MP3313 [MPS]
3-Channel, Max 38V Output, Linear/Exponential, Analog Dimming, Step-Up WLED Driver with I2C;
| 型号： | MP3313 |
| 厂家： | 
MONOLITHIC POWER SYSTEMS |
| 描述： | 3-Channel, Max 38V Output, Linear/Exponential, Analog Dimming, Step-Up WLED Driver with I2C |
| 文件： | 总26页 (文件大小：617K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MP3313
3-Channel, Max 38V Output,
Linear/Exponential, Analog Dimming,
Step-Up WLED Driver with I2C
DESCRIPTION
FEATURES
2.7 - 5.5V Input Voltage
The MP3313 is a step-up, white, LED converter.
The MP3313 uses peak-current mode and a
3-channel current sink to regulate the LED
current with up to 25mA on each channel
(100mA at flash mode) with 2.7 - 5.5V input
voltage.
300mΩ, 42V Internal MOSFET
3-Channel Current Sink, Each Channel
Enable/Disable Respectively
LED Current up to 25mA in Backlighting
Mode
LED Current up to 100mA in Flash Mode
250µA - 25mA LED Current with ±3%
Accuracy
±1% Typical Current Matching
Linear or Exponential Analog Dimming
11-Bit Dimming Resolution
The MP3313 integrates
a
300mΩ, 42V
MOSFET and supports selectable over-voltage
protection (17/23/30/38V). The MP3313 can
drive up to 10 LEDs in series for LCD panels
greater than 5”.
The MP3313 achieves ultra-high resolution
analog dimming by converting the pulse-width
input signal or internal register code to an 11-bit
brightness code. The MP3313 is designed with
two types of LED current dimming mapping:
linear and exponential mapping.
Selectable Switching Frequency: 500kHz or
1MHz with Optional -12% Shift
Auto-Switching Frequency (250kHz, 500kHz,
1MHz)
High-Speed I2C Interface (1.2MHz)
I2C Address External Selectable (A0 Pin)
Internal Soft Start (SS) to Reduce Inrush
Current
An auto-switching frequency function is
integrated to optimize efficiency performance.
Full protection features include LED open and
short protection, cycle-by-cycle current-limit
protection, and thermal shutdown.
The I2C interface can set the internal register to
program the MP3313 for flexible applications,
such as dimming mode, LED current slope, and
protection threshold.
Current-Limit Protection (0.75/1/1.25/1.5A)
LED Open Protection (17/23/30/38V)
LED Short Protection (2/3/5V)
Available in a WLCSP-12 (1.3mmx1.7mm)
Package
APPLICATIONS
Smart Phones
Tablets
GPS Receivers
LCD Video Displays with One-Cell Li-Ion
Battery
The MP3313 is available in a small WLCSP-12
(1.3mmx1.7mm) package.
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.
MP3313 Rev1.0
8/2/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
1
MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
TYPICAL APPLICATION
L1
D1
VIN
C1
SW
GND
IN
OUT
C2
PWM
PWM
MP3313
EN
EN
SDA
SCL
SDA
SCL
A0
LED1
LED2
LED3
GND
MP3313 Rev1.0
8/2/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
2
MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
ORDERING INFORMATION
Part Number*
Package
Top Marking
MP3313GC
WLCSP-12 (1.3mmx1.7mm)
See Below
* For Tape & Reel, add suffix –Z (e.g. MP3313GC–Z)
TOP MARKING
GA: Product code of MP3313GC
Y: Year code
LLL: Lot number
PACKAGE REFERENCE
TOP VIEW
1
2
3
LED1
A0
GND
A
B
LED2
SDA
SW
LED3
PWM
SCL
EN
OUT
VIN
C
D
WLCSP-12 (1.3mmx1.7mm)
MP3313 Rev1.0
8/2/2017
www.MonolithicPower.com
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
ABSOLUTE MAXIMUM RATINGS (1)
VIN ................................................ -0.3V to +6V
VSW ................................................. -1V to +42V
VLED1~3.......................................... -0.3V to +40V
VOUT ................................................ -1V to +40V
All other pins............................... -0.3V to +5.3V
Junction temperature...............................150°C
Lead temperature ....................................260°C
Thermal Resistance (4)
WLCSP-12 (1.3mmx1.7mm) ... 110...12 ... °C/W
θJA θJC
NOTE:
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)
WLCSP-12 (1.3mmx1.7mm)....................1.14W
Recommended Operating Conditions (3)
Supply voltage (VIN)..................... 2.7V to 5.5V
Operating junction temp. (TJ) ...-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.
MP3313 Rev1.0
8/2/2017
www.MonolithicPower.com
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4
MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
ELECTRICAL CHARACTERISTICS
VIN = 3.6V, 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
2.7
V
VIN = 3.6V, VEN = VPWM = high,
no switching, I2C active
Supply current (quiescent)
2.4
mA
μA
Supply current (shutdown)
Input UVLO threshold
IST
VEN = 0V, VIN = 3.6V
Rising edge
1
VIN_UVLO
2.4
2.6
V
Input UVLO hysteresis
200
mV
Oscillator
FS bit = 1
FS bit = 0
FSW = 500kHz
FSW = 1.0MHz
950
475
93
1000
500
95
1050
525
kHz
kHz
%
Switching frequency
Maximum duty cycle
fSW
DMAX
90
93
%
Minimum on time
TON_MIN
100
ns
Power Switch
Switch on resistance
Current Regulation
Minimum output current
Maximum output current
RDSON
VIN = 3.6V
300
mΩ
Linear/exponential mode
Linear/exponential mode
50
25
μA
ILED_min
ILED_max
mA
ILED = 25mA
ILED = 5mA
220
130
mV
mV
LEDx regulation voltage
Current accuracy
VREG
ILED = 250μA - 25mA, 2.7 - 5V,
linear/exponential dimming
ILED = 5 - 25mA, 2.7 - 5V,
linear/exponential dimming
ILED = 250μA - 5mA, 2.7 - 5V,
linear/exponential dimming
-3
-1
-1
0.1
0.1
0.1
3
1
2
%
%
%
Current matching (5)
EN and PWM Logic
PWM input low threshold
PWM input high threshold
EN low voltage
VPWM_LO
VPWM_HI
VEN_LOW
VEN_HIGH
VPWM falling
VPWM rising
VEN falling
VEN rising
0.4
0.4
V
V
V
V
1.2
1.2
EN high voltage
EN and PWM pull-down
resistor
RPD
1
MΩ
MP3313 Rev1.0
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8/2/2017
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
ELECTRICAL CHARACTERISTICS (continued)
VIN = 3.6V, VEN = VPWM = high, typical values are at TA = 25°C, unless otherwise noted.
