SGM37604A [SGMICRO]
Highly Efficient 4-String White LED Driver;
| 型号： | SGM37604A |
| 厂家： | 
Shengbang Microelectronics Co, Ltd |
| 描述： | Highly Efficient 4-String White LED Driver |
| 文件： | 总18页 (文件大小：930K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SGM37604A
High Efficiency 4-String White LED Driver
GENERAL DESCRIPTION
FEATURES
● 12-Bit Resolution for Dimming Control
● Up to 90% Boost Efficiency
● Switching Frequency: 1.2MHz
● Support 1 to 4 LED Strings in Parallel at Maximum
29.5V Output
The SGM37604A is a high efficiency 4-string white LED
driver with a 1.2MHz boost converter. The supply
voltage operates from 3V to 24V. The SGM37604A is
capable of driving up to 8 LEDs in series for 40mA
maximum LED current per string while achieving high
conversion efficiency. An adaptively current-regulated
method allows different LED string voltages while LED
current remains in regulation. The LED current is
programmed through an I2C interface or a PWM signal
input. These features make it optimized for compact
solutions and ideal for LCD display backlighting.
● 11% LED Current Matching across Process,
Voltage and Temperature at ILED = 12.21μA
● 1% LED Current Matching across Process,
Voltage and Temperature at ILED = 25mA
● 11% LED Current Accuracy across Process,
Voltage and Temperature at ILED = 12.21μA
● 3% LED Current Accuracy across Process,
Voltage and Temperature at ILED = 25mA
● PWM Dimming Interface
The SGM37604A is available in Green WLCSP-
1.78×1.36-12B and TDFN-3×3-12L packages. It
operates over the -40℃ to +85℃ temperature range.
● Programmable I2C Interface
● Phase Shift Function
● Hybrid PWM + Current Dimming for Higher LED
Driver Optical Efficiency
APPLICATIONS
● Low EMI by Conducting Ringing Cancelling
● Protection Features
Power Source for Smart Phone and Tablet Backlighting
Over-Voltage Protection
Over-Current Protection
Thermal Shutdown
TYPICAL APPLICATION
Up to 28V Output
L1
VLF504012MT-100M
VIN
3V to 24V
10μH
R3
10Ω
C1
22μF
D1
IN
SW
COUT
1μF
CIN
2.2μF
VIO
OUT
R1
R2
10kΩ
10kΩ
SGM37604A
SDA
SCL
LED1
LED2
LED3
LED4
SDA
SCL
PWM
PWM
HWEN
HWEN
GND
Figure 1. Typical Application
SG Micro Corp
JANUARY 2019 – REV. A. 1
www.sg-micro.com
SGM37604A
High Efficiency 4-String White LED Driver
PACKAGE/ORDERING INFORMATION
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
DESCRIPTION
ORDERING
NUMBER
PACKAGE
MARKING
PACKING
OPTION
MODEL
XXXXX
GX4
WLCSP-1.78×1.36-12B
SGM37604AYG/TR
Tape and Reel, 3000
Tape and Reel, 4000
-40℃ to +85℃
-40℃ to +85℃
SGM37604A
SGM
B4DF
XXXXX
TDFN-3×3-12L
SGM37604AYTDF12G/TR
MARKING INFORMATION
NOTE: XXXXX = Date Code and Vendor Code.
WLCSP-1.78×1.36-12B
TDFN-3×3-12L
X X X X X
X X X X X
Vendor Code
Vendor Code
Date Code - Week
Date Code - Year
Date Code - Week
Date Code - Year
Green (RoHS & HSF): SG Micro Corp defines "Green" to mean Pb-Free (RoHS compatible) and free of halogen substances. If
you have additional comments or questions, please contact your SGMICRO representative directly.
OVERSTRESS CAUTION
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed in Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to
absolute maximum rating conditions for extended periods
may affect reliability. Functional operation of the device at any
conditions beyond those indicated in the Recommended
Operating Conditions section is not implied.
