CN210381161U - Conversion system for converting RGB interface into HDMI interface - Google Patents

Abstract

The utility model discloses a conversion system for converting an RGB interface into an HDMI interface, which comprises an RGB video signal interface, a display interface conversion module, an EMI suppression module, an ESD protection module and an HDMI interface; the RGB video signal interface is used for receiving the RGB clock, the RGB control signal and the RGB data signal which are sent by the MCU and outputting the RGB clock, the RGB control signal and the RGB data signal to the display interface conversion module; the display interface conversion module converts the received RGB clock, RGB control signals and RGB data signals into serial HDMI differential signals and outputs the serial HDMI differential signals to the EMI suppression module; the EMI suppression module outputs the received HDMI differential signal to an HDMI interface through an ESD protection module after EMI suppression processing; the ESD protection module is used for electrostatic protection, and guarantees that HDMI signal transmission is not interfered by static electricity. The utility model has the advantages that the conversion from the RGB interface to the HDMI interface is realized by a hardware circuit, the stability is good, the FPGA program is not required to be developed, and the labor cost is reduced; the color effect can be improved, and the loss of precision can be reduced.

Description

Conversion system for converting RGB interface into HDMI interface

Technical Field

The utility model relates to a communication interface conversion system especially relates to a conversion system that is used for RGB interface to change HDMI interface.

Background

The existing display screen using the RGB video interface has different interface connector types, signal definitions and line sequences made by various manufacturers, so that the designed display screen driving board cannot be compatible with the display screen interfaces of the various manufacturers. Some MCUs (single chip microcomputers) support RGB video interfaces but not HDMI interfaces (high-definition multimedia interfaces), and cannot be directly connected with HDMI interfaces.

At present, the conversion from RGB video interface to HDMI interface is realized by FPGA (field programmable gate array), but there are disadvantages: 1. high manufacturing costs and the need to develop and maintain FPGA programs; 2. EMI (electromagnetic interference) suppression is not performed on HDMI signals, and the risk of overproof radiation exists; 3. ESD (electrostatic discharge) protection is not performed on the HDMI, so that ESD risk is caused; 4. some existing MCUs support up to 16-bit color (RGB 565 format), and the converted signal has some distortion compared to 24-bit color (RGB 888 format).

Disclosure of Invention

An object of the utility model is to provide a conversion system that is used for RGB interface to change HDMI interface.

In order to achieve the above purpose, the utility model adopts the following technical proposal:

the utility model discloses a conversion system for RGB interface changes HDMI interface, including RGB video signal interface, display interface conversion module, EMI restraines module, ESD protection module, HDMI interface; the RGB video signal interface is used for receiving the RGB clock, the RGB control signal and the RGB data signal sent by the MCU and outputting the RGB clock, the RGB control signal and the RGB data signal to the display interface conversion module; the display interface conversion module converts the received RGB clock, RGB control signals and RGB data signals into serial HDMI differential signals and outputs the serial HDMI differential signals to the EMI suppression module; the EMI suppression module outputs the received HDMI differential signal to the HDMI through the ESD protection module after EMI suppression processing; the ESD protection module is used for electrostatic protection, and guarantees that HDMI signal transmission is not interfered by static electricity.

The ESD protection module adopts an integrated circuit TPD12S521 and has 0.8pF ultralow junction capacitance.

The display interface conversion module adopts the integrated circuit TFP410, is compatible with RGB888 and RGB565 formats, fills original input data to the high-order end of the integrated circuit TFP410 for input signals in the RGB565 format, compensates the low-order of the integrated circuit chip TFP410 by using the low-order of the original input data, and carries out quantitative compensation on 16-order colors of the original input data.

The EMI suppression module is used for suppressing and processing the HDMI signals by connecting the HDMI special common mode inductors in series on the four groups of HDMI differential signal lines.

The utility model has the advantages that the conversion from the RGB interface to the HDMI interface is realized by hardware circuit, the stability is good, the cost is low compared with the conventional FPGA realization scheme, the FPGA program is not required to be developed, and the labor cost is reduced; the utility model performs EMI suppression on HDMI signals, and reduces the radiation overproof risk; ESD protection is carried out on the HDMI, and ESD risks are eliminated; simultaneously the utility model discloses carry out the color quantization compensation to 16 bit colours, can improve the color effect, reduce the loss in the precision.

Drawings

Fig. 1 is a schematic block diagram of the circuit of the present invention.

Fig. 2 is a circuit diagram of the display interface conversion module according to the present invention.

Fig. 3 is a circuit diagram of an ESD protection module according to the present invention.

Detailed Description

The following describes embodiments of the present invention in detail with reference to the drawings, which are implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific operation procedures are provided, but the scope of the present invention is not limited to the following embodiments.

A conversion system for RGB interface changes HDMI interface, as shown in fig. 1, by RGB video signal interface, show interface conversion module, EMI suppression module, ESD protection module, HDMI interface and constitute. The RGB video signal interface receives the RGB clock, the RGB control signal and the RGB data signal which are sent by the MCU. The display interface conversion module is composed of an integrated circuit TFP410 and a peripheral circuit, and converts an RGB clock, an RGB control signal, and an RGB data signal into a serial HDMI differential signal. The EMI suppression module has a good improvement effect on the radiation of the HDMI port through the common-mode inductor. The ESD protection module eliminates ESD risk of the HDMI port.

