MP3306EG-Z [MPS]
LED Driver,;
| 型号： | MP3306EG-Z |
| 厂家： | 
MONOLITHIC POWER SYSTEMS |
| 描述： | LED Driver, 驱动 接口集成电路 |
| 文件： | 总12页 (文件大小：429K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MP3306
30V, 700kHz Synchronous StepꢀUp
White LED Driver
DESCRIPTION
FEATURES
The MP3306 is a stepꢀup converter designed for
driving white LEDs from 3V to 12V power supply.
The MP3306 uses current mode, fixed frequency
architecture to regulate the LED current, which is
measured through an external highꢀside current
sense resistor. The low 202mV feedback voltage
and synchronous rectification reduces power loss
and improves efficiency.
•
•
•
3V~12V Input Voltage
Analog Dimming and PWM Dimming
OutputꢀtoꢀInput Disconnect in Shutdown
Mode
Programmable Open Load Shutdown
Output Short Protection
•
•
•
Low 202mV Feedback Voltage with +/ꢀ3%
accuracy
•
•
UVLO, Thermal Shutdown
Available in 2mm x 2mm QFN12 Package
The MP3306 is turned off if an overꢀvoltage
condition is present due to an open circuit
condition. The output disconnect feature allows
the output to be completely discharged. The
MP3306 includes underꢀvoltage lockout, current
limiting, output short protection and thermal
overload protection.
APPLICATIONS
•
•
•
Smart Phone, MID, PDA
Digital Still Cameras
Small LCD Displays
The MP3306 is available in small 12ꢀpin QFN
(2mm x 2mm) package.
All MPS parts are leadꢀfree 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
L1
C3
L
SW
VIN
IN
BST
OUT
C1
GND
EN
R1
MP3306
R2
R3
EN
FB
C2
LED1
LED6
PWMI
VCC
PMWI
GND
C4
OVP
PWMO
C5
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
1
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
ORDERING INFORMATION
Part Number*
Package
Top Marking
QFN12 (2x2mm)
MP3306EG
3Y
* For Tape & Reel, add suffix –Z (e.g. MP3306EG–Z).
For RoHS Compliant packaging, add suffix –LF (e.g. MP3306EG–LF–Z)
PACKAGE REFERENCE
BST
L
12
11
1
2
3
4
10
9
IN
VCC
EN
OUT
SW
GND
FB
8
PWMI
7
5
6
PWMO
OVP
Thermal Resistance (4)
QFN12 (2 x 2mm)...................80 ......16 ...°C/W
θJA
θJC
ABSOLUTE MAXIMUM RATINGS (1)
V
V
V
V
SW,
VOUT,
V
FB....................................ꢀ0.5V to 35V
BST................................. ..................... VSW +6V
L, ............................................ ꢀ0.5V to 14V
CC ........... ꢀ0.3V to 6.5V
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 junctionꢀtoꢀ
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 will cause excessive die temperature, and the
regulator will go into thermal shutdown. Internal thermal
shutdown circuitry protects the device from permanent
damage.
IN,
V
V
EN,
OVP,
VPWMI,
VPWMO,
V
(2)
Continuous Power Dissipation (TA = +25°C)
………………………………………………....1.6W
Storage Temperature...............ꢀ55°C to +150°C
Recommended Operating Conditions (3)
IN Supply Voltage VIN ........................ 3V to 12V
3) The device is not guaranteed to function outside of its
operating conditions.
4) Measured on JESD51ꢀ7, 4ꢀlayer PCB.
Vsw ................................................ ꢀ0.5V to 30V
Operating Junct. Temp (TJ)......ꢀ40°C to +125°C
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
2
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
ELECTRICAL CHARACTERISTICS
VIN = VEN = 5V, TA = +25°C, all voltages with respect to GND, unless otherwise noted.