Parameters
Protection
Symbol
Condition
Min
Typ
Max
Unit
16
22
29
37
OVP1:0 bit = 00
OVP1:0 bit = 01
OVP1:0 bit = 10
OVP1:0 bit = 11
17
23
30
38
18
24
31
39
V
V
V
V
OVP voltage
VOVP
OUT under-voltage
protection
VOUT_UV
1.2
V
OCP1:0 bit = 00
OCP1:0 bit = 01
OCP1:0 bit = 10
OCP1:0 bit = 11
0.6
0.8
1.0
1.2
4.5
0.75
1
0.9
1.2
1.5
1.8
5.5
A
A
A
A
V
Cycle-cycle current limit
ILIM
1.25
1.5
5
LEDX over-voltage threshold
LEDX under-voltage
threshold
Thermal shutdown threshold
Thermal shutdown
hysteresis
PWM Input (6)
VOVP_LED
VLEDX_UV
TST
40
150
25
mV
°C
°C
Minimum PWM frequency
Maximum PWM frequency
FPWML
FPWMH
50
Hz
kHz
ns
24MHz sample rate
24MHz sample rate
4MHz sample rate
800kHz sample rate
24MHz sample rate
4MHz sample rate
800kHz sample rate
24MHz sample rate
4MHz sample rate
800kHz sample rate
FILTER1:0 bit = 01
FILTER1:0 bit = 10
FILTER1:0 bit = 11
50
183.3
1100
5500
183.3
1100
5500
Minimum on time
Minimum off time
PWM shutdown time
TMIN_ON
TMIN_OFF
TPWM_SD
ns
ns
ns
ns
ns
0.6
3
ms
ms
ms
ns
25
80
PWM input glitch rejection
Delay time at power-on
TGLITCH
160
240
ns
ns
TPOWERON
EN power-on to start switching
3.5
5
ms
MP3313 Rev1.0
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8/2/2017
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
ELECTRICAL CHARACTERISTICS (continued)
VIN = 3.6V, VEN = VPWM = high, typical values are at TA = 25°C, unless otherwise noted.
Parameters
Symbol
Condition
Min
Typ
Max
Unit
I2C Interface
Input logic low
Input logic high
Output logic low
SCLH clock frequency
VIL
VIH
VOL
fSCL
0.4
V
V
1.3
ILOAD = 3mA
0.4
V
1200
kHz
Set-up time for (repeated)
start condition
Hold time for (repeated) start
condition
Low time for SCLH clock
High time for SCLH clock
Data set-up time
tSU,STA
160
160
ns
ns
tHD,STA
tLOW
tHIGH
160
60
ns
ns
ns
ns
ns
tSU,DAT
tHD,DAT
tR,SCL
10
0(7)
Data hold time
70
40
Rise time of SCLH clock
10
Rise time of SCLH clock
after repeated start and
acknowledge bit
tR,SCL1
10
80
ns
Fall time of SCLH clock
Rise time of SDAH data
Fall time of SDAH data
Set-up time for stop condition
tF,SCL
tR,SDA
tF,SDA
tSU,STO
10
10
40
80
80
ns
ns
ns
ns
10
160
Capacitive load for SDAH
line and SCLH line
Capacitive load for
SDAH+SDA line and
SCLH+SCL line
(8)
CB
100
400
pF
CB
pF
NOTES:
5) Matching is defined as the difference of the maximum to minimum current divided by 2 times average currents.
6) Guaranteed by design.
7) A device must provide a data hold time internally to bridge the undefined part between VIL and VIH of the falling edge of the SCLH signal.
An input circuit with a threshold as low as possible for the falling edge of SCLH signal minimizes the hold time.
8) For the bus line-load CB between 100pF and 400pF, the timing parameters must be increased linearly.
P
Sr
tF,SDA
tR,SDA
SDAH
SCLH
tSU,SDA
tHD,SDA
tHIGH
tSU,STA
tHD,STA
tSU,STA
tLOW
tLOW
tHIGH
Sr
tR,SCL1
tR,SCL
tR,SCL1
tF,SCL
Sr: Repeated START Condition
P: STOP Condition
I2C-Compatible Interface Timing Diagram
MP3313 Rev.1.0
8/2/2017
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 3.6V, 8*LEDs/string, ILED/Ch = 20mA, L = 10µH, TA = 25°C, unless otherwise noted.
