Display screen conversion circuit and industrial personal computer

Abstract

The embodiment of the utility model relates to the technical field of industrial control, and discloses a display screen conversion circuit and an industrial personal computer, which can realize the connection between a mainboard and different types of display screens so as to support the different types of display screens, do not need any software and hardware change for the mainboard, and are convenient to use. According to the LVDS display screen switching circuit board, different display screen switching circuit boards only need to be replaced, the occupied space of a mainboard can be greatly reduced, the LVDS display screen switching circuit board can adapt to different LVDS display screens under the condition that mainboard hardware and software are not changed, and the problems that different display screens are high in adaptation cost, poor in flexibility and the like are solved. Meanwhile, according to the display screen conversion circuit and the industrial personal computer provided by the embodiment of the invention, different resolutions can be set for the mainboard according to different parameters of the display screen needing to be connected with the mainboard, and the adaptability of the display screen conversion circuit is improved.

Description

Technical Field

[0001] The embodiment of the utility model relates to the technical field of industrial control, and in particular to a display screen conversion circuit and an industrial computer. Background Art

[0002] In the field of industrial automation, industrial computers play a vital role. They not only need to have high reliability and stability to meet the needs of long-term continuous operation, but also must have good openness and real-time performance to enable seamless integration and data exchange with other industrial equipment and systems. In addition, the human-machine interface design of industrial computers also tends to be more friendly and intuitive to reduce the difficulty of use for operators and improve operational efficiency and accuracy.

[0003] The applicant has found in research that when industrial tablet computers are used in different scenarios, they often have different display screen size and resolution requirements, and existing industrial computers cannot adapt to the operating requirements for different displays in different scenarios. Utility Model Content

[0004] In view of the above problems, the embodiments of the present utility model provide a display screen conversion circuit and an industrial computer, which are used to solve the above technical problems existing in the prior art.

[0005] According to one aspect of the embodiment of the utility model, a display screen conversion circuit is used to connect a circuit board and a display screen, including: a circuit board, a first conversion interface, a second conversion interface, a voltage conversion unit, a resolution adjustment unit and a signal conversion control unit;

[0006] The first conversion interface is arranged on the circuit board, and is used to connect to the mainboard and obtain the first display signal and the input voltage signal from the mainboard;

[0007] The second conversion interface is arranged on the circuit board and is used to connect with the display screen;

[0008] The voltage conversion unit is electrically connected to the first conversion interface and the second conversion interface respectively, converts the input voltage signal into an output voltage signal, and outputs the output voltage signal to the display screen through the second conversion interface;

[0009] The resolution adjustment unit is electrically connected to the signal conversion control unit to set resolution information for the display screen;

[0010] The signal conversion control unit is electrically connected to the first conversion interface, the second conversion interface and the resolution adjustment unit respectively, and is used to convert the first display signal into a second display signal according to the resolution information, and send the second display signal to the display screen through the second conversion interface.

[0011] In some embodiments, the resolution adjustment unit includes a multi-way DIP switch SW and a plurality of pull-up resistors R_SW; the signal conversion control unit includes a plurality of control data ports LVDS_GPIO;

[0012] One end of each of the dip switches SW is electrically connected to each of the control data ports LVDS_GPIO, and the other end is grounded;

[0013] One end of each pull-up resistor R_SW is electrically connected to each control data port LVDS_GPIO, and the other end is connected to a power supply.

[0014] In some embodiments, the signal conversion control unit includes a plurality of first display signal input ports; the first conversion interface includes a plurality of coupling capacitors;

[0015] One end of each of the coupling capacitors is respectively used to be connected to the mainboard, and the other end is respectively electrically connected to each of the first display signal input ports;

[0016] The signal conversion control unit further includes a plurality of second display signal output ports, and the plurality of second display signal output ports form a differential pair; the second conversion interface includes a plurality of matching resistors;

[0017] Two ends of each matching resistor are electrically connected to the second display signal output port forming a differential pair.

[0018] In some embodiments, the voltage conversion unit includes a first voltage input terminal VCC5, a second voltage input terminal VCC3_3SB, a first N-channel MOS transistor Q8, a second P-channel MOS transistor Q7 and a first voltage output terminal VCC3_3;

[0019] The first voltage input terminal VCC5 and the second voltage input terminal VCC3_3SB are respectively electrically connected to the mainboard through the first conversion interface;

[0020] The gate of the first N-channel MOS transistor Q8 is electrically connected to the first voltage input terminal VCC5, the source of the first N-channel MOS transistor Q8 is grounded, and the drain of the first N-channel MOS transistor Q8 is electrically connected to the second voltage input terminal VCC3_3SB;

[0021] The gate of the second P-channel MOS transistor Q7 is electrically connected to the drain of the first N-channel MOS transistor Q8, the source of the second P-channel MOS transistor Q7 is electrically connected to the second voltage input terminal VCC3_3SB, and the drain of the second P-channel MOS transistor Q7 is electrically connected to the first voltage output terminal VCC3_3;

[0022] The first voltage output terminal VCC3_3 is electrically connected to the display screen through the second conversion interface, and is used to provide an output voltage signal for the display screen.

[0023] In some embodiments, the voltage conversion unit further includes a second voltage output terminal VDD_LCD, a third N-channel MOS transistor Q14, a fourth P-channel MOS transistor Q13 and a selection switch JP7;

[0024] The signal conversion control unit includes a display screen power enable port LVDS_VDDEN;

[0025] The gate of the third N-channel MOS transistor Q14 is electrically connected to the display screen power enable port LVDS_VDDEN, the source of the third N-channel MOS transistor Q14 is grounded, and the drain of the third N-channel MOS transistor Q14 is electrically connected to the first voltage input terminal VCC5;

[0026] The gate of the fourth P-channel MOS transistor Q13 is connected to the drain of the third N-channel MOS transistor Q14, and the drain of the fourth P-channel MOS transistor Q13 is electrically connected to the selection switch JP7; the source of the fourth P-channel MOS transistor Q13 is electrically connected to the second voltage output terminal VDD_LCD;

[0027] The second voltage output terminal VDD_LCD is electrically connected to the display screen through the second conversion interface, and is used to provide the output voltage signal to the display screen;

[0028] The selection switch JP7 includes a first end, a second end and a third end, the first end is electrically connected to the first voltage input end VCC5, the third end is electrically connected to the first voltage output end VCC3_3, and the second end is electrically connected to the drain of the fourth P-channel MOS transistor Q13;

[0029] When the signal conversion control unit outputs a display screen power enable signal through the display screen power enable port LVDS_VDDEN, the third N-channel MOS transistor Q14 and the fourth P-channel MOS transistor Q13 are turned on, and the voltage at the second end of the selection switch JP7 is the voltage of the second voltage output end VDD_LCD; when the first end and the second end of the selection switch JP7 are turned on, the voltage of the second voltage output end VDD_LCD is the voltage of the first voltage input end VCC5; when the third end and the second end of the selection switch JP7 are turned on, the voltage of the second voltage output end VDD_LCD is the voltage of the first voltage output end VCC3_3.

