TDA9109N View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'TDA9109N' PDF : 32 Pages View PDF
TDA9109/N
OPERATING DESCRIPTION (continued)
II.4 - Output Section
The H-drive signal is sent to the output through a
shaping stage which also controls the H-drive duty
cycle (I2C adjustable) (see Figure 11). In order to
secure the scanning power part operation, the
output is inhibited in the following cases :
- when VCC or VDD are too low,
- when the XRAY protection is activated,
- during the Horizontal flyback,
- when the HDrive I2C bit control is off.
The output stage consists of a NPN bipolar
transistor. Only the collector is accessible
(see Figure 13).
Figure 13
VCC
26 H-DRIVE
This output stage is intended for ”reverse” base
control, where setting the output NPN in off-state
will control the power scanning transistor in off-
state (see Application Diagram).
Figure 14 : Safety Functions Block Diagram
VCC Checking
VCC
VSCinh
XRAY Protection
XRAY
VCC off or I2C Reset
SQ
R
Horizontal Flyback
0.7V
The maximum output current is 30mA, and the
corresponding voltage drop of the output VCEsat is
0.4V Max.
Obviously the power scanning transistor cannot be
directly driven by the integrated circuit. An interface
has to be added between the circuit and the power
transistor either of bipolar or MOS type.
II.5 - X-RAY Protection
The X-Ray protection is activated by application of
a high level on the X-Ray input (8V on Pin 25).
It inhibits the H-Drive and B+ outputs.
This protection is latched ; it may be reset either by
VCC switch off or by I2C (see Figure 14).
II.6 - Horizontal and Vertical Dynamic Focus
The TDA9109/N delivers a horizontal parabola
which is added on a vertical parabola waveform on
Pin 10. This horizontal parabola comes from a
sawtooth in phase with flyback pulse middle.This
sawtooth is present on Pin 9 where the horizontal
focus capacitor should be the same as C0 to obtain
the correct amplitude (from 2 to 4.7V typically).
Symmetry and amplitude are I2C adjustable
(see Figure 15). The vertical dynamic focus is
tracked with VPOSand VAMP.Its amplitudecan be
adjusted. It is also affected by S and C corrections.
This positive signal once amplified is to be sent to
the CRT focusing grids.
I2C Drive on/off
HORIZONTAL
OUTPUT
INHIBITION
I2C Ramp on/off
VERTICAL
OUTPUT
INHIBITION
BOUT
20/32
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