MP3312LGC-Z [MPS]
LED Driver,;
| 型号： | MP3312LGC-Z |
| 厂家： | 
MONOLITHIC POWER SYSTEMS |
| 描述： | LED Driver, 驱动 接口集成电路 |
| 文件： | 总16页 (文件大小：433K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MP3312L
2.7V-5.5V Input , 38V OVP,
Dual-Channel White LED Driver
The Future of Analog IC Technology
DESCRIPTION
FEATURES
The MP3312L is a dual-channel, step-up WLED
driver with an integrated 40V MOSFET. It
supports a 2.7V to 5.5V power supply input and
uses peak current mode to regulate the LED
current, which is set by an external resistor.
•
•
•
•
•
•
•
•
•
•
•
•
2.7V~5.5V Input Voltage
600kHz Switching Frequency
Dual Channels Support up to 30mA/String
1% Current Matching between LED Channels
+/-2% Current Accuracy
38V OVP
The MP3312L employs a 600kHz fixed switching
frequency. It supports both PWM input analog
dimming and digital analog dimming to regulate
the dimming current accurately.
PWM Input Analog Dimming Mode
5kHz to100kHz PWM Input Analog Dimming
1-Wire Interface for Digital Dimming
9-Bit Dimming Resolution
Internal Soft Start to Reduce Inrush Current
Available in WLCSP1.35x1.35-9mm Package
The MP3312L integrates a current source to
balance the LED current, which leads to good
ILED matching and accuracy performance.
APPLICATIONS
In addition, the MP3312L has both LED open and
short protection, cycle-by-cycle current limit
protection, and thermal shutdown protection. It is
•
•
•
•
Feature Phones and Smart Phones
Tablets
GPS Receivers
<10 Inch LCD Video Displays with One-Cell
Li-Ion Battery
available in
package.
a
tiny WLCSP1.35x1.35-9mm
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
89.8
89.6
89.4
89.2
89
88.8
88.6
88.4
88.2
88
87.8
2.5
3
3.5
4
4.5
5
5.5
6
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
1
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
ORDERING INFORMATION
Part Number*
Package
Top Marking
MP3312LGC
WLCSP1.35x1.35-9mm
See Below
* For Tape & Reel, add suffix –Z (e.g. MP3312LGC–Z)
TOP MARKING
DM: Product code of MP3312LGC
Y: Year code
LLL: Lot number
PACKAGE REFERENCE
Package Diagram
WLCSP1.35x1.35-9mm
ABSOLUTE MAXIMUM RATINGS (1)
VIN.................................................. -0.3V to +6V
VSW…………………………………....-1V to +40V
VLED1, VLED2 ………………………...-0.3V to +40V
All other pins................................. –0.3V to +6V
Junction temperature...............................150°C
Lead temperature ....................................260°C
Thermal Resistance (4)
WLCSP1.35x1.359mm....…………120…..12..°C/W
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-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 will produce 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)
WLCSP1.35x1.35-9mm ...........................1.04W
Recommended Operating Conditions (3)
Supply voltage (VIN) ....................... 2.7V to 5.5V
Operating junction temp...........-40°C to +125°C
3) The device is not guaranteed to function outside of its
operating conditions.
4) Measured on JESD51-7, 4-layer PCB.
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
2
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
ELECTRICAL CHARACTERISTICS
VIN = 3.7V, VEN = VPWM = high, typical values are at TA = 25°C, unless otherwise noted.
Parameters
Symbol
Condition
Min
Typ
Max
Unit
Power Supply
Operating input voltage
VIN
IQ
2.7
5.5
2
V
VIN = 3.7V, VEN = VPWM = high,
no load with switching
Supply current (quiescent)
1
mA
Supply current (shutdown)
Input UVLO threshold
Input UVLO hysteresis
Oscillator
IST
VEN = 0V, VIN = 3.7V
1
μA
V
VIN_UVLO Rising edge
2.4
2.6
200
mV
Switching frequency
Maximum duty cycle
Minimum on time(5)
Power Switch
fSW
500
93
600
95
720
kHz
%
DMAX
TON_MIN
100
ns
Main switch on resistance
Error Amplifier
RDSON_M VIN = 3.7V
0.2
Ω
Error amplifier transconductance
Max sink/source current
Current Regulation
VLEDx regulation voltage
ISET voltage
gm
370
42
µS
μA
VREG
VISET
KISET
ILED1 = ILED2 = 20mA
240
1.232
1020
mV
V
1.207
-2
1.247
Current multiplier
IISET = 20µA,
(|IMIN-IISET|/IISET,|IMAX-IISET|/
Current accuracy
Current matching
2
2
%
IISET
)
IISET = 20µA,
(IMAX –IMIN) /IAVG
1
%
Current sink max output current
EN & PWM Logic
30
1.2
1.2
mA
PWM input high threshold
PWM input low threshold
EN high voltage
VPWM_HI
VPWM rising
V
V
VPWM_LO VPWM falling
VEN_HIGH VEN rising
0.4
0.4
V
EN low voltage
VEN_LOW
RPD
VEN falling
V
EN & PWM pull-down resistor
800
kΩ
EN low logic
TSD_EN
EN high to low
2.5
20
ms
ms
to shutdown time
PWM low logic
to shutdown time
TSD_PWM PWM high to low
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
3
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
ELECTRICAL CHARACTERISTICS (continued)
VIN = 3.7V, VEN = VPWM = high, typical values are at TA = 25°C, unless otherwise noted.
