FAN7318A 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
OLR2
14
OLP2
15
OLR1
16
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 burst mode duty cycle from 0% to 100%.
This pin is for turning on/off the IC.
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 and short-lamp protection. It 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 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 predetermined time 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
FAN7318A • 1.0.0
4
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