"Abstract: tda9332h is a display processor suitable for high-end color TV produced by Philips. It can be used for TV signal processing of single scan (50 or 60Hz) and double scan (100 or 120Hz). This paper introduces the structure principle and performance characteristics of tda9332h, and gives the application method of tda9332h in high-grade color TV
Main features of 1tda9332h
Tda9332h is a display processor designed by Philips for high-end color TV sets. It adopts 44 pin QFP package, and figure 1 shows its pin arrangement. In addition, the chip has the following characteristics:
● it has YUV input terminal and RGB signal input terminal with fast blanking. Its OSD / text input terminal is separated from other video signal inputs, and it has both fast blanking function and mixed insertion; At the same time, RGB control processor is built in, which can implement continuous cathode correction (CCC), white spot and black level offset adjustment; It can provide RGB output with stable black current; It can effectively solve the defects such as color deviation and contrast reduction of CRT display image caused by long service time.
● programmable deflection processor capable of generating internal clock. These driving signals include row driving, field deflection and east-west corrected parabolic wave. Its circuit can adapt to both 4:3 picture tube and 16:9 picture tube.
● it can be used for single scanning (50Hz or 60Hz) or double scanning (100Hz or 120Hz).
● the internal clock generator for line and field deflection processing can be synchronized by a 12Mhz ceramic resonator, so as to improve the timing accuracy of line and field deflection processing circuit.
● row synchronization circuit with two control loops, and row oscillator does not need to be adjusted; Driving arterial impulse can implement slow start and slow stop; It has line and field geometric distortion processing ability and horizontal parallelogram and bow correction function.
● the built-in blue extension circuit can shift the near white color to the blue side, so as to improve the gorgeous degree of the white field area of the image.
● it also has black level extension processing function for non-standard brightness signals, so that video signals input from different sources have consistent image levels after processing by the circuit; At the same time, the device is also equipped with a switchable matrix suitable for color difference signal, which can be applied to the processing and display of multi-standard color difference signal;
● it has the zoom function in horizontal and vertical directions and the vertical frame rolling function suitable for 16:9 picture tube.
● the power supply voltage of the chip is + 8V and the total power supply current is 50mA. All functions inside the chip can be controlled by I2C bus. 2-pin function and internal structure
Tda9332h has 44 pins, and the functions of each pin are listed in Table 1. Figure 2 shows its internal structure block diagram. Table 1 pin functions of tda9332h
Pin identification
Pin number
Pin function description
Pin identification
Pin number
Pin function description
VDOA
one
Geometrically corrected field sawtooth wave output a
VD
twenty-three
Field synchronization input
VDOB
two
Geometrically corrected field sawtooth wave output B
HD
twenty-four
Row synchronization input
EWO
three
East West pillow correction throw special wave output
DACOUT
twenty-five
DAC output
EHTIN
four
High voltage stability detection signal output
VIN
twenty-six
V signal input
FLASH
five
Fast detection input
UIN
twenty-seven
U signal input
GND1
six
land
YIN
twenty-eight
Y signal input
DECVD
seven
Digital power filter
FBCSO
twenty-nine
Fixed beam current off input
HOUT
eight
Row excitation pulse output
RI1
thirty
Red primary color signal 1 insertion
SCO
nine
Sandburg pulse output
GI1
thirty-one
Green primary signal 1 insertion
SCL
ten
I2C bus clock line
BI1
thirty-two
Blue primary signal 1 insertion
SDA
eleven
I2C bus data line
BL1
thirty-three
Quick blanking 1 insertion
HSEL
twelve
Line frequency selection control
PWL
thirty-four
White peak limiting decoupling
HFB
thirteen
Line reverse pulse input
RI2
thirty-five
Red primary color signal 2 insertion
DPC
fourteen
Dynamic phase compensation
GI2
thirty-six
Green primary color signal 2 insertion
VSC
fifteen
The field sawtooth wave forms, and the external sawtooth wave forms capacitance
BI2
thirty-seven
Blue primary signal 2 insertion
IREF
sixteen
Field sawtooth wave formation reference current setting
BL2
thirty-eight
Quick blanking 2 insertion
VPI
seventeen
+8V power supply (line start)
VP2
thirty-nine
+8V power supply
DECBG
eighteen
Capacitor connection end of power supply voltage stabilizing filter (bandgap filtering)
RO
forty
Red primary color signal output
GND2
nineteen
land
GO
forty-one
Green primary color signal output
XTALI
twenty
12Mhz crystal oscillator input
BO
forty-two
Blue primary color signal output
XTALO
twenty-one
12Mhz crystal oscillator output
BCL
forty-three
Beam current limit input
LPSU
twenty-two
Low voltage starting circuit power supply
BLKIN
forty-four
Black current detection input
Working principle of 3tda9332h
3.1 image signal selection and display processing
The selection and display processing of image signal in tda9332h includes converting RGB signal into YUV signal, YUV selection, black level extension and chroma control, primary color matrix, contrast control, primary color signal selection, white peak and brightness control, peak limiting and beam current control, automatic adjustment of dark balance, blue level extension and output amplification. The tda9332h has three signal inputs, one YUV and two RGB inputs. The YUV input port supplies the field doubling / line by line processing part to output the YUV signal.
