【Chuanglong TL570x-EVM】Review 02 - LCD driver circuit analysis

小火苗

【Chuanglong TL570x-EVM】Review 02 - LCD driver circuit analysis [Copy link]

【Chuanglong TL570x-EVM】Review 02 - LCD Hardware Introduction

1. Circuit Design

As shown in the figure, the LCD display uses a standard VOUT video output interface, and there is also a four-wire touch screen interface that can be connected to a capacitive or resistive screen.

• LCD screen data interpretation

2.1

As shown in the picture, the path can be found in the LCD screen manual. It uses a 800*480 pixel 7.0 -inch LCD screen. The touch screen information does not seem to be provided, but the touch screen is more versatile and can be used with almost all interfaces. It may be for this reason that the official did not specifically describe the touch screen model.

2.2 Screen Interface

LCD uses a flexible cable connection ( FPC ), but the screen and the board cannot be directly connected. It is obvious that the LCD screen interface is 50P , while the industrial control board is 40P pin. The circuit board circuit used to fix the screen plays an important role in conversion. Next, we will analyze the conversion board circuit step by step.

2.3 RBG interface

1.RGB : D0-D15 corresponds to B0-B7 , G0-G7 , R0-R7 ,

2. Just check the suffixes of the four pins, CLK, HSYNC, VSYNC, LCDEN.

3. The recommended circuit is shown below, using the SN74AVC32T245 chip (SN74AVC32T245 32-bit dual-supply bus transceiver with configurable voltage translation, level translation, and {1} tri-state output).

2.4 Other functions required by the conversion board

1. Backlight power supply voltage conversion circuit

2. The power supply voltage circuit design is more complicated

VCC - 3.3V ( 5V can be stepped down directly)

VCOM - 3.6V (You can use the middle value of resistors in series to get 3.6V )

VGH - 16V

VGL - -7V

AVDD 10.5V

3. This is the end. Due to the limited testing time, there is no time to adjust this circuit, so this file is currently a personal theoretical analysis of it, without actual testing, but the probability of success of this design can reach more than 90% . If any friends have operated it personally, please communicate with me. . . .

nmg

There are still 20 days left until the end of the scheduled evaluation period. Does limited time mean that it is not enough?

freebsder

Large board, circuit analysis is more interesting.

wangerxian

The official should have a matching screen, which can be driven directly using the program, right?

小火苗

nmg posted on 2022-5-31 09:39 There are still 20 days left before the end of the stipulated evaluation period. Does limited time mean not enough?

LCD screen If you make it yourself, you won’t have enough time for circuit design + hardware debugging

小火苗

freebsder posted on 2022-5-31 09:49 The big board makes the circuit analysis more interesting.

Yes, yes, yes

小火苗

wangerxian posted on 2022-5-31 20:14 The official should have a matching screen, can it be driven directly using the program?

The official has a matching LCD screen.

Study how the official LCD is designed