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參數(shù)資料
| 型號(hào)： | TEA5040S |
| 廠(chǎng)商： | 意法半導(dǎo)體 |
| 英文描述： | WIDE BAND VIDEO PROCESSOR |
| 中文描述： | 寬帶視頻處理器 |
| 文件頁(yè)數(shù)： | 4/12頁(yè) |
| 文件大?。?/td> | 177K |
| 代理商： | TEA5040S |
pulse. Since this integrated circuit can be directly
connectedto twodifferent sources,it is necessary
then to have two separate insertion pulse inputs
(pin 8-9). Fast blanking can be inhibited by a one
active bit word. The two fast blankinginputs carry
out an OR function to insert R, G, B sources into
TV picture. The external fast blanking (FB ext.)
selects the appropriateR, G, B source.
Controls
Thefourbrightness,contrastandsaturationcontrol
functions are direct digitally controlled without us-
ing digital-to-analogconverters.
The contrast control of the Y channel is obtained
by means of a digital potentiometer which is an
attenuator including several switchable cells di-
rectly controlled by a 5 active bit word (address
number1). The brightnesscontrol is alsomade by
a digital potentiometer (5 active bit word,address
number 0). Since a + 3dB contrast capability is
required,the Y signal value could be up to 0.7Vpp
nominal. For both functions, the control charac-
teristics are quasi-linear.
In each R-Y and B-Y channel, a six-cell digital
attenuator is directly controlled by a 6 active bit
word (address number 6 and 7). The tracking
needed to keep the saturation constant when
changingthe contrast hasto be done externally by
the microcontroller. Furthermore, colour can be
disabledbyblankingR-YandB-Ysignalsusingone
active bit word (address number 2) to drive the
one-chipcolour ON/OFF switch.
Second Matrix, Clamp, PeakClipping, Blank-
ing
The second matrix receives the Y, R-Y and B-Y
signals and delivers the corresponding R, G, B
signals.As it is requiredto have the capability of +
6dB saturation, an internal gain of 2 is appliedon
bothR-Y and B-Ysignals.
Alow clipping level is included in orderto ensurea
correctblankingduringtheline andframeretraces.
Ahighclippinglevelensuresthepeakbeamcurrent
limitation. These limitations are correct only if the
DC bias of the three R, G, B signals are precise
enough. Therefore a clamp has been added in
eachchannel in order to compensatefor the inac-
curacy of the matrix.
Sandcastle Detector And Counter
The three level supersandcastle is used in the
circuit to delivertheburst pulse(CLP), thehorizon-
tal pulse (HP), and the composite vertical and
horizontal blanking pulse (BLI). This last one is
regenerated in the counter which delivers a new
compositepulse(BL)inwhichtheverticalpart lasts
23 lines when the vertical part of the supersand-
castle lasts more than11lines.
The TEA5040S cannot work properly if this mini-
mum durationof 11lines is not ensured.
The counterdeliversdifferentpulsesneededcircuit
and especiallythe line pulses 17 to 23 used in the
automaticdrive and cut-off control system.
Automatic Drive And Cut-off Control System
Cut-off and drive adjustments are no longer re-
quiredwiththis integratedcircuitasit hasasample
and hold feedback loop incorporating the final
stages of the TV-set. This system works in a se-
quentialmode.For thispurpose,specialpulsesare
inserted in G, R and B channels. During the lines
17, 18 and 19, a ”drive pulse” is inserted respec-
tivelyin the green,red and bluechannels. The line
20 is blanked on the three channels. During the
lines 21, 22 and 23, a ”quasi cut-off pulse” is
inserted respectively in the green, red and blue
guns.
The resulting signal is then applied to the input of
a voltage controlled amplifier. In the finalstages of
the TV-set, the current flowing in each green, red
and blue cathode is measured and sent to the
videoprocessorby a currentsource.
The threecurrentsare addedtogetherina resistor
matrix which can be programmed to set the ratio
between the three currents in order to get the
appropriate colour temperature.The output of the
matrix forms a high impedance voltage source
whichis connectedtotheintegratedcircuit (pin34).
Same measurement range betweendrive and cut-
off is achieved by internallygrounding an external
low impedanceresistor duringlines 17, 18 and 19.
This is due to the fact that the drive currents are
about one hundred times higher than the cut-off
and leakagecurrents.
Each voltage appearing sequentially on the wire
pin 34 is then a function of specific cathode cur-
rent :
- When a current due to a drivepulse occurs, the
voltage appearing on the pin 34 is compared
within the IC with an internal reference, and the
result of the comparison charges or discharges
an external appropriate drive capacitor which
storesthe valueduring the frame. This voltage is
applied to a voltage controlled amplifier and the
systemworks insuchawaythatthepulsecurrent
drive derivedfrom the cathodeis kept constant.
- During the line 20, the three guns of the picture
tube areblanked.Theleakagecurrentflowingout
of the final stages is transformed into a voltage
TEA5040S
4/12
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TEA5101A | 制造商:STMICROELECTRONICS 制造商全稱(chēng):STMicroelectronics 功能描述:RGB HIGH VOLTAGE VIDEO AMPLIFIER |
| TEA5101B | 功能描述:視頻放大器 RGB Amplifier RoHS:否 制造商:ON Semiconductor 通道數(shù)量:4 電源類(lèi)型: 工作電源電壓:3.3 V, 5 V 電源電流: 最小工作溫度: 最大工作溫度: 封裝 / 箱體:TSSOP-14 封裝:Reel |
| TEA5110 | 制造商:STMICROELECTRONICS 制造商全稱(chēng):STMicroelectronics 功能描述:LOW DROP-OUT 5V DUAL VOLTAGE REGULATOR |
| TEA5114 | 制造商:STMICROELECTRONICS 制造商全稱(chēng):STMicroelectronics 功能描述:RGB SWITCHING CIRCUIT |
| TEA5114A | 功能描述:視頻 IC Video Switch RoHS:否 制造商:Fairchild Semiconductor 工作電源電壓:5 V 電源電流:80 mA 最大工作溫度:+ 85 C 封裝 / 箱體:TSSOP-28 封裝:Reel |
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