MP4026GJ

MP4026
Primary-Side-Control,
Offline LED Controller with Active PFC
The Future of Analog IC Technology
DESCRIPTION
FEATURES
The MP4026 is a primary-side-control, offline
LED controller that achieves high-power factor
and accurate LED current for isolated, singlepower-stage lighting applications in a tiny
TSOT23-6 package. It is the next generation of
the successful MP4021A. The proprietary realcurrent-control method accurately controls LED
current from primary-side information with good
line and load regulation. The primary-side-control
eliminates
the
secondary-side
feedback
components and the opto-coupler to significantly
simplify LED-lighting-system design.
•
The MP4026 integrates power-factor correction
and works in valley switching mode to reduce
MOSFET switching losses.
The MP4026’s multiple protection features
greatly enhance system reliability and safety.
These features include over-voltage protection,
short-circuit protection, primary-side over-current
protection, brown out protection, cycle-by-cycle
current limiting, VCC under-voltage lockout, and
auto-restart over-temperature protection.
•
•
•
•
•
•
•
•
•
•
•
Real-Current Control without SecondaryFeedback Circuit
Good Line/Load Regulation
High Power Factor (≥0.9) over Universal
Input Voltage
Valley Switching Mode for Improved
Efficiency
Brown-Out Protection
Over-Voltage Protection
Short-Circuit Protection
Over-Temperature Protection
Primary-Side Over-Current Protection
Cycle-by-Cycle Current Limit
Input UVLO
Available in TSOT23-6
APPLICATIONS
•
•
Industrial and Commercial Lighting
Residential Lighting
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.
TYPICAL APPLICATION CIRCUIT
Mult
GATE
COMP
CS/ZCD
GND
VCC
MP4026 Rev. 1.1
9/9/2015
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© 2015 MPS. All Rights Reserved.
1
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
ORDERING INFORMATION
Part Number
MP4026GJ*
Package
TSOT23-6
Top Marking
See Below
* For Tape & Reel, add suffix –Z (e.g. MP4026GJ–Z);
TOP MARKING
AFS: product code of MP4026GJ;
Y: year code.
PACKAGE REFERENCE
TOP VIEW
VCC
1
6
GATE
MULT
2
5
CS/ZCD
3
4
GND
COMP
TSOT23-6
MP4026 Rev. 1.1
9/9/2015
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© 2015 MPS. All Rights Reserved.
2
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
ABSOLUTE MAXIMUM RATINGS (1)
Thermal Resistance
Input Voltage VCC ..........................-0.3V to +30V
Gate Drive Voltage .......................-0.3V to +17V
ZCD Pin .........................................-0.3V to 6.5V
Other Analog Inputs and Outputs ..-0.3V to 6.5V
Max. Gate Source Current ......................... 0.8A
Max. Gate Sink Current ................................ -1A
(2)
Continuous Power Dissipation (TA = +25°C)
TSOT23-6 ................................................ 1.25W
Junction Temperature ...............................150°C
Lead Temperature ....................................260°C
Storage Temperature............... -65°C to +150°C
TSOT23-6………………...
Recommended Operating Conditions
(3)
(4)
θJA
θJC
100.... 55.. °C/W
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.
Supply Voltage VCC ...........................12V to 28V
Operating Junction Temp. (TJ)..-40°C to +125°C
MP4026 Rev. 1.1
9/9/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
3
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
ELECTRICAL CHARACTERISTICS
Typical values are at VCC = 20V, TJ = +25°C, unless otherwise noted.
Minimum and maximum values are at VCC = 20V, TJ = -40°C to +125°C, unless otherwise noted,
guaranteed by characterization.