[0030] Some embodiments further include a backlight adjustment unit;

[0031] The backlight adjustment unit includes a fifth N-channel MOS transistor Q2, a sixth N-channel MOS transistor Q3 and a seventh N-channel MOS transistor Q11;

[0032] The signal conversion control unit includes an EDP backlight enable control port EDP_BKLT_ON, an LVDS backlight enable control port CS5211_BKLT_EN and a display backlight switch control port BL_SHUT;

[0033] The second conversion interface also includes an LVDS backlight control interface LCDB2;

[0034] The gate of the fifth N-channel MOS transistor Q2 is electrically connected to the EDP backlight enable control port EDP_BKLT_ON, the source of the fifth N-channel MOS transistor Q2 is grounded, and the drain of the fifth N-channel MOS transistor Q2 is electrically connected to the gate of the sixth N-channel MOS transistor Q3;

[0035] The source of the sixth N-channel MOS transistor Q3 is grounded, and the drain of the sixth N-channel MOS transistor Q3 is electrically connected to the LVDS backlight control interface LCDB2;

[0036] The source of the seventh N-channel MOS transistor Q11 is electrically connected to the LVDS backlight enable control port CS5211_BKLT_EN, the gate of the seventh N-channel MOS transistor Q11 is connected to the first voltage output terminal VCC3_3, and the drain of the seventh N-channel MOS transistor Q11 is electrically connected to the drain of the sixth N-channel MOS transistor Q3 and the LVDS backlight control interface LCDB2 respectively;

[0037] The display screen backlight switch control port BL_SHUT is used to receive a display screen backlight switch control signal, and output an LVDS backlight enable control signal through the LVDS backlight enable control port CS5211_BKLT_EN.

[0038] In some embodiments, the backlight adjustment unit further includes an eighth N-channel MOS transistor Q12;

[0039] The signal conversion control unit also includes a PWM signal output port CS5211_PWM_OUT;

[0040] The source of the eighth N-channel MOS transistor Q12 is electrically connected to the PWM signal output port CS5211_PWM_OUT, the gate of the eighth N-channel MOS transistor Q12 is connected to the first voltage output terminal VCC3_3, and the drain of the eighth N-channel MOS transistor Q12 is electrically connected to the LVDS backlight control interface LCDB2;

[0041] The signal conversion control unit adjusts the backlight of the display screen through the PWM signal output port CS5211_PWM_OUT.

[0042] Some embodiments further include a backlight adjustment button unit;

[0043] The backlight adjustment button unit includes a switch button K1, a decrease button K2 and an increase button K3;

[0044] The signal conversion control unit also includes a display backlight increase port BL_UP and a display backlight decrease port BL_DOWN;

[0045] The switch button K1 is electrically connected to the display backlight switch control port BL_SHUT, the increase button K3 is electrically connected to the display backlight increase port BL_UP, and the decrease button K2 is electrically connected to the display backlight decrease port BL_DOWN;

[0046] When the signal conversion control unit receives the key operation of the switch key K1, it is used to control the LVDS backlight enable control port CS5211_BKLT_EN; when the signal conversion control unit receives the key operation of the increase key K3 or the decrease key K2, it is used to control the output of the PWM signal output port CS5211_PWM_OUT.

[0047] Some embodiments further include a backlight indication unit;

[0048] The backlight indication unit includes an NPN transistor Q6 and an indicator light BL_LED;

[0049] The base of the NPN transistor Q6 is electrically connected to the LVDS backlight enable control port CS5211_BKLT_EN, the emitter of the NPN transistor Q6 is grounded, and the collector of the NPN transistor Q6 is electrically connected to the indicator light BL_LED.

[0050] In another embodiment, the present application further proposes an industrial computer, comprising a mainboard, a display screen, and a display screen conversion circuit proposed in any of the above embodiments;

[0051] The display screen conversion circuit is used to electrically connect the mainboard with the display screen.

[0052] The display screen conversion circuit and industrial computer provided in the embodiment of the present application can realize the connection between the mainboard and different types of display screens to support different types of display screens. There is no need to make any software and hardware changes to the mainboard. Only different display screen conversion circuit boards need to be replaced, which can greatly reduce the space occupied by the mainboard. Without changing the hardware and software of the mainboard, it can adapt to different LVDS display screens, solving the problems of high adaptation cost and poor flexibility of different display screens. At the same time, the display screen conversion circuit and industrial computer provided in the embodiment of the present application can set different resolutions for the display screen that needs to be connected to the mainboard according to different parameters, thereby improving the adaptability of the display screen conversion circuit.

[0053] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limiting of the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0055] Figure 1 The structure diagram of the display screen conversion circuit provided by the embodiment of the present invention is shown;

[0056] Figure 2 Another display screen conversion circuit structure diagram provided by an embodiment of the present invention is shown;

[0057] Figure 3 A circuit diagram of a display screen conversion circuit provided by an embodiment of the present invention is shown;

[0058] Figure 4a A circuit diagram of a voltage conversion circuit provided by an embodiment of the present invention is shown;

[0059] Figure 4b Another circuit diagram of a voltage conversion circuit provided by an embodiment of the present invention is shown;

[0060] Figure 4c A circuit diagram of a third voltage conversion circuit provided by an embodiment of the present invention is shown;

[0061] Figure 5 A circuit diagram of a backlight adjustment unit provided by an embodiment of the present invention is shown;

[0062] Figure 6A circuit diagram of a backlight adjustment key unit provided in an embodiment of the present invention is shown;

[0063] Figure 7 A circuit diagram of a backlight indication unit provided by an embodiment of the present invention is shown;

[0064] Figure 8 A circuit diagram of a touch screen control unit provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0065] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0067] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0068] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0069] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0070] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0071] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0072] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0073] On industrial production lines, industrial computers play a very important role as the center of data processing. Industrial tablet computers composed of industrial computers and industrial displays are the window of human-computer interaction and an important carrier of data input and output. They are often used in harsh industrial field control applications such as medical informationization, production line MES, single crystal furnaces, and electricity.

[0074] When industrial tablets are used in different scenarios, they often have different display screen sizes and resolution requirements. In the past, the way to cope with these different display screen adaptation requirements was to modify the hardware and debug the software to meet the adaptation of the new display screen. In this way, the display conversion circuit is fully integrated on the motherboard, which occupies the size of the motherboard, has poor flexibility, and increases costs.

[0075] At present, the interfaces commonly used by industrial hosts include DP display interface, LVDS display interface, VGA display interface and DVI display interface. In the embodiment of this application, for the convenience of explanation, the matching between DP display interface and LVDS display interface is used as an example for explanation. DP (Embedded Display Port) interface is a fully digital interface based on Display Port architecture and protocol, specially designed for embedded display panels of portable devices such as laptops, tablets, mobile phones, etc. DP interface has the advantages of high bandwidth, good integration, simple product design, etc., and can support displays with higher color depth, refresh rate and display resolution; LVDS (Low Voltage Differential Signaling) is a technology commonly used in display screens, especially in the field of liquid crystal displays (LCD). LVDS interface has been widely used in large-screen LCD displays due to its unique performance advantages. The core of LVDS technology is to use extremely low voltage swings for high-speed differential transmission of data, which makes it have the characteristics of low power consumption, low bit error rate, low crosstalk and low radiation.

[0076] The inventor of the present application has discovered through research that in order to adapt to the needs of display screens of different sizes, a display screen adapter board can be provided. In order to meet the needs of the host adapting to different display screens, the embodiment of the present application proposes a display screen conversion circuit and an industrial computer to solve the technical problems existing in the prior art.

[0077] The display screen conversion circuit and industrial computer proposed in the embodiment of the present application can make the host adapt to different types of display screens. The display screen and the mainboard are set together through the display screen conversion circuit. On the one hand, various types of video signals can be converted, such as converting the DP interface signal into the LVDS interface signal, so as to achieve the docking of the LVDS display screen and the DP interface. On the other hand, the display screen conversion circuit and industrial computer proposed in the present application can set different resolutions for the conversion circuit according to the different types of connected display screens to support display screens with different resolutions. Through the display screen conversion circuit and industrial computer proposed in the embodiment of the present application, the setting method between the display screen conversion circuit and the mainboard is flexible. For different display screens, only different display screen conversion circuit boards need to be replaced, which greatly improves the adaptability of the host to different types of display screens, and can also greatly reduce the space occupied by the mainboard. Without changing the hardware and software of the mainboard, it can adapt to different LVDS display screens, solving the problems of high adaptation cost and poor flexibility of different display screens.