IN.................................................................... -0.3V to 28.6V
OUT................................................................... -0.3V to 40V
SW..................................................................... -0.3V to 40V
LED1, LED2, LED3, LED4................................. -0.3V to 17V
HWEN, PWM, SDA, SCL..................................... -0.3V to 6V
Package Thermal Resistance
WLCSP-1.78×1.36-12B, θJA ...................................... 82℃/W
TDFN-3×3-12L, θJA.................................................... 50℃/W
Junction Temperature.................................................+150℃
Storage Temperature Range........................-65℃ to +150℃
Lead Temperature (Soldering, 10s)............................+260℃
ESD Susceptibility
ESD SENSITIVITY CAUTION
This integrated circuit can be damaged if ESD protections are
not considered carefully. SGMICRO recommends that all
integrated circuits be handled with appropriate precautions.
Failureto observe proper handlingand installation procedures
can cause damage. ESD damage can range from subtle
performance degradation tocomplete device failure. Precision
integrated circuits may be more susceptible to damage
because even small parametric changes could cause the
device not to meet the published specifications.
HBM.............................................................................2000V
MM.................................................................................200V
CDM ..............................................................................500V
RECOMMENDED OPERATING CONDITIONS
IN............................................................................3V to 24V
OUT.....................................................................0V to 30.5V
SW.......................................................................0V to 30.5V
LED1, LED2, LED3, LED4......................................0V to 12V
HWEN, PWM, SDA, SCL.......................................0V to 5.5V
Operating Temperature Range......................-40℃ to +85℃
DISCLAIMER
SG Micro Corp reserves the right to make any change in
circuit design, or specifications without prior notice.
SG Micro Corp
www.sg-micro.com
JANUARY 2019
2
SGM37604A
High Efficiency 4-String White LED Driver
PIN CONFIGURATION
SGM37604A (TOP VIEW)
SGM37604A (TOP VIEW)
1
2
3
PWM
LED3
SCL
1
2
3
4
5
6
12 HWEN
11 IN
LED1
LED4
GND
A
B
C
D
10 OUT
LED2
LED3
PWM
SDA
SCL
SW
OUT
IN
AGND
LED2
SDA
9
8
7
SW
GND
LED4
LED1
HWEN
WLCSP-1.78×1.36-12B
TDFN-3×3-12L
FUNCTION
PIN DESCRIPTION
PIN
NAME
I/O
WLCSP-1.78×1.36-12B TDFN-3×3-12L
Current Sink 1. The boost converter regulates the minimum
voltage between current sinks to VHR
Current Sink 4. The boost converter regulates the minimum
A1
A2
A3
B1
B2
B3
C1
C2
6
7
8
4
5
9
2
3
LED1
LED4
GND
LED2
SDA
SW
I
I
.
voltage between current sinks to VHR
.
O
I
Ground Pin.
Current Sink 2. The boost converter regulates the minimum
voltage between current sinks to VHR
.
I/O I2C Data Signal.
Drain Connection for Internal Low-side N-Channel MOSFET.
Connect to the anode of an external Schottky diode.
I
I
I
Current Sink 3. The boost converter regulates the minimum
LED3
SCL
voltage between current sinks to VHR
.
I2C Clock Signal.
Output Voltage Sense Pin. It is used for sensing the output
voltage for over-voltage protection. Connect to the positive
terminal of the output capacitor.
C3
10
OUT
I
D1
D2
D3
—
1
PWM
HWEN
IN
I
I
PWM Dimming Signal Input.
Hardware Enable Input Pin. Drive HWEN high to enable the
device and allow I2C write commands or PWM control.
12
11
Input Supply Pin. Connect a at least 2.2μF bypass capacitor
from IN to GND.
I
Power Ground Exposed Pad. It should be connected to ground
plane.
Exposed Pad
AGND
—
NOTE: I: input; O: output; I/O: input or output.