Parameters
Symbol Condition
Min
Typ Max Units
VIN
3
12
4.1
1
V
V
Operating Input Voltage
VCC Voltage
VVCC
ISD
VIN > 5.5V, VEN = 3V
3.7
3.9
0.1
380
690
93
Supply Current (Shutdown)
Supply Current (Quiescent)
Switching Frequency
Maximum Duty Cycle
Under Voltage Lockout
IN Under Voltage Lockout
Under Voltage Lockout Hysteresis
Protection
VEN = 0V
ꢁA
ꢁA
kHz
%
IQS
VEN = 5V, VOUT ꢀ VFB = 0.5V
300
550
460
830
fSW
DMAX
VFB = VOUT
VIN Rising
UVLO
2.5
2.7
2.9
V
130
mV
OVP Threshold
VOVPꢀTH
1.18 1.22 1.26
V
A
SW Current Limit (5)
Thermal Shutdown (5)
Enable
Duty Cycle = 60%
1.8
150
°C
EN OFF Threshold
EN ON Threshold
VENLO
VENHI
VEN Falling
VEN Rising
0.6
V
V
1.1
Dimming
PWMI Low Threshold
PWMI High Threshold
PWMI Input Frequency
VPWMIꢀLO VPMWI Falling
VPWMIꢀHI VPMWI Rising
FPWMI
0.8
V
V
1.2
0.1
50
kHz
Minimum PWMO Dimming
Threshold
VPWMOꢀMIN VFB = VOUT
25
mV
mV
Maximum PWMO Dimming
Threshold
VPWMOꢀMAX VOUTꢀVFB = 0.2V
850
Feedback
FB Voltage
VFB
IFB
VEN = 3V
VEN = 3V
196
3
202
7
208
11
mV
ꢁA
FB Input Bias Current
Disconnect Switch
OnꢀResistance (5)
RNDꢀON
0.5
ꢂ
Output Switch
HighꢀSide NMOS OnꢀResistance (5)
LowꢀSide NMOS OnꢀResistance(5)
RNHꢀON
RNLꢀON
0.6
0.6
ꢂ
ꢂ
Notes:
5) Guaranteed by design
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
3
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
PIN FUNCTIONS
Pin # Name Pin Function
Input Supply Pin. It provides the power for internal driver and logic circuit. Must be locally
bypassed.
1
2
3
4
IN
The Internal Linear Regulator Output. VCC provides power supply for the internal MOSFET
VCC switch gate driver and the internal control circuitry .Bypass VCC to GND with a ceramic
capacitor.
EN Control Input. A voltage greater than 1.1V turns the part on and less than 0.6V turns the
part off.
EN
Apply a PWM signal on this pin for brightness control. This signal is uniformed and filtered at
PWMI PWMO pin with an internal 100kꢂ resistance. With a capacitor at PWMO pin, the duty cycle
from 0% to 100% at PWMI pin is converted to 0V to 1.2V DC voltage at PWMO pin.
PWM Filter Output. Connect a capacitor from PWMO to GND. The voltage on this pin range
0V to 1.2V linearly controls the feedback voltage from 0V to 0.2V.
To use PWM dimming, connect the PWM input signal to PWMI pin.
5
PWMO
To use analog dimming, connect the analog input voltage to PWMO pin.
Over Voltage Protection Pin. Use one external resistor voltage divider to program OVP
OVP threshold. When the OVP pin voltage reaches the shutdown threshold 1.22V, the IC will be
turned off and latch up until EN is toggled again.
6
7
Feedback Input. The MP3306 regulates the voltage across the current sense resistor
FB
between FB and VOUT. Connect a current sense resistor from VOUT to the LED string.
Connect the anode of the LED string to FB. The regulation voltage is 202mV.
8
9
GND Ground.
The OUTPUT terminal. Connect the output cap on this pin, the output capacitor must be
OUT
SW
BST
L
ceramic type and be placed as short as possible between OUT pin and GND pin.
Power Switch Node. SW is the drain of the internal low side MOSFET switch. Connect the
power inductor to SW.
10
11
12
Bootstrap. A capacitor is connected between SW and BST pins to form a floating supply to
drive the high side MOSFET.
Power input pin. L is the source of internal disconnection MOSFET. Connect the inductor to
this pin.
