TDA9207 Ver la hoja de datos (PDF) - STMicroelectronics
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TDA9207 Datasheet PDF : 22 Pages
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TDA9207
Figure 4. Waveforms (Drive adjustment)
HSYNC
BPCP
BLK
Video IN
BFLK
OSD IN
VOUT1, VOUT2, VOUT3
VOSD
VBRT
VCONT
VBLACK
VDC
Two examples of drive
adjustment (1)
Note :
1.Drive adjustment modifies the following voltages : VCONT, VBRT and VOSD.
Drive adjustment doesn’t modify the following voltages : VDC and VBLACK.
4.10 Bandwidth Adjustment
A new feature: Bandwidth adjustment, has been
implemented on the TDA9207.
This function has several advantages:
– Depending on the external capacitive load and
on the peak-to-peak output voltage, the band-
width can be adjusted to avoid any slew-rate
phenomenon.
– The preamp bandwidth can be adjusted in order
to reduce electromagnetic radiation, since it is
possible to slow down the signal rise/fall time at
the CRT driver input without too much affecting
the rise/fall time at the CRT driver output.
– It is possible to optimize the ratio of the frequen-
cy response versus the CRT driver power con-
sumption for any kind of chassis, as the preamp
bandwidth adjustment also allows the adjust-
ment of the rise/fall time on the cathode (through
the CRT driver).
– In still picture mode, when a high Video swing
voltage is of greater interest than rise/fall time,
bandwidth adjustment is used to avoid any slew-
rate phenomenon at the CRT driver output and to
meet electromagnetic radiation requirements.
4.11 CRT Cathode Coupling
The powerfull multiplex capability of the TDA9207
allows to use the device with several kinds of CRT
cathode coupling.
4.11.1 AC coupling with DC restore ( Figure 5)
In this mode the output DC level (VDC) is adjusted
simultaneously for the 3 channels from 0.5 V to
2.35 V via Register 6 (4 bits). The cut-off voltage is
programmed independently for each channel from
0.17 V to 4.6 V using registers 10, 11, 12 (8 bits
each, see I2C Table 1).
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