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SGM37604A
High Efficiency 4-String White LED Driver
ELECTRICAL CHARACTERISTICS
(VIN = 3.6V, Full = -40℃ to +85℃, typical values are at TA = +25℃, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
TEMP MIN
TYP MAX UNITS
Boost
ILED = 12.21μA, VLED = 300mV
ILED = 25mA, VLED = 180mV
ILED = 12.21μA, VLED = 300mV
ILED = 25mA, VLED = 180mV
11
%
1
+25℃
+25℃
+25℃
+25℃
+25℃
+25℃
+25℃
+25℃
LED Current Matching ILED1 to ILED2 to ILED3 to
ILED4
(1)
IMATCH
11
%
3
Absolute Accuracy (ILED1, ILED2, ILED3, ILED4
)
Minimum LED Current (per string)
Maximum LED Current (per string)
ILED_MIN
ILED_MAX
VHR
12.21
25
μA
mA
mV
Ω
Regulated Current Sink Headroom Voltage
NMOS Switch On-Resistance
NMOS Switch Current Limit
Output Over-Voltage Protection
OVP Hysteresis
ILED = 25mA
ISW = 250mA
180
0.25
2.2
RNMOS
ICL
0.35
2.7
1.7
A
+25℃
Full
VOVP
28.5
29.5
3
30.5
V
V
+25℃
Full
Switching Frequency
fSW
950
90
1200 1400
94
kHz
%
Maximum Boost Duty Cycle
Shutdown Current
DMAX
ISHDN
Full
Chip enable bit = 0, SDA = SCL = IN or GND
0.5
160
20
1.5
μA
+25℃
Thermal Shutdown
TSD
℃
Thermal Shutdown Hysteresis
PWM Input
PWM Dimming Frequency Range
DFR
20
100
0.4
kHz
ms
+25℃
+25℃
PWM input active, PWM = logic high, HWEN
Turn-On Delay from Shutdown to Backlight
On
tSTART-UP input from low to high, fPWM = 20kHz (50%
duty cycle)
10
Input Logic High
Input Logic Low
VIH
VIL
HWEN, SCL, SDA, PWM inputs
HWEN, SCL, SDA, PWM inputs
Full
Full
1.4
V
NOTE:
1. LED Current Matching between strings is given as the worst case matching between any two strings. Matching is calculated as
(ILEDX - ILEDY)/(ILEDX + ILEDY) × 100.
I2C TIMING REQUIREMENTS
PARAMETER
SYMBOL
MIN
2.5
100
0
TYP
MAX
UNITS
μs
SCL Clock Period
t1
t2
t3
t4
t5
Data in Setup Time to SCL High
ns
Data Out Stable After SCL Low
ns
SDA Low Setup Time to SCL Low (Start)
SDA High Hold Time After SCL High (Stop)
100
100
ns
ns
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SGM37604A
High Efficiency 4-String White LED Driver
TYPICAL PERFORMANCE CHARACTERISTICS
At TA = +25℃, VIN = 3.7V, L1 = 10μH (VLF504012MT-100M), D1 = NSR0530P2T5G, unless otherwise noted.
Shutdown Current vs. Input Voltage
Quiescent Current (Switching) vs. Input Voltage
2
1.6
1.2
0.8
0.4
0
2.2
2.1
2.0
1.9
1.8
1.7
+125℃
+125℃
+30℃
+30℃
-40℃
-40℃
3
3
0
3.5
4
4.5
5
5.5
3
3
0
3.5
4
4.5
5
5.5
Input Voltage (V)
Input Voltage (V)
Boost Efficiency vs. Input Voltage
WLCSP-1.78×1.36-12B
Boost Efficiency vs. Input Voltage
TDFN-3×3-12L
95
90
85
80
75
70
95
90
85
80
75
70
4P8S LEDs
4P8S LEDs
4P6S LEDs
4P6S LEDs
4P7S LEDs
4P7S LEDs
4P5S LEDs
4P4S LEDs
4P5S LEDs
4P4S LEDs
3.5
4
4.5
5
5.5
3.5
4
4.5
5
5.5
Input Voltage (V)
Input Voltage (V)
Boost Efficiency vs. LED Current
WLCSP-1.78×1.36-12B
Boost Efficiency vs. LED Current
TDFN-3×3-12L
100
80
60
40
20
0
100
80
60
40
20
0
4P6S LEDs
4P6S LEDs
4P8S LEDs
4P7S LEDs
4P8S LEDs
4P7S LEDs
4P4S LEDs
4P5S LEDs
4P4S LEDs
4P5S LEDs
20
40
60
80
100
20
40
60
80
100
LED Current (mA)
LED Current (mA)
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SGM37604A
High Efficiency 4-String White LED Driver
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
At TA = +25℃, VIN = 3.7V, L1 = 10μH (VLF504012MT-100M), D1 = NSR0530P2T5G, unless otherwise noted.