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
4
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
TYPICAL PERFORMANCE CHARACTERISTICS
VIN=5V, VEN=5V, 8 LEDs in series, 20mA, unless otherwise noted.
Efficiency Steady State
= 3V
EN Startup
V
IN
94
92
V
90
88
86
84
82
80
78
SW
10V/dvi.
V
SW
10V/dvi.
V
5V/dvi.
EN
I
L
V
10V/dvi.
100mA/div.
OUT
I
200mA/div.
INDUCTOR
I
20mA/div.
LED
2
4
6
8
10 12 14
VIN (V)
EN Shutdown
V
SW
10V/dvi.
V
V
SW
10V/dvi.
SW
10V/dvi.
V
5V/dvi.
EN
I
10mA/div.
V
10V/dvi.
LED
OUT
V
5V/dvi.
PWM
I
L
V
5V/dvi.
OUT
100mA/div.
V
5V/dvi.
PWM
I
20mA/div.
LED
I
20mA/div.
LED
V
SW
10V/dvi.
V
SW
10V/dvi.
V
SW
10V/dvi.
V
10V/dvi.
OUT
V
10V/dvi.
OUT
I
L
V
10V/dvi.
OUT
500mA/div.
I
L
V
500mV/div.
OVP
100mA/div.
I
20mA/div.
LED
I
20mA/div.
I
200mA/div.
LED
OUT
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
5
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
FUNCTION DIAGRAM
Figure 1—Functional Block Diagram
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
6
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
OPERATION
The MP3306 uses a constant frequency, peak
current mode step up regulator architecture to
regulate the current flowing through series string of
white LEDs. The operation of the MP3306 can be
understood by referring to the block diagram of
Figure 1.
thus increasing the power charged in inductor and
delivered to the output.
MP3306 provides the analog and PWM dimming
solution, the internal resistor and external capacitor
one PWMO pin filters the PWM dimming signal on
PWMI pin to DC level that program the internal
reference to accomplish the analog dimming
function. When floating the PWMO pin, PWM
dimming function works.
At the start of each oscillator cycle the low side FET
(M2) is turned on through the control circuitry. To
prevent subꢀharmonic oscillations at duty cycles
greater than 50 percent, a stabilizing ramp is added
to the output of the current sense amplifier and the
result is fed into the positive input of the PWM
comparator. When this voltage equals the output
voltage of the error amplifier the power FET is
turned off. Then the inductor current flows into the
output capacitor and LED load through internal high
side Nꢀchannel MOSFET (M3), which forces the
inductor current to decrease.
Open Load protection shuts off the MP3306 if the
output voltage goes too high. In some cases an
LED may fail, this results in the feedback voltage
always being zero. The part then runs at maximum
duty cycle boosting the output voltage up. If the
output ever exceeds the programmable OVP
threshold, the MP3306 will shut down. The part
does not switch again until the EN pin or VIN is
toggled.
The voltage at the output of the error amplifier is an
amplified version of the difference between the
200mV reference voltage and the feedback voltage.
In this way the LED current is regulated accurately.
During Shutdown mode when EN is low, the IC
keeps the internal highꢀside Nꢀchannel MOSFET
(M1) off to disconnect the output from input.
MP3306 has cycle by cycle current limit to protect
the load and IC from over current. And the internal
MOSFET (M1) limits the input current to prevent
system damage when short VOUT condition occurs.
If the feedback voltage starts to drop, the output of
the error amplifier increases. This result in more
current flowing through the high side power FET,
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
7
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
APPLICATION INFORMATION
TP1
C6
VIN
10nF
R5
0
12
9
L
SW
1
2
11
IN
BST
10
JP1
OUT
VCC
R7
NS
TP5
U1
MP3306
TP2
TP3
7
3
4
FB
LED+
EN
EN
R1
51k
TP6
R2
0
8
R8
GND
PWMI
LED-
DIM
205k
R3
PWMO
5
OVP
6
51k
R4
NS
R9
TP4
C5
NS
10k
GND
Figure 2—3V~12V Input, Typical Application Driving 8 WLEDs in series
Figure 2 shows a typical application circuit that
Setting the LED Current
can drive up to 8 white LEDs with 20mA. A
0.22~2.2ꢁF output capacitor is sufficient for most
applications. The inductor with low DC inductor
resistance (DCR) will improve efficiency. Two
4.7ꢃF ceramic capacitors provide sufficient input
decoupling.