LED Current for Each Channel with
LED Current for Each Channel with
Register Code
Current Curve (Dimming by Code only)
PWM Input Duty
Current Curve (Dimming by PWM only)
30
25
20
15
10
5
30
25
20
15
10
5
Linear Mode
Expo Mode
Linear Mode
Expo Mode
0
0
0
0.2
0.4
0.6
0.8
1
0
500
1000
1500
2000
Dpwm
BRIGHTNESS CODE
Efficiency Curve E-IOUT
1MHz, 10μH, DCR = 49mΩ
Efficiency Curve E-IOUT
500kHz, 10μH, DCR = 49mΩ
100.00%
90.00%
80.00%
70.00%
60.00%
50.00%
40.00%
30.00%
20.00%
10.00%
0.00%
100.00%
90.00%
80.00%
70.00%
60.00%
50.00%
40.00%
30.00%
20.00%
10.00%
0.00%
fsw=500kHz
fsw=1MHz
0
10 20 30 40 50 60 70 80
0
10 20 30 40 50 60 70 80
IOUT (mA)
IOUT (mA)
Efficiency Curve E-VIN
LEDx Voltage vs. LED Current
10μH, DCR = 49mΩ
94.00%
89.00%
84.00%
79.00%
74.00%
69.00%
64.00%
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
VLED1
VLED2
VLED3
fsw=1MHz
fsw=500kHz
2.5
3
3.5
VIN (V)
4
4.5
5
0
5
10
15
20
25
ILED/string (mA)
MP3313 Rev1.0
8/2/2017
www.MonolithicPower.com
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 3.6V, 8*LEDs/string, ILED/Ch = 20mA, L = 10µH, TA = 25°C, unless otherwise noted.
Steady State
EN Power-On
CH1: VSW
20V/div.
CH1: VSW
20V/div.
CH2: VOUT
20V/div.
CH2: VEN
5V/div.
CH3: IL
200mA/div.
CH4: ILED
CH3: IL
500mA/div.
CH4: ILED
50mA/div.
50mA/div.
1µs/div.
20ms/div.
VIN Power On
Flash Mode
Flash Time = 300ms, Flash Current = 40mA/ch
CH1: VSW
20V/div.
CH1: VSW
20V/div.
CH2: VOUT
20V/div.
CH2: VIN
2V/div.
CH3: IL
CH3: IL
500mA/div.
500mA/div.
CH4: ILED
CH4: ILED
50mA/div.
50mA/div.
20ms/div.
100ms/div.
Short LED Protection (Mark Off)
Short one string
Short LED Protection (IC Latch Off)
Short LED1 String
CH1: VSW
20V/div.
CH1: VSW
20V/div.
CH2: VLED1
20V/div.
CH2: VLED1
20V/div.
CH3: IL
500mA/div.
CH4: ILED
CH3: IL
500mA/div.
CH4: ILED
50mA/div.
50mA/div.
20ms/div.
20ms/div.
MP3313 Rev1.0
8/2/2017
www.MonolithicPower.com
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 3.6V, 8*LEDs/string, ILED/Ch = 20mA, L = 10µH, TA = 25°C, unless otherwise noted.
Open LED Protection (Mark Off)
VOVP = 30V, Open 1 String
Open LED Protection (IC latch Off)
VOVP = 30V, Open 1 String
CH1: VSW
20V/div.
CH1: VSW
20V/div.
CH2: VOUT
20V/div.
CH2: VOUT
20V/div.
CH3: IL
CH3: IL
500mA/div.
500mA/div.
CH4: ILED
CH4: ILED
50mA/div.
50mA/div.
200µs/div.
100µs/div.
Thermal Shutdown Protection
(IC Latch Off)
Thermal Shutdown Protection
(Recoverable)
CH1: VSW
20V/div.
CH1: VSW
20V/div.
CH2: VOUT
20V/div.
CH2: VOUT
20V/div.
CH3: IL
CH3: IL
500mA/div.
500mA/div.
CH4: ILED
50mA/div.
CH4: ILED
50mA/div.
2s/div.
2s/div.
MP3313 Rev1.0
8/2/2017
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10
MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
PIN FUNCTIONS
Pin #
Name
I/O
Description
A1
LED1
I
Current sink for LED1.
LSB of I2C interface address select. If A0 is floating, it must be pulled up or
down externally. If A0 is pulled low, the I2C address LSB is 0. If A0 is pulled
high, the I2C address LSB is 1.
A2
A0
I
A3
B1
B2
B3
C1
C2
C3
GND
LED2
SDA
SW
I
Ground.
I
I/O
I
Current sink for LED2.
I2C interface data signal input.
Drain connection of the internal low-side MOSFET for boost converter.
Current sink for LED3.
LED3
SCL
I
I
I2C interface clock signal input.
OUT
O
Boost converter output connection.
PWM dimming input signal. Apply a 50Hz to 50kHz PWM pulse to the PWM
pin for analog dimming.
D1
D2
D3
PWM
EN
I
I
I
IC enable input. Drive EN to logic high to enable the IC. Drive EN to logic low
longer than 2.5ms to shut down the IC.
Power supply input with 2.7V to 5.5V. Connect a ceramic capacitor close to
VIN to bypass the IC.
VIN
MP3313 Rev1.0
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
BLOCK DIAGRAM
IN
SW
OUT
OVP
PWM
Control
M1
Current
Limit
Ref Min
EN
Fault
Control
RAMP
OSC
LED
Short
SCL
SDA
Channel
Select
I2C
Interface
Max
Min
A0
Feedback
Control
11-bit
Brightness
resolution
LED1
LED2
PWM
Sample
Linear/
Exponential
LED Current
Control
PWM
LED3
GND
Figure 1: Functional Block Diagram
MP3313 Rev1.0
8/2/2017
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
Note that the switching frequency -12% shift is
still active when the auto-switching frequency
function is enabled.
OPERATION
The MP3313 is a step-up converter with
peak-current-mode control architecture that
employs three channels of current sink to drive
three strings of white LED for an LCD panel.
The MP3313 supports 11-bit resolution analog
dimming via an internal register or external
pulse-width modulation (PWM) input signal.
Minimum Inductor Selection
To optimize the boost converter control loop, the
minimum inductance is limited for the MP3313,
which is set by the minimum inductor L_MIN bit.
When the L_MIN bit is set to 0, the minimum
inductor is 4.7μH. When the L_MIN bit is set to 1,
the minimum inductor is 10μH.