Among the above three input ports, the first RGB input port is used for external video RGB signal input, and the second RGB input port is used for RGB signal input of OSD and teletext. The signal conversion of the three input ports is controlled by the microprocessor through I2C bus.
The processing of RGB output signal includes white peak limiting, beam current limiting, continuous calibration of cathode beam current, blue level extension and so on.
3.2 synchronization, deflection small signal processing and geometric distortion correction Figure 2 （ 1) Clock generator and first phase locked loop
The clock generator in tda9332h generates the clock signal required for synchronization and deflection processing by a voltage controlled oscillator and the first phase-locked loop. The free oscillation frequency of the voltage controlled oscillator is 880 times (1fh mode) or 440 times (2fH mode) of the line frequency of the input signal. The internal VCO frequency is determined by the input line synchronization signal and the control potential at the mode selection terminal.
(2) Working principle of the second phase locked loop and horizontal phase shift
After frequency division by 880 or 440, the voltage controlled oscillator sends the obtained 1fh or 2fH line excitation signal to the second PLL for phase discrimination with the line reverse pulse. The error signal is internally filtered to control the phase of the line excitation pulse, and can also be used to correct the horizontal phase offset of the image caused by the change of beam current.
In order to correct the line amplitude change caused by the change of beam current, the tda9332h also has a dynamic line amplitude fine-tuning function. After the sampling voltage of dynamic amplitude fine tuning is introduced from one end of the high-voltage winding of the row output transformer through resistance to pin 14 of tda9332h, the change of beam current will cause the potential change of this pin. The internal correction circuit can automatically adjust the reverse pulse phase of the second phase detection ring according to the potential change of this point. When the beam current increases, the output of the second phase discrimination ring will reduce the line amplitude, otherwise, the line amplitude will increase, so as to realize the purpose of automatic fine-tuning of the line amplitude with the beam current.
In the tda9332h, the error control voltage output by the second PLL can be changed through I2C bus data to realize the stunt adjustment of the horizontal direction of the image; The stunt adjustment is realized by taking the vertical deflection center as the reference point and increasing the phase shift of the scanning lines of the upper and lower halves line by line.
(3) Geometric distortion correction
The field geometry correction circuit set in tda9332h can implement the functions of field amplitude adjustment, S-shape correction, field slope correction, field offset and field zoom, field roll frame (i.e. the graphics can be moved in the vertical direction when scanning and expanding on the spot), field waiting (i.e. the adjustable delay at the starting point of field scanning), etc.
The East-West geometric correction of tda9332h includes wide travel range, east-west upper angle and parabolic wave ratio, east-west lower angle and parabolic wave ratio, east-west trapezoidal distortion, etc.
Tda9332h also has an eht compensation input signal, which can be used to control the field and E-W output signals. At the same time, the relative control effects of the two can also be adjusted through I2C bus.
Application of 4tda9332h in high-end color TV
Figure 3 shows the typical application block diagram of tda9332h in high-end TV. The ordinary TV signal is converted into frequency doubling or line by line y, u and V signals through the scan rate converter. After the signal is added to pins 26, 27 and 28 of the tda9332h, the R, G and B signals output by the high-definition digital TV set-top box or the R, G and B signals output by the PC are added to pins 30, 31 and 32 of the tda9332h, Then, the signal is processed through the internal rgb-yuv matrix and the switch of video component signal, and a TV signal is selected for transmission. The R, G, B signals and blanking signals of OSD are input from pins 35, 36, 37 and 38, mixed with the incoming main TV signal, and then subjected to white spot and brightness control and output buffer. Then, they are output by pins 40, 41 and 42 and transmitted to the last stage video amplifier tda6120q with 32mhz bandwidth in three ways for power amplification, Finally, it is added to the cathode of the picture tube.
In order to improve the image quality, the tda9332h also adds a black level extension circuit, a blue level extension circuit, a white peak limiting circuit and an automatic brightness control circuit. The ABL voltage detected by the high-voltage winding of the line reverse transformer is amplified by the triode and applied to pin 43; The black current calibration voltage detected by the last stage visual amplifier, which reflects the change of CRT cathode current, is applied to pin 44 to automatically calibrate the brightness of CRT. 5 Conclusion
Because all functions of tda9332h are controlled by I2C bus, it has the advantages of simple application, few peripheral components, low power consumption and high cost performance. Therefore, the chip has been more and more widely used in various high-end TVs, such as progressive color TV and digital high-definition TV., Read the full text, technical section
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