Parameter
Supply Voltage
Operating Range
Turn-On Threshold
Turn-Off Threshold
Hysteretic Voltage
Supply Current
Start-up Current
Quiescent Current
Operating Current Under Fault
Condition
Operating Current
Multiplier
Linear Operation Range
Gain
Brown-Out Protection Threshold
Brown-Out Detection Time
Brown-Out-Protection-Hysteretic
Voltage
Symbol
Condition
Min
Typ
Max
Units
VCC
VCC_ON
VCC_OFF
VCC_HYS
After turn on
VCC rising edge
VCC falling edge
12
23
8.2
14.2
24.9
9.3
15.6
28
28
10.8
17.3
V
V
V
V
ISTARTUP
IQ
VCC= VCC_ON -1V
No switching
20
0.6
50
0.82
µA
mA
ICC
No switching
2
fs =70kHz, CGATE=1nF
2
VMULT
K(5)
0
mA
3
mA
3
280
25
1.3
300
42
316
60
V
1/V
mV
ms
90
100
110
mV
0.401
0.413
0.425
V
Error Amplifier
Feedback Voltage
VFB
Transconductance
(6)
GEA
125
µA/V
Upper Clamp Voltage
VCOMP_H
4.5
4.75
5.1
V
Lower Clamp Voltage
VCOMP_L
1.42
1.5
1.58
V
Max. Source Current
Max. Sink Current
(6)
(6)
ICOMP
50
µA
ICOMP
-200
µA
Current Sense Comparator and Zero Current Detector
CS/ZCD Bias Current
IBIAS_CS/ZCD
500
nA
Leading-Edge-Blanking Time
tLEB_CS
200
320
550
ns
Current-Sense-Clamp Voltage
Over-Current-Protection,
Leading-Edge-Blanking Time
Over-Current-Protection
Threshold
Zero-Current-Detection
Threshold
Zero-Current-Detect Hysteresis
VCS_CLAMP
1.9
2.0
2.1
V
tLEB_CSOCP
130
200
380
ns
VCS_OCP
2.4
2.5
2.6
V
0.270
0.295
0.318
V
562
595
628
mV
MP4026 Rev. 1.1
9/9/2015
VZCD_T
VZCD_HYS
VZCD falling edge
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4
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
ELECTRICAL CHARACTERISTICS (continued)
Typical values are at VCC = 20V, TJ = +25°C, unless otherwise noted.
Minimum and maximum values are at VCC = 20V, TJ = -40°C to +125°C, unless otherwise noted,
guaranteed by characterization.
Parameter
Symbol
tLEB_ZCD
ZCD Blanking Time
tLEB_ZCD
Over-Voltage Blanking Time
tLEB_OVP
tLEB_OVP
Over-Voltage Threshold
Minimum Off Time
Starter
Start-Timer Period
Gate Driver
Output-Clamp Voltage
Minimum-Output Voltage
Max. Source Current(6)
Max. Sink Current(6)
Thermal Shutdown
Thermal Shutdown Threshold(7)
Thermal Shutdown Recovery
Hysteresis(7)
VZCD_OVP
tOFF_MIN
Condition
After turn-off,
VMULT_O >0.3V
After turn-off,
VMULT_O ≤0.3V
After turn-off,
VMULT_O >0.3V
After turn-off,
VMULT_O ≤0.3V
1.6μs delay after turn-off
Min
Typ
Max
Units
1.2
1.6
2.1
μs
0.6
0.8
1.1
μs
1.2
1.6
2.1
μs
0.6
0.8
1.1
μs
4.9
4
5.1
5.5
5.4
8
V
µs
tSTART
VGATE_CLAMP VCC=28V
VGATE_MIN
VCC=VCC_OFF + 50mV
IGATE_SOURCE
IGATE_SINK
190
13
6.7
14.5
µs
17
0.8
-1
V
V
A
A
TSD
150
℃
THYS
25
℃
Notes:
5) The multiplier output is given by: Vcs=k*VMULT*(VCOMP-1.5)
6). Guaranteed by design.
7). Guaranteed by characterization.
MP4026 Rev. 1.1
9/9/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
5
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 90V-265V, VOUT = 10-20V, ILED=350mA, TA = 25°C, unless otherwise noted.