NMOS Switch On-Resistance vs. Temperature
Output Over-Voltage Protection Threshold vs. Temperature
0.5
0.4
0.3
0.2
0.1
0
29.7
29.6
29.5
29.4
29.3
29.2
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
Temperature (℃)
Temperature (℃)
LED Current Production Distribution
35
30
25
20
15
10
5
1000 Samples
1 Production Lot
0
LED Current (mA)
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SGM37604A
High Efficiency 4-String White LED Driver
FUNCTIONAL BLOCK DIAGRAM
SW
Over-Voltage
Protection
IN
OUT
HWEN
OVP
Boost Control
Fault Detection
Over-Voltage
LED String Short
LED String Open
Current Limit
Thermal
Shutdown
TSD
Thermal Shutdown
Boost
Switching
Frequency
LED
Fault
OCP
Boost
Current
Limit
SDA
SCL
Min Headroom
Select
I2C Interface
Current Sinks
LED1
LED2
LED3
LED4
12-Bit
Brightness
Code
LED String
Enables
Mode
Control
Dimming
Control
Low-Pass Filter
(PWM-Based Code)
PWM
Figure 2. Functional Block Diagram
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SGM37604A
High Efficiency 4-String White LED Driver
REGISTER MAPS
Note: Read of Reserved (R) register returns 0/1 as below.
All registers are 8-bit and individual bits are named from D[0] (LSB) to D[7] (MSB).
R/W:
R:
Read/Write bit(s)
Read only bit(s)
PORV: Power-On Reset Value
I2C Slave Address of SGM37604A is: 0x36 (0b0110110 + R/W)
Table 1. Register Map
ADDRESS
0x01
REGISTER NAME
Software Reset
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
Reserved
SOFT_RST
DEV_EN
0x10
Enable Control
Reserved
LED4_EN LED3_EN LED2_EN LED1_EN
0x11
Brightness Control
Brightness Code 0
Brightness Code 1
Fault Information
Maximum LED Current
Reserved
LED_MOD[1:0]
Reserved
RAMP_EN
Reserved
0x1A
BRT_COD[3:0]
0x19
BRT_COD[11:4]
SO_FLAG SC_FLAG TSD_FLAG OC_FLAG OVP_FLAG
Reserved ILED_MAX[1:0]
0x1F
Reserved
0x1B
Table 2. Software Reset Register Details (Register Address: 0x01)
BITS
BIT NAME
DESCRIPTION
PORV
TYPE
D[7:1]
Reserved
Reserved
0000000
R
Software Reset
D[0]
SOFT_RST
0 = Normal Operation
0
R/W
1 = Reset the device. It will return 0 automatically.