[0078] The display screen conversion circuit proposed in the embodiment of the present application can be applied to a variety of scenarios, including but not limited to industrial computers, home computers, etc. It is not limited to converting DP interface signals into LVDS interface signals, and can convert between multiple interface signals to adapt to different types of display screens.

[0079] Figure 1 and Figure 2 A schematic diagram of the structure of a display screen conversion circuit proposed in an embodiment of the present application is shown. The display screen conversion circuit 100 includes: a first conversion interface 110, a resolution adjustment unit 120, a signal conversion control unit 130, a voltage conversion unit 140 and a second conversion interface 150. The above-mentioned interfaces and units are arranged on a circuit board.

[0080] The first conversion interface 110 is arranged on the circuit board, and is used to connect with the mainboard 200 and obtain the first display signal and the input voltage signal from the mainboard 200; the second conversion interface 150 is arranged on the circuit board, and is used to connect with the display screen 300; the voltage conversion unit 140 is electrically connected to the first conversion interface 110 and the second conversion interface 150 respectively, converts the input voltage signal into an output voltage signal, and outputs the output voltage signal to the display screen 300 through the second conversion interface 150; the resolution adjustment unit 120 is electrically connected to the signal conversion control unit 130, and sets the resolution information for the display screen 300; the signal conversion control unit 130 is connected to the first conversion interface 110, the second conversion interface 150 and the resolution adjustment unit 120 respectively, and is used to convert the first display signal into a second display signal according to the resolution information, and send the second display signal to the display screen 300 through the second conversion interface 150.

[0081] Among them, the product form of the display screen conversion circuit 100 is an independent circuit board structure, and the circuit board can realize the connection between the external main board 200 and the external display screen 300. The connection between the display screen conversion circuit 100 and the main board 200 can be connected in a plug-in manner, for example: an interface slot is provided on the main board 200, and the circuit board of the display screen conversion circuit 100 is inserted into the slot to realize the connection with the main board 200; it can also be connected in a cable manner, and the cable manner is a flexible connection, which can lengthen the connection distance between the main board 200 and the display screen conversion circuit 100. Similarly, the connection between the display screen conversion circuit 100 and the display screen 300 can also be connected in a plug-in manner or a cable manner. In actual applications, the connection method can be flexibly selected according to the actual application scenario, and is not limited in the embodiments of the present application.

[0082] like Figure 1 and Figure 2As shown, the first conversion interface 110 is disposed on the circuit board for connecting to the main board 200. The position and shape of the first conversion interface 110 can be determined as needed. For example, a gold finger can be disposed on one edge of the circuit board to facilitate plugging with the main board 200. A plug connector can also be disposed in the middle of one side of the circuit board to connect to the main board 200 by cable, which is not limited in the embodiment of the present application. The first conversion interface 110 is mainly used to connect to the main board 200 and to exchange signals with the main board 200, including but not limited to obtaining a first display signal, an input voltage signal, a USB signal, an SMBUS signal, a power supply and a hard disk indicator light signal, etc. It should be pointed out that the first conversion interface 110 is a general term. It is not necessarily only one interface. It can be an interface that is separately disposed at different positions and connected to the main board 200. They are collectively referred to as the first conversion interface. Figure 2 As shown, the first conversion interface 110 is a 2x8Pin 2mm pitch Wafer connector, which integrates USB2.0 signals, SMBUS signals, power and hard disk indicator signals, etc., for realizing the expansion of other related functions besides display; at the same time, the first conversion interface 110 also includes a DP display signal interface eDP CONN, which can adopt a 2x15Pin vertical BTW connector to connect to the motherboard 200.

[0083] The second conversion interface 150 is also provided on the circuit board for connecting to the display screen 300. Its location can be determined as needed and is not necessarily related to the location of the first conversion interface 110. For example, in order to facilitate the connection with the display screen 300, it can be provided as a gold finger at one edge of the circuit board 200 to facilitate plugging with the display screen 300; or a plug connector can be provided in the middle of one side of the circuit board 200 to connect to the display screen 300 by cable, which is not limited in the embodiment of the present application. Figure 2 In the example, the second conversion interface 150 is LCDB1 CONN. It should be noted that the second conversion interface 150 is a general term, and it is not necessarily only one interface. It can be an interface connected to the display screen 300 and is separately arranged at different positions, and is collectively referred to as a second conversion interface.

[0084] The voltage conversion unit 140 is electrically connected to the first conversion interface 110 and the second conversion interface 150, respectively, and is used to convert the input voltage signal into an output voltage signal, and output the output voltage signal to the display screen 300 through the second conversion interface 150. As mentioned above, the first conversion interface 110 is a general term, and it is not necessarily only one interface. Figure 2As shown, the voltage conversion unit 140 can be directly electrically connected to the output power supply PWR on the mainboard 200 through a lead, and the output PWR on the mainboard 200 can output one voltage signal or multiple voltage signals. In the embodiment of the present application, when converting the EDP signal into an LVDS signal, the output power supply PWR on the mainboard 200 usually outputs a 5V voltage signal and a 3.3V voltage signal. The voltage conversion unit 140 provides power for the display screen 300 on the one hand, and also provides power for each circuit unit on the display screen conversion circuit 100 on the other hand. Therefore, the voltage conversion unit 140 often needs to output multiple voltage signals. For example, when converting the EDP signal into an LVDS signal, the voltage conversion unit 140 needs to output 3.3V and 1.8V voltages to provide power for the signal conversion control unit 130. At the same time, the voltage conversion unit 140 also needs to output 5V and 3.3V voltages to provide power for the display screen 300.

[0085] In order to adapt to display screens with different resolutions, in the embodiment of the present application, a resolution adjustment unit 120 is also provided, and the resolution adjustment unit 120 is electrically connected to the signal conversion control unit 130, and sets resolution information for the display screen 300 to be connected. The resolution adjustment unit 120 can be used in conjunction with the signal conversion control unit 130 to set a suitable resolution for the display screen, or it can be used as an independent unit to set a suitable resolution for the display screen. For example: the resolution adjustment unit 120 can be a dip switch circuit, and the signal conversion control unit 130 stores a variety of resolution information, namely EDID information, for example: the EDID information includes single / dual channel, resolution, number of bits, color depth, etc. According to the type of the display screen to be connected, the resolution adjustment unit can set the corresponding information through the dip switch, and the signal conversion control unit 130 detects the state of the dip switch, and then calls the corresponding EDID information data for the display screen to be connected according to the state of the dip switch.

[0086] The signal conversion control unit 130 can use a general controller or a dedicated signal conversion chip. In the embodiment of the present application, the CS5211 chip can be used. The chip has a built-in MCU, a simple peripheral circuit, and rich functions. Of course, a Pin to Pin chip solution with the same function but different models, such as CH7511, etc., can also be used. In the embodiment of the present application, the CS5211 chip will be used as an example for explanation. The signal conversion control unit 130 is respectively connected to the first conversion interface 110, the second conversion interface 150 and the resolution adjustment unit 120, and is used to convert the first display signal into a second display signal according to the resolution information, and send the second display signal to the display screen 300 through the second conversion interface 150.

[0087] Among them, the display signal conversion function of the CS5211 chip is a signal conversion function commonly used in the prior art; at the same time, the function of the CS5211 chip calling EDID information is also a common function supported by the chip. In the embodiment of the present application, no changes are made to the software function of the chip.