Boost Converter Switching Frequency
The MP3313 has two selectable switching
frequencies (FS) through the I2C interface.
When the register bit FS = 1, the switching
frequency is set to 1MHz. When the register bit
FS = 0, the switching frequency is set to 500kHz.
Additionally, the switching frequency can be
shifted down 12% by the register FS_SHFT.
System Start-Up
If input voltage is higher than the under-voltage
lockout (UVLO) threshold and EN is pulled high,
the MP3313 enters standby mode. In this mode,
only the I2C is active and ready to communicate
with the host. Meanwhile, the MP3313 monitors
the topology connection and safety limits,
including two checks:
Auto-Switching Frequency
To optimize the efficiency in different loads, the
MP3313 can select the switching frequency
automatically by comparing the auto-switching
frequency low threshold (register 0x16) and
auto-switching frequency high threshold
(register 0x15) to 8MSBs of the brightness code
(register 0x19).
The MP3313 checks whether the OUT pin
connection is correct or not. An OUT voltage
(VOUT) of less than 1.2V cannot implement
device switching and sets the FT_UVP bit to
1.
The MP3313 checks if the device has
triggered LED open/short protection,
The auto-switching frequency function includes
three different working frequency points: 1MHz,
500kHz, and 250kHz. At the high threshold, the
device switches from 1MHz to 500kHz. At the
low threshold, the device switches from 250kHz
from 500kHz (see Table 1).
over-current
limit
protection,
or
over-temperature protection (OTP). If all
protections pass, the MP3313 then starts
boosting the step-up converter with an
internal soft start.
Table 1: Switching Frequency Auto-Function
To prevent a large inrush current, it is
recommended that the power-on sequence be
from VIN power-on to PWM power-on to EN
power-on. If the external EN pin is always pulled
high or to VIN by a resistor, it is requested to
write EN to 1 after VIN powers on. When
dimming is done by the internal code only, the
PWM signal can be ignored.
8MSBs of Brightness Code
(register 0x19)
Switching
Frequency
<auto switching frequency low
threshold (register 0x16)
>auto switching frequency low
threshold (register 0x16)
<auto switching frequency high
threshold (register 0x15)
>auto switching frequency high
threshold (register 0x15)
250kHz
500kHz
1MHz
Boost Converter Operation
The MP3313 uses peak-current mode to control
the output voltage. At the start of the internal
oscillator cycle, the low-side MOSFET (LS-FET)
(M1) is turned on. To prevent sub-harmonic
oscillation at duty cycles greater than 50%, 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 generation
comparator. When this voltage equals the
To
disable
auto-frequency,
both
the
auto-switching frequency high threshold and low
threshold must be set to zero. Once the
auto-function is disabled, the MP3313 works at
a fixed frequency set by the FS bit. The
auto-frequency function can be enabled by
setting a non-zero code for any one of
auto-switching frequency thresholds.
MP3313 Rev1.0
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
output voltage of the error amplifier, the LS-FET
circuit to regulate the current linearly or
exponentially.
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
from the LED load cathode. The converter
chooses the lowest active LEDx pin voltage
automatically to provide a high enough bus
voltage to power all of the LED arrays. If the
feedback voltage drops below the reference, the
output of the error amplifier increases. This
results in more current flowing through the
LS-FET and delivers more power to the output.
This forms a closed control loop that regulates
the output voltage.
Calculate the linear analog dimming with
Equation (1):
(1)
I
40.806A 12.195ACode
ILED
Where Code ranges from 1 to 2047. Code 0
sets the LED current to 0.
Calculate the exponential analog dimming with
Equation (2):
I
51.1A1.003040572Code
(2)
ILED
Where Code ranges from 1 to 2047. Code 0
sets the LED current to 0.
Figure 2 shows the linear and exponential
dimming curve for the LED current.
LED String Selection
There are three LED strings for the MP3313,
and each string has an independent EN bit. This
allows for 1-string, 2-string, or 3-string
application. By default, all three strings are
enabled.
Flash Mode
The MP3313 can also work in flash mode by
setting the FL_EN bit to 1. The flash time
depends on the FL_T bit and ranges from 50 -
800ms. The flash current is set by I_FL bit.
When flash mode is enabled, the inductor
peak-current limit value jumps to the flash
current limit automatically, which is set by the
FL_CL bit (2.5A/3A selectable), and the LED
current jumps to the flash current. When the
flash is timed out, the LED current and inductor
peak current limit returns to backlight mode, and
the FL_EN bit is reset to 0. When protection is
triggered during the flash, flash mode ends, and
the FL_EN bit is reset.
Figure 2: LED Current for Each Channel with
Brightness Code
LED Current Ramp Up/Down
The LED current ramps up and down
step-by-step from one brightness code to the
next when the LED current slope function is
enabled by setting the SLPEN bit to 1. The ramp
time can be calculated with Equation (3):
Dimming Control
The MP3313 supports ultra-high resolution
analog dimming by converting the PWM input
signal or internal register code to the 11-bit
brightness code. Two kinds of LED current
dimming curve are available: linear and
exponential mapping.
tRAMP RAMP(Code1Code01)
(3)
Where RAMP is the slope rate set by the TSLP
bit, Code 0 is the original brightness point, and
Code 1 is the target brightness point.
PWM Sample Frequency
The MP3313 converts the external PWM signal
into an internal reference via the duty detection
Three different sample frequencies can be
chosen for the input PWM dimming signal for
the MP3313.
MP3313 Rev1.0
8/2/2017
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
1. Internal register only: When the brightness
control mode bits are set to 000, the LED
current is controlled by the internal
brightness register only without the PWM
signal. The LED current changes only when
the eight MSBs are written. Write three
LSBs first, then write eight MSBs for 11-bit
brightness change.
PWMSR1:0 bit = 00, sample frequency =
800kHz.
