1 - 14
1.4.3
Composite sync V separation circuit
• LPF input step (HS* or GS*)
When 74F14 V
OL
= 0.5V (Max.): 1
OL
= 20mA
The LPF, 74ACT157 and 74LCX14 input impedance is high, so if it ignored, the current led in
at 74F14 V
OL
will be 4.8mA [5V/(1K+33)
Ω
], and the maximum value at HS* and GS* Lo level
will be 0.66V = 0.5V [75F14 V
OL
(Max.)] + 33
Ω
x 4.8mA.
74LCX14 V
IL
= 0.72V (Min.) (at VCC = 3.3V conversion) > 0.66V
OK
74ACT157 V
IL
= 0.8V (Min.) > 0.66V
OK
• LPF output step
74LCX4MTCX threshold level (at VCC = 3.3V conversion)
Min.
Max.
V
IH
1.38V
2.50V
V
IL
0.72V
1.74V
The V signal sampling circuit's constant was set in consideration of the 74LCX14MTCX thresh-
old level fluctuation. (Confirmation with the over-range of input signal SPEC timing, confirma-
tion with different polarity, etc.)
A5V
A5V
A5V
1K
100
1K
1.2K -F
2SC2412
V signal sampling circuit
74F14
74LCX14MTCX
2.7K -F
5600P
D3 3V
D3 3V
D3 3V
A5V
33
74LCX14MTCX
74ACT157
4.7K
74LCX14MTCX
100
AH*
C/S_V* or S/G_V*
HS* or GS*
LPF
IC201
IC300, IC303
IC300, IC303
IC300, IC303
IC301, IC304
C/S_H* or S/G_H*
To microcomputer
To ASIC
To microcomputer
Composite sync
* indicates the input Ch 1 or 2.
Summary of Contents for LCD1550X-BK
Page 88: ...SCHEMATIC DIAGRAM POWER LCD1550X Normal Power Save 1ch Pin 4 2ch Pin 1 3ch Pin 2 4ch Pin 5 ...
Page 89: ...SCHEMATIC DIAGRAM PWB MAIN POWER LCD1550X ...
Page 90: ...SCHEMATIC DIAGRAM PWB MAIN INPUT LCD1550X ...
Page 91: ...SCHEMATIC DIAGRAM PWB MAIN SYNC LCD1550X ...
Page 92: ...SCHEMATIC DIAGRAM PWB MAIN TMDS LCD1550X ...
Page 96: ...SCHEMATIC DIAGRAM PWB MAIN ASIC LCD1550X ...
Page 97: ...SCHEMATIC DIAGRAM INVERTER LCD1550X 1ch Q701 B 2ch Q702 B ...
Page 98: ...SCHEMATIC DIAGRAM PWB SW LCD1550X ...
Page 100: ...SCHEMATIC DIAGRAM POWER LCD1550X ...
Page 101: ...SCHEMATIC DIAGRAM PWB MAIN POWER LCD1550X ...
Page 102: ...SCHEMATIC DIAGRAM PWB MAIN INPUT LCD1550X ...
Page 103: ...SCHEMATIC DIAGRAM PWB MAIN SYNC LCD1550X ...
Page 104: ...SCHEMATIC DIAGRAM PWB MAIN TMDS LCD1550X ...
Page 105: ...SCHEMATIC DIAGRAM PWB MAIN MC LCD1550X ...
Page 106: ...SCHEMATIC DIAGRAM PWB MAIN ASIC LCD1550X ...
Page 107: ...SCHEMATIC DIAGRAM INVERTER LCD1550X ...
Page 108: ...SCHEMATIC DIAGRAM PWB SW LCD1550X ...
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