[0088] It can be seen from the above that the display screen conversion circuit provided in the embodiment of the present application, as an independent circuit unit, can realize the connection between the mainboard and different types of display screens to support different types of display screens. There is no need to make any software and hardware changes to the mainboard. It only needs to replace different display screen conversion circuit boards, which can greatly reduce the space occupied by the mainboard. Without changing the hardware and software of the mainboard, it can adapt to different LVDS display screens, solving the problems of high adaptation cost and poor flexibility of different display screens. At the same time, the display screen conversion circuit provided in the embodiment of the present application can set different resolutions for the display screen that needs to be connected to the mainboard according to different parameters, thereby improving the adaptability of the display screen conversion circuit.

[0089] In order to further improve the adaptability to different display screens, such as Figure 3 As shown, in the embodiment of the present application, a circuit structure of a resolution adjustment unit 120 is proposed.

[0090] like Figure 3 As shown, the resolution adjustment unit 130 includes a multi-way dip switch SW and a plurality of pull-up resistors R_SW; the signal conversion control unit 130 includes a plurality of control data ports LVDS_GPIO; one end of each dip switch SW is electrically connected to each control data port LVDS_GPIO, and the other end is grounded; one end of each pull-up resistor R_SW is electrically connected to each control data port LVDS_GPIO, and the other end is connected to a power supply.

[0091] like Figure 3 As shown, the signal conversion control unit 130 is U1, which can use the CS5211 chip. The CS5211 uses two independent power supplies of 3.3V and 1.8V, which are powered by ports VCC3_3 and VCC1_8. Both power supplies can use LC filtering design to effectively filter out the coupling and interference of high-frequency signals on the power supply. The reset signal RESET is pulled up to 1.8V through a 10K resistor R451. Its function is to reset the CS5211 system after the 1.8V power supply is powered on, and the reset pin is connected to a capacitor C339 to prevent interference signals from erroneously triggering the reset signal.

[0092] The CS5211 chip U1 includes four control data ports, LVDS_GPIO0, LVDS_GPIO1, LVDS_GPIO2 and LVDS_GPIO3, which can adapt to 16 different types of display screens. U1 obtains the resolution information set for the display screen through the control data port. Of course, in order to improve the adaptability of the display screen conversion circuit, multiple control data ports can also be set.

[0093] The resolution adjustment unit 130 includes a dip switch SW, which may be a four-way switch, such as Figure 3 As shown, Pin1 and Pin8 are one way, Pin2 and Pin7 are one way, Pin3 and Pin6 are one way, Pin4 and Pin5 are one way, and the dip switches represent different resolution information in different positions. In order to improve the accuracy of the dip switch SW, in the embodiment of the present application, a pull-up resistor R_SW is set at each control data port LVDS_GPIO, one end of each pull-up resistor R_SW is electrically connected to each control data port LVDS_GPIO, and the other end is electrically connected to VCC3_3. The pull-up resistor R_SW can be 10K. Through the dip switch, the connection and disconnection of each switch can be controlled, so that a 4-bit LVDS_GPIO[0:3] data signal can be generated. CS5211 detects these 4-bit GPIOs and can set the output of up to 16 different EDIDs in the firmware to adapt to different types of display screens.

[0094] The embodiment of the present application can conveniently and accurately set the resolution information of the display screen to be connected by setting a multi-way DIP switch SW and multiple pull-up resistors R_SW, so that the display screen conversion circuit can adapt to a variety of different types of display screens, greatly improving the adaptability of the display screen conversion circuit.

[0095] Continue to refer Figure 3 The embodiment of the present application further provides a circuit structure diagram of the first conversion interface 110 and the second conversion interface 150.

[0096] like Figure 3 As shown, the signal conversion control unit 130 includes a plurality of first display signal input ports DDI_TP0, DDI_TN0, DDI_TP1, DDI_TN1, DDI_AUXP and DDI_AUXN; the first conversion interface includes a plurality of coupling capacitors C1, C2, C3, C4, C5 and C6.

[0097] like Figure 3As shown, one end of the coupling capacitor C1 is connected to the EDP_TXP0_C of the mainboard 200, and the other end is connected to the DDI_TP0 port; one end of the coupling capacitor C2 is connected to the EDP_TXN0_C of the mainboard 200, and the other end is connected to the DDI_TN0 port; one end of the coupling capacitor C3 is connected to the EDP_TXP1_C of the mainboard 200, and the other end is connected to the DDI_TP1 port; one end of the coupling capacitor C4 is connected to the EDP_TXN1_C of the mainboard 200, and the other end is connected to the DDI_TN1 port; one end of the coupling capacitor C5 is connected to the EDP_AUXP_C of the mainboard 200, and the other end is connected to the DDI_AUXP port; one end of the coupling capacitor C6 is connected to the EDP_AUXN_C of the mainboard 200, and the other end is connected to the DDI_AUXN port, wherein the coupling capacitor can be 0.1uF.

[0098] The signal conversion control unit 130 also includes a second display signal output port LVDS_D0P~LVDS_D7P, LVDS_D0N~LVDS_D7N, wherein LVDS_D0P and LVDS_D0N form a differential pair, LVDS_D1P and LVDS_D1N form a differential pair, LVDS_D2P and LVDS_D2N form a differential pair, LVDS_D3P and LVDS_D3N form a differential pair, LVDS_D4P and LVDS_D4N form a differential pair, LVDS_D5P and LVDS_D5N form a differential pair, LVDS_D5P and LVDS_D5N form a differential pair, and LVDS_D7P and LVDS_D7N form a differential pair; the second conversion interface includes a plurality of matching resistors R17~R28, whose resistance can be set to 100 ohms.

[0099] Both ends of each matching resistor are electrically connected to the second display signal output port forming a differential pair, such as Figure 3 As shown, R17 is set between the differential pair LVDS_D0P and LVDS_D0N, R18 is set between the differential pair LVDS_D1P and LVDS_D1N, and so on.

[0100] The embodiment of the present application reduces the reflection of high-speed signals by setting coupling capacitors and matching resistors, ensures the integrity of the signals, and makes the signals of the first conversion interface and the second conversion interface more stable.

[0101] In order to make the display conversion circuit able to connect to different types of display screens, in addition to considering the resolution of the display screen, it is also necessary to consider the voltage supported by the display screen. Different display screens require different voltages, so the display conversion circuit needs to provide multiple voltage output solutions. Figure 4a , Figure 4b and Figure 4cAs shown, a circuit diagram of the voltage conversion unit 140 proposed in an embodiment of the present application is shown.

[0102] like Figure 4a As shown, a circuit diagram for providing a 3.3V voltage to a display screen is shown. In the embodiment of the present application, the voltage conversion unit 140 includes a first voltage input terminal VCC5, a second voltage input terminal VCC3_3SB, a first N-channel MOS transistor Q8, a second P-channel MOS transistor Q7 and a first voltage output terminal VCC3_3; the first voltage input terminal VCC5 and the second voltage input terminal VCC3_3SB are electrically connected to the mainboard through the first conversion interface respectively; the gate of the first N-channel MOS transistor Q8 is electrically connected to the first voltage input terminal VCC5, the source of the first N-channel MOS transistor Q8 is grounded, and the first N-channel The drain of the second P-channel MOS transistor Q8 is electrically connected to the second voltage input terminal VCC3_3SB; the gate of the second P-channel MOS transistor Q7 is electrically connected to the drain of the first N-channel MOS transistor Q8, the source of the second P-channel MOS transistor Q7 is electrically connected to the second voltage input terminal VCC3_3SB, the drain of the second P-channel MOS transistor Q7 is electrically connected to the first voltage output terminal VCC3_3, and the first voltage output terminal VCC3_3 is electrically connected to the display screen through the second conversion interface, so as to provide an output voltage signal for the display screen.