Parameters
Symbol
Condition
Min
Typ
Max
Unit
Protection
OVP voltage
VOVP
ILIM
ILIM_START
TLIM_HALF
37
38
1.8
1
39.5
V
A
Cycle-by-cycle current limit
Start-up current limits(5)
Time step for half current limit(5)
LEDx threshold when no switching
LEDx over-voltage threshold
Thermal shutdown threshold
Thermal shutdown hysteresis
1-Wire Interface
Max duty cycle
Max duty cycle
1.2
A
6
ms
mV
V
560
5
VOVP_LED
TST
4.5
5.5
150
25
°C
°C
1-wire detection delay time
1-wire detection time
tDELAY
tDETECTION
tWIN
100
260
1
μs
μs
ms
μs
μs
μs
1-wire detection window
Start time of program stream
End time of program stream
High time of logic 0 bit
tSTART
tEOS
2
2
360
180
tH_LB
5
Low time of logic 0 bit
tL_LB
3* tH_LB
360
μs
High time of logic 1 bit
tH_HB
tL_HB
tACKval
tACK
3* tL_HB
360
180
2
μs
μs
μs
μs
Low time of logic 1 bit
5
Acknowledge valid time
Duration of acknowledge signal
512
Open
RPULLUP = 15kΩ
to VIN
drain,
Acknowledge output voltage low(6)
VACKL
0.4
V
NOTES:
5) Guaranteed by design and characterization.
6) ACK signal is active 0 (when ACK signal is true, the data line is pulled down by the chip). This signal only replies when the RFA bit is set
to 1. If you want to use the ACK signal, the master should have an open-drain output, and the data line should be pulled high by the
master with a resistor load.
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
4
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
TYPICAL CHARACTERISTICS
350
300
250
200
350
300
250
200
150
100
0.7
0.6
0.5
0.4
0.3
0.2
150
100
50
0
0.1
0
50
0
-50 -30 -10 10 30 50 70 90 110130
-50 -30 -10 10 30 50 70 90 110130
-50 -30 -10 10 30 50 70 90 110130
1.242
1.24
1.238
1.236
1.234
1.232
1.23
1.228
-50 -30 -10 10 30 50 70 90 110130
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
5
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 3.7V, 6*LEDs/string, ILED1 = ILED2 = 20mA, L = 10µH, TA = 25°C, unless otherwise noted.
5
4
3
2
1
45
40
35
30
25
45
40
35
30
25
20
15
10
5
0
20
15
-1
-2
-3
10
5
0
-4
-5
00
20
40
60
80
100
0
20
40
60
80 100
2.5
3
3.5
4
4.5
5
5.5
6
90
88
86
84
82
80
78
76
0
20
40
60
80
100
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
6
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 3.7V, 6*LEDs/string, ILED1 = ILED2 = 20mA, L = 10µH, TA = 25°C, unless otherwise noted.
V
V
SW
SW
V
10V/div.
SW
10V/div.
10V/div.
V
IN
V
OUT
2V/div.
10V/div.
V
IN
2V/div.
I
L
I
I
LED
L
200mA/div.
20mA/div.
200mA/div.
I
I
I
LED
50mA/div.
LED
L
50mA/div.
500mA/div.
V
V
V
SW
SW
SW
10V/div.
10V/div.
10V/div.
V
PWM
V
V
EN
EN
5V/div.
5V/div.
5V/div.
V
I
I
OUT
L
L
20V/div.
200mA/div.
200mA/div.
I
I
I
LED
LED
LED
50mA/div.
50mA/div.
20mA/div.
V
SW
V
SW
20V/div.
