SGM37603 [SGMICRO]

Highly Efficient 3-String White LED Driver;
SGM37603
型号: SGM37603
厂家: Shengbang Microelectronics Co, Ltd    Shengbang Microelectronics Co, Ltd
描述:

Highly Efficient 3-String White LED Driver

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中文:  中文翻译
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SGM37603  
High Efficiency 3-String White LED Driver  
GENERAL DESCRIPTION  
FEATURES  
11-Bit Resolution for Dimming Control  
Up to 90% Boost Efficiency  
Switching Frequency: 1.2MHz  
Support 1 to 3 LED Strings in Parallel at Maximum  
29.5V Output  
The SGM37603 is a high efficiency 3-string white LED  
driver with a 1.2MHz boost converter. The supply  
voltage operates from 3V to 24V. The SGM37603 is  
capable of driving up to 8 LEDs in series for 25mA  
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 SGM37603 is available in Green WLCSP-  
1.78×1.36-12B and TDFN-3×3-12L packages. It  
operates over an ambient temperature range of -40℃  
to +85.  
Programmable I2C Interface  
Hybrid PWM + Current Dimming for Higher LED  
Driver Optical Efficiency  
Low EMI by Conducting Ringing Cancelling  
Protection Features  
APPLICATIONS  
Over-Voltage Protection  
Power Source for Smart Phone and Tablet Backlighting  
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  
10kΩ  
R2  
10kΩ  
SGM37603  
SDA  
LED1  
LED2  
LED3  
GND  
SDA  
SCL  
PWM  
SCL  
PWM  
HWEN  
HWEN  
Figure 1. Typical Application  
SG Micro Corp  
JANUARY 2019 – REV. A.1  
www.sg-micro.com  
SGM37603  
High Efficiency 3-String White LED Driver  
PACKAGE/ORDERING INFORMATION  
SPECIFIED  
TEMPERATURE  
RANGE  
PACKAGE  
DESCRIPTION  
ORDERING  
NUMBER  
PACKAGE  
MARKING  
PACKING  
OPTION  
MODEL  
XXXXX  
37603  
WLCSP-1.78×1.36-12B  
SGM37603YG/TR  
Tape and Reel, 3000  
Tape and Reel, 4000  
-40to +85℃  
-40to +85℃  
SGM37603  
SGM  
37603DF  
XXXXX  
TDFN-3×3-12L  
SGM37603YTDF12G/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............................................ -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........................-65to +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.................................................0V to 12V  
HWEN, PWM, SDA, SCL.......................................0V to 5.5V  
Operating Temperature Range......................-40to +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
SGM37603  
High Efficiency 3-String White LED Driver  
PIN CONFIGURATIONS  
SGM37603 (TOP VIEW)  
SGM37603 (TOP VIEW)  
1
2
3
PWM  
LED3  
SCL  
1
2
3
4
5
6
12 HWEN  
11 IN  
LED1  
NC  
GND  
A
B
C
D
10 OUT  
LED2  
LED3  
PWM  
SDA  
SCL  
SW  
OUT  
IN  
AGND  
LED2  
SDA  
9
8
7
SW  
GND  
NC  
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  
A1  
A2  
A3  
B1  
B2  
B3  
C1  
C2  
6
7
8
4
5
9
2
3
LED1  
NC  
I
O
I
voltage between current sinks to VHR  
.
No Connection.  
GND  
LED2  
SDA  
SW  
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.  
