TDA9110 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'TDA9110' PDF : 29 Pages View PDF
TDA9110
OPERATING DESCRIPTION (continued)
II.4 - Output Section
The H-drive signal is sent to the output through a
shaping block ensuring Ts and H-drive duty cycle
(I2C adjustable) (see Figure 13). In order to secure
the scanning power part operation, the output is
inhibited in the following cases :
- when VCC is 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 15).
Figure 15
VCC
26 H-DRIVE
The output NPN is in off-state when the power
scanning transistor is also in off-state.
The maximum output current is 30mA, and the
corresponding voltage drop of the output VCEsat is
0.4V typically.
Figure 16 : Safety Functions Block Diagram
VCC Checking
VCC
Ref
XRAY Protection
XRAY
VCC off or I2C Reset
SQ
R
Horizontal Flyback
0.7V
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 of 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). The
consequencies of X-Ray protection are :
- inhibition of H-Drive output
- activation of vertical blanking output.
This protection is reset either by VCC switch off or
by I2C (see Figure 16).
II.6 - Horizontal and Vertical Dynamic Focus
The TDA9110 delivers a horizontalparabola which
is added on a vertical parabola waveform on Pin
15. This horizontal parabola comes from a saw-
tooth. The phase advance versus Horizontal fly-
back middle is kept constant for each frequency
(about 860ns). This sawtooth is present on Pin 16
where the horizontal focus capacitor is the same
as C0 to obtain a controlled amplitude (from 2 to
4.7V typically).
Symmetry (keystone) and amplitude areI2C adjust-
able (see Figure 17). 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 has to be connectedto the CRT
focusing grids.
I2C Drive on/off
HORIZONTAL
OUTPUT
INHIBITION
I2C Ramp on/off
VERTICAL
OUTPUT
INHIBITION
19/29
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