Table 3. Enable Control Register Details (Register Address: 0x10)
BITS
BIT NAME
DESCRIPTION
PORV
TYPE
D[7:5]
Reserved
Reserved
000
R
LED4 Enable
D[4]
D[3]
D[2]
D[1]
D[0]
LED4_EN
LED3_EN
LED2_EN
LED1_EN
DEV_EN
1
1
1
1
1
R/W
R/W
R/W
R/W
R/W
0 = Disabled
1 = Enabled (default)
LED3 Enable
0 = Disabled
1 = Enabled (default)
LED2 Enable
0 = Disabled
1 = Enabled (default)
LED1 Enable
0 = Disabled
1 = Enabled (default)
Device Enable
0 = Disabled
1 = Enabled (default)
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SGM37604A
High Efficiency 4-String White LED Driver
REGISTER MAP (continued)
Table 4. Brightness Control Register Details (Register Address: 0x11)
BITS
BIT NAME
DESCRIPTION
PORV
TYPE
D[7]
Reserved
Reserved
00 = I2C Only
0
R
01 = PWM Only
10 = I2C × PWM
11 = I2C × PWM (default)
Ramp Enable
D[6:5] LED_MOD[1:0]
11
R/W
D[4]
RAMP_EN
Reserved
0
R/W
R
0 = Disabled (default)
1 = Enabled
D[3:0]
Reserved
0101
Table 5. Brightness Code 0 Register Details (Register Address: 0x1A)
BITS
BIT NAME
DESCRIPTION
PORV
1111
TYPE
R
D[7:4]
Reserved
Reserved
D[3:0] BRT_COD[3:0] Lower 4 Bits of the 12-Bit Brightness Code
1111
R/W
Table 6. Brightness Code 1 Register Details (Register Address: 0x19)
BITS
BIT NAME
DESCRIPTION
PORV
TYPE
D[7:0] BRT_COD[11:4] High Byte of the 12-Bit Brightness Code
11111111
R/W
Table 7. Fault Information Register Details (Register Address: 0x1F)
BITS
BIT NAME
DESCRIPTION
PORV
TYPE
D[7:5]
Reserved
Reserved
000
R
LED String Open Fault Flag
0 = No LED Open Fault (default)
1 = LED Open Fault
Short Circuit Fault Flag
0 = No short-circuit fault (default)
1 = Short-circuit fault
Thermal Shutdown Fault Flag
0 = No thermal shutdown fault (default)
1 = Thermal shutdown fault
Current Limit Fault Flag
0 = No current limit fault
1 = Current limit fault
D[4]
D[3]
D[2]
D[1]
D[0]
SO_FLAG
SC_FLAG
TSD_FLAG
OC_FLAG
OVP_FLAG
0
0
0
0
0
R
R
R
R
R
Output Over-Voltage Fault Flag
0 = No over-voltage fault (default)
1 = Over-voltage fault
Table 8. Maximum LED Current Register Details (0x1B)
BITS
BIT NAME
DESCRIPTION
PORV
TYPE
D[7:2]
Reserved
Reserved
000000
R
Maximum LED Current Setting
00 = Maximum LED Current of 25mA (default)
D[1:0] ILED_MAX[1:0] 01 = Maximum LED Current of 30mA
10 = Maximum LED Current of 35mA
00
R/W
11 = Maximum LED Current of 40mA
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SGM37604A
High Efficiency 4-String White LED Driver
DETAILED DESCRIPTION
Table 9. SGM37604A Operating Modes
LED Enable
Device Enable LED1_EN & LED2_EN &
DEV_EN Bit LED3_EN & LED4_EN
Bits
I2C Brightness Code Brightness Mode
LED Current
PWM Input
BRT_COD[11:0]
LED_MOD[1:0]
0
1
1
1
1
1
1
1
1
XXXX
X
XXX
XXX
XX
XX
Off, device disabled
Boost enabled, LED current disabled
Off, device in standby mode
See (1)
0000
X
At least one enabled
At least one enabled
At least one enabled
At least one enabled
At least one enabled
At least one enabled
At least one enabled
X
000
00
X
Code > 000
XXX
00
0
01
Off, device in standby mode
See (1)
PWM Signal
XXX (2)
XXX
01
0
X
10 or 11
10 or 11
10 or 11
Off, device in standby mode
Off, device in standby mode
See (1)
000
PWM Signal
Code > 000
NOTE:
1. ILED is calculated by the equations from Equation 1 to Equation 8 below in Brightness Control Modes.
2. Code is forbidden to set to 0.
Brightness Control Modes
The SGM37604A has 3 brightness control modes:
1. I2C Only (brightness mode 00)
2. PWM Only (brightness mode 01)
3. I2C × PWM (brightness mode 10 or 11)
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SGM37604A
High Efficiency 4-String White LED Driver
DETAILED DESCRIPTION (continued)
I2C Only (Brightness Mode 00)
In brightness control mode 00, only the I2C Brightness
registers control the LED current. The 12-bit code (0 to
4095) is in control of the LED current as follows:
and follows the relationship by Equation 3 (see Figure
4). The LED current is also in current-to-PWM control,
and the duty cycle is 16/256 constantly, and the
amplitude of current pulse is 16 times of its
corresponding average current.
