TDA9106 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'TDA9106' PDF : 30 Pages View PDF
TDA9106
OPERATING DESCRIPTION (continued)
III - VERTICAL PART
III.1 - Geometric Corrections
The principle is represented in Figure 21.
Starting from the vertical ramp, a parabola shaped
current is generated for E/W correction, dynamic
horizontal phase control correction, and vertical
dynamic Focus correction.
The base of the parabola generator is an analog
multiplier the output current of which is equal to :
∆I = k ⋅ (VOUT - VDCOUT)2
Where Vout is the vertical output ramp, typically
comprised between 2 and 5V, Vdcout is the vertical
DC output adjustable in the range 3.2V ≥ 3.8V in
order to generatea dissymetric parabolaif required
(keystone adjustment).
Corner and Corner Balance corrections may be
added to the E/W one. These are respectively 3rd
and 2nd order waveforms.
In order to keep a good screen geometry for any
end user preferences adjustment we implemented
the “geometry tracking”.
Due to large output stages voltage range (E/W,
FOCUS), the combination of tracking function with
maximum vertical amplitude max or min vertical
position and maximum gain on the DAC control
Figure 21 : Geometric Corrections Principle
may lead to the output stages saturation. This must
be avoided by limiting the output voltage by apro-
priate I2C registers values.
For E/Wpart and Dynamic Horizontal phase control
part, a sawtooth shaped differential current in the
following form is generated :
∆I’ = k’ ⋅ (VOUT - VDCOUT)2
Then ∆I and ∆I’ are added together and converted
into voltage for the E/W part.
Each of the four E/W components or the two Dy-
namic Horizontal phase control ones may be inhib-
ited by their own I2C select bit.
The E/W parabolais availableon Pin 31 by the way
of an emitter follower which has to be biased by an
external resistor (10kΩ). It can be DC coupled with
external circuitry.
The output connection of the vertical Dynamic Fo-
cus is the same as the E/W one.
This reverse parabola is available on Pin 32.
Dynamic Horizontal phase control current drives
internally the H-position, moving the Hfly position
on the Horizontal sawtooth in the range ± 2.8% Th
both on SidePin Balance and Parallelogram.
2
VDCOUT
32
Vertical Ramp VOUT
EW amp
VDCIN
Vertical Ramp VOSC
VMID
VDCOUT
Keystone
31
Corner
Corner Balance
Vertical Dynamic
Focus Output
EW Output
24/30
Sidepin amp
VDCOUT
To Horizontal
Phase
Parallelogram
Sidepin Balance
Output Current
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