Line/Load Regulation
VFB Temperature Tendency
0.416
0.359
IOUT (A)
0.413
0.412
6LEDs
0.85
0.355
0.414
VFB (V)
0.87
3LEDs
0.357
0.415
0.83
4LEDs
0.353
0.351
-10
20
50
80 110 140
0.79
6LEDs
0.345
90 120 150 180 210 240 270
VIN (VAC)
PF @Full Load
5LEDs
5LEDs
0.347
0.41
-40
3LEDs
0.81
0.349
0.411
Efficiency
4LEDs
0.77
0.75
90
120 150 180 210 240 270
VIN (VAC)
Steady State
Steady State
VIN =110V
VIN =110V
1
0.99
0.98
ILED
200mA/div.
0.97
PF
0.96
0.95
0.94
0.93
VDRAIN
100V/div.
VCOMP
1V/div.
VCS/ZCD
2V/div.
VCS/ZCD
2V/div.
VGATE
10V/div.
VGATE
10V/div.
0.92
0.91
0.9
90
120 150 180 210 240 270
VIN (VAC)
Steady State
VIN =110V
IIN
100mA/div.
VIN
100V/div.
MP4026 Rev. 1.1
9/9/2015
Steady State
Steady State
VIN =230V
VIN =230V
ILED
200mA/div.
VDRAIN
200V/div.
VCOMP
1V/div.
VCS/ZCD
2V/div.
VCS/ZCD
2V/div.
VGATE
10V/div.
VGATE
10V/div.
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6
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 90V-265V, VOUT = 10-20V, ILED=350mA, TA = 25°C, unless otherwise noted.
Steady State
VIN Start up
VIN Start up
VIN =230V
VIN = 110V
VIN = 230V
IIN
50mA/div.
VIN
200V/div.
ILED
200mA/div.
ILED
200mA/div.
VVCC
10V/div.
VVCC
10V/div.
VCOMP
1V/div.
VGATE
10V/div.
VCOMP
1V/div.
VGATE
10V/div.
Open LED Protection
VIN = 110V, Open LED @ Working
Open LED Protection
Short Circuit Protection
VIN =230V, Open LED @ Working
VIN =110V
Short LED+ to LED- @ Working
ILED
200mA/div.
ILED
200mA/div.
ILED
200mA/div.
VVCC
10V/div.
VCOMP
2V/div.
VVCC
10V/div.
VCOMP
2V/div.
VVCC
10V/div.
VCOMP
2V/div.
VGATE
10V/div.
VGATE
10V/div.
VGATE
10V/div.
Short Circuit Protection
Primary-Side OCP Protection
Primary-Side OCP Protection
VIN =230V
Short LED+ to LED- @ Working
VIN =110V
Short primary winding @ Working
VIN =230V
Short primary winding @ Working
ILED
200mA/div.
ILED
200mA/div.
ILED
200mA/div.
VVCC
10V/div.
VCOMP
2V/div.
VVCC
10V/div.
VCOMP
2V/div.
VVCC
10V/div.
VCOMP
2V/div.
VGATE
10V/div.
VGATE
10V/div.
VGATE
10V/div.
MP4026 Rev. 1.1
9/9/2015
www.MonolithicPower.com
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7
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
PIN FUNCTIONS
Pin
Name
1
VCC
Power Supply. Supplies power for the control signals and the high-current
MOSFET. Bypass to ground with an external bulk capacitor (typically 4.7µF).
2
MULT
Input Voltage Sense. Connect to the tap of resistor divider between the rectified AC
line and GND. The half-wave sinusoid provides a reference signal for the internalcurrent-control loop.
The MULT pin is also used for brown-out protection detection.
3
COMP
Loop Compensation. Connect a compensation network to stabilize the LED driver
and maintain an accurate LED current.
4
GND
5
CS/ZCD
6
GATE
MP4026 Rev. 1.1
9/9/2015
Description
Ground. Current return for the control signal and the gate-drive signal.
