Circuit Descriptions
7.
7.2.3
Connector overview
Table 7-1 Connector overview
7.3
DC/DC Converters
The on-board DC/DC converters deliver the following voltages
(depending on set execution):
•
+3V3-STANDBY, permanent voltage for the standby
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)
•
+V-LNB, input voltage for LNB supply IC (item no. 7T50)
•
+5V-DVBS, input intermediate supply voltage for DVB-S2
(diagram B08A)
•
+3V3-DVBS, clean voltage for silicon tuner and DVB-S2
channel decoder
•
+2V5-DVBS, clean voltage for DVB-S2 channel decoder
•
+1V-DVBS, core voltage for DVB-S2 channel decoder.
A +12 V under-voltage detector
(see diagram B03C) enables
the 12V to 3.3V and 12V to 5V DC/DC converters via the
ENABLE-3V3-5V line, and the 12V to 1.8V DC/DC converter
via the ENABLE-1V8 line. DETECT2 is the signal going to the
standby microcontroller and ENABLE-3V3n is the signal
coming from the standby microcontroller.
Diagram B03D
contains the following linear stabilisers:
•
+2V5 stabiliser, built around item no. 7UCO
•
+5V-TUN stabiliser, built around items no. 7UA6 and 7UA7
•
+1V2 stabiliser, built around items no. 7UA3 and 7UA4.
Diagram B08A
contains the DVB-S2-related DC/DC
converters and -stabilisers:
•
a +24V under-voltage detection circuitry is built around
item no. 7T04
•
the switching frequency of the 24 to 14...20V switched
mode converter is 350 kHz (item no. 7T03 and +V-LNB
lines)
•
the output signal on the +V-LNB line goes to the LNBH23Q
(item no. 7T50)
•
the LNBH23Q (item no. 7T50) sends a feedback signal via
the V0-CNTRL line
•
the switching frequency of the +5V-DVBS to +1-DVBS
switched mode converter is 900 kHz (item no. 7T00)
•
a delay line for the +2V5-DVBS and +1V-DVBS lines is
created with item no. 3T03 (R=10k) and 2T06 (C=100n)
•
a 3.3V to 2.5V linear stabiliser is built around item no. 7T01
•
a 5V to 3.3V linear stabiliser is built around item no. 7T02.
7.4
Front-End Analogue and DVB-T, DVB-C;
ISDB-T reception
7.4.1
European/China region
The Front-End for the European/China region consist of the
following key components:
•
Hybrid Tuner
•
Switchable SAW filter 7/8 MHz (Eur.), or single SAW filter
(8 MHz) (China)
•
Bandpass filter
•
Amplifier
•
PNX85500 SoC TV processor with integrated DVB-T and
DVB-C channel decoder and analogue demodulator.
Below find a block diagram of the front-end application for this
region.
Figure 7-6 Front-End block diagram European/China region
7.4.2
Brazil region
The Front-End for the Brazil region consist of the following key
components:
•
Hybrid Tuner with integrated SAW filter and amplifier
•
External ISDB-T channel decoder covering the Brazilian
digital terrestrial TV standard
•
Bandpass filter
•
Amplifier
•
PNX85500 SoC TV with integrated analogue demodulator.
Below find a block diagram of the front-end application for this
region.
Figure 7-7 Front-End block diagram Brazil region
Connector
no.
1308
1311
1319
1316
1M95
1M99
1M09
1MP1
Descr. mains
mains
disp.
disp.
to SSB to SSB Amb.
T-con
Pin
CN1
CN2
CN3
CN4
CN5
CN6
CN7
CN8
1
N
L’
t.b.d.
t.b.d.
3V3std
+12V
24Vb
+12V
2
L
L”
t.b.d.
t.b.d.
Stndby
+12V
24Vb
+12V
3
-
-
-
-
GND1
GND1
GND1
n.c.
4
-
-
-
-
GND1
GND1
GND1
GND1
5
-
-
-
-
GND1
BL_ON
_OFF
-
GND1
6
-
-
-
-
+12V
DIM
-
-
7
-
-
-
-
+12V
Boost
-
-
8
-
-
-
-
+12V
n.c.
-
-
9
-
-
-
-
+Vsnd
POK
-
-
10
-
-
-
-
GND_
SND
-
-
-
11
-
-
-
-
n.c.
-
-
-
12
-
-
-
-
-
-
-
-
1
8
770_2
3
5_100127.ep
s
100219
1
8
770_2
3
6_100127.ep
s
100219