[0103] The first voltage input terminal VCC5 and the second voltage input terminal VCC3_3SB are used to receive the voltage output on the mainboard 200. The mainboard 200 provides 3.3V and 5V voltage inputs for the display screen conversion circuit 100. The first voltage input terminal VCC5 is the 5V voltage output after the mainboard 200 is started, and the second voltage input terminal VCC3_3SB is the 3.3V standby voltage of the mainboard. In practice, the display screen conversion circuit requires voltage input on the one hand, and the display screen also requires corresponding voltage input on the other hand. Therefore, the display screen conversion circuit needs to convert the voltage signal input from the mainboard.

[0104] like Figure 4aAs shown, when the 5V voltage provided by the mainboard 200 is powered on through the first voltage input terminal VCC5, it is divided by R104 and R118. Since the gate of the first N-channel MOS transistor Q8 is connected to VCC5 through R104, when the voltage across R118 after the voltage division is greater than the threshold voltage of the first N-channel MOS transistor Q8, the first N-channel MOS transistor Q8 is turned on, one end of the resistor R103 is equivalent to being connected to the ground, and the gate of the second P-channel MOS transistor Q7 is pulled down to the ground through R103. Since the source of the second P-channel MOS transistor Q7 is connected to the second voltage input terminal VCC3_3SB, the second P-channel MOS transistor Q7 is turned on, and the drain of the second P-channel MOS transistor Q7 outputs a voltage of 3.3V through the first voltage output terminal VCC3_3, wherein the filter capacitors C37 and C38 are used to filter the output current.

[0105] When the mainboard 200 is not powered on, that is, when the 5V voltage is not output through the first voltage input terminal VCC5, the mainboard 200 only provides a 3.3V standby voltage through the second voltage input terminal VCC3_3SB. At this time, the first N-channel MOS transistor Q8 and the second P-channel MOS transistor Q7 are both in the cut-off state. Therefore, the first voltage output terminal VCC3_3 has no voltage output.

[0106] The above embodiment well realizes the output control of 3.3V voltage by providing the first N-channel MOS transistor Q8 and the second P-channel MOS transistor Q7. The circuit structure is simple and the consumption of 3.3V standby voltage is avoided when the mainboard 200 is not powered on.

[0107] Furthermore, since the signal conversion control unit 130 requires a 1.8V power supply, the display screen conversion circuit 100 also needs to provide a 1.8V voltage output. Figure 4b The voltage conversion circuit diagram shown further provides a 1.8V voltage output circuit. Figure 4b In the figure, VCC3_3 is input from Pin3 of the voltage regulator chip U54 and connected to the ground by the decoupling capacitor C552. Pin2 is the enable pin. After VCC3_3 is divided by the voltage divider resistors R678 and R690, it is ensured that the output of the VCC1.8 voltage at the R690 end is later than the output of VCC3_3 and is input to the Pin2 enable end. Pin1 is the power ready signal connected to VCC3_3 through R670. When VCC1_8 is output normally, Pin1 will be set high; Pin6 is the output pin of VCC1_8, connected to the filter capacitors C550 and C551, and after the feedback resistors R671 and R672 divide the voltage, it is connected to the feedback pin Pin7. The output voltage VCC1_8 is calculated by the formula Vout = (16.2k + 12.7k) * 0.8 / 12.7k = 1.8V.

[0108] Furthermore, Figure 4c The circuit diagram is for providing voltage to a display screen. In practical applications, different types of display screens require different voltages. Therefore, the display screen conversion circuit needs to provide different output voltages for different types of display screens as needed.

[0109] exist Figure 4c In the embodiment, the voltage conversion unit 140 further includes a second voltage output terminal VDD_LCD, a third N-channel MOS transistor Q14, a fourth P-channel MOS transistor Q13 and a selection switch JP7; the signal conversion control unit 130 includes a display screen power enable port LVDS_VDDEN.

[0110] The gate of the third N-channel MOS transistor Q14 is electrically connected to the display screen power enable port LVDS_VDDEN, the source of the third N-channel MOS transistor Q14 is grounded, and the drain of the third N-channel MOS transistor Q14 is electrically connected to the first voltage input terminal VCC5; the gate of the fourth P-channel MOS transistor Q13 is connected to the drain of the third N-channel MOS transistor Q14, and the drain of the fourth P-channel MOS transistor Q13 is electrically connected to the selection switch JP7; the source of the fourth P-channel MOS transistor Q13 is ... gate of the fourth P-channel MOS transistor Q13 is connected to the drain of the third N-channel MOS transistor Q14, and the drain of the fourth P-channel MOS transistor Q13 is electrically connected to the selection switch JP7; the gate of the fourth P-channel MOS transistor Q13 is connected to the drain of the third N-channel MOS transistor Q14, and the drain of the fourth P-channel MOS transistor Q13 is electrically connected to the selection switch JP7; the gate of the fourth P- The second voltage output terminal VDD_LCD is electrically connected; the second voltage output terminal VDD_LCD is electrically connected to the display screen through the second conversion interface, and is used to provide the output voltage signal for the display screen; the selection switch JP7 includes a first terminal Pin1, a second terminal Pin2 and a third terminal Pin3, the first terminal Pin1 is electrically connected to the first voltage input terminal VCC5, the third terminal Pin3 is electrically connected to the first voltage output terminal VCC3_3, and the second terminal Pin2 is electrically connected to the drain of the fourth P-channel MOS tube Q13.

[0111] When the signal conversion control unit 130 outputs a display screen power enable signal through the display screen power enable port LVDS_VDDEN, the third N-channel MOS transistor Q14 and the fourth P-channel MOS transistor Q13 are turned on, and the voltage of the second end Pin2 of the selection switch JP7 is the voltage of the second voltage output end VDD_LCD; when the first end Pin1 and the second end of the selection switch JP7 are turned on, the voltage of the second voltage output end VDD_LCD is the voltage of the first voltage input end VCC5; when the third end Pin3 and the second end of the selection switch JP7 are turned on, the voltage of the second voltage output end VDD_LCD is the voltage of the first voltage output end VCC3_3.

[0112] Please refer to Figure 3 and Figure 4c The display screen conversion circuit 100 provides power supply to the display screen 300 through the second voltage output terminal VDD_LCD. The selection switch JP7 can be a single-pole double-throw switch or a jumper selection switch. Its first end is Pin1, the second end is Pin2, and the third end is Pin3. Its Pin1 is connected to VCC5 to provide 5V power supply, and Pin3 is connected to VCC3_3 to provide 3.3V power supply. When the mainboard 200 is started, the signal conversion control unit 130 controls the power supply to the display screen through the display screen power enable port LVDS_VDDEN. When the mainboard 200 is powered on and needs to provide power to the display screen, the signal conversion control unit 130 outputs a high level through the display screen power enable port LVDS_VDDEN, the third N-channel MOS transistor Q14 is turned on, VCC5 is grounded through R706, and the gate of the fourth P-channel MOS transistor Q13 is low level. Therefore, the fourth P-channel MOS transistor Q13 is turned on, and VDD_LCD is connected to the second end Pin2 of the selection switch JP7, that is, the voltage of VDD_LCD is the same as the voltage of the second end Pin2. When Pin1 and Pin2 of the selection switch JP7 are connected, a 5V voltage is provided to Pin2; when Pin3 and Pin2 of the selection switch JP7 are connected, a 3.3V voltage is provided to Pin2. That is, when the signal conversion control unit 130 provides a high level signal through the display screen power enable port LVDS_VDDEN, the user can choose to provide a 3.3 or 5V voltage output to the display screen through the selection switch JP7.

