/div.
Input Power Shutdown
SCP
SCP Entry & Recorvery
V
SOURCE
100V/div.
V
DS
100V/div.
V
OUT
10V/div.
I
I
L
L
I
L
100mA/div.
50mA/div.
100mA/div.
OVP Entry
OVP Recovery
Output-Current Ripple
V
V
OUT
OUT
10V/div.
10V/div.
I
I
L
L
100mA/div.
100mA/div.
I
OUT
20mA/div.
MP4050A Rev. 1.01
1/14/2016
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 230VAC, 13 LEDs in series, VOUT = 40V, ILED=115mA, L = 4.7mH, COUT=47μF, TA = 25°C,
unless otherwise noted.
Thermal Current
Foldback Curve
Line & Load Regulation
120
100
80
60
40
20
0
1.2
0.8
0.4
0
9LEDs
7LEDs
-0.4
-0.8
-1.2
13LEDs
11LEDs
120 125 130 135 140 145 150 155 160
85 105125145165185205225245265
INPUT VOLTAGE (VAC)
MP4050A Rev. 1.01
1/14/2016
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
PIN FUNCTIONS
Pin #
Name Description
TSOT23-5 SOIC-8
Power Supply. Supply power for the control signals and the high-current
MOSFET. Bypass to ground with an external bulk capacitor.
1
2
3
4
1
2
3
4
VCC
PRO
Open LED Detection Input. During the turn-off interval, if PRO voltage is
higher than VOVP, the over-voltage protection is triggered.
Ground. The reference ground for the control signal and the gate drive
signal.
GND
Source of Internal Power MOSFET & Feedback Input. Connect current-
sensing resistor from SOURCE to GND to set the LED current.
SOURCE
5
7
DRAIN Drain of Internal Power MOSFET & Integrated HV Current Source Input.
--
5, 6, 8
NC
No Connection. Do Not Connect.
MP4050A Rev. 1.01
1/14/2016
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
FUNCTION BLOCK DIAGRAM
Power
Management
VCC
Start-Up Unit
DRAIN
Driving Signal
Unit
Protection Unit
PRO
GND
Average Current
Control
Thermal
Protection
Peak Current
Limit
SOURCE
Minimum
Frequency
Control
FIGURE 1. Functional Block Diagram
MP4050A Rev. 1.01
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
OPERATION
The MP4050A is a non-isolated, cost-effective,
high-efficiency converter designed to drive high-
brightness LEDs from a universal AC grid input
or DC input. As shown in the typical application
diagram (see Fig. 1), the regulator is designed
to operate with a minimum number of external
components.
Constant-Current Operation
The MP4050A is a fully integrated regulator.
The internal feedback logic responds to the
internal sample and hold circuit to achieve
constant output-current regulation. The voltage
of the internal sampling capacitor (VFB) is
compared to the internal reference (VREF) when
the sampling capacitor voltage (VFB) falls below
the reference voltage (which indicates an
insufficient output current). Then the integrated
MOSFET is turned on. The on period is
determined by the peak current limit. After the
on period elapses, the integrated MOSFET is
turned off (see Fig. 3).
Start-Up and Under-Voltage Lockout (UVLO)
Initially, the chip is self-supplied by the internal
high-voltage VCC regulator (which is drawn
from DRAIN). The IC starts switching and the
internal high-voltage regulator turns off as soon
as the VCC reaches VCCOFF. When VCC drops
below VCCON, the internal high-voltage
regulator turns on again to charge the external
VCC capacitor. Finally, VCC is regulated at
VCCNOR for normal operation.
A small capacitor with several μF capacitances
is enough to hold on to the VCC supply voltage.
Also, a smaller capacitor reduces component
cost. When VCC drops below VCCSTOP, the IC
stops working and the internal high-voltage
regulator re-charges the VCC capacitor.
FIGURE 3. VFB vs. IOUT
When fault conditions occur (such as open LED
protection or over-temperature protection), the
MP4050A stops working, and an 18µA internal
sink current source discharges the VCC capacitor.
After VCC drops below VCCPRO, the internal high-
voltage regulator recharges the VCC capacitor
again. The re-start time can be calculated by the
following equation,
Thus, by monitoring the internal sampling
capacitor voltage, the output current can be
regulated. The output current is determined by
the following equation:
VREF
IOUT
RS
VCCNOR VCCPRO
18A
VCCOFF VCCPRO
tRESTART CVCC
CVCC
The peak inductor current at normal operation
can be obtained with the following equation:
5mA
Fig. 2 shows the typical waveforms with VCC
under-voltage lockout.
VLIMIT
IPK
RS
Where RS is the sensing resistance connected
from SOURCE to GND.
