Acer AC511 SERIES Service Manual page 11

5-2 DEFLECTION CIRCUIT
The deflection circuit is achieved by a high performance and efficient solution IC 401 (TDA9115) for this
monitor. The concept is fully DC controllable and can be used in applications with a micro-controller solutions.
The TDA9115 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 C446 at pin29. The maximum oscillator
frequency is determined by a resistor R403 4.7K form pin28 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 C401,R401,C402 is connected to Pin26.
PLL2 Phase Detector
This phase detector is similar to the PLL1 detector and compares the line flyback pulse at pin 1 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 pin30.
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:
Pin7 (BDRV) is floating
Pin6 (HDRV) is floating
Pin12, 13 ( VOUT 1, 2) are floating
Vertical Oscillator
The vertical free –running frequency is determined by the resistor R608 at pin23, with capacitor C604 at pin24.
Usually the free-running frequency should be lower than the minimum trigger frequency.
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