SG Micro Corp  
www.sg-micro.com  
JANUARY 2019  
3
SGM37603  
High Efficiency 3-String White LED Driver  
ELECTRICAL CHARACTERISTICS  
(VIN = 3.6V, Full = -40to +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℃  
(1)  
LED Current Matching ILED1 to ILED2 to ILED3  
IMATCH  
11  
%
3
Absolute Accuracy (ILED1, ILED2, ILED3  
)
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  
SG Micro Corp  
www.sg-micro.com  
JANUARY 2019  
4
SGM37603  
High Efficiency 3-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
3
3.5  
4
4.5  
5
5.5  
5.5  
5.5  
3
3
3
3.5  
4
4.5  
5
5.5  
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  
WLCSP-1.78×1.36-12B  
92  
90  
88  
86  
84  
82  
80  
92  
90  
88  
86  
84  
82  
80  
3P8S LEDs  
3P6S LEDs  
2P8S LEDs  
2P6S LEDs  
2P7S LEDs  
2P5S LEDs  
3P7S LEDs  
3P5S LEDs  
3P4S LEDs  
2P4S LEDs  
3.5  
4
4.5  
5
3.5  
4
4.5  
5
Input Voltage (V)  
Input Voltage (V)  
Boost Efficiency vs. Input Voltage  
TDFN-3×3-12L  
Boost Efficiency vs. Input Voltage  
TDFN-3×3-12L  
92  
88  
84  
80  
76  
72  
90  
88  
86  
84  
82  
80  
3P8S LEDs  
2P8S LEDs  
3P6S LEDs  
2P6S LEDs  
2P5S LEDs  
3P7S LEDs  
3P5S LEDs  
3P4S LEDs  
2P7S LEDs  
2P4S LEDs  
3.5  
4
4.5  
5
3.5  
4
4.5  
5
Input Voltage (V)  
Input Voltage (V)  
SG Micro Corp  
www.sg-micro.com  
JANUARY 2019  
5
SGM37603  
High Efficiency 3-String White LED Driver  
TYPICAL PERFORMANCE CHARACTERISTICS (continued)  
At TA = +25, VIN = 3.7V, L1 = 10μH (VLF504012MT-100M), D1 = NSR0530P2T5G, unless otherwise noted.  
Boost Efficiency vs. LED Current  
WLCSP-1.78×1.36-12B  
Boost Efficiency vs. LED Current  
WLCSP-1.78×1.36-12B  
100  
80  
60  
40  
20  
0
100  
80  
60  
40  
20  
0
3P6S LEDs  
3P7S LEDs  
2P8S LEDs  
2P7S LEDs  
3P8S LEDs  
2P6S LEDs  
3P4S LEDs  
3P5S LEDs  
2P4S LEDs  
2P5S LEDs  
0
16  
32  
48  
64  
80  
0
10  
20  
30  
40  
50  
LED Current (mA)  
LED Current (mA)  
Boost Efficiency vs. LED Current  
TDFN-3×3-12L  
Boost Efficiency vs. LED Current  
TDFN-3×3-12L  
100  
80  
60  
40  
20  
0
100  
80  
60  
40  
20  
0
3P6S LEDs  
3P7S LEDs  
3P8S LEDs  
2P6S LEDs  
2P8S LEDs  
2P7S LEDs  
3P4S LEDs  
3P5S LEDs  
2P4S LEDs  
2P5S LEDs  
0
16  
32  
48  
64  
80  
0
10  
20  
30  
40  
50  
LED Current (mA)  
LED Current (mA)  
NMOS Switch On-Resistance vs. Temperature  
Output Over-Voltage Protection Threshold vs. Temperature  
29.7  
0.5  
0.4  
0.3  
0.2  
0.1  
0
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 ()  
SG Micro Corp  
www.sg-micro.com  
JANUARY 2019  
6
SGM37603  
High Efficiency 3-String White LED Driver  
TYPICAL PERFORMANCE CHARACTERISTICS (continued)  
At TA = +25, VIN = 3.7V, L1 = 10μH (VLF504012MT-100M), D1 = NSR0530P2T5G, unless otherwise noted.  
