LG -T300 Service Manual page 46

CAM_IO_1V8
CAM_D_1V5
C318
1u
The RT9396 is a power management IC (PMIC) for backlighting and phone camera applications.
The PMIC contains a 6-Channel charge pump white LED driver and four low dropout linear regulators.
The charge pump drives up to 6 white LEDs with regulated constant current for uniform intensity. Each
channel (LED1 to LED6) supports up to 25mA of current. These 6-Channels can be also programmed as
4 plus 2-Channels or 5 plus 1-Channels with different current setting for auxiliary LED application. The
RT9396 maintains highest efficiency by utilizing a x1/ x1.5/ x2 fractional charge pump and low dropout
current regulators. An internal 6-bit DAC is used for backlight brightness control. Users can easily
configure up to 64-steps of LED current via the I2C interface control. The RT9396 also comprises low
noise, low dropout regulators, which provide up to 200mA of current for each of the four channels. The
four LDOs deliver 3% output accuracy and low dropout voltage of 200mV @ 200mA.
Users can easily configure LDO output voltage via the I2C interface control. The LDOs also provide
current limiting and over-temperature functions. The RT9396 is available in a WQFN-24L 3x3 package.
Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes
CAM_A_2V8
FM_LNA_EN
VBAT
C321 C322
C320 C319
2.2u 2.2u
2.2u 2.2u
Figure 3-9-2. RT9396 CIRCUIT DIAGRAM
3. TECHNICAL BRIEF
CHARGE PUMP
C323 1u
C324
1u
6 24
AGND VOUT
7 23
VIN LED1
U302
8 22
LDOIN LED2
9 21
LDO4 LED3
10 20
LDO3 LED4
11 19
LDO2 LED5
12 18
LDO1 LED6
C316
R313
0.1u
100K
- 47 -
3. TECHNICAL BRIEF
MLED1
MLED2
MLED3
MLED4
MLED5
C317
1u
I2C_SCL
I2C_SDA
LCD_BL_CTRL
LED_PWM
LGE Internal Use Only