AME9001 Datasheet, PDF (14/27 Pages) Analog Microelectronics – CCFL BACKLIGHT CONTROLLER

AME, Inc.
AME9001
CCFL Backlight Controller
Figure 10. Duty Cycle Dimming
Outside Chip
Brightness
control
voltage
Inside Chip
BRIGHT
CT1
C4
+
-
+
3V ^-
-
500mV ⁺
CHOP
CHOP causes the CCFL
to turn on and off
periodically.
S
Q
R
Figure 11. Alternative Brightness Control
Inside Chip Outside Chip
CHOP
Always Hi
T1
BRIGHT
5V
CT
-
COMP
To PWM
-
Comparator
+
To Fault
-
Control Logic
FB
2.5V
CSDET
250mV
R₂
RF
R₁
2R
R
This method disables
duty cycle dimming
Maximum current=
K
R₁//(2R+R)
Minimum current=
K
(R₁+R₂)//(2R+R)
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