Current Sense or Zero-Current Detection. When the gate driver turns on, a sensing
resistor senses the MOSFET current. The comparison between the sensed voltage
and the internal sinusoidal-current reference determines when the MOSFET turns
off. If the pin voltage exceeds the current limit (2.0V, after turn-on blanking) the gate
drive turns off.
When the gate driver turns off, the negative falling-edge (after the blanking time)
triggers the external MOSFET’s turn-on signal. Connect this pin to a resistor divider
though a diode between the auxiliary winding and GND.
Over-voltage condition is detected through ZCD. For every turn-off interval, if the
ZCD voltage exceeds the over-voltage-protection threshold after the 1.6µs
(Vmult_o >0.3V) or 0.8µs (Vmult_o ≤0.3V) blanking time, over-voltage protection triggers
and the system stops switching until auto-restart.
CS/ZCD is also used for primary-side over-current-protection, if the sensing voltage
reaches to 2.5V after a blanking time at gate turn-on interval, the primary-side overcurrent-protection triggers and the system stops switching until auto-restart.
A 10pF ceramic cap is recommended to connect from CS/ZCD to GND to bypass
the high frequency noise. In order to reduce the RC delay influence to the sample
accuracy of the current sensing signal, the CS/ZCD down side resistance (RZCD2 in
figure 7) is suggested to be selected as small as 1kΩ.
Gate Drive Output. This totem-pole output stage can drive a high-power MOSFET
with a peak current of 0.8A source and 1A sink. The high-voltage limit is clamped to
14.5V to avoid excessive gate-drive voltage. The low-voltage is higher than 6.7V to
guarantee a sufficient drive capacity.
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8
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
FUNCTION DIAGRAM
N:1
EMI
Filter
MULT
UVLO
GND
Internal
Power supply
Peak
detector
Brown out
VCC
Multiplier
PWM generator
Driver
Gate
Q1
Brown out
OTP
Current
Sense
COMP
CS/ZCD
Current
Limit
OCP
Real Current
Control
OVP
OCP
ZCD_OVP
detection
Zero Crossing
detecti on
Figure 1—MP4026 Function Block Diagram
MP4026 Rev. 1.1
9/9/2015
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9
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
OPERATION
The MP4026 is a primary-side-controlled, offline
LED controller for high-performance LED
lighting. It has primary-side real-current control
for accurate LED current regulation. It also has
active power factor correction (PFC) to
eliminate harmonic noise on the AC line. The
rich protections can achieve a high safety and
reliability in real application.
VDRAIN
VBUS+NVOUT
VBUS
Turn On
Start Up
IPRI
Initially, AC line charges up VCC through the
start-up resistor. When VCC reaches 24.9V, the
control logic starts. Then the power supply is
taken over by the auxiliary winding when the
voltage of auxiliary winding builds up.
ISEC/N
Magnetizing
Current
tON
tOFF
VCS/ZCD
The MP4026 will shut down when VCC drops
below 9.3V.
0
The high hysteretic voltage allows for a small
VCC capacitor (typically 4.7μF) to shorten the
start-up time.
Figure 2: Valley Switching Mode
Valley Switching Mode
During the external MOSFET ON-time (tON), the
rectified-input voltage (VBUS) charges the
primary-side inductor (LP) causing the primaryside current (IPRI) to increase linearly from zero
to peak value (IPK). When the MOSFET turns off,
the energy stored in the inductor is transferred
to the secondary-side, which activates the
secondary-side diode to power the load. The
secondary current (ISEC) decreases linearly from
its peak value to zero. When the secondary
current decreases to zero, the MOSFET drainsource voltage starts oscillating, which is
caused by the primary-side magnetizing
inductance and parasitic capacitances—the
voltage ring also is reflected on the auxiliary
winding (see Figure 2). To improve primarycontrol precision, the chip monitors when ZCD
voltage falls to zero twice before the next
switching period. The zero-current detector
from CS/ZCD generates GATE turn-on signal
when the ZCD voltage falls below 0.295V the
second time (see Figure 3).
