Compal JHT01 Service Manual page 84

JHT01 Service Manual
Lamp current
13
over-shoot
Current
14 Waveform
factor
Unbalance
15
Rate
Turn off
16 current
(Hight side)
Turn off
17 voltage
(Low side)
Voltage Rise
18 time (Low
side)
Voltage fall
19 time (Low
side)
Notes:
• The inverter can work in 7.5V input voltae (continuous), but 7.5V electronic
characteristic will not be care. (Note: the display must be normal and can not
glitter or become dark)
• Limited lamp maximum current by DAC_BRIG signal:
When DAC_BRIG voltage is 0V and INV_PWM enables (100%), lamp has
max.-limited current.
When DAC_BRIG voltage is 3.3V and INV_PWM enables (100%), lamp has
min.-limited current.
When add 1V DAC, the 100% Lamp current will decrease 0.5mA.
DAC_BRIG signal comes from system chipset with internal resistance of 3KΩ.
• Inverter operating frequency should be within specification (45~65kHz) at
max. and min. brightness load.
• 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%.
• The system interface signals belong to 3.3V.
• Please make sure open lamp output voltage should be within starting voltage
specification.
4-14
30 --
--
I
p
2
1.27
I
rms
−
I I
−
p p
-10% 0
I
rms
IHL -- --
Voff -- --
Trise -- --
Tfall -- --
100 %
Line transient (10.8V to
10 % 21V/100us) and turn on
1.56 Multiple
+10% Multiple
0 A
150Vp-
V
p
300us Us
300us Us
Ton
Duty =
Period
transient
I
−
p
OR *10
I
rms
PWM=30%
PWM=30%
PWM=30%
PWM=30%