Acer 420 User Manual
Page 39
Chapter 1
31
NOTE:
*1. The inverter can work in 7.5V input voltage (continuous), but 7.5V electronic characteristic will
not be care.
*2. Limited lamp maximum current by DAC_BRIC signal:
When DAC_BRIG voltage is 0V and INV_PWM enables (100%), lamp has max. current.
When DAC_BRIG voltage is 3.3V and INV_PWM enables (100%), lamp has min. current.
When add 1V DAC, the 100% Lamp current will decrease 0.5mA.
DAC_BRIG signal comes from system chipset with internal resistance of 3K
*3. Inverter operating frequency should be within specification (45~65kHz) at max. and min.
brightness load.
*4. INV_PWM enable implies INV_PWM signal is High level (On duty cycle is 100%). It is a square
wave of 150Hz to adjust backlight brightness that is a function of PWM duty cycle. Backlight
brightness is maximum value under INV_PWM at 100% and brightness is minimum under
INV_PWM at 30%.
*5.The system interface signals belong to 3.3V.
*6. Please make sure open lamp output voltage should be within starting voltage specification.
*7. Inverter should pass human body safety test.
*8. Inverter should be no smoking by any component open/short test.
*9. Transformer voltage stress should not be over 85% under any condition.
(turn on overshoot transient and line transient.)
*10. Audio noise should be less than 36dB at 10cm distance.
.
Thermal
16
Voltage
Rise time
(Low side)
Trise
--
--
300us
us
PWM=30%
17
Voltage fall
time (Low
side)
Tfall
--
--
300us
us
PWM=30%
Electrical specification
No
.
Symbol
Min.
Typ.
Max.
Unit
Comment
1
V oper*
--
650
--
Vrms
Lamp operating voltage
(650+/-50)
Il
6.2
6.5
6.8
mArms
DAC_BRIG: 0 V, PWM:
100%
Il
3.0
3.3
3.6
mArms
DAC_BRIG: 0 V,
PWM:30%
Il
5.7
6.0
6.3
mArms
DAC_BRIG: 0V,
PWM:100%
Il
2.7
3.0
3.3
mArms
DAC_BRIG: 1V,
PWM:30%
F
45
55
65
kHz
η
80%
--
--
--
No
.
Parameter
Symbol
Min.
Typ.
Max.
Unit
Comment
Ω
SG_TM420_Ch1.fm Page 31 Thursday, September 26, 2002 9:23 AM