Circuit Descriptions
EN 48 Q551.1E LA7.
2010-Jun-25
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Figure 7-13 Backlight application (xxPFL9xxx sets 40" & 46"
200 Hz “2D” scanning)
Figure 7-14 Backlight application (xxPFL9xxx sets 58" 21:9 (3-d)
200 Hz “2D” scanning)
7.3.1 LED Drivers
The traditional concept for the LED drivers uses
• Linear drivers, or
• DC/DC drivers.
This concept has been explained in previous Service Manuals.
Some sets use an alternative “balancing” concept
with the use of
• C-balance drivers, or
• L-balance drivers (currently not implemented).
This introduces the “C-balancer board” for some of the
xxPFL9xxx sets.
C-balancing Concept for LED driving
The advantages of the C-balancing concept are:
• Cost reduction
• Higher efficiency
• Higher reliability, because of less components used.
The C-balance drivers and -components are mounted on a
separate C-balancer board. This PWB is mounted on the LCD
panel by the LCD manufacturer, though developed by Philips.
There are two possible configurations:
• For edge-lit displays & direct-lit displays + “0D” dimming
• For direct-lit displays + “2D” dimming.
Refer to Figure 7-15
and Figure 7-16 for the application.
Figure 7-15 Balancing LED-drivers application for edge-lit
displays & direct-lit displays in combination with “0D” dimming
Figure 7-16 Balancing LED-drivers application for direct-lit
displays in combination with “2D” dimming
7.4 DC/DC Converters
The on-board DC/DC converters deliver the following voltages
(depending on set execution):
• +3V3-STANDBY, permanent voltage for the Stand-by
controller, LED/IR receiver and controls; connector 1M95
pin 1
• +12V, input from the power supply for TV550 common
(active mode); connector 1M95 pins 6, 7 and 8
• +24V, input from the power supply for DVB-S2 (in active
mode); connector 1M09 pins 1 and 2
• +1V1, core voltage supply for PNX85500; has to be started
up first and switched "off" last (diagram B03B)
• +1V2, supply voltage for analogue blocks inside
PNX85500
• +1V8, supply voltage for DDR2 (diagram B03B)
• +2V5, supply voltage for analogue blocks inside
PNX85500 (see diagram B03E)
• +3V3, general supply voltage (diagram B03E)
• +5V, supply voltage for USB and CAM (diagram B03E)
• +5V-TUN, supply voltage for tuner (diagram B03E)
18750_205_100415.eps
100423
BL-I2S
Current
B acklightBoos t
Lamp -ON
P S DL
Tcon 200 Hz
S h arp
1F53
PNX
85500
1M99
1G511G 5 0
B ackLight
DirectLED
sca nning
PWM
2D-D I M
I2 S / SPI
PNX
5120
LVD S splitter
1G51
PNX
5120
A S IC A S IC
SSB TV 550
18750_206_100415.eps
100423
BL-I2S
Current
B acklightBoos t
Lamp -ON
P S DL
Tcon 200 Hz 3D
S h arp
1F53
PNX
85500
1M99
1G511G5 0
B ackLight
DirectLED
sca nning
PWM
2D-D I M
I2 S / SPI
PNX
5120
LVD S splitter
1G51
PNX
5120
A S IC A S IC
SSB TV 550
FPGA
18750_209_100415.eps
100416
AC
in
380 to
400 V
DC
Bala ncing 1
Bala ncing 2
Bala ncing 3
Bala ncing n
Power
Conversion 1
Power
Conversion 2
DC to LED-drivers)
Rectifier
Resonant
topology
Driver-part
Backlight-unit
(LED-strings)
Part of Power Supply Part of Display
18750_210_100415.eps
100416
AC
in
380 to
400 V
DC
Bala ncing 1
Bala ncing 2
Bala ncing 3
Bala ncing n
Power
Conversion 1
Power
Conversion 2b
DC to LED-drivers)
Power
Conversion 2a
DC to LED-drivers)
Rectifier
Resonant
topolo g y
Driver-part
Backlight-unit
(LED-strings)
Part of Power Supply Part of Display
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