This virtually eliminates switch turn-on loss and
diode reverse-recovery losses, ensuring high
efficiency and low EMI noise.
MP4026 Rev. 1.1
9/9/2015
Figure 3: Zero-Current Detector
Real-Current Control
The proprietary real-current-control method
allows the MP4026 to control the secondaryside LED current using primary-side information.
The mean output LED current is approximately:
Io ≈
N ⋅ VFB
2 ⋅ Rs
Where:
• N is the primary-side-to-secondary-side turn
ratio,
• VFB is the feedback reference voltage
(typically 0.413V), and
•
Rs is the sensing resistor connected
between the MOSFET source and GND.
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10
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
Power-Factor Correction
Minimum Off Time
The MULT pin is connected to a pull up resistor
from the rectified-instantaneous-line voltage and
fed as one input of the Multiplier. The multiplier
output is sinusoidal.. This signal provides the
reference for the current comparator and
comparing with the primary-side-inductor current,
which sets the sinusoidal primary-peak current.
This helps to achieve a high-power factor.
The MP4026 operates with a variable switching
frequency; the frequency changes with the
instantaneous-input-line voltage. To limit the
maximum frequency and get a good EMI
performance, the MP4026 employs an internal,
minimum-off-time limiter—5.5µs.
Multiplier output
Inductor current
Figure 4: Power-Factor Correction
The maximum voltage of the multiplier output to
the current comparator is clamped at 2V for a
cycle-by-cycle current limit.
Leading-Edge Blanking
To avoid premature switching-pulse termination
due to the parasitic capacitances discharging
when the MOSFET turns on at normal operation,
the MP4026 uses an internal-leading edge
blanking (LEB) unit between the CS/ZCD pin and
the current-comparator input. During the blanking
time, the path from the CS/ZCD pin to the current
comparator input is blocked. Figure 6 shows the
leading-edge blanking. The LEB time of primaryside OCP detection is relatively short, 200ns.
VCS
tLEB =320ns
VCC Under-Voltage Lockout
When VCC drops below the UVLO threshold
(9.3V), the MP4026 stops switching and shuts
down. The operating current is very low under
this condition, the VCC will be charged up again
by the external start up resistor from AC line.
Figure 5 shows the typical VCC under-voltage
lockout waveform.
Vcc
Auxiliary Winding Takes Charge
And Regulates the VCC
Protection happens
24.9V
9.3V
Gate
Switching
Pu lses
Figure 5: VCC Start-Up Waveform
Auto Starter
The MP4026 has an integrated auto starter. The
starter times when the MOSFET is OFF: If ZCD
fails to send out another turn-on signal after
190µs, the starter will automatically send out the
turn-on signal to avoid unnecessary shutdowns
due to missing ZCD detections.
MP4026 Rev. 1.1
9/9/2015
t
Figure 6: Leading-Edge Blanking
Output Over-Voltage Protection
Output
over-voltage
protection
prevents
component damage during an over-voltage
condition. The auxiliary-winding voltage’s positive
plateau is proportional to the output voltage: the
OVP uses the auxiliary winding voltage instead of
directly monitoring the output voltage. Figure 7
shows the OVP sampling unit. Once the ZCD
voltage exceeds 5.1V at gate turn off interval, the
OVP signal will be triggered and latched, the gate
driver will be turned off and the IC works at
quiescent mode, the VCC voltage dropped below
the UVLO which will make the IC shut down, and
the system restarts again.
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11
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
voltage drops to follow the secondary-winding
voltage, VCC drops to less than the UV threshold,
and the system restarts. This sequence limits
the output power and IC temperature rise if an
output short occurs.
