Philips 105G7 Series Service Manual page 13

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Pin22 is used for the automatic Beam Limiter input.
Pin1, V Fly back, required for OSD synchronization and is also used for vertical blanking of the video outputs.
Pin2, V ref Bypass, provides filtering for the internal voltage.
Pin3, Vref, sets the internal bias current level for optimum performance.
5.2 DEFLECTION CIRCUIT
The deflection circuit is achieved by a high performance and efficient solution IC 401 (TDA4841) for this
monitor. All functions are controllable by IIC –bus.
The TDA4841 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 such as TDA486*/TDA835*.
Horizontal Oscillator
The oscillator is of the relaxation type and requires a capacitor at pin29. A resistor from pin28 to ground
determines the minimum oscillator frequency. A resistor from pin28 to pin27 defines the frequency range.
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 is connected to Pin26.
PLL2 Phase Detector
This phase detector is similar to the PLL1 detector and compares the line fly back pulse 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-fly back and H-sync can be controlled at
pin30.
X-ray Protection
The X-ray protection input pin2 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:
Pin6 (BDRV) is floating
Pin8 (HDRV) is floating
Pin13/12 (VOUT1 and VOUT2) are floating
Vertical Oscillator
The vertical free –running the capacitor at pin24 and the resistor at pin23 determine frequency. Usually the
free-running frequency should be lower than the minimum trigger frequency.
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