PWMSR1:0 bit = 01, sample frequency =
4MHz (default).
PWMSR1:0 bit = 1x, sample frequency =
24MHz.
Choose a PWM sample frequency based on the
required dimming resolution, input dimming
frequency, and efficiency (the higher the sample
frequency, the higher the input consumption
current is). A low-level PWM signal that lasts for
a certain amount of time can disable the device
(see Table 2). The lower the PWM sample
frequency is, the longer the PWM shutdown
time is.
In linear mapping mode, the LEDs can be
calculated with Equation (4) and Equation
(5):
(4)
(5)
I
40.806A 12.195ACode0
ILED0
I
ILED1 40.806A 12.195ACode1
In exponential mapping mode, the LEDs can
be calculated with Equation (6) and
Equation (7):
Table 2: PWM Shutdown Time vs. Sample
Frequency
(6)
I
51.1A1.003040572Code0
ILED0
fsample (Hz)
24M
TPWM_SD (ms)
ILED1 51.1A1.003040572Code1
0.6
3
(7)
I
4M
The ramp time in either mapping mode can
be calculated with Equation (8):
800k
25
PWM Hysteresis
(8)
tRAMP RAMP(Code1Code01)
To prevent the input PWM dimming signal jitter
from causing LED flicker, the MP3313 offers
selectable PWM hysteresis.
2. Input PWM duty only: When the brightness
control mode bits are set to 001, the LED
current is controlled by the input dimming
signal only. The internal brightness code is
ignored. The MP3313 samples the PWM
signal and translates it into an 11-bit code to
HYS2:0 = 000: no hysteresis
HYS2:0 = 001: 1 clock
HYS2:0 = 100: 4 clock (default)
HYS2:0 = 110: 6 clock
regulate
the
current.
Choose
the
corresponding PWM frequency based on
the PWM sample rate and resolution
request.
Where 1 clock = 1/fsample. Different sample
rates produce different clocks.
In linear mapping mode, the LEDs can be
calculated with Equation (9) and Equation
(10):
The PWM hysteresis is active only when the
direction of the LED brightness changes. Once
the LED brightness direction changes, the input
PWM signal must overcome the hysteresis, and
then the brightness changes. Otherwise, if the
LED brightness changing direction remains the
same, the PWM signal hysteresis function is
unused.
(9)
40.806A 12.195A2047DPWM0
I
ILED0
(10)
IILED1 40.806A 12.195A2047DPWM1
In exponential mapping mode, the LEDs can
be calculated with Equation (11) and
Equation (12):
Brightness Control Mode
51.1A1.0030405722047DPWM0 (11)
The LED current is controlled either by the input
PWM dimming signal or internal brightness
register. Five different brightness control modes
can be selected and set by the BRTMD2:0 bit.
I
ILED0
I
ILED1 51.1A1.0030405722047DPWM1 (12)
MP3313 Rev.1.0
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
The LED current jumps immediately when
the duty changes, as shown in Equation
(20):
The ramp time in either mapping mode can
be calculated with Equation (13):
tRAMP RAMP| 2047DPWM1 2047DPWM0 1|
(13)
(20)
40.806A 12.195ACode0DPWM1
I
ILED0+
3. Internal register multiplies PWM duty before
ramping: LED slope step controlled by
internal register and PWM duty. When the
brightness control mode bits are set to 010,
the LED current is controlled by the input
PWM dimming duty multiplied by the internal
brightness register. The slope step is also
controlled by the PWM dimming duty
multiplied by the brightness register.
The LED current follows the code changes
shown in Equation (21):
(21)
IILED1 40.806A 12.195ACode1DPWM1
In exponential mapping mode, the original
current can be calculated with Equation (22):
I
51.1A1.003040572Code0DPWM0 (22)
ILED0-
The LED current jumps immediately when
the duty changes, as shown in Equation
(23):
In linear mode, the LEDs can be calculated
with Equation (14) and Equation (15):
(14)
(15)
I
40.806A 12.195ACode0DPWM0
ILED0
I
51.1A1.003040572Code0DPWM1
(23)
ILED0+
IILED1 40.806A 12.195ACode1DPWM1
Then, the LED current follows the code
changes shown in Equation (24):
In exponential mode, the LEDs can be
calculated with Equation (16) and Equation
(17):
I
ILED1 51.1A1.003040572Code1DPWM1 (24)
I
51.1A1.003040572Code0DPWM0 (16)
The ramp time in either mode can be
calculated with Equation (25):
ILED0
I
ILED1 51.1A1.003040572Code1DPWM1 (17)
tRAMP RAMP|Code1Code01|
(25)
The ramp time in either mapping mode can
be calculated with Equation (18):
For example, the PWM duty changes from
50% to 100%, and the brightness register
changes from 1024 to 2047, the slope is
1ms/step in linear analog dimming.
tRAMP RAMP|Code1DPWM1 Code0DPWM0 1|
(18)
4. Ramp before internal register multiplies
input PWM dimming duty, LED slope step
controlled by internal register only: When the
brightness control mode bits are set to 011,
the LED current is controlled by the input
PWM dimming duty multiplied by the internal
brightness register. The slope step is
controlled by the internal brightness register
only.
The original LED current can be calculated
with Equation (26):
I
40.806A 12.195A(10240.5) 6.28mA (26)
ILED0-
Then the LED current jumps immediately, as
shown in Equation (27):
(27)
40.806A 12.195A(10241) 12.52mA
I
ILED0+
In this mode, the LED current jumps
immediately when the external PWM
dimming duty changes. Then the LED
current changes step-by-step to the new
brightness register.