The output-OVP-set point is then:
VOUT _ OVP ⋅
NAUX
R ZCD2
⋅
= 5.1V
NSEC R ZCD1 + R ZCD2
Where:
•
VOUT_OVP
is
the
protection point,
output-over-voltage-
•
NAUX is the number of auxiliary-winding
turns, and
•
NSEC is the number of secondary-winding
turns.
Gate
Gate_OFF
CS/ZCD
+
-
Latch
5.1V
OVP
Blanking time
RZCD 2
R1
RZCD 1
Primary-Side Over-Current Protection
The primary-side over-current protection
prevents device damage caused by extremely
excessive current, like primary winding short. If
the CS/ZCD pin voltage rising to 2.5V at gate
turn on interval, as shown in Figure 9, the
primary-side over-current protection signal will
be triggered and latched, the gate driver will be
turned off and the IC works at quiescent mode,
the VCC voltage dropped below the UVLO which
will make the IC shut down, and the system
restarts again.
To avoid mis-trigger by the parasitic
capacitances discharging when the MOSFET
turns on, a LEB time is needed, this LEB time is
relatively smaller than current regulation
sensing LEB time, typical 200ns.
Gate
Figure 7: OVP Sampling Unit
To prevent a voltage spike from mis-triggering
OVP after the switch turns off, OVP sampling
has a tLEB_OVP blanking period (typically 1.6µs
when VMULT_O > 0.3V and 0.8µs when VMULT_O ≤
0.3V) as shown in Figure 8.
VCS/ZCD
Gate_ON
CS/ZCD
Latch
+
-
2.5V
OCP
Blanking time
RZCD 2
R1
RZCD 1
Sampling Here
Figure 9: Primary-side OCP Sampling Unit
0V
t LE B _OV P
Figure 8: ZCD Voltage and OVP Sampler
Output Short-Circuit Protection
If an output short occurs, the ZCD can not
detect the transformer’s zero-current-crossing
point, so the 190μs auto-restart timer triggers
the power MOSFET’s turn-on signal. Then the
switching frequency of the power circuit drops
to about 5kHz, and the output current is limited
to its nominal current. The auxiliary-winding
MP4026 Rev. 1.1
9/9/2015
Brown-Out Protection
The MP4026 has brown-out protection: the
internal peak detector detects the peak value of
the rectified sinusoid waveform in MULT pin. If
the peak value is less than the brown-outprotection threshold 0.3V for 42ms, the IC
recognizes this condition as a brown-out,
quickly drops the COMP voltage to zero, and
disables the power circuit. If the peak value
exceeds 0.4V, the IC restarts and the COMP
voltage rises softly again. This feature prevents
both the transformer and LED currents from
saturating during fast ON/OFF switching. Figure
10 shows the brown-out waveforms.
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12
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
IC Thermal Shut Down
VCC
Brown out
happen
Vbus
Brown out
detected
Brown
out
recover
To prevent from any lethal thermal damage,
when the inner temperature exceeds the OTP
threshold, the MP4026 shuts down switching
cycle and latched until VCC drop below UVLO
and restart again.
Design Example
For the design example, please refer to MPS
application note AN076 for the detailed design
procedure.
V peak_ Mult
Vcomp
Vgate
Figure 10: Brown-Out Protection Waveforms
MP4026 Rev. 1.1
9/9/2015
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13
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
NON-ISOLATED APPLICATIONS
The isolated solution can prevent human body
from an electric shock by grid when touching
the load. But the power loss and the cost are
increased. Recur to safety enclosure frame of
the lamp, compared with isolated solution, the
non-isolated solution can achieve higher
efficiency and highly cost-effective.
voltage, since the higher output voltage can
extend the duty cycle to improve the PF and
THD and the efficiency can also be improved
meanwhile.
For the non-isolated solution with low output
voltage, the tapped-inductor can be applied to
improve the PF and THD.
Generally, the Flyback converter is common for
the offline isolated applications. As topology
transmutation, the non-isolated low-side Buckboost converter is also popular. Besides fitting
in isolated application, the MP4026 can also
operate in the offline non-isolated LED lighting
applications.
