Philips 32PF9968/10 Service Manual page 80

EN 80 9.
9.2 Power Supply
9.2.1 Block Diagram
FILTER &
RECTIFIER
SWITCH
MH COIL
Degaussing Supply (V_DG)
RELAY
Derived from =Vaudio
DEGAUSS
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
Power ON To
Standby
Normal
3, 3.3, 6V
POWER_DOWN
STDBY
+1V8 EXT.
Stdby_con
Vbat, Vaudio
STB bit
VT_supply
+5V
10ms
PIP Supplies
B
Closed
Relay status
1s 2s 100ms
200ms
(ref) (ref) (ref)
Figure 9-3 Timing diagram Standby
L04A AD Circuit Descriptions, Abbreviation List, and IC Data Sheets
Vbatt (to deflection & DVD interface board)
-Vaudio
+Vaudio
MAIN 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)
AUX SMPS
supply +5V & +3.3V)
Vaux (for IDTV)
B (connected to HERCULES port B to
switch ON/OFF Vaux)
Out of Power OFF
Standby
Standby Normal
Perform
mode
hard-reset
Open
2s 2s 20ms 10ms 10ms
800ms 200ms
(ref) (ref) (ref) (ref) (ref)
E_14770_047.eps
010904
Power ON - To Semi Standby - Out of Semi Standby -
Power OFF
3, 3.3, 6V
POWER_DOWN
STDBY
+1V8 EXT.
Stdby_con
Vbat, Vaudio
STB bit
E_14480_072.eps
VT_supply
120504
+5V
PIP Supplies
B
Relay status
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
Pin Symbol
2 Gnd
3 V_cc
5 RC
6 REG
11 Demag
12 Sense
14 Drain
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).
Power ON To Out of
Standby Standby
Normal Standby
mode
10ms
Closed
1s 2s
200ms 800ms
(ref) (ref)
Description
This pin is Ground of the IC.
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.
Frequency setting
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.
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.
This pin contains three different functions.: 1) Dectection of soft
start, protection levels of 2) OCP, and 3) SWP.
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.
Power OFF
Normal
Perform
hard-reset
Open
20ms 10ms 10ms
(ref) (ref) (ref)
E_14770_048.eps
010904