FIGURE 2. VCC Under-Voltage Lockout (UVLO)
MP4050A Rev. 1.01
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
Minimum Operating Frequency Limit
The MP4050A incorporates minimum
operating frequency (22kHz) to eliminate
audible noise.
Open LED Protection (OLP)
a
If PRO voltage (VPRO) is higher than VOVP when
the MOSFET turns off, the MP4050A stops
working, and a re-start cycle begins. Open LED
protection operates in hiccup mode. The
When the operating frequency is less than
22kHz, the internal peak-current regulator
decreases the peak-current value to keep the
operating frequency constant at about 22kHz.
MP4050A
monitors
the
PRO
voltage
continuously, and the VCC cap is discharged
and charged repeatedly. The MP4050A
resumes work once the fault disappears.
If the inductance is too large to make the
operating frequency drop to the minimum
operating frequency, the converter enters CCM
operation. Generally, the converter works in
DCM when the operating frequency is larger
than 22kHz for normal operation.
Short-Circuit Protection (SCP)
When an LED short circuit occurs, the switching
off time is extended. Due to the minimum
operating frequency limit, the IC can reduce
automatically the switching frequency and
achieve close loop control. Then the output
power at this condition is limited within a safe
range. The MP4050A resumes work in normal
operation once the device recovers from the
short circuit.
Minimum Off-Time Limit
A minimum off-time limit is implemented. During
normal operation, the minimum off-time limit is
4.7μs. During the start-up period, the minimum
off-time limit is shortened gradually from
16.45μs to 4.7μs (see Fig. 4). Each minimum
off-time limit maintains 32 switching cycles. This
soft-start function enables a safe start-up.
Leading Edge Blanking (LEB)
Internal leading edge blanking (LEB) is
employed to prevent a switching pulse from
terminating prematurely due to parasitic
capacitance discharging when the MOSFET
turns on. During the blanking time, the path
from SOURCE to the current comparator input
is blocked (see Fig. 5)
FIGURE 4. Minimum Off-Time Limit at
Start-up
Thermal Shutdown (TSD)
To prevent thermal damage to the system and
IC, the chip reduces the reference to decrease
the output power if the junction temperature
exceeds 145C. This limits the rising
temperature speed of the IC. Typically, the
reference voltage drops to around 20% when
the junction temperature rises to 160C. If the
temperature exceeds 160C, the MP4050A
stops switching, and the IC is latched off. Once
the junction temperature drops below 110C,
the chip resumes operation.
FIGURE 5. Leading Edge Blanking (LEB)
MP4050A Rev. 1.01
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
APPLICATION INFORMATION
If the inductance is too large, the converter
enters CCM, and the frequency drops to the
minimum operating frequency. If this occurs,
the reverse recovery of the freewheeling diode
results in more power loss. Normally, it’s better
to have the converter operate in DCM. The
following expression calculates the limit of the
minimum operating frequency:
Component Selection
Input Capacitor
The input capacitor is used to supply DC input
voltage to the converter. Fig. 6 shows the
typical DC bus voltage waveform of a full-bridge
rectifier.
2IO
1
Lm
1
2
fSW _MIN (
)IPK
VDC(MIN) VO VO
Freewheeling Diode
The diode’s maximum reverse-voltage rating is
higher than the maximum input voltage. The
current rating of the diode is determined by the
output current (which is larger than 1.5 to 2
times the output current).
FIGURE 6. Input Voltage Waveform
When a full-bridge rectifier is used, the input
capacitor is set usually as 2μF/W for the
universal input range. With a low-power output,
the half-bridge rectifier can be used with a
bigger capacitor.
Slow recovery diodes cause excessive leading
edge current spikes during start-up. The long
reverse-recovery time of the freewheeling diode
affects efficiency and the operation of the
system. An ultrafast diode (trr<75ns), such as
WUGC10JH or EGC10GH, is recommended.
Very low DC input voltage causes thermal
problems in LED applications with buck
topology. The minimum DC voltage is limited by
the maximum duty cycle of the MP4050A as
follows:
Output Capacitor
An output capacitor is required to filter the
inductance current and maintain the DC output
voltage.
VO (tON_MAX tOFF _MIN
)
VDC(MIN)
tON_MAX
The output-current ripple is reduced by using a
bigger output capacitor. A low ESR capacitor is
necessary in low-temperature applications.
