Only For Training And Service Purposes - LG -P520 Service Manual

3. TECHNICAL BRIEF
BACKLIGHT CHARGE PUMP
CAM_IOVDD
CAM_DVDD
FB500
1000
C524
1u
The RT9396 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
RT9396 also provides two low- dropout, low-noise linear regulators for powering a camera module or
other peripheral circuits.
The RT9396 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 100 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 A
in shutdown.
LGE Internal Use Only
CAM_AVDD
VBAT
FB501 FB502
1000 1000
C528
C525 C526
2.2u 2.2u 2.2u
Figure 3.10.2. RT9396 CIRCUIT DIAGRAM
C515 1u
1u
C516
6 24
AGND VOUT
7 23
VIN LED1
8 22
LDOIN LED2
9 21
U500
LDO4 LED3
10 20
LDO3 EUSY0344403 LED4
11 19
LDO2 LED5
12 18
LDO1 LED6
R520 1
R521 1
R522
0.1u
100K
C532
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Copyright © 2010 LG Electronics. Inc. All right reserved.
3. TECHNICAL BRIEF
MLED1
MLED2
MLED3
MLED4
MLED5
C523
2.2u
I2C_SCL
I2C_SDA
LCD_BL_CTRL
LED_PWM

Only for training and service purposes