[0113] The embodiment of the present application can control the power supply to the display screen through the display screen power enable port LVDS_VDDEN, and at the same time, different output voltages can be selected for the display screen through the selection switch JP7 to meet the needs of LVDS display screens with different voltages, thereby greatly improving the adaptability of the display screen conversion circuit.

[0114] Further, such as Figure 2 , Figure 3 and Figure 5 As shown, in order to control the backlight of the display screen, the display screen conversion circuit proposed in the embodiment of the present application also includes a backlight adjustment unit 160, and the backlight adjustment unit 160 includes a fifth N-channel MOS transistor Q2, a sixth N-channel MOS transistor Q3 and a seventh N-channel MOS transistor Q11.

[0115] like Figure 3 As shown, the signal conversion control unit 130 includes an EDP backlight enable control port EDP_BKLT_ON, an LVDS backlight enable control port CS5211_BKLT_EN and a display backlight switch control port BL_SHUT; the second conversion interface also includes an LVDS backlight control interface LCDB2.

[0116] like Figure 5 As shown, EDP_BKLT_ON is electrically connected to the gate of the fifth N-channel MOS transistor Q2 through R128, the source of the fifth N-channel MOS transistor Q2 is grounded, the drain of the fifth N-channel MOS transistor Q2 is electrically connected to the gate of the sixth N-channel MOS transistor Q3, and is connected to VCC5 through R96; the source of the sixth N-channel MOS transistor Q3 is grounded, the drain of the sixth N-channel MOS transistor Q3 is electrically connected to the LVDS backlight control interface LCDB2, and is connected to VCC5 through a pull-up resistor R97, and C49 and C51 are filter capacitors.

[0117] The LVDS backlight enable control port CS5211_BKLT_EN is electrically connected to the source of the seventh N-channel MOS transistor Q11 through R34, and the gate of the seventh N-channel MOS transistor Q11 is connected to the power supply through R127, wherein R33 is a pull-up resistor and C50 is a filter capacitor. The drain of the seventh N-channel MOS transistor Q11 is electrically connected to the drain of the sixth N-channel MOS transistor Q3 and the LVDS backlight control interface LCDB2 respectively; the display screen backlight switch control port BL_SHUT is used to receive the display screen backlight switch control signal, and output the LVDS backlight enable control signal through the LVDS backlight enable control port CS5211_BKLT_EN. The Pin1 pin of the LVDS backlight control interface LCDB2 is grounded through a capacitor C556.

[0118] In practice, when controlling the backlight of a display screen, there are multiple shutdown control requirements. One is the control requirement from the motherboard 200, such as controlling the shutdown of the display screen through the DP interface; the other is the user's operation, such as shutting down the display screen through a switch button.

[0119] In order to meet various control requirements, in the embodiment of the present application, the signal conversion control unit 130 issues a control instruction through the EDP backlight enable control port EDP_BKLT_ON according to the instruction of the mainboard 200. CS5211_BKLT_EN is a shutdown signal output by the signal conversion control unit 130 through the LVDS backlight enable control port CS5211_BKLT_EN after receiving a shutdown signal through the display backlight switch control port BL_SHUT according to the key operation of the user.

[0120] like Figure 5As shown, when the signal conversion control unit 130 sends a low level signal through the EDP backlight enable control port EDP_BKLT_ON according to the instruction of the mainboard 200, the fifth N-channel MOS transistor Q2 and the sixth N-channel MOS transistor Q3 are turned on, VCC5 is grounded through R97, the voltage of Pin3 of the sixth N-channel MOS transistor Q3 is low level, the Pin3 pin of the LVDS backlight control interface LCDB2 is low level, and the display screen is turned off.

[0121] When the signal conversion control unit 130 detects that the user presses the shutdown button according to the user's key operation, it receives the display backlight switch control signal through the display backlight switch control port BL_SHUT, and outputs a low-level signal through the LVDS backlight enable control port CS5211_BKLT_EN. When CS5211_BKLT_EN outputs a low-level signal, the seventh N-channel MOS transistor Q11 is turned on, and the Pin3 pin of the seventh N-channel MOS transistor Q11 outputs a low level, and the display screen is turned off.

[0122] like Figure 5 As shown, since the drain of the sixth N-channel MOS transistor Q3 and the drain of the seventh N-channel MOS transistor Q11 are both connected to the Pin3 pin of the LVDS backlight control interface LCDB2, which is equivalent to being connected to the Pin3 pin of the LVDS backlight control interface LCDB2 in a logical AND relationship, when the mainboard 200 or any key pressed by the user sends a display screen off signal, the backlight of the LVDS display screen will be turned off. In this way, the control of the display screen backlight is improved and the control efficiency is improved.

[0123] Furthermore, in order to adjust the brightness of the backlight of the display screen, the embodiment of the present application also provides a control circuit diagram, such as Figure 3 and Figure 5 As shown, the backlight adjustment unit also includes an eighth N-channel MOS transistor Q12; the signal conversion control unit 130 also includes a PWM signal output port CS5211_PWM_OUT; the source of the eighth N-channel MOS transistor Q12 is electrically connected to the PWM signal output port CS5211_PWM_OUT, the gate of the eighth N-channel MOS transistor Q12 is connected to the power supply, and the drain of the eighth N-channel MOS transistor Q12 is electrically connected to the LVDS backlight control interface LCDB2; the signal conversion control unit 130 adjusts the backlight of the display screen through the PWM signal output port CS5211_PWM_OUT.

[0124] The CS5211_PWM_OUT signal is a PWM control signal sent by the signal conversion control unit 130. The signal conversion control unit 130 adjusts the backlight brightness of the display screen by adjusting the duty cycle of the PWM control signal. The PWM signal output port CS5211_PWM_OUT is electrically connected to the source of the eighth N-channel MOS transistor Q12 through R702, VCC3_3 is electrically connected to the gate of the eighth N-channel MOS transistor Q12 through R703, and is electrically connected to the source of the eighth N-channel MOS transistor Q12 through R704.

[0125] When CS5211_PWM_OUT outputs a low level, that is, the source of the eighth N-channel MOS transistor Q12 is at a low level, the eighth N-channel MOS transistor Q12 is turned on, and the drain of the eighth N-channel MOS transistor Q12 is also at a low level, and a low level is output to the LVDS backlight control interface LCDB2. When CS5211_PWM_OUT outputs 3.3V, that is, the source of the eighth N-channel MOS transistor Q12 is 3.3V, the eighth N-channel MOS transistor Q12 is turned off, and the drain voltage of the eighth N-channel MOS transistor Q12 is pulled up to 5V through VCC5, that is, a high level 5V is output to the LVDS backlight control interface LCDB2. In order to prevent the eighth N-channel MOS transistor Q12 from being burned out due to excessive impact current, an RC delay circuit R703 and C557 are added to the gate of the eighth N-channel MOS transistor Q12 to extend the opening time of the eighth N-channel MOS transistor Q12 and reduce the impact current. Through the above circuit, the signal conversion control unit 130 can adjust the backlight of the display screen.

[0126] In order to better control the display screen, such as Figure 2 , Figure 3 and Figure 6 As shown, the embodiment of the present application provides a backlight adjustment button unit 170; the backlight adjustment button unit 170 includes a switch button K1, an increase button K3 and a decrease button K2; the signal conversion control unit 130 also includes a display backlight increase port BL_UP and a display backlight decrease port BL_DOWN.

[0127] The switch button K1 is electrically connected to the display backlight switch control port BL_SHUT, the increase button K3 is electrically connected to the display backlight increase port BL_UP, and the decrease button K2 is electrically connected to the display backlight decrease port BL_DOWN.

