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Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3. TECHNICAL BRIEF
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
The SC624 is a high efficiency charge pump LED driver using Semtech’s proprietary mAhXLifeTM technology.
Performance is optimized for use in single-cell Li-ion battery applications.
The charge pump provides backlight current in conjunction with four matched current sinks. The load and
supply conditions determine whether the charge pump operates in 1x, 1.5x, or 2x mode. An optional fading
feature that gradually adjusts the backlight current is provided to simplify control software. The SC624 also
provides two low- dropout, low-noise linear regulators for powering a camera module or other peripheral
circuits.
The SC624 uses the proprietary SemWireTM single wire interface. The interface controls all functions of the
device, including backlight current and two LDO voltage outputs. The single wire implementation
minimizes microcontroller and interface pin counts.
In sleep mode, the device reduces quiescent current to 100μA while continuing to monitor the serial
interface. The two LDOs can be enabled when the device is in sleep mode. Total current reduces to 0.1μA in
shutdown.
Figure 3-9-2. SC624 CIRCUIT DIAGRAM
LCD CHARGEPUMP & CAM LDO
1uC324
VBAT
C330
2V8_AVDD
1V5_DVDD
1u
1u
C327
11
THER_GND
21
VIN
19
16
VOUT
BL1
BL2
5
6
BL3
BL4
7
13
BYP
C1+
18
C1-
20
C2+
17
1
C2-
GREF
9
LDO1
15
LDO2
14
NC1
3
10
NC2
12
NC3
PGND
2
SWIF
EUSY0263105
SC624ULTRT
U302
8
AGND
4
1uC326
C329 1u
22nC328
C325
2.2u
MLED
MLED1
MLED2
MLED3
SWIF
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