AOC S761U, Руководство по обслуживанию, Страница: 13 / 60

13
5-2 DEFLECTION CIRCUIT
The deflection circuit is achieved by a high performance and efficient solution IC 401 (TDA9111) for this monitor. The
concept is fully DC controllable and can be used in applications with a micro-controller solutions.
The TDA9111 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
TDA9302H.
Horizontal Oscillator
The oscillator is of the relaxation type and requires a capacitor of 1nF C447 at pin5. The free running frequency is
determined by a resistor R410 4.7K form pin6 to ground.
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 C435, C437, R411, D403 is connected to Pin7.
PLL2 Phase Detector
This phase detector is similar to the PLL1 detector and compares the line flyback pulse at pin 12 with the oscillator saw-
tooth voltage. 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 pin4.
X-ray Protection
The X-ray protection input pin25 provides a voltage detector with a precise threshold. If the voltage exceeds this
threshold for a certain time, an internal latch switches the whole IC into protection mode. In this mode several pins are
forced into defined states:
Pin28 (BDRV) is floating
Pin26 (HDRV) is floating
Pin21, 23 ( VOUT 1, 2) are floating
Vertical Oscillator
The vertical free –running frequency is determined by the resistor C613, C616, R616 at pin22. Usually the free-running
frequency should be lower than the minimum trigger frequency.