When the code is from 256 to 4095, the average LED
current increases proportionally to the brightness code
and follows the below relationship (see Figure 4).
I
LED_AVG = 12.21μA × 1.149( code - 1)
(3)
Code 1 programs the LED current to 12.21μA with
25mA maximum LED current. If the bits[1:0] are not set
to all 0 in register 0x1B, the maximum LED current will
increase and the minimum current (code = 1) will
proportionally increase. Code 0 programs 0 current.
When the code is an odd integer,
ILED_AVG = 12.21μA × 0.5 × (code - 1)
When the code is an even integer,
ILED_AVG = 12.21μA × 0.5 × code
(1)
(2)
When bit[4] is set to 1 in register 0x11, ramp function is
enabled. Then when bits[7:4] in registers 0x19 are not
all 0 (codes from 256 to 4095), the ramp rate is
128μs/step. When bits[7:4] in registers 0x19 are all 0
(codes from 1 to 255), the ramp rate is 1024μs/step.
For example, if the code is set from 2000 to 4001,
ILED_AVG will change from 12.21mA to 24.42mA, the
corresponding ramp rate = 128μs/step, so the ramp
time for ILED_AVG = [(4001 - 1) × 0.5 - 2000 × 0.5] ×
128μs = 128ms.
Where:
ILED_AVG = average LED current
When the code is from 16 to 255, the average LED
current is calculated by Equation 1 and Equation 2 and
the LED current is in current-to-PWM control (see Figure 4)
with a constant maximum current, while the duty cycle
changes following the code.
When the code is from 1 to 15, the average LED
current increases exponentially to the brightness code
VOUT
Boost
Digital Domain
Analog Domain
Min VHR
ILED1
ILED2
ILED3
ILED4
Driver 1
BRT Code = I2C Code
DACi
I2C Brightness Reg
DAC
Driver 2
Driver 3
Driver 4
RAMP_EN
Figure 3. Brightness Control 00 (I2C Only)
25000
PWM Duty
16
256
64
256
128
256
192
256
254
256
1562.9
16
256
Average Current
97.7
12.21
0
0
4
8
12 16 32
64
128
192
254
4095
Code
Figure 4. LED Current vs. Brightness Code (Mode 00)
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SGM37604A
High Efficiency 4-String White LED Driver
DETAILED DESCRIPTION (continued)
PWM Only (Brightness Mode 01)
In brightness mode 01, only the PWM signal input sets
the brightness. The I2C code is ignored and forbidden
to set to 0. The LED current is proportional with the
PWM duty cycle and the maximum LED current is
25mA.
Then the value of VREF is the PWM-based code for
brightness dimming. The LED current increases
proportionally to the brightness code and follows the
relationship (see Figure 6):
ILED_AVG = 12.21μA × code
(5)
This is valid from codes 1 to 2048. Code 0 programs 0
current. When the code < 16, the LED current is in
current-to-PWM control. The duty cycle of the PWM is
1/8, and the amplitude of current pulse is 8 times of its
corresponding average current. Figure 6 (a) shows the
zoomed graph from codes 0 to 16 in Figure 6. There is
no ramp function in this mode.
When the PWM pin is constantly high, the VREF voltage
is regulated to 2048mV typically. When the duty cycle
of the input PWM signal is low, the regulation voltage is
reduced, and the LED current is reduced; therefore, it
achieves LED brightness dimming. The relationship
between the duty cycle and VREF regulation voltage is
given by Equation 4:
Thus, the user can easily control the WLED brightness
by controlling the duty cycle of the PWM signal. The
PWM frequency is in the range from 20kHz to 100kHz.
