Lcd Back-Light Illumination - LG GM360i Service Manual

3. TECHNICAL BRIEF

3.10 LCD back-light illumination

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The RT9393 is a write-only single wire interface. It provides access to up to 32 registers that control device
functionality. In this system, two sets of pulse trains are transmitted via the SPIF pin. The first pulse set is used to
set the desired address. After the bus is held high for the address hold period, the next pulse set is used to write
the data value. After the data pulses are transmitted the bus is held high again for the data hold period to signify
the data write is complete. At this point the slave device latches the data into the address that was selected by
the first set of pulses. The protocol for using this interface is described in the following subsection.
LG Electronics
LGE Internal Use Only
VBAT
MLED
C409
1uF
LCD_BACKLIGHT_EN
C412
1uF
Figure 12 LCD Back light unit and Flash LED charge pump IC
Figure 13 I2C Serial data port control method
LCD Backlight
U400
1
GND
14
VOUT
2
C2N
C411
3
C1N
13
1uF
LED1
4 12
C1P LED2
5 11
C2P LED3
10
LED4
6 9
VIN LED5
8
LED6
7
EN
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Copyright © 2010 LG Electronics. Inc. All right reserved.
MLED1
MLED2
MLED3
MLED4
MLED5
C415
1uF
LGE Property
Only for training and service purposes