Figure 16 is a 30W low-side Buck-boost LED
driver with MP4026.
Operation of Low-side Buck-boost
The low-side Buck-boost can be treated as
Flyback converter with 1:1 turn ratio transformer.
So, the whole operation is absolutely same as
the description above. Different from isolated
solution, there are no separate primary- and
secondary-winding, so a smaller core size is
available for design. Without the impact of the
leakage
inductance,
the
snubber
is
unnecessary. All of these can save cost and
improve the efficiency of the driver.
The Selection of FET & Rectifier Diode
Since it is just an inductor for non-isolated
solution, compared with isolated solution, at
same output voltage, the power FET can be
selected with lower voltage rating. But,
oppositely, the voltage rating of rectifier diodes
for output and aux-winding must be increased.
Improvement of RF EMI
CY1 in Figure 16 is added for RF EMI
improvement. The recommended value is from
10nF to 47nF with 630V rating.
Improvement of PFC & THD
The impact of non-turn-ratio is that the duty
cycle of the converter becomes smaller at same
spec. Based on MP4026 PFC principle, the PF
and THD of the converter drops compared with
isolated solution. So, generally, the non-isolated
solution is especially suitable for high output
MP4026 Rev. 1.1
9/9/2015
Figure 11: Tapped-inductor for Low-side Buckboost Solution
Shown in Figure 11, the tapped-inductor
includes two windings (N1 & N2) and a tap to
connect the rectifier diode. When the power
FET is turned on, the current goes thru both of
the windings. But when the power FET is off,
just N1 conducts the current thru the rectifier
diode. The stored energy of N2 is released by
flux couple. So, the tapped-inductor features a
similar turn-ratio like the transformer in isolated
solution.
The nominal turn-ratio is
n=
N1 + N2
>1
N1
The duty cycle of the converter is obviously
extended by tapped-inductor, and then the
better PF and THD are available.
But, like transformer, the snubber is necessary
to clamp the voltage spike caused by leakage
inductance.
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14
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
On the other hand, the non-dimmable solution
usually needs to cover universal input range.
The input range is very wide, from 85VAC to
264VAC. The MULT pin is used to detect the
input voltage signal, but the resistor divider of
MULT is fixed. So, at high line input, the signal
for MULT input is very low, which results in
adverse effect for internal multiplier sampling,
then affect the PFC performance.
Figure 12 shows an improved circuitry on MULT
resistor divider to adjust the ratio of the divider
to achieve better THD.
BUS
ZD1
RMULT1
Figure 13: The MULT Signal with THD Improved
Circuitry
As Figure 13 shown, after adding the THD
improved circuitry, the top part of the MULT
voltage rises up as the dashed line. Then the
input current at top of BUS is increased while
the input current at the zero-crossing is reduced,
which results in the input current more like
sinusoid and then the THD is improved.
RMULT3
MULT
Multiplier
RMULT2
COMP
CCOMP
Figure 12: THD Improved Circuitry
The ZD1 is a HV Zener diode. The common
voltage rating is from 80V to 130V.
At low line input, the BUS can not breaks down
ZD1, the MULT pin signal is
VMULT = VBUS ×
RMULT2
RMULT1 + RMULT 2
When the input voltage rises up, once the BUS
breaks down ZD1, RMULT3 is paralleled with
RMULT1 to increase the ratio of the divider to
raise the MULT signal.