Inductor
The MP4050A has a minimum off-time limit and
maximum on-time limit. Both time limits affect
the inductance. The maximum and minimum
inductance values can be obtained as follows:
If the output-voltage ripple is limited, ceramic,
tantalum, or low ESR electrolytic capacitors are
recommended. The output-voltage ripple can
be estimated by the following equations:
(VDC(MIN) VO ) tON_MAX
i
8fSWCO
Lm LMAX
VCCM_Ripple
iRESR
in CCM
IPK
VO tOFF _MIN
IPK
IO
I I
Lm LMIN
V
( PK O )2 IPK RESR in DCM
DCM_Ripple
fSWCO
IPK
MP4050A Rev. 1.01
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
Sensing Resistor
Dummy Load
Choose an appropriate sensing resistor for
good output-current regulation. The right
resistor guarantees stable output-current
regulation in high/low temperature conditions.
The sensing resistor should have 1% tolerance.
Placing two 1% tolerance sensing resistors in
parallel further improves the resistance error. A
resistor with a ± 400PPM/C temperature
coefficient can be used for better output-current
regulation in high/low temperature conditions.
The dummy load is used to consume the power
transferred to the output capacitor in OVP
hiccup mode without any power consumption.
Normally, a dummy load less than 1mA is
recommended. A dummy load less than 1mA
does not deteriorate system efficiency and also
guarantees normal, open LED protection.
PRO Decoupling Capacitor
The floating GND is sensitive to the voltage
noise spike in a high-side buck solution.
Generally, the time constraint on the OVP
comparator mechanism is sufficient to shield
the noise against an open LED fault mistrigger.
Sometimes, a decoupling cap is also applied
between PRO and GND.
PRO Feedback Resistor Divider
The PRO feedback resistor divider is used to
detect an over-voltage fault condition. Fig. 7
shows the PRO feedback resistor divider’s
connection.
A ceramic capacitor around 30 pF is used in
SOIC-8 package applications. For the smaller
TSOT23-5 package, no less than a 100pF
ceramic capacitor is recommended. Fig. 8
shows the PRO decoupling capacitor
connection.
FIGURE 7. PRO Feedback Resistor Divider
The over-voltage protection threshold can be
calculated with the following equation:
R2 R3
VOUT _ OVP VOVP
VD
R2
Where VD is the freewheeling diode forward
voltage drop.
FIGURE 8. Decoupling Capacitor
PRO Time Constant
The upper feedback resistor (R3) should be
larger than 100kꢀ to avoid an efficiency
reduction in the application. A 1% tolerance
type is recommended to achieve accurate
protection when open LED occurs.
The MP4050A detects the PRO voltage to
judge the open LED condition when internal the
MOSEFET turns off. If the PRO decoupling
capacitor is connected, the PRO time constant
(τ) should satisfy the following expression to
guarantee normal open LED protection:
R2 has a small 0603 package. Taking the
voltage rating of the dielectric into consideration,
R3 is recommended to have a minimum 1206
package.
R2R3
R2 R3
CPRO
1s
MP4050A Rev. 1.01
1/14/2016
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15
MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
Power Factor (PF)
The MP4050A is designed mainly for non-
isolated, space constrained, and cost sensitive
LED driver solutions. The MP4050A is the best
option for the PF>0.5 under 120VAC input
requirement. The input capacitance is reduced
to achieve the highest possible power factor as
PF>0.7 @ 120VAC and PF>0.5 @ 230VAC (if
the output-current regulation is not limited).
Surge
Select the appropriate input capacitance to
obtain good surge performance. With the input
capacitor C2 (4.7µF) and C3 (4.7µF) in Fig. 11,
the board can pass a 1kV differential input line
1.2/50µs surge test (IEC61000-4-5). It is
recommended to increase the input capacitor
value to suppress a surge test above 1kV. As
for the high PF required, applications with lower
input capacitor values give a greater voltage
rise. Typically, a metal oxide varistor (MOV) is
required to pass a surge test above 1kV.
Top Layer
Table 1 shows the input capacitor values
required to pass the differential surge test.
Bottom Layer
TABLE 1. Recommended Input Capacitance
Surge
Figure 10. Recommended PCB Layout
500V
1kV
1.5kV
2kV
Voltage
C2
C3
3.3μF 4.7μF 4.7μF
3.3μF 4.7μF 10μF
Shown in
Fig. 9
PCB Layout Guidelines
Efficient PCB layout is critical to achieve
reliable operation, good EMI, and good thermal
performance, especially in very small sized LED
applications. For best results, refer to Fig. 10
and follow the guidelines below:
The board can pass the 2kV differential surge
test by adopting the circuit setup below (see Fig.
9):
1. Add a MOV RV1 (TVR14431).
2. Add a fuse F1 (SS-5-2A).
1. Keep the loop formed between the DRAIN
to SOURCE, inductor, freewheeling diode,
and output capacitor as small as possible
for better EMI.
L1 1mH/0.1A
FR1 10/1W
F1 250V/2A
L
85~265VAC
BD1
MB6S
600V/0.5A
2. Ensure the AC input is far away from the
switching nodes to minimize the noise
coupling that may bypass the input filter.
