FAN7318B Datasheet, PDF (4/24 Pages) Fairchild Semiconductor – LCD Backlight Inverter Drive IC

Pin Definitions
Pin #
1
Name
TIMER
2
CMP
3
ADIM
4
CT
5
REF
6
BCT
7
BDIM
8
ENA
9
GND
10
OUTB
11
OUTA
12
VIN
13
OLR4
14
OLP4
15
OLR3
16
OLP3
17
OLR2
18
OLP2
19
OLR1
20
OLP1
Description
This pin is for protection delay time setting.
Error amplifier output. Typically, a compensation capacitor is connected to this pin from the
ground.
This pin is the input for negative analog dimming.
This pin is for programming the switching frequency. Typically, a capacitor is connected to
this pin from ground and a resistor is connected to this pin from the REF pin.
This pin is 5V reference output. Typically, resistors are connected to this pin from the CT pin
and the BCT pin.
This pin is for programming the frequency of the burst dimming. Typically, a capacitor is
connected to this pin from ground and a resistor is connected to this pin from the REF pin.
This pin is the input for negative burst dimming. The voltage range of 0.5 to 2V at this pin
controls the burst-mode duty cycle from 0% to 100%.
This pin turns the IC on / off.
This pin is the ground.
This pin is NMOS gate-drive output.
This pin is PMOS gate-drive output.
This pin is the supply voltage of the IC.
This pin is for open-lamp regulation. Its functions are the same as the OLR1 pin.
This pin is for open-lamp protection and feedback control of lamp currents. Its functions are
the same as the OLP1 pin.
This pin is for open-lamp regulation. Its functions are the same as the OLR1 pin.
This pin is for open-lamp protection and feedback control of lamp currents. Its functions are
the same as the OLP1 pin.
This pin is for open-lamp regulation. Its functions are the same as the OLR1 pin.
This pin is for open-lamp protection and feedback control of lamp currents. Its functions are
the same as the OLP1 pin.
This pin is for open-lamp regulation and short-lamp protection. It has the same functions as
other OLR pins and is connected to the full-wave rectifier internally. When the maximum of
rectified OLR inputs is between 1.34V and 2V, the error amplifier output current is limited to
3.0µA. When the maximum of rectified OLR inputs reaches 2V, the error amplifier output
current is 0A and its output voltage maintains constant. The maximum of rectified OLR
inputs is inputted to the negative of another error amplifier for feedback control of lamp
voltage. When the maximum of rectified OLR inputs is more than 2.2V, another error
amplifier for OLR is operating and lamp voltage is regulated. In normal mode, if the
maximum of rectified OLR inputs is higher than 1.34V or if the minimum of rectified OLR
inputs is lower than 0.3V for a predetermined time by the TIMER pin capacitor and an
internal current source 50µA; the IC shuts down to protect the system in over-voltage
condition or short-lamp condition, respectively.
This pin is for open-lamp protection and feedback control of lamp currents. It has the same
functions as other OLP pins and is connected to the half-wave rectifier and the full-wave
rectifier internally. In striking mode, if the minimum of rectified OLP inputs is less than 0.7V
for a time predetermined by the TIMER pin capacitor and an internal current source or; in
normal mode, if the minimum of rectified OLP inputs is less than 0.5V for another
predetermined time by the TIMER pin capacitor and another internal current source; the IC
shuts down to protect the system in open-lamp condition. The maximum of rectified OLP
inputs is inputted to the negative of the error amplifier for feedback control of lamp current.
© 2009 Fairchild Semiconductor Corporation
FAN7318B • 1.0.0
4
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