SGM3145
8-Channel PWM Dimming
Charge Pump White LED Driver
GENERAL DESCRIPTION
The SGM3145 is a high performance white LED driver. It
integrates current sources and automatic mode selection
charge pump. The part maintains the high efficiency by
utilizing a 1×/1.5× fractional charge pump and low
dropout current sources. The small equivalent 1× mode
open loop resistance and ultra-low dropout voltage of
current source extend the operating time of 1× mode and
optimize the efficiency of Li-ion battery in white LED
applications.
The SGM3145 supports up to 8 white LEDs and
regulates a constant current which the initial value can be
set by an internal resistor. The part implements PWM
dimming to adjust the brightness of LED. Users can
easily configure the LED current from 0mA to 27mA by a
digital PWM signal. SGM3145 can be turned off by EN
pin. The operating voltage range is 2.7V to 5.5V. Internal
soft-start circuitry effectively reduces the in-rush current
while both start-up and mode transition.
The SGM3145 is available in Green TQFN-3×3-20L
package and is rated over the -40°C to +85°C
temperature range.
FEATURES
Input Voltage Range: 2.7V to 5.5V
Drives up to 8 LEDs at 27mA Each
PWM Dimming
High Efficiency by Fractional Conversion with
1× and 1.5× Modes
Switching Frequency: 0.93MHz
Regulated Output Current with ±4.8% Matching
Internal Soft-Start Limits Inrush Current
Low Input Ripple and Low EMI
Over-Current and Over-Temperature Protection
Under-Voltage Lockout with Hysteresis
Available in Green TQFN-3×3-20L Package
APPLICATIONS
Mobile Phone, DSC, MP3
White LED Backlighting
LCD Display Supply
SG Micro Corp
www.sg-micro.com
REV. A. 1
SGM3145
PACKAGE/ORDERING INFORMATION
MODEL
SGM3145
ORDER NUMBER
SGM3145YTQG20G/TR
PACKAGE
DESCRIPTION
TQFN-3×3-20L
8-Channel PWM Dimming
Charge Pump White LED Driver
SPECIFIED
TEMPERATURE
RANGE
-40℃ to +85℃
PACKAGE
OPTION
Tape and Reel, 3000
MARKING
INFORMATION
SGM3145QG
ABSOLUTE MAXIMUM RATINGS
V
IN
to GND……………………...……….….....….….. -0.3V to 6V
The Other Pins to GND……………….………....….. -0.3V to V
IN
Power Dissipation, P
D
@ T
A
= 25℃
TQFN-3×3-20L………………………………………………1.48W
Storage Temperature Range……….…………..-65℃ to +150℃
Junction Temperature…………………………………….....150℃
Operating Temperature Range...…………...……-40℃ to +85℃
Lead Temperature (Soldering 10 sec)
…………………………………..…..………......….….…….. 260℃
ESD Susceptibility
HBM…………………………………………………………...2000V
MM………………………………………….……………..……200V
CAUTION
This integrated circuit can be damaged by ESD if you don’t pay
attention to ESD protection. SGMICRO recommends that all
integrated circuits be handled with appropriate precautions.
Failure to observe proper handling and installation procedures
can cause damage. ESD damage can range from subtle
performance degradation to complete device failure. Precision
integrated circuits may be more susceptible to damage
because very small parametric changes could cause the device
not to meet its published specifications.
SGMICRO reserves the right to make any change in circuit
design, specification or other related things if necessary without
notice at any time. Please contact SGMICRO sales office to get
the latest datasheet.
NOTE:
Stresses beyond those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device. These
are stress ratings only, and functional operation of the device at
these or any other conditions beyond those indicated in the
operational sections of the specifications is not implied.
Exposure to absolute maximum rating conditions for extended
periods may affect device reliability.
SG Micro Corp
www.sg-micro.com
2
SGM3145
8-Channel PWM Dimming
Charge Pump White LED Driver
PIN CONFIGURATION
(TOP VIEW)
AGND
17
PWM
N.C.
20
19
18
16
15
VIN
EN
LED8
LED7
LED6
LED5
LED4
1
C2N
C1N
C1P
C2P
N.C.