V
SW
10V/div.
20V/div.
V
LED1
20V/div.
V
COMP
1V/div.
V
OUT
I
L
V
EN/1-WIRE
2V/div.
20V/div.
200mA/div.
I
L
200mA/div.
I
LED
I
I
LED
LED
50mA/div.
20mA/div.
20mA/div.
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
7
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
PIN FUNCTIONS
Pin #
Name
Description
Full scale LED current set. Connecting a resistor between ISET and GND sets the full
scale current.
A1
ISET
A2
A3
LED2
LED1
LED2 current sink.
LED1 current sink.
PWM signal input. A 5kHz to 100kHz PWM signal is recommended for PWM for analog
current dimming. Low logic for >20ms shuts down the IC.
B1
PWM
B2
B3
C1
COMP
GND
EN
Internal error amplifier output . Connect a capacitor to compensate the system.
Ground.
Enable and 1-wire input. Logic high enables the IC, and low logic >2.5ms shuts down the
IC.
C2
C3
VIN
SW
Power supply input. Connect a ceramic capacitor close to VIN to bypass the IC.
Drain connection of the internal N-channel power MOSFET.
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
8
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
FUNCTIONAL BLOCK DIAGRAM
L1
D1
VOUT
VIN
C1
C2
SW
VIN
OVP
Shutdown
OSC
PWM
Control
EN
EN
Detection
RAMP
PWM
Analog
Dimming
PWM
Comparator
VREF
EA
LED1
COMP
GND
Feedback
Control
Current Control
LED2
ISET
R2
C3
Min.
Max.
Short
Protection
EN
R1
Figure 1: Functional Block Diagram
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
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© 2015 MPS. All Rights Reserved.
9
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
OPERATION
The MP3312L employs a fixed switching
frequency, peak-current-mode control
power delivered to the output. This forms a
closed loop that regulates the output voltage.
architecture, and two regulated current sinks to
power the LED array (see Figure 1).
Dimming Control
The MP3312L supports analog dimming and 1-
wire digital set dimming mode to regulate the
WLED current.
System Start-Up
Pulling EN and PWM high enables the IC while
pulling EN to GND for >2.5ms (or pulling PWM
to GND for >20ms) shuts down the IC.
For analog dimming, apply a PWM signal to
PWM by adjusting the LED current amplitude.
The internal filter is integrated, and the PWM
signal (5k~100kHz range) is supported. The
internal dimming signal duty detection circuit
changes the internal reference linearly to
regulate the current automatically.
When enabled, the MP3312L checks the
topology connection first. Also, the MP3312L
checks UVLO and over-temperature protection
(OTP). If all the protections pass, the chip starts
boosting the step-up converter with an internal
soft start.
In addition, EN supports a 1-wire interface for
current dimming control.
It is recommended that the enable signal occurs
after the establishment of the input voltage and
PWM dimming signal during the start-up
sequence to avoid large inrush current.
1-Wire Interface
1-wire interface is based on a master-slave
structure, which is designed for digital dimming.
EN is a multipurpose single port that receives
LED brightness data. The rate to detect the bit
ranges from 1.39kit/sec to 50kBit/sec.
Switching Operation
At the start of each oscillator cycle, the main
low-side FET (M1) is turned on through the
control circuitry. To prevent sub-harmonic
oscillation at a duty cycle greater than 50%, a
stabilizing ramp is added to the output of the
current sense amplifier; the result is fed into the
positive input of the PWM generation
comparator. When this voltage equals the
output voltage of the error amplifier, the main
power FET is turned off. Then the inductor
current flows through the free-wheeling diode,
which forces the inductor current to decrease.
The output voltage of the internal error amplifier
is an amplified signal of the difference between
the reference voltage and the feedback voltage.
The converter chooses the lowest active LEDX
pin voltage automatically to provide a high
enough bus voltage to power all the LED arrays.
The command sent to the chip (slave) contains
24 bits and 9-bit dimming data. Also, an 8-bit
device address and RFA bit are included. The
chip detects the bit in the series and transmits
the LSB first and the MSB last.
Refer to Figure 2 and the description of the
control bits below:
•
D0-D8 are the dimming data bits, which
achieve a 9-bit dimming resolution.
•
•
Bit 9 and bit 11-bit 15 are reserved. Set to 0.
The RFA bit indicates if the master needs to
request acknowledgment or not.
•
The device address byte is DA0-DA7. The
device address byte is set to 0x8F.