[0128] When the signal conversion control unit 130 receives the key operation of the switch key K1, it controls the LVDS backlight enable control port CS5211_BKLT_EN; when the signal conversion control unit 130 receives the key operation of the increase key K3 or the decrease key K2, it controls the output of the PWM signal output port CS5211_PWM_OUT.

[0129] like Figure 6 As shown, one end of each switch button K1, K2 and K3 is grounded, and the other end is connected to the 3.3V voltage through the pull-up resistors R1, R2 and R3 respectively, and is electrically connected to the corresponding port of the signal conversion control unit 130. When the switch button is pressed, the pins at both ends of the button will be short-circuited to the ground, that is, the key input signal connected to the signal conversion control unit is low level; when the button is released, the signal is input to a high level through the 10K pull-up resistor, and the capacitors C564, C562 and C563 are connected in parallel to the ground, which is used to eliminate jitter interference of the key signal and avoid misjudgment.

[0130] When the user presses the switch button K1, the signal conversion control unit 130 controls the switch of the display screen through the LVDS backlight enable control port CS5211_BKLT_EN;

[0131] When the user presses the decrease button K2, the signal conversion control unit 130 controls the output of the PWM signal output port CS5211_PWM_OUT to gradually reduce the duty cycle of PWM and gradually dim the backlight of the display screen.

[0132] When the user presses the decrease button K3, the signal conversion control unit 130 controls the output of the PWM signal output port CS5211_PWM_OUT to gradually increase the duty cycle of PWM and gradually brighten the backlight of the display screen.

[0133] Furthermore, in order to better display the status of the display screen, such as Figure 2 , Figure 3 and Figure 7 As shown, the display screen conversion circuit proposed in the embodiment of the present application also includes a backlight indication unit 180; the backlight indication unit 180 includes an NPN transistor Q6 and an indicator light BL_LED; the base of the NPN transistor Q6 is electrically connected to the LVDS backlight enable control port CS5211_BKLT_EN through R681, the emitter of the NPN transistor Q6 is grounded, the collector of the NPN transistor Q6 is electrically connected to the indicator light BL_LED, and is connected to VCC3_3 through a resistor R680, R680 can be 100 ohms, and is used to prevent BL_LED from burning due to excessive current when Q6 is turned on.

[0134] When the display backlight is working normally, the LVDS backlight enable control port CS5211_BKLT_EN will be set high, the NPN transistor Q6 will be turned on, and the indicator light BL_LED will be lit. Here, the indicator light BL_LED is controlled by the LVDS backlight enable control port CS5211_BKLT_EN, because when the backlight of the display is turned on, the indicator light will be lit together. Therefore, the two share the LVDS backlight enable control port CS5211_BKLT_EN for control, which simplifies the control process and ensures the accuracy of the indicator light control.

[0135] Meanwhile, the display screen conversion circuit 100 may also include other indicator lights, such as a power indicator light, a hard disk indicator light, etc., which will not be described in detail here.

[0136] In practical applications, different types of display screens support different functions. For example, some display screens have a touch function. In order to further expand the function of the display screen conversion circuit, the display screen conversion circuit proposed in the embodiment of the present application further includes a touch function control unit 190, such as Figure 2 and Figure 8 As shown, the touch function control unit 190 is electrically connected to the signal conversion control unit 130 and the second conversion interface 150, and includes a power management chip U5 and a USB interface J4.

[0137] The power management chip U5 may be a TPS2052 chip, which is a power management integrated circuit widely used in various electronic devices, including laptops, tablet computers, smart phones, and other portable devices that require USB fast charging. The USB interface J4 is used to connect to the touch function power interface of the display screen 300 to power the touch function of the display screen.

[0138] The specific circuit structure is as follows: Figure 8 As shown, the enable ports EN1 and EN2 of the power management chip U5 are electrically connected to the LVDS backlight enable control port CS5211_BKLT_EN of CS5211 through the resistor R683, and CS5211 sends a control instruction to the power management chip U5 through the CS5211_BKLT_EN port. In the embodiment of the present application, the power management chip U5 is controlled through the CS5211_BKLT_EN port, which can be synchronized with the backlight switch and the power indication, indicating that as long as the display screen is powered on, power needs to be provided for the touch function of the display screen. This control method is in line with actual usage, shares the same control pin, and simplifies the circuit structure.

[0139] When CS5211 provides a high-level enable signal to the power management chip U5 through the CS5211_BKLT_EN port, the power management chip U5 is powered on and enabled, so that VCC and OUT1 and OUT2 are turned on, that is, VCC5 outputs voltage through OUT1 and OUT2, and the OUT1 and OUT2 pins of the power management chip U5 are connected to Pin1 of the USB interface J4 through the magnetic bead FB10, so that when the display is connected to the USB interface J4, power is supplied to the touch function and the touch function of the display is started. Among them, the magnetic bead FB10 is used to filter the output current; the VCC5 is grounded through the filter capacitor C35, which can provide a more stable voltage for VCC.

[0140] When CS5211 provides a low level to the power management chip U5 through the CS5211_BKLT_EN port, the power management chip U5 is in the cut-off state, so that VCC and OUT1, OUT2 are disconnected, that is, VCC5 cannot output voltage through OUT1 and OUT2, and Pin1 of the USB interface J4 cannot power the touch function of the display.

[0141] By supplying power to the touch screen in the above manner, the circuit structure is simplified, the function of the display screen conversion circuit is expanded, and various types of display screens can be better supported.

[0142] Some embodiments of the present application further provide an industrial computer, comprising a mainboard, a display screen, and a display screen conversion circuit provided in the above embodiments; the display screen conversion circuit is used to electrically connect the mainboard with the display screen. The display screen conversion circuit is not described in detail here.

[0143] In summary, the display screen conversion circuit and industrial computer provided in the embodiment of the present application can realize the connection between the mainboard and different types of display screens to support different types of display screens. There is no need to make any software and hardware changes to the mainboard. Only different display screen conversion circuit boards need to be replaced, which can greatly reduce the space occupied by the mainboard. Without changing the hardware and software of the mainboard, it can adapt to different LVDS display screens, solving the problems of high adaptation cost and poor flexibility of different display screens. At the same time, the display screen conversion circuit and industrial computer provided in the embodiment of the present application can set different resolutions for the display screen that needs to be connected to the mainboard according to different parameters, thereby improving the adaptability of the display screen conversion circuit.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A display screen conversion circuit for connecting a circuit board and a display screen, characterized in that: include: A circuit board, a first conversion interface, a second conversion interface, a voltage conversion unit, a resolution adjustment unit and a signal conversion control unit; The first conversion interface is arranged on the circuit board, and is used to connect to the mainboard and obtain the first display signal and the input voltage signal from the mainboard; The second conversion interface is arranged on the circuit board and is used to connect with the display screen; The voltage conversion unit is electrically connected to the first conversion interface and the second conversion interface respectively, converts the input voltage signal into an output voltage signal, and outputs the output voltage signal to the display screen through the second conversion interface; The resolution adjustment unit is electrically connected to the signal conversion control unit to set resolution information for the display screen; The signal conversion control unit is electrically connected to the first conversion interface, the second conversion interface and the resolution adjustment unit respectively, and is used to convert the first display signal into a second display signal according to the resolution information, and send the second display signal to the display screen through the second conversion interface.

2. The display screen conversion circuit according to claim 1, characterized in that: The resolution adjustment unit includes a multi-way DIP switch SW and a plurality of pull-up resistors R_SW; the signal conversion control unit includes a plurality of control data ports LVDS_GPIO; One end of each of the dip switches SW is electrically connected to each of the control data ports LVDS_GPIO, and the other end is grounded; One end of each pull-up resistor R_SW is electrically connected to each control data port LVDS_GPIO, and the other end is connected to a power source.

