LG KE820 - Keypad Back-Light Illumination

3. TECHNICAL BRIEF
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Most of numeric keys are located on the sub PCB, Jog key for menu navigation is on the main PCB,
and Power on (End key), MP3 hot key, Camera AF trigger, shutter and volume up & down keys are
connected via 50pin board to board connector between main PCB and FPCB.
3.9. Keypad back-light illumination
There are 7 snow white color LEDs on the sub PCB for keypad illumination. Keypad Back-light is
controlled by SM-Power LED port which has constant current control function.
The whole configuration of the SM-POWER LED drivers is shown in below Figure16. ( SLED1, SLED2
port are not used in the KE820.KG99)
AF
shutter
VBAT
SW1
1
23
4
V_DOWN
V_UP
MP3
END
END_KEY
KP_IN(5)
KP_OUT(4)
KP_OUT(3)
KP_OUT(3:4)
KP_IN(4)
KP_IN(3)
KP_IN(2)
KP_IN(2:5)
Figure 14 FPCB part key matrix