MP4068
Non-Isolated,TRIAC Dimmable PFC
LED Driver for 120VAC, Up to 10W LEDs
The Future of Analog IC Technology
DESCRIPTION
FEATURES
The MP4068 is a highly integrated TRIAC
dimmable LED driver with a high power factor
(PF). It regulates precisely LED current in nonisolated lighting applications. Only a single
winding inductor is required to realize the
solution. For low-line (120VAC) applications,
the integrated 500V MOSFET ensures that the
system can withstand a 500V surge test without
MOV or TVS. It features MPS’ proprietary
hybrid operation mode, which is designed to
achieve good dimming performance. The
MP4068 is designed specifically for low-line
input (120VAC) and TRIAC dimmable LED
lighting applications, especially for low cost and
small form factor applications.
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The accurate output LED current is achieved by
an internal averaging current feedback loop. An
internal high-voltage regulator makes the
MP4068 start-up quickly without a perceptible
delay. The power de-rating at high temperature
makes the system flicker-free when the ambient
temperature is high.
The MP4068 has protection features such as
VCC under-voltage lockout (UVLO), overvoltage protection (OVP), and short-circuit
protection (SCP). All of these features make
MP4068 an ideal solution for simple, off-line,
and non-isolated TRIAC dimmable LED lighting
applications.
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Excellent TRIAC Dimming Performance
Lowest Cost BOM
Constant Current LED Driver
Integrated 500V MOSFET
Internal HV Fast Start-Up
Single Winding Inductor
High Power Factor(>0.7)
Good LED Current Accuracy
Supports Buck/Buck-Boost Topology
LED Current Foldback at High Temperature
Thermal Shutdown (Auto Re-Start with
Hysteresis)
VCC Under-Voltage Lockout with Hysteresis
(UVLO)
Programmable Over-Voltage Protection
Output Short-Circuit Protection
Available in SOIC8-7A/SOIC-8 EP
Packages
APPLICATIONS
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120VAC, Up to 10W LED Lighting
Residential and Commercial Lighting
TRIAC Dimmible LED Lighting, A19, GU10,
PAR Lamps
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.
The MP4068 is available in SOIC8-7A and
SOIC-8 EP packages.
MP4068 Rev. 1.01
7/30/2015
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1
MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
TYPICAL APPLICATION (BUCK)
HV
L2
VCC
R4
C2
TRIAC
Dimmer
R5
C3
RF1
C1
D1
OVF
C4
MP4068
C5
CS
GND
108-132Vac
D2
R2
R3
VOUT
L1
R1
C6
TYPICAL APPLICATION (BUCK-BOOST)
MP4068 Rev. 1.01
7/30/2015
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© 2015 MPS. All Rights Reserved.
2
MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
ORDERING INFORMATION
Part Number
Top Marking
MP4068GN*
Package
SOIC-8 EP
MP4068GS**
SOIC8-7A
See Below
See Below
* For Tape & Reel, add suffix –Z (e.g. MP4068GN–Z)
** For Tape & Reel, add suffix –Z (e.g. MP4068GS–Z)
TOP MARKING (MP4068GN)
MP4068: product code of MP4068GN;
LLLLLLLL: lot number;
MPS: MPS prefix;
Y: year code;
WW: week code;
TOP MARKING (MP4068GS)
MP4068: product code of MP4068GS;
LLLLLLLL: lot number;
MPS: MPS prefix;
Y: year code;
WW: week code;
MP4068 Rev. 1.01
7/30/2015
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© 2015 MPS. All Rights Reserved.
3
MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
PACKAGE REFERENCE
TOP VIEW
VCC 1
TOP VIEW
8 HV
GND 2
VCC
1
8
NC
OVF
2
7
HV
OVF 3
6 GND
GND
3
6
NC
CS 4
5 GND
CS
4
5
NC
SOIC8-7A
SOIC-8 EP
ABSOLUTE MAXIMUM RATINGS (1)
Thermal Resistance
HV to CS .......................................-0.3V to 500V
VCC, CS to GND ............................-0.3V to6.5V
OVF to GND ..................................-0.7V to 6.5V
Source Current on OVF ............................. 4mA
(2)
Continuous Power Dissipation (TA = +25°C)
SOIC8-7A .................................................. 1.6W
SOIC-8 EP ................................................. 2.6W
Lead Temperature ....................................260°C
Storage Temperature............... -60°C to +150°C
ESD Capability Human Body Mode .......... 2.0kV
CDM ESD Capability................................. 2.0kV
SOIC8-7A ............................... 76 ...... 35... °C/W
SOIC-8 EP.............................. 48 ...... 10... °C/W
Recommended Operating Conditions
(3)
Operating VCC Range .......................4.1V to 5V
MP4068 Rev. 1.01
7/30/2015
(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 produces an excessive die temperature, causing
the regulator to 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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MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
ELECTRICAL CHARACTERISTICS
Typical values are VCC =5V, TJ = 25°C, unless otherwise noted.
