FAN7318B Datasheet, PDF (2/24 Pages) Fairchild Semiconductor – LCD Backlight Inverter Drive IC

Block Diagram
OLR1
Min.
0.3V
Short-Lamp Protection
-
+
OLR2
OLR3
Min. &
Max.
Detector
/Full Wave
Recifier
Max.
1.34V
2V
Over-Voltage Protection
+
-
+
-
OLR4
+
1.34V _-
-
2.2V
+
0μA
3.2μA
Error. Amp. source
current change
Gm Amp.
Open-Lamp Regulation
max. 2V
On @ striking
min. 0.5V
CT
-
Protection
Oscillator
50µA @ OVP,SLP
2µA @ OLP.CMP high
3V/1V @ striking/normal
TSD 150^oC
Output Driver
Control
Logic
CMP
ADIM
OLP1
OLP2
OLP3
OLP4
Error. Amp. source
current change
Negative
Analog
Vref
+
Error Amp.
Dimming
+
-
3.5V
-
+
High_CMP
52μA burst
sink current on
High CMP Protection
disable @ striking
OLP max.
Striking off
-
+
Hys. 0.45V
UVLO 5.5V
1.35V
200k
Voltage Reference
& Internal Bias
5V, max. 3mA
Min. & Max.
Detector
/Full or Half
Wave
Rectifier
OLP min.
-
0.7V/0.5V
+
Striking/normal
17 Pulses Counter
And OLR<1.4V
OLP
150μs
Delay
52μA burst
sink current on
If ENA>2.5V, OLP & SLP disable.
If ENA<2.1V, OLP & SLP enable.
max. 2V
min. 0.5V
disable @ striking
TIMER
OUTA
OUTB
GND
VIN
ENA
REF
BCT
BDIM
Figure 1. Internal Block Diagram
© 2009 Fairchild Semiconductor Corporation
FAN7318B • 1.0.0
2
www.fairchildsemi.com