3. TECHNICAL BRIEF
- 43 -
3.9. Keypad back-light illumination
3.10. LCD back light illumination
Employed the AAT2807 is a dual charge pump designed to support both the white LED backlight and
flash applications for systems operating with lithium-ion/polymer batteries. The backlight charge pump
is capable of driving up to four LEDs at a total of 60mA. The current sinks may be operated individually
or in parallel for driving higher current LEDs. To maximize power efficiency, the charge pump operates
in 1X, 1.5X, or 2X mode, where the mode of operation is automatically selected by comparing the
forward voltage of each LED with the input voltage.
VBAT
56
R534
R530
100K
C530
1uF
1
A
2
C
C531
1uF
SSC-SWTS1007
LD504
1
A
2
C
R533
56
LD503
SSC-SWTS1007
3
VIN
VOUT
4
BH33FB1WHFV
U502
6
BGND
2
GND
NC
5
STBY
1
NA
C542
C543
NA
LGF_EN
LCD BACKLIGHT & CAMERA FLASH LED DRIVER
C222
27p
FB201
VBAT
C201
1u
27p
C220
C214
1u
C218
1u
R203
120
R212
100K
120
R210
LD201
LEWWH25LA
120
R206
100K
R213
C219
1u
R208
120
C202
FB202
1u
1u
C203
C221
27p
8
PGND
17
4
VIN
VOUT_BL
13
VOUT_FL
3
C1+
11
12
C1-
14
C2+
C2-
15
2
C3+
C3-
1
16
EN_FLSH
EN_SET
10
9
GND
ISINK1
5
ISINK2
6
7
ISINK3
ISINK4
U202
AAT2805IXN-4.5-T1
R271
0
LCD_BACKLIGHT
MLED1
MLED2
MLED3
MLED
FLASH_EN
Figure 12 Keypad Back-light LEDs
Figure 13 LCD Back light unit and Flash LED charge pump IC
Summary of Contents for KE 770
Page 1: ...Service Manual Model KE770 Service Manual KE770 Date April 2007 Issue 1 0 ...
Page 3: ... 4 ...
Page 5: ... 6 ...
Page 49: ...3 TECHNICAL BRIEF 50 3 15 BLUETOOTH Figure 22 BLUETOOTH Functional block diagram ...
Page 57: ...3 TECHNICAL BRIEF 58 RF Block Diagram III 2 RF circuit ...
Page 76: ...Check Points 5 Trouble shooting 77 ...
Page 78: ...5 Trouble shooting 79 ...
Page 82: ...5 Trouble shooting 83 ...
Page 87: ...5 Trouble shooting 88 ...
Page 100: ... 101 6 Download S W upgrade Click on the blue text to select the COM port ...
Page 101: ...6 Download S W upgrade 102 Will change the window as below ...
Page 103: ...6 Download S W upgrade 104 During download the screen will look something like this ...
Page 105: ... 106 ...
Page 111: ... 112 8 PCB LAYOUT ...
Page 112: ... 113 8 PCB LAYOUT ...
Page 113: ... 114 8 PCB LAYOUT ...
Page 114: ... 115 8 PCB LAYOUT ...
Page 115: ... 116 8 PCB LAYOUT ...
Page 121: ...10 Stand alone Test 122 4 Click Update Info for communicating Phone and Test Program ...
Page 125: ... 126 ...
Page 143: ...Note ...
Page 144: ...Note ...