RV1
C3
4.7
C2
4.7
TVR14431
400V
400V
3. Place the VCC and PRO capacitors close to
the IC and GND.
N
FIGURE 9. 2kV Surge Solution
4. Place the PRO feedback resistor as close to
PRO as possible and minimize the feedback
sampling loop to minimize the noise
coupling route.
MP4050A Rev. 1.01
1/14/2016
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16
MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
5. Keep the copper area connected to
SOURCE short (in the high-side buck
topology) to minimize EMI with the thermal
constraints of the design (since SOURCE is
a switching node).
6. Maximize the connection of the copper area
to DRAIN to improve heat sink (since
DRAIN is a static node connected to the DC
input).
MP4050A Rev. 1.01
1/14/2016
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
TYPICAL APPLICATION CIRCUITS
Fig. 11 shows a typical application example of a 40V, 115mA non-isolated, buck topology LED driver
using MP4050AGJ.
L1 1mH
U1 MP4050A
C1 2. 2µF/ 10V
5
1
DRAIN
VCC
PRO
2
R5
BD1
MB6S
10kꢀ/0805
4
3
600V/0.5A
SOURCE GND
R2
R1
9.31kꢀ/1%
FR1
200kꢀ/1%/1206
10 ꢀ/1W
L
C2
C3
LED+
85VAC to 265VAC
N
4.7µF/400V
4.7µF/400V
R3
L2 4.7mH
3.3 ꢀ/1%/1206
R4 3.3 ꢀ/1%/ 1206
D1
C4
47µF/50V
R6
40V/115mA
200kꢀ
WUGC10JH
600V/1A
LED-
FIGURE 11. Typical Buck Converter Application
MP4050A Rev. 1.01
1/14/2016
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18
MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
FLOW CHART
FIGURE 12. Control Flow Chart
MP4050A Rev. 1.01
1/14/2016
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MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
PACKAGE INFORMATION
TSOT23-5
0.60
TYP
0.95
BSC
2.80
3.00
5
4
1.20
TYP
1.50
1.70
2.60
3.00
2.60
TYP
1
3
TOP VIEW
RECOMMENDED LAND PATTERN
0.70
0.90
1.00 MAX
SEATING PLANE
0.09
0.20
0.30
0.50
0.00
0.10
0.95 BSC
SEE DETAIL "A"
SIDE VIEW
FRONT VIEW
NOTE:
GAUGE PLANE
0.25 BSC
1) ALL DIMENSIONS ARE IN MILLIMETERS.
2) PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH,
PROTRUSION OR GATE BURR.
3) PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH
OR PROTRUSION.
4) LEAD COPLANARITY(BOTTOM OF LEADS AFTER FORMING)
SHALL BE0.10 MILLIMETERS MAX.
0.30
0.50
0o-8o
5) DRAWING CONFORMS TO JEDEC MO-193, VARIATION AA.
6) DRAWING IS NOT TO SCALE.
DETAIL “A”
MP4050A Rev. 1.01
1/14/2016
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20
MP4050A – NON-ISOLATED, HIGH-BRIGHTNESS LED DRIVER, WITH ENHANCED THERMAL FEATURE
PACKAGE INFORMATION (continued)
SOIC-8
0.189(4.80)
0.197(5.00)
0.050(1.27)
0.024(0.61)
0.063(1.60)
8
5
0.150(3.80)
0.157(4.00)
0.228(5.80)
0.244(6.20)
0.213(5.40)
PIN 1 ID
1
4
TOP VIEW
RECOMMENDED LAND PATTERN
0.053(1.35)
0.069(1.75)
SEATING PLANE
0.004(0.10)
0.010(0.25)
0.0075(0.19)
0.0098(0.25)
0.013(0.33)
0.020(0.51)
SEE DETAIL "A"
0.050(1.27)
BSC
SIDE VIEW
FRONT VIEW
0.010(0.25)
0.020(0.50)
x 45o
NOTE:
1) CONTROL DIMENSION IS IN INCHES. DIMENSION IN
BRACKET IS IN MILLIMETERS.
GAUGE PLANE
0.010(0.25) BSC
2) PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH,
PROTRUSIONS OR GATE BURRS.
3) PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH
OR PROTRUSIONS.
4) LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING)
SHALL BE 0.004" INCHES MAX.
0.016(0.41)
0.050(1.27)
0o-8o
5) DRAWING CONFORMS TO JEDEC MS-012, VARIATION AA.
6) DRAWING IS NOT TO SCALE.
DETAIL "A"
NOTICE: The information in this document is subject to change without notice. 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.
MP4050A Rev. 1.01
1/14/2016
www.MonolithicPower.com
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© 2016 MPS. All Rights Reserved.
21
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