MP4026 Rev. 1.1
9/9/2015
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15
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
TYPICAL APPLICATION CIRCUITS
R3
5.1k/1206
L3
1.5mH/0.25A
BD1
MB6S
RM6
Lp=2.18mH
Np:Ns:Naux=115:23:26
R14
100k/1206
C6
22nF/630V
C2
100nF/400V
1
CX1
22nF/275VAC
W
R4
470k/0.5W
R7
C7
LED-
R10
U1
MP4026J
1
VCC
GATE
6
R8
20
D4
BAV21W
200V/0.2A
1
3
2
F1
250V/2A
B
R15
C3
R9
1
2
N
LED+
20V/350mA
Aux+
RV1
TVR10431
L
C8
R13
30k/1206
6
D2
BAV21W
200V/0.2A
R2
5.1k/1206
D1
MBRS320T3
200V/3A
2
2
L1
1.5mH/0.25A
L2
1.5mH/0.25A
R1
5.1k/1206
T1
D3
S1ML
1000V/1A
R6
R5
C4
2.2nF/50V
MULT
CS/ZCD
CY1
2.2nF/4kV
Q1
ISU04N65A
650V/4A
5
C1
10pF/50V
3
90VAC-265VAC
C5
COMP
GND
4
R11
R12
Figure 14: A19 Bulb Driver, 90-265VAC Input, Isolated Flyback Converter, VO =20V, IO=350mA
EVB Model: EV4026-J-00A
Figure 15: PAR38 Driver, 90-265VAC Input, Isolated Flyback Converter, VO =40V, IO=500mA
EVB Model: EV4026-J-00B
MP4026 Rev. 1.1
9/9/2015
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16
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
R3
5.1k/1%/1206
LED-
L3
1mH/0.5A
BD1
KBP206
600V/2A
T1
EE25
Lm=460uH
C2
CX1
47nF/275VAC
470nF/450V
R4
300k/1W
R1
5.1k/1%
1206
L1
1mH
0.5A
L2
1mH
0.5A
90Ts
R6
499k/1%/1206
R18
20/1%/1206
R2
5.1k/1%
1206
R7
4.3M/1%
R17
499k/1%/1206
L4
10mH/0.7A
U1
MP4026
1
2
1
2
2
F1
250V/3.15A
1
RV1
TVR14431
D4
BZT52C27
VCC
2
R5
6.2k/1%
90VAC-264VAC
6
MULT
CS/ZCD
COMP
GND
5
R9
2.2k/1%
1
3
2
87V/350mA
L5
600uH
D1
STTH3R06S
600V/3A
C8
C7
100uF/160V 100uF/160V
26Ts
LED+
CY1
47nF/630V
1206
R15
0/1%/1206
Q1
AP3990I
600V/10A
C1
10pF/50V
C4
2.2nF/50V
1
N
R8
20/0805
GATE
C3
6.8uF/50V
3
L
R10
10.2k/1%
D2
BAV23A/SOT-23
200V/0.2A
R13
100k/1206
4
R11
0.3/1%/1206
R16
1.5/1%/1206
C5
2.2uF/6.3V/0805
R12
0.3/1%/1206
Figure 16: 90-264VAC Input, Non-isolated Low-side Buck-boost Converter, VO =87V, IO=350mA
MP4026 Rev. 1.1
9/9/2015
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17
MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC
PACKAGE INFORMATION
TSOT23-6
0.95
BSC
0.60
TYP
2.80
3.00
6
4
1.20
TYP
See Note 7
EXAMPLE
TOP MARK
PIN 1
AAAA
1
1.50
1.70
2.60
3.00
2.60
TYP
3
TOP VIEW
R EC OMMEN DED LA ND PA TTERN
0.84
0.90
1.00 MAX
0.09
0.20
SEATING PLANE
0.30
0.50
0.95 BSC
0.00
0.10
SEE DETAIL "A"
FRONT VIEW
SIDE VIEW
NOTE:
GAUGE PLANE
0.25 BSC
o
0 -8
o
0.30
0.50
D ETA IL “A”
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 BE 0.10 MILLIMETERS MAX.
5) DRAWING CONFORMS TO JEDEC MO-193, VARIATION AB.
6) DRAWING IS NOT TO SCALE.
7) PIN 1 IS LOWER LEFT PIN WHEN READING TOP MARK FROM
LEFT TO RIGHT, (SEE EXAMPLE TOP MARK)
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.
MP4026 Rev. 1.1
9/9/2015
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18