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5. CIRCUIT DESCRIPTION
5-1 MICRO
CONTROLLER CIRCUIT
MICRO Controller
The IC101 contains a 8031 8-bit CPU core, 60K bytes of RAM, 16K bytes of ROM,14 channel 8 bit
PWM D/A converters, 2 channel A/D converters for key detection,0.5sec watch-dog timer, internal H-
sync and V-sync signals processor providing mode detection, watch- dog timer preventing system from
abnormal operation, and an I²C bus interface.
H/V sync signals processor
The functions of the sync processor include polarity detection, H-SYNC & V-SYNC signals counting,
Programmable SYNC signals output, free running signal generator. Pin41/Pin42 are for the H-SYNC
and V-SYNC input, Pin34/Pin33 will output the same signal as input sync signal without delay, and the
polarity are setting in the positive. When no signal input, the Pin32 will output a 60Hz V-SYNC free run
signal. The Pin33 will output a 48KHz H-SYNC free run signal. for the monitor testing use.
5-2 DEFLECTION
CIRCUIT
The deflection circuit is achieved by a high performance and efficient solution IC 401 (STV 9118) for
this monitor. The concept is fully DC controllable and can be used in applications with a micro-
controller solutions.
The STV9118 provides sync. Processing with full auto sync. Capability, a flexible SMPS block and an
extensive set of geometry control facilities. Further the IC generates the drive waveforms for DC
coupled vertical boosters to the STV9118.
Horizontal Oscillator
The oscillator is of the relaxation type and requires a capacitor of 1nF C405 at pin29.
PLL 1 Phase Detector
The phase detector is a standard one using switched current sources. It compares the middle of H-
sync. with a fixed point on the oscillator saw-tooth voltage. The PLL loop filter R411,C437,C435 is
connected to Pin9.
PLL2 Phase Detector
The PLL2 detector thus compensates for the delay in the external H-deflection circuit by adjusting the
phase of the HDRV output pulses. The phase between H-flyback and H-sync can be controlled at pin5.
X-ray Protection
Summary of Contents for P774B-2NT Series
Page 21: ...20 7 MECHANICAL OF CABINET FRONT DIS ASSEMBLY...
Page 39: ...38 10 IC BLOCK DIAGRAM IC401 STV9118 IC101 NT6865...
Page 40: ...39 IC102 24LC08...
Page 41: ...40 IC601 STV9302A IC801 NT6812K...
Page 42: ...41 IC802 LM2476 IC901 STR G5643D...
Page 43: ...42 11 PCB LAYOUT 11 1 MAIN PCB LAYOUT...
Page 44: ...43 11 2 CRT BOARD LAYOUT...