If the feedback voltage drops below the
reference, the output of the error amplifier
increases. This results in more current flowing
through the MOSFET, thus increasing the
MP3312L Rev. 1.0
8/11/2015
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© 2015 MPS. All Rights Reserved.
10
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
Figure 2: 1-Wire Command Structure
EN must distinguish the EN signal and the
digital dimming signal when setting up the boost
driver. The chip only receives the 1-wire signal
when the EN signal matches the 1-wire protocol
during the 1ms 1-wire detection window. The 1-
wire dimming sequence is described below and
shown in Figure 4.
The 1-wire interface defines logic 0 and logic 1
by comparing the time between the signal’s low
level and high level; 1 cycle means 1 logic bit.
The bit detection starts with a falling edge on
EN and ends with the next falling edge. Low
logic (logic 0): tLOW≥3* tHIGH. High logic (logic 1):
tHIGH≥3* tLOW (see Figure 3).
1. VIN and PWM are pulled high.
2. The data line is pulled from low to high for
tDELAY (1-wire detection delay time, 100µs).
This rising edge is the start of the 1-wire
detection window.
3. After the 1-wire detection delay time, the data
line pulls low for more than tDETECTION (1-wire
detection time, 260µs). Then the data line
pulls high.
4. The sum of the 1-wire detection delay time
and the 1-wire detection time should be less
than tWIN (the time of 1-wire detection window,
1ms).
Figure 3: 1-Wire Bit Definition
Figure 4: 1-Wire Dimming Sequence
MP3312L Rev. 1.0
8/11/2015
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© 2015 MPS. All Rights Reserved.
11
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
In addition, before the chip starts to receive each
Whether the ACK signal feedback is sent to the
master or not is dependent on the RFA bit. If
ACK is needed, the master should have an open-
drain output, and the data line should be pulled
high by the master with a resistor load.
command with the first falling edge, the data line
should remain high for tSTART (minimum, 2µs). The
transmission of each command is completed with
low levels for tEOS (minimum 2µs). See Figure 5.
Figure 5: Data-Line Timing When RFA = 0
Figure 6: Data-Line Timing When RFA=1
If RFA = 0, there is no ACK signal feedback.
the slave for tACK (max. 512µs). If the master
reads this low logic, it means the chip has
received the 1-wire data successfully, and the
data line is pulled to static high (see Figure 6).
After all 24 bits of data are transferred, the data
line remains low for a tEOS (minimum 2µs) delay,
and then it is pulled to static high (see Figure 5).
If RFA = 1, the ACK signal feedback is sent to
the master. After all 24 bits of data are
transferred, the data line remains low for tACKval
(maximum, 2µs), then the data line should be
released to output high impedance. After this
occurs, the master is ready to detect the ACK
signal from the slave. After tACKval, if the ACK
signal is “false” (1-wire data is not received
successfully), the data line will be pulled high
directly. After tACKval, if the ACK signal is “true” (1-
wire data is received successfully), the data line
is pulled low continuously (VACKL (max. 0.4V)) by
The MP3312L has a 9 bit DAC for digital
dimming control; the dimming resolution is 1/511.
The default code value of D0 (LSB)-D8(MSB) is
“111111111” when the device is first enabled.
The LED current is dependent on the internal
register value D0-D8 according to Equation (1):
code
ILED = ILEDfull ×
(1)
511
ILEDfull is the full scale output current set by RISET
to ISET. The code is the DEC value of the
resolution bit (D0-D8).
MP3312L Rev. 1.0
8/11/2015
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© 2015 MPS. All Rights Reserved.
12
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
Short-String Protection
Cycle-by-Cycle Current Limit Protection
The MP3312L monitors the LEDX voltage to
detect if the short string has occurred. If one
string is short, the respective LEDX pin is pulled
up to the boost output and tolerates high voltage
stress. If the LEDX voltage is higher than 5V and
the LED current is larger than the 8% of the full-
scale setting current, the short-string condition is
detected. If this condition lasts longer than 8ms,
the fault string current source is disabled until
VIN and EN are reset for enable.
The MP3312L provides cycle-by-cycle current
limit protection to avoid damage caused by too
large of a current rating. During start-up, the
current limit is clamped to 1A for around 6ms to
avoid output overshoot and inrush current. After
start-up, the current limit returns back to a normal
1.8A.
Open-String Protection
Open-string protection is achieved by detecting
VOUT. If the LED string is open, the feedback
voltage is lower than the reference voltage, and
thus the COMP rises up and keeps the charge of
the output capacitor until VOUT hits the
protection point OVP. Then the IC stops
switching and shuts down until VIN and EN are
reset for enable.
