TDA9109 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'TDA9109' PDF : 30 Pages View PDF
TDA9109/SN
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 transis-
tor. Only the collector is accessible(see Figure 13).
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).
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 integratedcircuit. 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 or VDD switch off or by I2C (see Figure 14).
Figure 14 : Safety Functions Block Diagram
VCC Checking
VCC
VSCinh
VDD Checking
VDD
VSDinh
XRAY Protection
XRAY
VCC or VDD off or I2C Reset
SQ
R
Horizontal Flyback
0.7V
Figure 12 : Flyback Input Electrical Diagram
HFLY 12
400Ω
Q1
20kΩ
Figure 13
GND 0V
VCC
26 H-DRIVE
II.6 - Vertical Dynamic Focus
The TDA9109/SN delivers a vertical parabola
waveform on Pin 10.
This vertical dynamic focus is tracked with VPOS
and VAMP. Its amplitude can be adjusted. It is also
affectedby Sand Ccorrections. 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
20/30
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