1 - 5
VR5
VR4
0V
0.76
ON width control
Conventionally, the charging current of the oscillator's capacitor was changed by the
photocoupler current, and the charging time until the threshold voltage Vth (1) $ 0.73[V] was
changed. However, with the STR-G6452, the DC bias is controlled.
(3)
Pin
OCP/FB terminal and OCP circuit
This is a pulse bypass method overcurrent protection circuit that detects the MOSFET
drain current's peak value every pulse, and reverses the oscillator output.
The MOSFET drain current is detected by connecting R906 across the pin
MOSFET
source terminal and pin
GND terminal, and inputting the drop voltage into the OCP/FB
terminal.
The OCP terminal's threshold voltage r+h(1) is approx. 0.76V (typ.) in respect to the
GND. R905, R935 and C909 are the filter circuits used to prevent malfunctions by the
surge current generated when MOSFET turns ON.
When the secondary output drops in the overload state, the primary auxiliary coil voltage
drops in proportion. Thus, the pin
voltage drops to below the operation stop voltage,
and the operation stops.
In this case, the circuit current drops simultaneously, so the pin
voltage rises again
with the charging current from R903 and R934, and intermittent operation that restarts
with the operation start voltage takes place.
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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