Thermal Shutdown Protection
To prevent the IC from operating at exceedingly
high temperatures, thermal shutdown is
implemented in this chip by detecting the silicon
die temperature. When the die temperature
exceeds the upper threshold (150°, typically), the
IC shuts down. It resumes normal operation once
the die temperature drops below the lower
threshold. Typically, the hysteresis value is 25°C.
Unused LED Channel
In some cases, if one LED current channel is not
used, LEDX must be connected to the
corresponding GND to remove it from the control
loop.
MP3312L Rev. 1.0
8/11/2015
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13
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
APPLICATION INFORMATION
In order to avoid hitting the current limit, the
worst-case inductor peak current should be less
than 80% of the current limit (ILIM). Generally, a
4.7µH~10µH inductor will suffice for most
applications. Note that the system efficiency is
dependent on the DC resistance of the inductor,
and a larger DC resistance causes more power
loss.
Setting the LED Current
The full scale LED current is set through the
current-setting resistor on FB using Equation (2).
V
ISET(V)
ILED(mA) =
*1020
(2)
RISET(kΩ)
For VISET = 1.232V and RISET = 63.4kꢀ, the LED
current is set to 20mA. Please do NOT leave
ISET open.
Selecting the Output Capacitor
The output capacitor keeps the output voltage
ripple small and ensures feedback loop stability.
The output capacitor impedance must be low at
the switching frequency. Ceramic capacitors with
X7R dielectrics are recommended for their low
ESR characteristics. Please note that ceramic
capacitance is also dependent on the voltage
rating; DC bias voltage and the value can lose as
much as 50% of its capacitance at its rated
voltage rating. Please leave a high enough
voltage rating margin when selecting the
component. However, if the capacitance is too
low, it will cause loop instability. For most
applications, a 1μF~4.7μF ceramic capacitor will
suffice.
Selecting the Input Capacitor
The input capacitor reduces the surge current
drawn from the input supply and the switching
noise from the device. The input capacitor
impedance at the switching frequency should be
much less than the input source impedance to
prevent the high-frequency switching current
from passing through to the input. Use ceramic
capacitors with X5R or X7R dielectrics for their
low ESR and small temperature coefficients. For
most applications,
capacitor will suffice.
a
1µF~4.7μF ceramic
Selecting the Inductor
The MP3312L requires an inductor to supply a
higher output voltage while being driven by the
input voltage. A larger value inductor results in
less ripple current, resulting in lower peak
inductor current, which reduces stress on the
internal N-channel MOSFET. However, the larger
value inductor has a larger physical size, a higher
series resistance, and a lower saturation current.
Selecting the External Schottky Diode
To optimize efficiency, a high-speed and low-
reverse recovery current Schottky diode is
recommended. Make sure the diode’s average
and peak current ratings exceed the output
average LED current and the peak inductor
current. In addition, the diode’s breakdown
voltage rating should be larger than the
maximum voltage across the diode. Usually,
unexpected high-frequency spikes in the voltage
can be seen across the diode when the diode
turns off. When selecting a diode, always leave a
sufficient voltage rating margin to guarantee
normal, long-term operation.
Choose an inductor that does not saturate under
the worst-case load conditions. Select the
minimum inductor value to ensure that the boost
converter works in continuous conduction mode
with high efficiency and good EMI performance.
Calculate the required inductance value using
Equation (3) and Equation (4):
PCB Layout Guidelines
η× VOUT × D×(1− D)2
L ≥
(3)
(4)
Efficient PCB layout is critical to prevent noise
and electromagnetic interference. If the loop of
MP3312L’s internal low-side MOSFET, Schottky
diode, and output capacitor flows with a high
frequency ripple current, it MUST be minimized.
The input and output capacitor should be placed
2× fSW × ILOAD
V
IN
D = 1−
VOUT
Where VIN and VOUT are the input and output
voltages, fSW is the switching frequency, ILOAD is
the total LED load current, and η is the efficiency.
The switching current is used for the peak-
current-mode control.
as
close
to
the
IC
as
possible.
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
14
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
TYPICAL APPLICATION CIRCUITS
10µH
1µF
1µF
63.4k
330nF
Figure 7: Typical Application for Dual String 6 LEDs, 20mA/String
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
15
MP3312L － 2.7V-5.5V INPUT, 38V OVP, DUAL-CHANNEL WHITE LED DRIVER
PACKAGE INFORMATION
WLCSP1.35X1.35-9
NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications.
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.
MP3312L Rev. 1.0
8/11/2015
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
16
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