Minimum and maximum values are at VCC =5V, TJ = -40°C to +125°C, unless otherwise noted,
guaranteed by characterization.
Parameter
Symbol
Condition
Min
Typ
Max
Units
IREGULATOR
VCC=0V;VHV=100V
3.8
5
6.1
mA
IHV_LKG
VCC=5V;VHV=400V
14
22
μA
Start-Up Current Source (HV)
Internal Regulator Supply
Current
Leakage Current from HV
Supply Voltage Management (VCC)
VCC Upper Threshold for
Internal Regulator TurnOff
VCC Lower Threshold for
Internal Regulator TurnOn
VCC Hysteresis between
Regulator On/Off
VCC Lower Threshold for
IC Shutdown
VCC Hysteresis between
Regulator Off/IC
Shutdown
VCC Lower Threshold at
which the Protection
Phase Ends
Internal IC Consumption
Internal IC Consumption,
Latch-Off Phase
Internal MOSFET (HV to CS)
Breakdown Voltage
On-State Resistance
VCCOFF
VCC Rising Edge
4.3
4.65
5
V
VCCON
VCC Falling Edge
4.10
4.40
4.75
V
0.15
0.24
0.32
V
3.0
3.4
3.8
V
0.93
1.25
1.60
V
1.90
2.35
2.80
V
VCC=4.6V, fsw=63kHz,
D=56%
350
400
μA
VCC=5V
18
32
μA
VCCHYS
VCCSTOP
VCC Falling Edge
VCCHYS-STOP
VCCPRO
ICC
ICC_LATCH
VCC Falling Edge
VBR
RON
500
V
IHV=10mA, TJ =25°C
8.5
12
Ω
VCC= VCCSTOP +50mV,
ID=10mA, TJ =25°C
8.5
12
Ω
0.46
0.52
V
Current Sampling Management (CS)
Peak Current Limit at
Normal Operation
Leading Edge Blanking
Feedback Threshold to
Turn On MOSFET
Minimum Off-Time
Limitation at Normal
Operation
MP4068 Rev. 1.01
7/30/2015
VLIMIT
0.40
tLEB
200
ns
VREF
0.186
0.195
0.204
V
tOFF_MIN
5.4
7
8.5
μs
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MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
ELECTRICAL CHARACTERISTICS (continued)
Typical values are VCC =5V, TJ = 25°C, unless otherwise noted.
Minimum and maximum values are at VCC =5V, TJ = -40°C to +125°C, unless otherwise noted,
guaranteed by characterization.
Parameter
Maximum On-Time Limitation
Ratio of Max_on/Min_off
Symbol
tON_MAX
σ
Condition
Min
6.7
1.09
Typ
9
1.29
Max
11.5
1.5
Units
μs
1.89
2.0
2.15
V
32
μs
Protection Input (OVF)
Threshold to Trigger OVP
VOVP
Time Constraint on OVP Comparator
tOVP
21
TSTART
TSD
145
160
°C
°C
THYS
50
°C
Thermal Protection
Power De-Rating Threshold (5)
Thermal Shutdown Threshold (5)
Thermal Shutdown Recovery
Hysteresis (5)
Notes:
5) Guaranteed by characterization.
MP4068 Rev. 1.01
7/30/2015
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MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
TYPICAL CHARACTERISTICS
MP4068 Rev. 1.01
7/30/2015
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MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
TYPICAL PERFORMANCE CHARACTERISTICS
Performance waveforms are tested on the evaluation board of the Design Example section.
VIN = 120VAC, VOUT = 50V, IOUT=160mA, L = 1mH, TA = 25°C, unless otherwise noted.
