Inverter Circuit Operation Theory; Lcdm Inverter Controller --- Oz9933; Pin Assignment Of Oz9933 - BenQ G2420HD Product Service Manual

P-MOSFET Q852 is used for switching of step-down converter. And FD852/FD853 are the
flywheel diodes.
R874/R875 determine the feedback to IC851 to set up the output to +5V or +3.3V.
V-INVERTER
IC851
TL1451ACN

#8 Inverter Circuit Operation Theory

LCDM Inverter Controller --- OZ9933

OZ9933 is a high performance, cost-effective CCFL controller designed for driving large-size
LCD applications requiring 2 to 6 CCFLs.
The controller converts unregulated DC voltages into a nearly sinusoidal lamp voltage and
current waveforms.
The OZ9933 supports full-bridge power conversion topologies while maintaining high-
efficiency operation, current and voltage regulation, over-voltage and over-current protection,
high drive capability.
The control logic provides s regulated ignition voltage and appropriate protection features for
over-voltage or over-current conditions.

Pin Assignment of OZ9933

F851
32V 2A
R872
R871
C867
+
22K
3.3K
220U 25V
Q855
B
PMBS3904
P10
R882
R862
2.7K J 22
Q856
B
2N3906S
- 66 -
Q852
2SJ598
S D
FD852 FD853
ERB83-004 ERB83-004
L853
Z45/100MHZ
L852
47U
R874 C869
1200P K
3.09K F
C868
470P K
R875
1K F
PANEL_+5V
C871
+
220U 25V