1 - 7
1.2.4.3
Overvoltage protection circuit
This circuit operates the latch circuit when the voltage of pin
exceeds 25.5V (typ.). Basi-
cally, this functions as the overvoltage protection for pin
in the control circuit. Normally, the
pin
is supplied from the transformer's secondary coil. This voltage is proportional to the
output voltage, and also functions for the secondary output overvoltage when the control circuit
is open, etc.
+
-
REC
Latch
Delay
Drive
Internal Bias
UVLO
Vin
4
Vin (on) = 17.5V
Vin (off) = 10V
+
-
+
-
OVP
Vth = 25.5V
Ta = 155
°
C
REG
TSD
S
PWM Latch
INH Latch
Tcoff = 50
µ
S
R
_
Q
Q R
S
OSC
+
-
+
-
INH Comp.
OCP Comp.
Vth=1.45V
Vth=0.73V
Icont
GND
OCP/FB
3
S
D
2
1
5
Functions of each terminal
Terminal No.
1
2
3
4
5
Symbol
D
S
GND
V
IN
O.C.P. / F.B
Name
Drain terminal
Source terminal
Ground terminal
Power terminal
Overcurrent/feedback terminal
Function
MOSFET drain
MOSFET source
Ground
Control circuit power input
Overcurrent detection signal and
constant-voltage control signal input
Summary of Contents for NEC MultiSync LCD1550X LCD1550X LCD1550X
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...
Page 127: ...16 Document No VSPF A028 Bave Average brightness of 1 to 9 10 50 90 90 10 50 5 1 2 3 6 9 8 7 4...
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