3. The display screen conversion circuit according to claim 1, characterized in that: The signal conversion control unit includes a plurality of first display signal input ports; the first conversion interface includes a plurality of coupling capacitors; One end of each of the coupling capacitors is respectively used to be connected to the mainboard, and the other end is respectively electrically connected to each of the first display signal input ports; The signal conversion control unit further includes a plurality of second display signal output ports, and the plurality of second display signal output ports form a differential pair; the second conversion interface includes a plurality of matching resistors; Two ends of each matching resistor are electrically connected to the second display signal output port forming a differential pair.

4. The display screen conversion circuit according to claim 1, characterized in that: The voltage conversion unit includes a first voltage input terminal VCC5, a second voltage input terminal VCC3_3SB, a first N-channel MOS transistor Q8, a second P-channel MOS transistor Q7 and a first voltage output terminal VCC3_3; The first voltage input terminal VCC5 and the second voltage input terminal VCC3_3SB are respectively electrically connected to the mainboard through the first conversion interface; The gate of the first N-channel MOS transistor Q8 is electrically connected to the first voltage input terminal VCC5, the source of the first N-channel MOS transistor Q8 is grounded, and the drain of the first N-channel MOS transistor Q8 is electrically connected to the second voltage input terminal VCC3_3SB; The gate of the second P-channel MOS transistor Q7 is electrically connected to the drain of the first N-channel MOS transistor Q8, the source of the second P-channel MOS transistor Q7 is electrically connected to the second voltage input terminal VCC3_3SB, and the drain of the second P-channel MOS transistor Q7 is electrically connected to the first voltage output terminal VCC3_3; The first voltage output terminal VCC3_3 is electrically connected to the display screen through the second conversion interface, and is used to provide the output voltage signal to the display screen.

5. The display screen conversion circuit according to claim 4, characterized in that: The voltage conversion unit further includes a second voltage output terminal VDD_LCD, a third N-channel MOS transistor Q14, a fourth P-channel MOS transistor Q13 and a selection switch JP7; The signal conversion control unit includes a display screen power enable port LVDS_VDDEN; The gate of the third N-channel MOS transistor Q14 is electrically connected to the display screen power enable port LVDS_VDDEN, the source of the third N-channel MOS transistor Q14 is grounded, and the drain of the third N-channel MOS transistor Q14 is electrically connected to the first voltage input terminal VCC5; The gate of the fourth P-channel MOS transistor Q13 is connected to the drain of the third N-channel MOS transistor Q14, and the drain of the fourth P-channel MOS transistor Q13 is electrically connected to the selection switch JP7; the source of the fourth P-channel MOS transistor Q13 is electrically connected to the second voltage output terminal VDD_LCD; The second voltage output terminal VDD_LCD is electrically connected to the display screen through the second conversion interface, and is used to provide the output voltage signal to the display screen; The selection switch JP7 includes a first end, a second end and a third end, the first end is electrically connected to the first voltage input end VCC5, the third end is electrically connected to the first voltage output end VCC3_3, and the second end is electrically connected to the drain of the fourth P-channel MOS transistor Q13; When the signal conversion control unit outputs a display screen power enable signal through the display screen power enable port LVDS_VDDEN, the third N-channel MOS transistor Q14 and the fourth P-channel MOS transistor Q13 are turned on, and the voltage at the second end of the selection switch JP7 is the voltage of the second voltage output end VDD_LCD; when the first end and the second end of the selection switch JP7 are turned on, the voltage of the second voltage output end VDD_LCD is the voltage of the first voltage input end VCC5; when the third end and the second end of the selection switch JP7 are turned on, the voltage of the second voltage output end VDD_LCD is the voltage of the first voltage output end VCC3_3.

6. The display screen conversion circuit according to claim 4, characterized in that: Also includes a backlight adjustment unit; The backlight adjustment unit includes a fifth N-channel MOS transistor Q2, a sixth N-channel MOS transistor Q3 and a seventh N-channel MOS transistor Q11; The signal conversion control unit includes an EDP backlight enable control port EDP_BKLT_ON, an LVDS backlight enable control port CS5211_BKLT_EN and a display backlight switch control port BL_SHUT; The second conversion interface also includes an LVDS backlight control interface LCDB2; The gate of the fifth N-channel MOS transistor Q2 is electrically connected to the EDP backlight enable control port EDP_BKLT_ON, the source of the fifth N-channel MOS transistor Q2 is grounded, and the drain of the fifth N-channel MOS transistor Q2 is electrically connected to the gate of the sixth N-channel MOS transistor Q3; The source of the sixth N-channel MOS transistor Q3 is grounded, and the drain of the sixth N-channel MOS transistor Q3 is electrically connected to the LVDS backlight control interface LCDB2; The source of the seventh N-channel MOS transistor Q11 is electrically connected to the LVDS backlight enable control port CS5211_BKLT_EN, the gate of the seventh N-channel MOS transistor Q11 is connected to the first voltage output terminal VCC3_3, and the drain of the seventh N-channel MOS transistor Q11 is electrically connected to the drain of the sixth N-channel MOS transistor Q3 and the LVDS backlight control interface LCDB2 respectively; The display screen backlight switch control port BL_SHUT is used to receive a display screen backlight switch control signal, and output an LVDS backlight enable control signal through the LVDS backlight enable control port CS5211_BKLT_EN.

7. The display screen conversion circuit according to claim 6, characterized in that: The backlight adjustment unit further includes an eighth N-channel MOS transistor Q12; The signal conversion control unit also includes a PWM signal output port CS5211_PWM_OUT; The source of the eighth N-channel MOS transistor Q12 is electrically connected to the PWM signal output port CS5211_PWM_OUT, the gate of the eighth N-channel MOS transistor Q12 is connected to the first voltage output terminal VCC3_3, and the drain of the eighth N-channel MOS transistor Q12 is electrically connected to the LVDS backlight control interface LCDB2; The signal conversion control unit adjusts the backlight of the display screen through the PWM signal output port CS5211_PWM_OUT.

8. The display screen conversion circuit according to claim 7, characterized in that: Also includes a backlight adjustment button unit; The backlight adjustment button unit includes a switch button K1, a decrease button K2 and an increase button K3; The signal conversion control unit also includes a display backlight increase port BL_UP and a display backlight decrease port BL_DOWN; The switch button K1 is electrically connected to the display backlight switch control port BL_SHUT, the increase button K3 is electrically connected to the display backlight increase port BL_UP, and the decrease button K2 is electrically connected to the display backlight decrease port BL_DOWN; When the signal conversion control unit receives the key operation of the switch key K1, it is used to control the LVDS backlight enable control port CS5211_BKLT_EN; when the signal conversion control unit receives the key operation of the increase key K3 or the decrease key K2, it is used to control the output of the PWM signal output port CS5211_PWM_OUT.

9. The display screen conversion circuit according to claim 8, characterized in that: Also includes a backlight indication unit; The backlight indication unit includes an NPN transistor Q6 and an indicator light BL_LED; The base of the NPN transistor Q6 is electrically connected to the LVDS backlight enable control port CS5211_BKLT_EN, the emitter of the NPN transistor Q6 is grounded, and the collector of the NPN transistor Q6 is electrically connected to the indicator light BL_LED.

10. An industrial computer, characterized in that: It comprises a mainboard, a display screen and a display screen conversion circuit as claimed in any one of claims 1 to 9; The display screen conversion circuit is used to electrically connect the mainboard with the display screen.

Images