MP4068 Rev. 1.01
7/30/2015
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© 2015 MPS. All Rights Reserved.
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MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
Performance waveforms are tested on the evaluation board of the Design Example section.
VIN = 120VAC, VOUT = 50V, IOUT=160mA, L = 1mH, TA = 25°C, unless otherwise noted.
MP4068 Rev. 1.01
7/30/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
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MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
Performance waveforms are tested on the evaluation board of the Design Example section.
VIN = 120VAC, VOUT = 50V, IOUT=160mA, L = 1mH, TA = 25°C, unless otherwise noted.
MP4068 Rev. 1.01
7/30/2015
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© 2015 MPS. All Rights Reserved.
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MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
PIN FUNCTIONS
Pin #
Pin #
SOIC8-7A SOIC-8 EP
Name
1
1
VCC
2,5,6
3
GND
3
2
OVF
4
4
CS
8
7
HV
5,6,8
NC
MP4068 Rev. 1.01
7/30/2015
Description
Power Supply. Supply power for all the control circuits. Typically, connect
VCC to an external 2.2uF capacitor.
Ground. Virtual Ground of the IC.
Output Voltage Feedback. The over-voltage condition is detected on
OVF. When the voltage on OVF exceeds the VOVP (after a blanking time),
the OVP is triggered, and the chip shuts down.
Current Sense of the Internal Power MOSFET. Connect a resistor from
CS to GND to sense the current through the inductor. When the voltage on
CS exceeds 0.46V, the internal MOSFET is turned off. If the start-up time
exceeds the maximum on time (9us), the internal MOSFET is turned off
(even though the voltage on CS has not reached 0.46V).
High-Voltage Input of the Internal Power MOSFET. HV is also the input
of the internal high-voltage current source.
No Connection. Do NOT connect.
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MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
BLOCK DIAGRAM
FIGURE 1. Functional Block Diagram
MP4068 Rev. 1.01
7/30/2015
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MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
OPERATION
The MP4068 is a highly integrated and costeffective TRIAC dimmable LED driver with a
high power factor (PF). Minimal external
components make the MP4068 a competitive
IC in low-line (120VAC) input, non-isolated
applications, especially for small form factor
applications. Hybrid operation mode achieves
both good dimming performance and an
accurate output current. The power factor is
higher than 0.7 in most applications to eliminate
the harmonic pollution on AC line. The
integrated high-voltage regulator enables fast
start-up without any perceptible delay. The
power de-rating function at high temperatures
protects the IC from thermal damage.
When the voltage on VCC drops below
VCCSTOP (3.4V, typically), the IC stops working,
and the internal high-voltage regulator recharges the VCC capacitor.
Hybrid Operation Mode
To
achieve
smooth
TRIAC
dimming
performance, the MP4068 implements an MPS
proprietary hybrid operation mode, in which the
IC self-adjusts the internal PWM control mode
between CCM and DCM during different times
of the AC cycle. The hybrid operation mode
actively maintains the latching current and
holding current of the leading edge TRIAC, and
it enables good power factor.
Also, the hybrid operation mode achieves the
small dimming duty condition. The IC works in
CCM during the entire dimming on time when
the dimmer is set to a small dimming duty. The
higher and smoother input current achieves
excellent dimming performance.
Power Supply
The IC is self supplied by the internal highvoltage regulator (which is drawn from the
drain). The IC starts switching and the internal
high-voltage regulator turns off as soon as the
voltage on
VCC reaches VCCOFF (4.65V,
typically). When the voltage on VCC falls below
VCCON (4.4V, typically), the internal highvoltage regulator turns on again to charge the
external VCC capacitor. A small capacitor
(several μF) is recommended. In TRIAC
dimming applications, the internal high-voltage
regulator works only when the dimmer is on and
cannot afford enough power supply for the chip,
so an external charging circuit is recommended
(see Fig. 2).
When OVP occurs, the MP4068 stops working,
and an 18μA internal current source discharges
the VCC capacitor. After VCC drops below
VCCPRO (2.35V, typically), the internal highvoltage regulator re-charges the VCC capacitor
again. The re-start time can be calculated by the
following equation:
MP4068 Rev. 1.01
7/30/2015
MP4068
R1
VCC
C2
C1
D1
OVF
L
GND
LED+
FIGURE 2. VCC Charging Circuit
trestart = CVcc ×
Vcc − 2.35V
4.65V − 2.35V
+ CVcc ×
18μA
5mA
Fig. 3 shows the typical waveform with VCC
under-voltage lockout.