VREF = Duty × 2048mV
(4)
Where:
Duty = duty cycle of the PWM signal
2048mV = internal reference voltage
VOUT
Boost
Digital Domain
Analog Domain
Min VHR
ILED1
ILED2
ILED3
ILED4
Driver 1
PWM Input
Low-Pass Filter
VREF
Driver 2
Driver 3
Driver 4
(PWM-Based Code)
Figure 5. Brightness Control 01 (PWM Only)
1
8
PWM Duty
25000
1465.2
Average
Current
1465.2
195.4
97.7
195.4
0
12.21
16
0
0
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
2048
See Figure 6 (a)
Code
Code
Figure 6 (a).
Figure 6. LED Current vs. Brightness Code (Mode 01)
SG Micro Corp
www.sg-micro.com
JANUARY 2019
12
SGM37604A
High Efficiency 4-String White LED Driver
DETAILED DESCRIPTION (continued)
I2C + PWM (Brightness Mode 10 or 11)
In brightness control mode 10 or 11, both the I2C code
and the PWM duty cycle control the LED current. The
brightness code is calculated by PWM duty cycle and
the I2C brightness code, and follows the relationship
(see Figure 7):
current to 12.21μA with 25mA maximum LED current. If
the bits[1:0] are not set to all 0 in register 0x1B, the
maximum LED current will increase and the minimum
current (code = 1) will proportionally increase. Code 0
programs 0 current (see Figure 8). When the
brightness code < 16, the LED current is in current-to-
PWM control. The duty cycle of the PWM is 1/8, and
the amplitude of current pulse is 8 times of its
corresponding average current. Figure 8 (a) shows the
zoomed graph from codes 0 to 16 in Figure 8.
When the I2C code is an odd integer,
BRT code = (I2C code - 1) × 0.5 × PWM duty cycle (6)
When the I2C code is an even integer,
When bit[4] is set to 1 in register 0x11, ramp function is
enabled . When bits[7:4] in registers 0x19 are not all 0
(codes from 256 to 4095), regardless of PWM duty
cycle, the ramp rate is 128μs/step. When bits[7:4] in
registers 0x19 are all 0 (codes from 1 to 255),
regardless of PWM duty cycle, the ramp rate is
1024μs/step. For example, if PWM duty cycle is set to
10% and the code is set from 2000 to 4001, when
bit[1:0] in register 0x1B is 00, ILED_AVG will change from
1.221mA to 2.442mA, the corresponding ramp rate =
128μs/step, so the ramp time for ILED_AVG = [(4001 - 1) ×
0.5 - 2000 × 0.5] × 128μs = 128ms.
BRT code = I2C code × 0.5 × PWM duty cycle (7)
Where:
BRT code = the brightness code
I2C codes are valid from 0 to 4095. The codes should
be integers.
The average LED current increases proportionally to
the brightness code and is calculated by Equation 8.
ILED_AVG = 12.21μA × code
(8)
This is valid from codes 1 to 2047 and the codes could
be integers or decimals. Code 1 programs the LED
VOUT
Boost
Digital Domain
Analog Domain
Min VHR
ILED1
ILED2
I
I
L
E
D
3
L
E
D
4
Driver 1
Driver 2
Driver 3
Driver 4
BRT Code = I2C × Duty Cycle
DACi
I2C Brightness Reg
DAC
RAMP_EN
PWM Input
Low-Pass Filter
Figure 7. Brightness Control 10 or 11 (I2C + PWM)
1
PWM Duty
8
25000
1465.2
Average
Current
1465.2
195.4
97.7
195.4
0
12.21
16
0
0
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
2047
See Figure 8 (a)
Code
Code
Figure 8 (a).