The LED current rise up step-by-step,
shown in Equation (28):
(28)
IILED1 40.806A 12.195A(20471) 25mA
The ramp-up time can be calculated with
Equation (29):
In linear mapping mode, the original current
can be calculated with Equation (19):
tRAMP 1ms/step| 204710241|1022ms
(29)
(19)
40.806A 12.195ACode0DPWM0
I
ILED0-
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
5. LED current multiplied by the input PWM
Over-Voltage Protection and Open-String
Protection
duty, LED slope step controlled by the
internal register only: When the brightness
control mode bits are set to 100, the LED
current is dimmed by the input PWM
dimming duty, and slope step is controlled
by the internal brightness register only.
When VOUT is higher than the over-voltage
protection (OVP) threshold, OVP is triggered,
the IC stops switching, and the FT_OVP bit is
set. When the output voltage drops low,
switching recovers.
In linear mode, the LEDs can be calculated
with Equation (30) and Equation (31):
The OVP threshold is set by the internal register
OVP1:0. Four different thresholds can be
selected.
(30)
(31)
I
(40.806A 12.195ACode0)DPWM0
ILED0
OVP1:0 = 00: 17V
IILED1 (40.806A 12.195ACode1)DPWM1
OVP1:0 = 01: 23V
In exponential mode, the LEDs can be
calculated with Equation (32) and Equation
(33):
OVP1:0 = 10: 30V
OVP1:0 = 11: 38V (default)
51.1A1.003040572Code0 DPWM0
If the LED string is open, the feedback voltage is
lower than the reference voltage, and VOUT rises
up and continues charging the output capacitor
until OUT reaches the protection point (VOVP),
and OVP is triggered. The IC also monitors the
LEDx voltage. When the LEDx voltage is lower
than 40mV, open LED protection is triggered.
Three different actions can be set by
OVP_MD1:0 through the I2C after a fault is
triggered.
(32)
I
ILED0
ILED1 51.1A1.003040572Code1 DPWM1
(33)
I
The ramp time in either mode can be
calculated with Equation (34):
tRAMP RAMP|Code1Code01|
(34)
Cycle-by-Cycle Current Limit
To prevent the external components from
exceeding the current stress rating, the MP3313
uses a cycle-by-cycle current limit protection.
The limit value can be selected by the register
bit CL1:0. When the internal LS-FET current
exceeds the current limit threshold, the
MOSFET turns off until the next clock cycle
begins.
OVP_MD1:0 = 00: FT_OVP is set, and
FT_OLP is set.
OVP_MD1:0 = 01: FT_OVP is set, FT_OLP
is set, and the string is marked off with LEDx
< 40mV.
OVP_MD1:0 = 10: FT_OVP is set, and the
IC latches off when the OVP fault is
detected.
Over-Current Protection (OCP)
The FT_OCP flag is set when over-current
protection (OCP) occurs. To prevent the
transient over-current from setting the FT_OCP
bit, the MP3313 designs an OCP counter. If the
inductor current always reaches the threshold in
a 128µs period, the counter increases by 1.
Every eight 128µs periods, if the OCP counter is
higher than 2, the FT_OCP bit is set to 1.
Short LED Protection
The MP3313 monitors the LEDx voltage to
determine if a short string has occurred. If a
short occurs, the respective LEDx pin is pulled
up and can tolerate high voltage stress. If the
LEDx voltage is higher than the short-protection
threshold and lasts for 2ms, a short string fault is
detected. The threshold is set by S_TH1:0.
If OCP_SD = 0, the IC latches off when OCP is
triggered. If OCP_SD = 1, the IC is recoverable
when OCP is triggered.
Short LED protection is programmed by
SLP_MD1:0.
MP3313 Rev.1.0
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
SLP_MD1:0 = 00: The short LED fault
detection is disabled.
0
1
1
0
1
1
A0 r/w
SLP_MD1:0 = 01: The short LED fault
detection is enabled, and the FT_SLP is set
when the fault is detected.
SLP_MD1:0 = 10: The short LED fault
detection is enabled, the FT_SLP is set, and
the string is marked off with the LEDx
voltage that is higher than the threshold.
Figure 3: The I2C Compatible Device Address
To avoid a glitch in the operation, the following
bit changes only when the IC EN bit (0x10,
bit[0]) or the three LED channel enable bits
(0x10, bit[3:1]) are set to 0.
The following bit should contain these bits:
1. Mapping mode bit (MAPMOD, 0x11, bit[7])
SLP_MD1:0 = 11: FT_SLP is set, and the IC
latch off when the fault is detected.
2. Brightness mode bits (BRTMD2:0, 0x11,
bit[6:4])
Thermal Shutdown Protection
3. Slope enable bit (SLPEN, 0x11, bit[3])
4. Slope time bit (TSLP2:0, 0x11, bit[2:0])
To prevent the IC from operating at an
exceedingly
high
temperature,
thermal
shutdown is implemented in the MP3313 by
detecting the silicon die temperature. When the
die temperature exceeds the upper threshold
(TST), the IC shuts down and resumes normal
operation when the die temperature drops
below the lower threshold. Typically, the
hysteresis value is 25°C. If OTP_SD = 0, the IC
latches off when OTP is triggered.
5. PWM sample rate bit (PWMSR1:0, 0x12,
bit[7:6])
6. PWM polarity bit (PWM_P, 0x12, bit[5])
7. PWM hysteresis bit (HYS2:0, 0x12, bit [4:2])
8. PWM filter bit (FILTER1:0, 0x12, bit[1:0])
9. Auto
(FS_AUTOH7:0, 0x15, bit[7:0])
10. Auto frequency low threshold
frequency
high
threshold
bit
I2C Chip Address
bit
(FS_AUTOL7:0, 0x16, bit[7:0])
The 7-bit MSB device address is 0x36 - 0x37
selected by A0. If A0 is floating, it must be pulled
up or down externally to set the address.
After the start condition, the I2C-compatible
master sends a 7-bit address followed by an
eighth read (1) or write (0) bit. The following bit
indicates the register address to or from which
the data is written or read (see Figure 3).
