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LGE Internal Use Only
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3. TECHNICAL BRIEF
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
Figure 3-10-2 SC624 CIRCUIT DIAGRAM
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 SemWire 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 100
μ
A while continuing to monitor the serial
interface. The two LDOs can be enabled when the device is in sleep
mode. Total current reduces to 0.1
μ
A in shutdown.
C105
FB101
2.2u
VBAT
FB100
C108
22n
R118
1
R115
100K
1u
C107
1V5_CAM
1u
C104
C109
C106
1u
2.2u
2V8_LCD
9
GREF
15
LDO1
14
LDO2
3
NC1
NC2
10
NC3
12
2
PGND
11
SWIF
21
THER_GND
19
VIN
VOUT
16
U100
SC624ULTRT
A
GND
8
BL1
4
5
BL2
BL3
6
7
BL4
BYP
13
18
C1+
20
C1-
17
C2+
C2-
1
1u
C102
C103
2.2u
FB103
LED_CA4
LED_CA2
LED_CA3
LED_CA1
LCD_BL_CTRL
MLED