Philips L04A AB, Руководство по обслуживанию, Страница: 74 / 90

Circuit Descriptions, List of Abbreviations, and IC Data Sheets EN 74 L04A AB 9.
9.2 Power Supply
9.2.1 Block Diagram
Figure 9-2 Block diagram power supply
Stdby_con signal
The Hercules generates this signal. This line is logic “low” (0 V)
under normal operation and in semi-Standby of the TV, and is
“high” (3.3 V) during Standby.
Power_down signal
The AUX SMPS generates this signal. It is logic “high” (3 .3 V)
under normal operation of the TV and goes “low” (0 V) when the
AC power (or Mains) input voltage supply goes below 70 V_ac.
B (Hercules port)
This port is used to switch the AUX SMPS output V_aux “On/
Off”. This is required for DVD and iDTV (for future extensions).
9.2.2 Timing Diagrams
Notes: Shown timings may be different, given timings are for
information only.
Power ON - To Standby - Out of Standby - Power OFF
Figure 9-3 Timing diagram Standby
Power ON - To Semi Standby - Out of Semi Standby -
Power OFF
Figure 9-4 Timing diagram Semi Standby
9.2.3 Startup Sequence
When the set is connected to the AC power, the rectified line
voltage (via winding 4-5 of L5531 connected to pin 14 of
IC7531) will start the internal voltage source to charge the V_cc
capacitor (C2532). The IC starts to switch as soon as the V_cc
reaches the V_cc start level of 9.5 V. This supply is
automatically taken over by winding 1-2, as soon as the V_cc
is high enough, and the internal supply source will stop (for high
efficiency switching).
Table 9-1 Pinning overview TEA1623
As C2532 of IC7531 is charged, it will also start to charge the
V_cc capacitor (C2511) of IC7511. Via resistor R3519 and
C2511, the TEA1506 starts to switch as soon as the V_cc
voltage reaches the V_cc start level of is about 11 V. The V_cc
voltage is automatically taken over by the main transformer
L5512 (winding 2-3) when the V_cc is high enough (when this
voltage is even higher than the voltage on C2511, there is no
current flow from C2532 to C2511 due to diode D6512).
SWITCH
FILTER &
MH COIL
RECTIFIER
RELAY
DEGAUSS
Degaussing Supply (V_DG)
Derived from =Vaudio
MAIN SMPS
AUX SMPS
+6V (from AUX SMPS for Stdby feedback)
Stdby_Con (from HERCULES)
Power_Down (to HERCULES)
+3V (to derive HERCULES supply 1.8V)
+6V (to derive HERCULES & TUNER)
5V & +3.3V)
Vaux (for IDTV)
B (connected to HERCULES port B to
switch ON/OFF Vaux)
E_14480_072.eps
120504
Vbatt (to deflection & DVD interface board)
-Vaudio
+Vaudio
3, 3.3, 6V
Vbat, Vaudio
VT_supply
+5V
STDBY
+1V8 EXT.
B
Stdby_con
STB bit
PIP Supplies
Relay status
Perform
hard-reset
Closed
Open
E_14770_047.eps
010904
1s
(ref)
2s
(ref)
2s
(ref)
2s
(ref)
200ms
100ms
(ref)
10ms
(ref)
10ms
(ref)
20ms
(ref)
10ms
800ms 200ms
Normal Standby
mode
Normal
Power ON Power OFF To
Standby
Out of
Standby
POWER_DOWN
Pin Symbol Description
2 Gnd This pin is Ground of the IC.
3 V_cc This pin is connected to the supply voltage. An internal current
charges the V_cc capacitor (2532), and the start-up sequence
is initiated when this voltage reaches a level of 9.5 V. Note: The
output power is disabled when the voltage gets below 9 V
(UVLO). Operating range is between 0 to 40 V.
5 RC Frequency setting
6 REG This pin is connected to the feedback loop. The pin contains two
functions: 1) Between 1 to 1.425 V it controls the "on" time. 2)
Above the threshold of 3.5 V, it is possible to initiate "burst
mode" standby.
11 Demag This pin is connected to the V_cc winding of 5531. It has three
functions: 1) During Magnetisation, the input voltage is sensed
to compensate OCP level for OPP. 2) During demagnetisation,
the output voltage is sensed for OVP and 3) A comparator is
used to prevent continuous conduction when output is
overloaded.
12 Sense This pin contains three different functions.: 1) Dectection of soft
start, protection levels of 2) OCP, and 3) SWP.
14 Drain This pin is connected to the drain of the switch or center tap of
the transformer. It contains three functions: 1) M-level (mains-
dependent operation-enabling level), 2) Supply for start-up
current, and 3) Valley detection.
3, 3.3, 6V
Vbat, Vaudio
VT_supply
+5V
STDBY
+1V8 EXT.
B
Stdby_con
STB bit
PIP Supplies
Relay status
Perform
hard-reset
Closed
Open
E_14770_048.eps
010904
1s
(ref)
2s
(ref)
200ms
10ms
(ref)
10ms
(ref)
20ms
(ref)
10ms
800ms
Normal Standby
mode
Normal
Power ON Power OFF To
Standby
Out of
Standby
POWER_DOWN
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