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
Table 3: Register Mapping
Add
00H
01H
10H
11H
12H
13H
14H
15H
16H
17H
18H
19H
1EH
1FH
D7
D6
D5
D4
D3
D2
D1
D0
REV_ID0
SRST
EN
DEV_ID3
DEV_ID2
DEV_ID1
DEV_ID0
RESERVED
REV_ID3
REV_ID2
REV_ID1
RESERVED
CH3EN
SLPEN
HYS2:0
CH2EN
CH1EN
MAPMD
BRTMD2:0
PWM_P
FS
TSLP2:0
PWMSR1:0
FILTER1:0
CL1:0
NA
FS_SHFT
L_MIN
OVP1:0
IFL6:0
FS_AUTOH7:0
FL_CL
FS_AUTOL7:0
FL_T3:0
RESERVED
RESERVED
FL_EN
BRT2:0
BRT10:3
S_TH1:0
RESERVED
SLP_MD1:0
FT_UVP FT_OLP
OVP_MD1:0
FT_SLP FT_OTP
OTP_SD
FT_OCP
OCP_SD
FT_OVP
Table 4: Chip ID Register
Addr: 0x00
Description
Bit
Bit Name
Access
Default
000
7:4
3:0
DEV_ID
REV_ID
r
r
Device ID.
0001
Revision ID.
Table 5: Software Reset Register
Addr: 0x01
Bit
Bit Name
N/A
Access
r
Default
Description
7:1
N/A
Reserved.
Software reset bit.
0: normal operation
0
SRST
r/w
0
1: device resets, all registers are reset to default (this bit automatically
resets back to 0)
Table 6: Enable Register
Addr: 0x10
Description
Bit
Bit Name
N/A
Access
r
Default
N/A
7:4
Reserved.
LED3 enable bit.
3
2
1
0
CH3EN
CH2EN
CH1EN
EN
r/w
r/w
r/w
r/w
1
1
1
1
1: LED3 enabled
0: LED3 disabled
LED2 enable bit.
1: LED2 enabled
0: LED2 disabled
LED1 enable bit.
1: LED1 enabled
0: LED1 disabled
IC enable bit
1: IC enabled
0: IC disabled
MP3313 Rev1.0
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
Table 7: Brightness Control Register
Addr: 0x11
Bit
7
Bit Name
MAPMD
Access
r/w
Default
0
Description
LED current mapping mode bit.
0: linear mapping
1: exponential mapping
Brightness mode control bits.
000: brightness register only
001: PWM duty only
6:4
3
BRTMD2:0
SLPEN
r/w
r/w
011
0
010: brightness register multiplies PWM duty before ramp
011: ramp before brightness register multiplies PWM duty
100: LED current multiplies PWM duty
LED current slope enable bit.
0: LED current slope disabled
1: LED current slope enabled
LED current slope time for each step.
000: 0.125ms/step
001: 0.25ms/step
010: 0.5ms/step
011: 1ms/step
100: 2ms/step
101: 4ms/step
110: 8ms/step
111: 16ms/step
2:0
TSLP2:0
r/w
000
Table 8: PWM Control Register
Addr: 0x12
Description
Bit
Bit Name
PWMSR
Access
r/w
Default
01
PWM sample frequency set bits.
00: 800kHz
01: 4MHz
7:6
1x: 24MHz
PWM input polarity set bit.
5
PWM_P
HYS2:0
r/w
r/w
1
0: active low
1: active high
PWM hysteresis set bits.
000: no hysteresis
001: 1 clock
010: 2 clock
011: 3 clock
100: 4 clock
101: 5 clock
110: 6 clock
111: reserved
4:2
100
PWM input filter bits.
00: no filter
01: 80ns
1:0
FILTER1:0
r/w
11
10: 160ns
11: 240ns
MP3313 Rev.1.0
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
Table 9: Boost Control Register
Addr: 0x13
Bit
7
Bit Name
N/A
Access
r
Default
N/A
Description
Reserved.
Switching frequency shift bit.
6
5
4
FS_SHFT
FS
r/w
r/w
r/w
1
1
0
0: -12% shift
1: no shift
Boost switching frequency set bit.
0: 500kHz
1: 1MHz
Minimum inductor select bit.
L_MIN
0: 4.7μH
1: 10μH
Over-voltage protection set bits.
00: 17V
01: 23V
10: 30V
11: 38V
3:2
1:0
OVP1:0
CL1:0
r/w
r/w
11
11
Current limit set bits.
00: 0.75A
01: 1A
10: 1.25A
11: 1.5A
Table 10: Flash Current Set Register
Addr: 0x14
Bit
7
Bit Name
FL_CL
Access
r/w
Default
0
Description
Current limit in flash mode.
0: 2.5A
1: 3A
Flash current set register. 1mA/step.
0x0A: 10mA
0x0B: 11mA
....
0x28: 40mA (default)
...
6:0
IFL6:0
r/w
0101000
0x64: 100mA
0x64~7F: reserved
Table 11: Auto-Switching Frequency High Threshold
Addr: 0x15
Bit
Bit Name
Access
r/w
Default
Description
Auto-switching frequency high threshold (500kHz to 1MHz). Compared
with the 8 MSBs of the brightness code. The function is disabled when
both FS_AUTOH and FS_AUTOL are set to 0.
7:0
FS_AUTOH
00000000
Table 12: Auto-Switching Frequency Low Threshold
Addr: 0x16
Bit
Bit Name
Access
r/w
Default
Description
Auto-switching frequency low threshold (250kHz to 500kHz).
Compared with the 8 MSBs of the brightness code. The function is
disabled when both FS_AUTOH and FS_AUTOL are set to 0.
7:0
FS_AUTOL
00000000
MP3313 Rev.1.0
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MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
Table 13: Flash Mode Control Register
Addr: 0x17
Bit
Bit Name
FL_T
Access
r/w
Default
Description
Flash time set register. 50ms/step.
