AME, Inc.
AME9002
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inar
lim
Pre
CCFL Backlight Controller
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Pin Description
Pin #
Pin Name
Pin Description
Current sense detect. Connect this pin to the CCFL current sense resistor divider.
During the initial startup period this pin senses that the CCFL has struck when
V(CSDET) > 1.25 volts. If, after the initial start up period, this pin is below 1.25V for 4
consecutive clock cycles after SSC > 3V then the circuit will shutdown.
UVLO feedback pin. If this pin is above 1.5V then the OUTA pin is allowed to switch, if
below 1.25V then OUTA is disabled.
Drives one of the external NFETs, opposite phase of OUTAPB.
Drives one of the external NFETs, opposite phase of OUTC.
Drives the high side PFET.
Battery input. This is the positive supply for the OUTA driver.
Brightness polarity control. When this pin is low the CCFL brightness increases as
the voltage at the BRIGHT pin increases. When this pin is high the CCFL brightness
decreases
as the voltage at the BRIGHT pin increases.
Regulated 5V supply input.
Sets the dimming cycle frequency. Usually about 100Hz.
Negative input of the voltage control loop error amplifier.
Output of the voltage control loop error amplifier.
Brightness control input. A DC voltage on this controls the duty cycle of the dimming
cycle. This pin is compared to a 3V ramp at the CT1 pin.
Soft start ramp for the voltage control loop. (20uA source current.) The voltage at SSV
clamps the voltage at COMP to be no greater than SSV thereby limiting the increase of
the switching duty cycle.
Drives the base of an external PNP transistor used for the 5V LDO.
11
CSDET
12
13
14
15
16
BATTFB
OUTC
OUTAPB
OUTA
VBATT
17
BRPOL
18
19
20
21
VDD
CT1
FB
COMP
22
BRIGHT
23
SSV
24
PNP
3
AKM [ ASAHI KASEI MICROSYSTEMS ]