The LED current is controlled by the current
setting resistor, R1. The current through the
LEDs is given by: ILED = 202mV/R1.
Table 1 shows the selection of resistors for a
given LED current.
Table 1—ILED vs. R1 RSET
Selecting the Inductor
ILED (mA)
R1 (ꢁ)
200
40
20
10
3.33
1.11
1
The inductor forces a higher output voltage
driven from a lower input voltage. A larger
inductor value results in less ripple current, a
lower peak inductor current, and reduces stress
on the internal NꢀChannel MOSFET. However,
largerꢀvalue inductor has a larger physical
footprint, higher series resistance, and lower
saturation current.
1
5
10
20
60
180
200
The internal ramped compensation voltage
added to the current sense amplifier reduces the
maximum output current as the duty cycle
increases. As more LEDs are added, the output
voltage rises but the maximum current delivered
to the load falls as well. Figure 3 shows the
current limit curve, and the max LED current is
gotten as the formula.
Choose an inductor that does not saturate under
the worstꢀcase load conditions. Calculate the
required inductance value using the following
equations:
η× VOUT × D×(1− D)2
L ≥
2× fSW × ILOAD
V
IN
D = 1−
V ×D
IN
VOUT
ILOAD(max) = (IPK
−
)×(1− D)× 0.8
2×L × fSW
Where VIN and VOUT are the input and output
voltages, fSW is the switching frequency, ILOAD is
the LED load current, and η is the efficiency.
Where, IPK is the peak current corresponding duty
cycle from current limit curve, the L is inductor,
the 0.8 means the margin coefficient.
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
8
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
Current Limit vs. Duty
Layout Considerations
Careful attention must be paid to the PCB board
layout and components placement. Proper layout
of the high frequency switching path is critical to
prevent noise and electromagnetic interference
problems. The loop of MP3306’s internal low side
MOSFET, synchronous MOSFET, and output
capacitor is flowing with high frequency ripple
current, it must be minimized. So the output
capacitor should be placed to IC as close as
possible.
2
1.5
1
0.5
0
0 1020 304050 60 70 8090100
Figure 3—Current Limit Curve
Analog and PWM Dimming
MP3306 provides 2 types of dimming solutions,
analog dimming and PWM dimming.
For analog, connect an external capacitor on
PWMO pin to form the low pass filter with internal
resistor R, the PWM dimming signal on PWMI pin
is filtered to DC signal to set the internal
reference to accomplish the analog dimming. The
time constant should be ten times greater than a
PWM waveform cycle:
RC > 10 ⋅ TPWM
For PWM dimming, floating PWMO pin and apply
the PWM dimming signal on PWMI pin.
Setting Over Voltage Protection Threshold
Open Load protection will shut off the MP3306 if
the output voltage goes too high. In some cases
an LED may fail, this will result in the feedback
voltage always being zero. The part boots the
output voltage higher and higher. If the output
voltage ever exceeds the programmed OVP
threshold as the formula,
VOVP =1.22×(1+ R2/R3)
The MP3306 will shut down. The part will not
switch again until the power is recycled.
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
9
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
TYPICAL APPLICATION CIRCUIT
Figure 4— 4 LEDs in Series 20mA
Figure 5— 4 LEDs in Series 20mA
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
10
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
Figure 6— 6 LEDs in Series with PWM Dimming
Figure 7— 3 LEDs in Series 20mA with 5~10V Input Voltage
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
11
MP3306-30V 700kHz SYNCHRONOUS STEPꢀUP WHITE LED DRIVER
PACKAGE INFORMATION
QFN12 (2x2mm)
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.
MP3306 Rev.1.0
3/6/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
12
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