LED Current Production Distribution  
35  
1000 Samples  
1 Production Lot  
30  
25  
20  
15  
10  
5
0
LED Current (mA)  
SG Micro Corp  
www.sg-micro.com  
JANUARY 2019  
7
SGM37603  
High Efficiency 3-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  
11-Bit  
Brightness  
Code  
LED String  
Enables  
Mode  
Control  
Dimming  
Control  
Low-Pass Filter  
(PWM-Based Code)  
PWM  
Figure 2. Functional Block Diagram  
SG Micro Corp  
JANUARY 2019  
www.sg-micro.com  
8
SGM37603  
High Efficiency 3-String White LED Driver  
REGISTER MAP  
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 SGM37603 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  
RSD_FL  
RAMP_EN  
SOFT_RST  
DEV_EN  
0x10  
Enable Control  
Reserved  
LED3_EN LED2_EN LED1_EN  
Reserved  
0x11  
Brightness Control  
Brightness Code 0  
Brightness Code 1  
Fault Information  
Reserved  
LED_MOD[1:0]  
Reserved  
0x18  
BRT_COD[2:0]  
0x19  
BRT_COD[10:3]  
SO_FLAG SC_FLAG TSD_FLAG OC_FLAG OVP_FLAG  
0x1F  
Reserved  
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  
D[7:5]  
D[4]  
BIT NAME  
Reserved  
RSD_FL  
DESCRIPTION  
PORV  
000  
1
TYPE  
R
Reserved  
Reserved Flag. It is set to 1 by default.  
R/W  
LED3 Enable  
D[3]  
D[2]  
D[1]  
D[0]  
LED3_EN  
LED2_EN  
LED1_EN  
DEV_EN  
1
1
1
1
R/W  
R/W  
R/W  
R/W  
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)  
Table 4. Brightness Control Register Details (Register Address: 0x11)  
BITS  
BIT NAME  
DESCRIPTION  
PORV  
TYPE  
D[7]  
Reserved  
Reserved  
0
R
00 = I2C Only  
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  
SG Micro Corp  
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JANUARY 2019  
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SGM37603  
High Efficiency 3-String White LED Driver  
REGISTER MAP (continued)  
Table 5. Brightness Code 0 Register Details (Register Address: 0x18)  
BITS  
BIT NAME  
DESCRIPTION  
PORV  
00000  
111  
TYPE  
R
D[7:3]  
Reserved  
Reserved  
D[2:0] BRT_COD[2:0] Lower 3 Bits of the 11-Bit Brightness Code  
R/W  
Table 6. Brightness Code 1 Register Details (Register Address: 0x19)  
BITS  
BIT NAME  
DESCRIPTION  
PORV  
TYPE  
D[7:0] BRT_COD[10:3] High Byte of the 11-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  
SG Micro Corp  
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JANUARY 2019  
10  
SGM37603  
High Efficiency 3-String White LED Driver  
DETAILED DESCRIPTION  
Table 8. SGM37603 Operating Modes  
LED Enable  
LED1_EN & LED2_EN  
& LED3_EN Bits  
Device Enable  
DEV_EN Bit  
I2C Brightness Code Brightness Mode  
LED Current  
PWM Input  
BRT_COD[10:0]  
LED_MOD[1:0]  
0
XXX  
X
XXX  
XXX  
XX  
XX  
Off, device disabled  
Boost enabled, LED current disabled  
Off, device in standby mode  
See (1)  
1
000  
X
1
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  
1
X
Code > 000  
XXX  
00  
1
0
01  
Off, device in standby mode  
See (1)  
1
PWM Signal  
XXX (2)  
XXX  
01  
1
0
X
10 or 11  
10 or 11  
10 or 11  
Off, device in standby mode  
Off, device in standby mode  
See (1)  
1
1
000  
PWM Signal  
Code > 000  
NOTE:  
1. ILED is calculated by the Equation 1 or Equation 2 below in Brightness Control Modes.  
2. Code is forbidden to set to 0.  
Brightness Control Modes  
The SGM37603 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)  
SG Micro Corp  
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JANUARY 2019  
11  
SGM37603  
High Efficiency 3-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 11-bit code (0 to  
2047) is in control of the LED current as follows:  
follows the relationship by Equation 2 (see Figure 4).  
The LED current is also in current-to-PWM control, and  
the duty cycle is 8/128 constantly, and the amplitude of  
current pulse is 16 times of its corresponding average  
current.  
When the code is from 128 to 2047, the average LED  
current proportionally increases to the brightness code  
and follows the relationship (see Figure 4):  
ILED_AVG = 16.17μA × 1.14(2 × code - 2)  
(2)  
Code 0 programs 0 current.  