As shown in fig. 2, in the display interface conversion module, the RGB clock, the RGB control signal, and the RGB data signal are connected to the integrated circuit TFP 410. The TFP410 supports the highest pixel clock of 165Mhz, and can meet the requirement of high-definition display of an HDMI (high-definition multimedia interface); the integrated circuit TFP410 needs to set its own working mode, including the clock edge of data acquisition, data bit width, data acquisition delay, etc., and may be set in two ways: firstly, the ISEL pin of the integrated circuit TFP410 is set to be low level through an external power supply, the IIC configuration function is invalid, the pin configuration function is effective, and the integrated circuit TFP410 can work in a set mode according to the configuration of the pin after being electrified; secondly, the ISEL pin of the integrated circuit TFP410 is set to be at a high level through an external power supply, the pin configuration function fails, the IIC configuration function takes effect, and the integrated circuit TFP410 can configure a corresponding register through an IIC instruction issued by the MCU and work in a specified mode.

The RGB data signals are typically in the format of RGB888, RGB565, etc.: RGB888 format, namely 8 bits RED signal, 8 bits GREEN signal, 8 bits BLUE signal; RGB565 format, i.e., 5-bit RED signal, 6-bit GREEN signal, 5-bit BLUE signal; the utility model discloses a display interface conversion module can compatible formats such as RGB888, RGB565, to RGB888 formats, is connected to integrated circuit TFP 410's DATA23~ DATA0 pin respectively with 8 bit RED signals, 8 bit GREEN signals, 8 bit BLUE signals.

For the RGB565 format, as shown in FIG. 2, the 5-bit RED signal is connected to the pins DATA 23-DATA 19, respectively, and the last three bits of the RED signal are connected to the pins DATA 18-DATA 16, respectively; the 6-bit GREEN signal is respectively connected to the pins DATA 15-DATA 10, and the last two bits of the GREEN signal are respectively connected to the pins DATA 9-DATA 8; the 5-bit BLUE signals are respectively connected to the pins DATA 7-DATA 3, and the last three bits of BLUE signals are respectively connected to the pins DATA 2-DATA 0.

For signal connection in the RGB565 format, the original input data is filled in the upper bits of the integrated circuit TFP410, the lower bits of the TFP410 are compensated by using the lower bits of the original input data, and 16-bit color of the original input data is quantitatively compensated from the aspect of hardware, so that the color effect can be improved, and the loss in precision can be reduced.

As shown in fig. 3, the EMI suppression module connects HDMI-dedicated common-mode inductors L1, L2, L3, and L4 (characteristic impedance 90 ohms) in series to four sets of HDMI differential signal lines, because the parasitic capacitance of the common-mode inductor is too large, which may cause the failure of the HDMI differential impedance matching test, and the HDMI-dedicated common-mode inductors L1, L2, L3, and L4 have better suppression for the risk of exceeding the frequency multiplication radiation of the HDMI signal, particularly the HDMI clock. ESD protection module adopts special ESD protection integrated circuit TPD12S521 of HDMI, provides the ESD protection to the HDMI interface, and has 0.8pF ultralow knot electric capacity, and low knot electric capacity can guarantee that HDMI signal transmission quality is not influenced.

Claims (4)

1. A conversion system for converting an RGB interface into an HDMI interface is characterized in that: the device comprises an RGB video signal interface, a display interface conversion module, an EMI suppression module, an ESD protection module and an HDMI interface; the RGB video signal interface is used for receiving the RGB clock, the RGB control signal and the RGB data signal sent by the MCU and outputting the RGB clock, the RGB control signal and the RGB data signal to the display interface conversion module; the display interface conversion module converts the received RGB clock, RGB control signals and RGB data signals into serial HDMI differential signals and outputs the serial HDMI differential signals to the EMI suppression module; the EMI suppression module outputs the received HDMI differential signal to the HDMI through the ESD protection module after EMI suppression processing; the ESD protection module is used for electrostatic protection, and guarantees that HDMI signal transmission is not interfered by static electricity.

2. The system of claim 1, wherein the system comprises: the ESD protection module adopts an integrated circuit TPD12S521 and has 0.8pF ultralow junction capacitance.

3. Conversion system for RGB-to-HDMI interface according to claim 1 or 2, characterized in that: the display interface conversion module adopts the integrated circuit TFP410, is compatible with RGB888 and RGB565 formats, fills original input data to the high-order end of the integrated circuit TFP410 for input signals in the RGB565 format, compensates the low-order of the integrated circuit chip TFP410 by using the low-order of the original input data, and carries out quantitative compensation on 16-order colors of the original input data.

4. Conversion system for RGB-to-HDMI interface according to claim 1 or 2, characterized in that: the EMI suppression module is used for suppressing and processing the HDMI signals by connecting the HDMI special common mode inductors in series on the four groups of HDMI differential signal lines.

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