2
14
3
GND
13
4
12
5
6
7
8
9
10
11
TQFN-3×3-20L
PIN DESCRIPTION
PIN
1, 2, 3, 4,
5, 6, 7, 8
9
10
11, 20
12
13
14
15
16
17
18
19
Exposed
Pad
NAME
LED8－LED1
PGND
VOUT
N.C.
C2P
C1P
C1N
C2N
VIN
AGND
PWM
EN
GND
I/O
I
-
O
-
-
-
-
-
I
-
I
I
-
FUNCTION
Current Sink Input. Connect the cathode of the white LEDs to these inputs.
Power Ground.
Output Voltage Source. Connect the output capacitor and the anode of the
LEDs to this pin.
No Internal Connection.
Positive Terminal of Bucket Capacitor 2.
Positive Terminal of Bucket Capacitor 1.
Negative Terminal of Bucket Capacitor 1.
Negative Terminal of Bucket Capacitor 2.
Supply Voltage Input.
Analog Ground.
PWM Dimming Pulse. Duty cycle = 0%, I
OUT
= 0mA; duty cycle =100%, I
OUT
=
27mA.
Enable or Disable SGM3145. Logic high to enable chip, logic low to disable
chip. For normal operation, suggest connecting to VIN only after the VIN has
settled if the VIN ramping up is slow.
Exposed pad should be soldered to PCB board and connected to GND.
SG Micro Corp
www.sg-micro.com
PGND
VOUT
LED3
LED2
LED1
3
SGM3145
8-Channel PWM Dimming
Charge Pump White LED Driver
ELECTRICAL CHARACTERISTICS
(V
IN
= 3.6V, EN = V
IN
, T
A
= +25℃, unless otherwise noted.)
PARAMETER
SUPPLY VOLTAGE AND CURRENT
Input Voltage Range
Quiescent Power Supply Current
Shutdown Supply Current
CHARGE PUMP STAGE
Over-Voltage Limit
Start-Up Time
Soft-Start Duration
Switching Frequency
Efficiency
Shutdown Temperature
Shutdown Temperature Hysteresis
Input Current Limit
CURRENT SINKS
Recommended Maximum Current per
Current Sink
Current Matching between Any Two Outputs
Line Regulation
Voltage at LED
X
to GND
V
SOURCE
I
LEDx
3.2V
≤
V
IN
≤
5.5V
V
LEDx
= 3.2V, I
LEDx
= 27mA
3.3V < V
IN
< 5.5V, V
LEDx
= 3.2V
V
IN
= 4.2V
24
-4.8
27
1
1.4
550
30
4.8
mA
%
%
mV
f
η
At 1× Mode before switching to 1.5× Mode
Temperature rising
0.7
V
OUT
C
OUT
= 1μF, I
LEDx
≥
0.9 × I
LEDx-set
5.4
280
150
0.93
90
140
10
300
1.25
V
µs
µs
MHz
%
℃
℃
mA
V
IN
I
Q
I
Q
I
SHDN
V
IN
= 4.2V, 1× Mode, I
LEDx
= 0mA
1.5× Mode, I
LEDx
= 0mA
EN = GND, V
IN
= 4.2V
2.7
155
1.35
0.01
2.5
5.5
240
V
µA
mA
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
THRESHOLD OF SWITCHING BETWEEN 1× AND 1.5× MODE
1× Mode to 1.5× Mode
1.5× Mode to 1× Mode
EN AND PWM LOGIC
PWM Low Time for Dimming
PWM High Time for Dimming
Threshold
Logic-High Voltage
Logic-Low Voltage
T
LO
T
HI
V
IH
V
IL
0.5
4
1.2
0.4
µs
µs
V
V
V
LEDX
= 3.2V
V
LEDX
= 3.2V
3.48
3.65
V
V
SG Micro Corp
www.sg-micro.com
4
SGM3145
8-Channel PWM Dimming
Charge Pump White LED Driver
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs. Input Voltage
95
Quiescent Current vs. Temperature
0.20
Quiescent Current (mA)
0.18
0.16
0.14
0.12
V
IN
= 4.2V
0.10
-55
-35
-15
5
25
45
65
85
105
85
Efficiency (%)
75
65
V
LED
= 3.2V
55
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Input Voltage (V)
Temperature (℃)
SG Micro Corp
www.sg-micro.com
5
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