0000: 50ms
0001: 100ms
....
0101
(300ms)
7:4
1111: 800ms
3:1
0
N/A
r
000
0
Reserved.
Backlight flash mode enable bit.
0: disable
1: enable
FL_EN
r/w
Automatically resets to 0 when flash timeout or protection is triggered.
Table 14: Brightness Register LSB
Addr: 0x18
Bit
Bit Name
N/A
Access
r
Default
N/A
Description
7:3
Reserved.
2:0
BRT2:0
r/w
111
3-bit LSB of the brightness register.
Table 15: Brightness Register MSB
Addr: 0x19
Bit
Bit Name
BRT10:3
Access
r/w
Default
Description
7:0
11111111
8-bit MSB of the brightness register.
Table 16: Fault Control Register
Addr: 0x1E
Description
Bit
Bit Name
S_TH
Access
r/w
Default
LED short-protection threshold setting. If the LEDx voltage is higher
than the threshold, short protection is triggered.
00: 2V
01: 3V
7:6
01
10: 5V
11: reserved
LED short protection mode selection.
00: LED short protection is disabled
5:4
3:2
SLP_MD
OVP_MD
r/w
r/w
00
00
01: FT_SLP is set when a fault is detected
10: FT_SLP is set and the fault string is marked off
11: FT_SLP is set and the IC latches off
Over-voltage protection mode selection.
00: FT_OVP is set when a fault is detected
01: FT_OVP is set and the open string is marked off
10: FT_OVP is set and the IC latches off
11: reserved
Thermal shutdown latch off disable bit.
1
0
OTP_SD
OCP_SD
r/w
r/w
1
1
0: IC latches off when OTP is triggered
1: no latch off
Over-current protection latch off disable bit.
0: IC latches off when OCP is triggered
1: no latch off
MP3313 Rev.1.0
8/2/2017
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22
MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
Table 17: Fault Flag Register
Addr: 0x1F
Bit
Bit Name
N/A
Access
r
Default
N/A
Description
7:6
Reserved.
Output under-voltage fault flag.
5
4
3
2
1
0
FT_UVP
FT_OLP
FT_SLP
FT_OTP
FT_OCP
FT_OVP
r
r
r
r
r
r
0
0
0
0
0
0
0: no fault
1: fault, clear after readback
LED open fault flag.
0: no fault
1: fault, clear after readback
LED short fault flag.
0: no fault
1: fault, clear after readback
Thermal shutdown fault flag.
0: no fault
1: fault, clear after readback
Over-current protection fault flag.
0: no fault
1: fault, clear after readback
Output voltage OVP fault flag.
0: no fault
1: fault, clear after readback
MP3313 Rev.1.0
8/2/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
23
MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
Selecting the Output Capacitor
APPLICATION INFORMATION
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. Note that the ceramic
capacitance is dependent on the voltage rating.
With a DC bias voltage, the capacitance can
lose as much as 50% of its value at its rated
voltage rating. Leave a large enough voltage
rating margin when selecting the component.
Too low a capacitance value causes loop
instability. For most applications, a 10μF
ceramic capacitor is sufficient.
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. Ceramic
capacitors with X5R or X7R dielectrics are
recommended for their low ESR and small
temperature coefficients. For most applications,
a 1 ~ 4.7μF ceramic capacitor is sufficient.
Selecting the Inductor
The converter requires an inductor to supply a
high output voltage while being driven by the
input voltage. A larger value inductor results in
less ripple current, lower peak inductor current,
and less stress on the internal N-channel
MOSFET. However, the larger inductor also has
a larger physical size, higher series resistance,
and lower saturation current.
Selecting the External Schottky Diode
To optimize the efficiency, a high-speed and low
reverse-recovery current Schottky diode are
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 break-down
voltage rating should be large than the maximum
voltage across the diode. Usually, unexpected
high-frequency voltage spikes can be seen
across the diode when the diode turns off.
Therefore, leaving some voltage rating margin is
always needed to guarantee normal long-term
operation when selecting a diode.
Choose an inductor that will not saturate under
the worst-case load conditions. Select the
minimum inductor value to ensure that the boost
converter works in continuous conduction mode
(CCM) with high efficiency and good EMI
performance.
Calculate the required inductance value using
Equation (35) and Equation (36):
PCB Layout Guidelines
Efficient PCB layout is critical for stable
operation. Proper layout of the high-frequency
switching path is critical to prevent noise and
electromagnetic interference problems. For best
results, refer to the guidelines below.
η VOUT D(1D)2
L
(35)
(36)
2 fSW ILOAD
V
IN
D 1
VOUT
1. Minimize the loop of MP3313’s internal
LS-FET, Schottky diode, and output
capacitor, since it is flowing with
high-frequency ripple current.
Where VIN is the input voltage, VOUT is the output
voltage, fSW is the switching frequency, ILOAD is
the LED load current, and η is the efficiency.
2. Place the input and output capacitors as
close to the IC as possible.
The
switching
current
is
used
for
peak-current-mode control. To prevent hitting
the current limit, the worst-case inductor peak
current should be less than 80% of the current
limit (ILIM). For most applications, a 4.7 ~ 10µH
inductor is sufficient.
MP3313 Rev1.0
8/2/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
24
MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
TYPICAL APPLICATION CIRCUIT
Figure 4: Typical Application for Single-String 3*7LEDs, 20mA/String
MP3313 Rev1.0
8/2/2017
www.MonolithicPower.com
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25
MP3313 – 3-CHANNEL, LINEAR/EXPONENTIAL DIMMING, WLED DRIVER W/ I2C
PACKAGE INFORMATION
CSP12 (1.3mmx1.7mm)
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.
MP3313 Rev.1.0
8/2/2017
www.MonolithicPower.com
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© 2017 MPS. All Rights Reserved.
26
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