Application solutions based on HDTV image processing chips

PLM1000 is an analog/digital hybrid processing chip developed by Jingbaoli Microelectronics Co., Ltd. and designed specifically for ordinary CRT TVs. The product can digitize the input analog TV signal, then perform digital signal processing, and finally restore the digital signal to an analog TV signal and output it to the analog TV. Its main processing function is to convert 480p, 576p, 720p, 1080i, 1080p and other high-definition analog signals and VGA signals into 480i or 576i standard-definition analog signals, and support brightness, chroma, color saturation adjustment, support color space conversion and other functions.

With the cooperation and promotion of Jingbaoli Microelectronics Co., Ltd. and Juhai Technology Co., Ltd., PLM1000 has been recognized by CRT manufacturers and put into large-scale use.

1 PLM1000 system solution design principle

Figure 1 is a schematic diagram of the PLM1000 system solution design application. PLM1000 converts analog high-definition signals or VGA signals output by high-definition equipment, computers, etc. into standard-definition YUV signals, and inputs them to ordinary analog CRT TVs for display. The PLM1000 system board is very simple, mainly including the PLM1000 chip, crystal oscillator and 3.3V/1.8V power supply.

Figure 1 Schematic diagram of the PLM1000 system solution

After the system is powered on, the external MCU performs power-on initialization on the PLM1000 chip and performs necessary register configuration. After the power-on initialization is completed, the MCU reads the automatic format detection results inside the PLM1000 chip, and determines the current input signal format according to the pre-set rules, writes the corresponding register configuration according to the input signal format, and the PLM1000 outputs a standard 480i or 576i format signal to the component input terminal of an ordinary analog CRT TV. The subsequent processing is exactly the same as that of an ordinary analog CRT TV.

During the normal display of the image, if the detection results for N consecutive times are different from the current signal format, the current detection result is set as the new chip format, the MCU turns off the video output of the PLM1000 chip, and turns on the video output after configuring the chip with the corresponding working parameters; if they are the same, the original configuration is maintained, that is, the PLM1000 works in the original format.

2 PLM1000 application solution examples

PLM1000 has two main different application solution designs to adapt to different application environments and requirements.

Application Solution 1: As shown in Figure 2, this PLM1000 solution board is very simple. The main components are PLM1000 and 3.3V/1.8V power supply. PLM1000 is controlled by the MCU in the original CRT solution through the I2C bus. This application solution has a relatively low cost and strong functions. For example, users can switch between the two channels of PLM1000, choose between HD input and computer VGA input, and display the input signal format under different signal sources.

Figure 2: System block diagram of application solution 1 based on PLM1000

This application solution is suitable for mass production of some large factories. The mass production cost is low and the system integration is relatively good. However, it requires more changes to the original system. The main thing is that the original system software needs to add control of PLM1000 and changes to user operations and user menus. The development is difficult and the development cycle is long.

At the same time, PLM1000 provides two packages, DIP and QFP64. If DIP is used, the chip can be placed on the original CRT baseboard, which can further reduce system costs and after-sales maintenance costs. However, most small and medium-sized CRT TV baseboards are small in size, so the double-sided board with QFP64 package is more suitable. The board interface only needs to leave YPbPr input, YCbCr output, I2C interface and power supply.

Figure 3: System block diagram of application solution 2 based on PLM1000 Application

solution 2: As shown in Figure 3, compared with solution 1, this PLM1000 solution board has an additional independent MCU. PLM1000 is controlled by this independent MCU, and the MCU software will automatically switch according to the input signal port and format. The connection line of this solution board is simple, only power supply (+5V) is required, and +1.8V and +3.3V voltages are obtained through 3.3V and 1.8V LDO respectively, and data input and output lines (YUV) are sufficient. It can also be regarded as an external device without changing the design of the TV motherboard (including hardware and software). It can be fixed in the TV and connected by flying wires. The debugging method is simple, fast and low-cost. For different versions and different packages of PLM1000, Juhai Technology Company has produced complete related supporting products, and can adjust the circuit board structure size according to the actual needs of customers. The existing design circuit board size can reach the specification of 45mmⅹ65mm.

This application solution is mainly aimed at SKD kit manufacturers who are not convenient to change the TV main chip program, and TV manufacturers who purchase ordinary SKD kits. With this solution, CRT TV manufacturers do not need to modify the software and hardware design of the CRT TV motherboard, so it is flexible and easy to use. Only a few processes need to be added to realize the function of ordinary CRT TVs receiving high-definition signals and increase CRT TV functions to achieve the purpose of increasing sales and expanding profits. This way of using existing solutions has greatly saved some companies' early development time and costs, flexibly responded to market changes, and is deeply loved by customers.

3 Summary of this article

As a high-definition TV image processing chip with completely independent intellectual property rights, PLM1000 makes high-definition images enter ordinary people's homes; at the same time, this low-cost high-definition TV image processing solution also extends the industrial cycle of CRT TVs, thereby driving the optimal allocation of resources in the entire industry.