I
LED_AVG = 12.21μA × code  
(1)  
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 128 to 2047), the ramp rate is  
128μs/step. When bits[7:4] in registers 0x19 are all 0  
(codes from 1 to 127), the ramp rate is 1024μs/step.  
For example, if the code is set from 1000 to 2000,  
ILED_AVG will change from 12.21mA to 24.42mA, the  
corresponding ramp rate = 128μs/step, so the ramp  
time for ILED_AVG = (2000 - 1000) × 128μs = 128ms.  
Where:  
ILED_AVG = Average LED Current  
When the code is from 8 to 127, the average LED  
current is calculated by Equation 1, 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 7, the average LED current  
exponentially increases to the brightness code and  
VOUT  
Boost  
Digital Domain  
Analog Domain  
Min VHR  
ILED1  
ILED2  
ILED3  
Driver 1  
BRT Code = I2C Code  
I2C Brightness Reg  
DACi  
DAC  
Driver 2  
Driver 3  
RAMP_EN  
Figure 3. Brightness Control 00 (I2C Only)  
25000  
PWM Duty  
9
32  
64  
96  
128  
128  
128  
128  
128  
128  
8
128  
1562.9  
8
128  
Average  
Current  
97.7  
16.17  
0
0
89  
32  
64  
96  
128  
2047  
Figure 4. LED Current vs. Brightness Code (Mode 00)  
SG Micro Corp  
www.sg-micro.com  
JANUARY 2019  
12  
 
SGM37603  
High Efficiency 3-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.  
2048mV = internal reference voltage  
Then the value of VREF is the PWM-based code for  
brightness dimming. The LED current increases  
proportionally to the brightness code and is calculated  
by the Equation 1 (see Figure 6). 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 3:  
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  
(3)  
Where:  
Duty = duty cycle of the PWM signal  
VOUT  
Boost  
Digital Domain  
Analog Domain  
Min VHR  
ILED1  
ILED2  
ILED3  
Driver 1  
Driver 2  
Driver 3  
PWM Input  
Low-Pass Filter  
(PWM-Based Code)  
VREF  
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  
0
16  
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16  
0
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  
13  
 
SGM37603  
High Efficiency 3-String White LED Driver  
DETAILED DESCRIPTION (continued)  
I2C + PWM (Brightness Mode 10 or 11)  
In brightness control mode 10 or 11, both the I2C  
brightness code and the PWM duty cycle control the  
LED current. The code is equal to the PWM duty cycle  
multiplied with the I2C brightness code (see Figure 7).  
The average LED current increases proportionally to  
the brightness code and is calculated by the Equation 1  
(see Figure 8). This is valid from codes 1 to 2047. Code  
0 programs 0 current. 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 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 128 to 2047), 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 127),  
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 1000 to 2000, ILED_AVG will  
change from 1.221mA to 2.442mA, the corresponding  
ramp rate = 128μs/step, so the ramp time for ILED_AVG  
(2000 - 1000) × 128μs = 128ms.  
=
VOUT  
Boost  
Digital Domain  
Analog Domain  
Min VHR  
ILED1  
ILED2  
ILED3  
Driver 1  
Driver 2  
Driver 3  
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)  
25000  
1
8
PWM Duty  
1465.2  
Average  
Current  
1465.2  
195.4  
97.7  
195.4  
0
12.21  
16  
0
0
2047  
See Figure 8 (a)  
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16  
Code  
Code  
Figure 8. LED Current vs. Brightness Code (Mode 10 or  
Mode 11)  
Figure 8 (a).  
SG Micro Corp  
www.sg-micro.com  
JANUARY 2019  
14  
 
 
SGM37603  
High Efficiency 3-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  
R2  
10kΩ  
10kΩ  
SGM37603  
SDA  
LED1  
LED2  
LED3  
GND  
SDA  
SCL  
PWM  
SCL  
Floating or connected to GND  
PWM  
HWEN  
HWEN  
Figure 9. Typical Application for Less than Three 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........................................................................................................................................................................10  
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  
15  
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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