Chapter 13 Circuit Description; Power On/Off Signal Timing Sequence - Samsung HPS5073X/XAA Service Manual

13. Circuit Description

13-1 Power ON/OFF Signal Timing Sequence

AC POWER ON/OFF
Stand-By, (POP Option outputs)
PS_ON (Active Low)
from PS External
(Remote controller ON/OFF)
PFC output
DC OUTPUTS
Va
DC OUTPUTS
D5.3V,A6.5V,12V,Vamp,Vt
OUTPUTS
Vg
VS_ON (Active high)
from P/S External
DC OUTPUT
Vs
DISPLAY ON / OFF
1. When connecting the AC power cord, Stand-By 5V from the Main SMPS is supplied to the Main Board (Pin 3 of CN1002 of Main
Board).
2. When pressing the Power button on the remote control or on the main body, PS_ON (Pin 5 of CN1002 of Main Board)
changes from High to Low.
3. If the PS_ON signal changes to Low, the Main SMPS supplies power to the Main Board and Logic Board, and Va and Vg power
is supplied to the DC-DC SMPS.
4. If the VS_ON signal from the Logic Board changes from Low to High, the Main SMPS supplies VS power to the X and Y Main
Board through the DC-DC SMPS, and the screen displays a picture on it.
Samsung Electronics
AC POWER OFF AC POWER OFF
Remote Controller ON Remote Controller ON
Vca
VS_ON VS_ON
Vcs
DISPLAY ON
DISPLAY ON
70 m Sec. 70 m Sec.
OFF Remote Controller ON Remote Controller ON
OFF
VS_ON VS_ON
DISPLAY ON
DISPLAY ON
Circuit Description
Standby step turn-off
for µ-processor reset µ
5 V 5 V
3.4 V 3.4 V
Vg vs. 3.4V
turn-off sequence
Keep Display 'ON'w/o
display flicker while
3cycle full-dip condition
13-1