Acer TravelMate -550, Service Manual

Page: 36 / 132

28 Chapter 1
General Description
This inverter is designed for the CCFL of
α
550 14.1” LCD which are using on the
α
550 notebook. We use
two signals to control the LCD brightness. One is the Enable , which turn on and turn off the birightness of
LCD. The other is the PWM , which tune the brightness by modulating the duty cycle. This inverter uses open
loop control circuit and meets with safety requirements.
Features
1. +5V Fixed input voltage
2. Birghtness adjustment by PWM duty cycle
3. Current Limited function, meet with safety requirement
Windows 95 keys Yes
Internal & external keyboard work simultaneously Yes
Battery
Item Specification
Vendor & model name Panasonic/SUMSUNG
Battery Type Li-ion
Pack capacity 57Wh
Cell voltage V/cell
Number of battery cell 8
Package configuration 4 cells in series, 2 series in parallel
Package voltage 14.8V
LCD Inverter Specification FOR 14.1”
Panel List
No. LCD Type Vendor Model No.
Frequency range
(Min./Typ./Max)
Lamp current
(mArms)
Min/Typ/Max
1 14.1” SVGA
TFT HANSTAR HSD141PX11-
A REV1 40/50/60KHz 20-6.5mA
2 14.1” SVGA
TFT IBM ITXG77X 40/60/65HKz 2.5-6.4mA
Inverter Characteristics
No
.
Parameter Symbol Min. Typ. Max. Unit Conditions
1 Input
voltage +5V 4.75 4.85 4.95 V
2 Input
current Iin -- --- 1A A
3
Lamp
Current IL 5.50 5.75 6.00 mArms Enable= H,
PWM Duty = 100%
3.0 mArms Enable = H,
PWM Duty = 30%
4
Lamp
voltage
625 Vrms
At IL = 6.0 mArms
Keyboard
Item Specification