VCC
Internal
Voltage
Regulator
VCC OFF
VCC ON
ON
VCC STOP
OFF
Driving
Signal
FIGURE 3. VCC Under-Voltage Lock Out (UVLO)
Constant Current Operation
The MP4068 is a highly integrated driver. 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 (0.195V). When the
sampling capacitor voltage (VFB) falls below the
reference voltage (which indicates an insufficient
output current), the integrated MOSFET is
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MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
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.
4).
FIGURE 5. tminoff at Start-Up
Thermal Protection (TSD)
FIGURE 4. VFB vs IOUT
By monitoring the internal sampling capacitor
voltage, the output current can be regulated.
The output current is determined by the
following equation:
IO =
0.195V
R1
The peak current can be calculated as follows:
IPeak =
0.46V
R1
Where R1 is the sense resistor.
Minimum Operating Frequency Limit
The MP4068 incorporates a minimum operating
frequency (22kHz) to eliminate audible noise
when the frequency is less than 20kHz.
When the operating frequency is less than
22kHz, the internal peak current regulator will
decrease the peak current value to keep the
operating frequency constant (about 22kHz).
Minimum Off-Time Limit
A minimum off-time limit is implemented. During
normal operation, the minimum off-time limit is
7μs. During the start-up period, the minimum
off-time limit is shortened gradually from 24μs
to 12μs to 7μs (see Fig. 5). Each minimum off
time maintains a 32 switching cycle. This softstart function enables a safe start-up.
MP4068 Rev. 1.01
7/30/2015
To prevent the IC and system from thermal
damage, the MP4068 reduces the reference to
decrease the output current. This limits the
temperature rising speed of the IC when the
junction temperature exceeds 145°C. Typically,
the output current drops to around 20% when
the IC temperature rises to 160°C. Once the
junction temperature exceeds 160°C, the
MP4068 shuts down the switching cycle. As
soon as the junction temperature drops below
110°C, the power supply resumes operation.
During the thermal shutdown condition, the
VCC is discharged to VCCPRO, and then it is recharged by the internal high-voltage regulator.
Over-Voltage Protection (OVP)
When the MOSFET turns off, if VOVF is higher
than VOVP, the MP4068 stops working, and a restart cycle begins. When OVP occurs, the chip
works in hiccup mode; the MP4068 monitors
the OVF voltage continuously, and the VCC
voltage discharges and re-charges repeatedly.
The MP4068 resumes operation once the fault
disappears.
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 reduces
automatically the switching frequency and
achieves close loop control. Then the output
power at this condition is limited at a safe range.
The MP4068 resumes working in normal
operation once the short circuit is released.
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14
MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
Leading Edge Blanking (LEB)
There are parasitic capacitances in the circuit
which can cause a high-current spike during the
turn-on period of the internal MOSFET. In order
to avoid premature termination of the switching
pulse, an internal leading edge blanking (LEB)
unit is employed. During the blanking time, the
current comparator is disabled and blocked
from turning off the internal MOSFET (see Fig.
6).
MP4068 Rev. 1.01
7/30/2015
VLimit
TLEB
t
FIGURE 6. Leading Edge Blanking (LEB)
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15
MP4068 – HIGH PF, NON-ISOLATED, TRIAC DIMMABLE LED DRIVER
APPLICATION INFORMATION
Component Selection
Inductor
The MP4068 has a minimum off-time limit. The
inductor current ripple at CCM is determined by
the inductor value and the minimum off-time
limit. The current ripple is limited to 80% to get
a tradeoff between the PF and dimming
performance. The inductance value can be
calculated as follows:
L=
MP4068
VCC
OVF
The diode should have a maximum reversevoltage rating, which is greater than the
maximum input voltage. The current rating of
the diode is determined by the output current,
which should be larger than 1.5 to 2 times the
output current.
Slow diodes cause excessive leading edge
current spikes during start-up, which is not
acceptable. Long reverse-recovery time of the
freewheeling diode can also affect the efficiency
and the circuit operation. An ultrafast diode
(trr
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