Figure 8. LED Current vs. Brightness Code (Mode 10 or
Mode 11)
SG Micro Corp
www.sg-micro.com
JANUARY 2019
13
SGM37604A
High Efficiency 4-String White LED Driver
DETAILED DESCRIPTION (continued)
Up to 28V Output
L1
VLF504012MT-100M
VIN
3V to 24V
10μH
R3
10Ω
C1
22μF
D1
IN
SW
COUT
1μF
CIN
2.2μF
VIO
OUT
R1
10kΩ
R2
10kΩ
SGM37604A
SDA
SCL
SDA
LED1
LED2
LED3
LED4
GND
SCL
PWM
Floating or connected to GND
PWM
HWEN
HWEN
Figure 9. Typical Application for Less than Four Parallel LED Strings
REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
JANUARY 2019 ‒ REV.A to REV.A.1
Changed Register Maps section..........................................................................................................................................................................9
Changed Detailed Description section ...............................................................................................................................................................16
Changes from Original (SEPTEMBER 2018) to REV.A
Changed from product preview to production data.............................................................................................................................................All
SG Micro Corp
www.sg-micro.com
JANUARY 2019
14
PACKAGE INFORMATION
PACKAGE OUTLINE DIMENSIONS
WLCSP-1.78×1.36-12B
A1 CORNER
0.24
0.20
12 × Φ
0.4
0.4
TOP VIEW
RECOMMENDED LAND PATTERN
1.355± 0.025
12 × Φ0.260± 0.020
3
2
1
A
B
C
D
0.4
1.775± 0.025
0.040± 0.005
0.195± 0.020
0.385± 0.013
0.4
0.620± 0.038
SIDE VIEW
BOTTOM VIEW
NOTE: All linear dimensions are in millimeters.
SG Micro Corp
TX00137.000
www.sg-micro.com
PACKAGE INFORMATION
PACKAGE OUTLINE DIMENSIONS
TDFN-3×3-12L
D
e
N7
N12
E1
N1
D1
k
E
N6
L
b
BOTTOM VIEW
TOP VIEW
2.55
1.60
2.8
A
A1
0.6
A2
SIDE VIEW
0.2
0.45
RECOMMENDED LAND PATTERN (Unit: mm)
Dimensions
In Millimeters
Dimensions
In Inches
Symbol
MIN
MAX
0.800
0.050
MIN
0.028
0.000
MAX
0.031
0.002
A
A1
A2
D
0.700
0.000
0.203 REF
0.008 REF
2.924
2.450
2.924
1.500
3.076
2.650
3.076
1.700
0.115
0.096
0.115
0.059
0.121
0.104
0.121
0.067
D1
E
E1
k
0.200 MIN
0.450 TYP
0.008 MIN
0.018 TYP
b
0.150
0.324
0.250
0.476
0.006
0.013
0.010
0.019
e
L
SG Micro Corp
www.sg-micro.com
TX00062.000
PACKAGE INFORMATION
TAPE AND REEL INFORMATION
REEL DIMENSIONS
TAPE DIMENSIONS
P2
P0
W
Q2
Q4
Q2
Q4
Q2
Q4
Q1
Q3
Q1
Q3
Q1
Q3
B0
Reel Diameter
P1
A0
K0
Reel Width (W1)
DIRECTION OF FEED
NOTE: The picture is only for reference. Please make the object as the standard.
KEY PARAMETER LIST OF TAPE AND REEL
Reel Width
Reel
Diameter
A0
B0
K0
P0
P1
P2
W
Pin1
Package Type
W1
(mm)
(mm) (mm) (mm) (mm) (mm) (mm) (mm) Quadrant
WLCSP-1.78×1.36-12B
TDFN-3×3-12L
7″
9.2
1.46
3.30
1.90
3.30
0.81
1.10
4.0
4.0
4.0
8.0
2.0
2.0
8.0
Q1
Q1
13″
12.4
12.0
SG Micro Corp
TX10000.000
www.sg-micro.com
PACKAGE INFORMATION
CARTON BOX DIMENSIONS
NOTE: The picture is only for reference. Please make the object as the standard.
KEY PARAMETER LIST OF CARTON BOX
Length
(mm)
Width
(mm)
Height
(mm)
Reel Type
Pizza/Carton
7″ (Option)
368
442
386
227
410
280
224
224
370
8
18
5
7″
13″
SG Micro Corp
www.sg-micro.com
TX20000.000
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