CN-121982998-A - Multi-screen compatible embedded main board circuit system and display self-adaption method thereof

CN121982998ACN 121982998 ACN121982998 ACN 121982998ACN-121982998-A

Abstract

The invention relates to the technical field of electronics related to a display driving printed circuit, in particular to a multi-screen compatible embedded main board circuit system and a display self-adapting method thereof. Wherein, a set of multiplexing signal pins of the main control chip are electrically connected to the first display interface and the second display interface at the same time, and respond to the software configuration to directly drive one of them. The configurable screen power module provides a plurality of selectable operating voltages for the second display interface through selection of the physical device. The method comprises the steps of physically configuring the screen power supply voltage, configuring the pin working mode by software and the like. The invention can make a single main board hardware platform compatible with display screens with different interface standards and power supply specifications by utilizing the pin multiplexing function built in the main control chip and combining with a hardware configurable power supply scheme under the condition of not adding an external protocol conversion chip.

Inventors

YANG WEI
WANG JINLIANG
ZHU ZHANGYONG

Assignees

广州佩特电子科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260123

Claims (10)

1. A multi-screen compatible embedded motherboard circuit system, comprising: a main control chip; the display interface module comprises at least one first display interface and at least one second display interface, and the first display interface and the second display interface are respectively used for connecting display screens conforming to a first display standard and a second display standard; The main control chip comprises a first display interface, a second display interface, a first multiplexing signal pin, a second multiplexing signal pin, a first control module and a second control module, wherein the first multiplexing signal pin is electrically connected to the signal end of the first display interface and the signal end of the second display interface at the same time, and is configured to respond to software configuration and selectively work in a first working mode or a second working mode so as to respectively output display signals conforming to the first display standard or the second display standard, thereby directly driving the first display interface or the second display interface; The system also comprises a configurable screen power supply module, wherein the configurable screen power supply module comprises: at least two power rails respectively carrying different voltage values; The input ends of the power supply selection interface are respectively and electrically connected with the at least two power supply rails, and the output ends of the power supply selection interface are electrically connected with a power supply pin of the second display interface; The power supply selection interface is used for selecting one of the plurality of input ends to be conducted with the output end through the plug-in or short-circuit of the physical device so as to provide the required working voltage for the display screen connected to the second display interface.
2. The multi-screen compatible embedded motherboard circuitry of claim 1 wherein the first display interface is a MIPI-DSI interface and the second display interface is an LVDS interface, the power selection interface is a multi-pin jumper pin, the physical device is a jumper cap, and the at least two power rails comprise at least two of 3.3 volt, 5 volt, and 12 volt power rails.
3. The multi-screen compatible embedded motherboard circuitry of claim 2 further comprising a touch screen interface, said touch screen interface comprising: A touch screen connector; The power noise isolation circuit comprises a pi-type filter network, wherein the pi-type filter network is composed of magnetic beads connected in series between a system power supply and a power supply pin of the touch screen connector and two capacitors respectively positioned between two ends of the magnetic beads and the ground, and is used for inhibiting power noise generated by a high-speed digital signal of the display interface module from being conducted to the touch screen connector.
4. The multi-screen compatible embedded motherboard circuitry of claim 2 further comprising a main logic power control circuit for the second display interface, the main logic power control circuit comprising: the power switch tube is connected in series between a system power supply and a logic power supply output end for supplying power to a display screen connected with the second display interface; The on and off of the control triode is controlled by an enabling signal from the main control chip, and the output end of the control triode is connected with the control electrode of the power switch tube; and a pull-down resistor for providing default low-level bias is also connected between the base electrode of the control triode and the ground so as to ensure that the control triode is kept in a cut-off state when the enabling signal is in a high-resistance state, thereby enabling the power switch tube to be in a cut-off state.
5. The multi-screen compatible embedded motherboard circuit system of claim 4 wherein a capacitor is further connected in parallel between the control electrode and the source electrode of the power switching tube, the capacitor and a pull-up resistor connected to the control electrode together forming an RC network for smoothing the turn-on speed of the power switching tube, thereby suppressing a surge current generated when powering up a display screen connected to the second display interface.
6. The multi-screen compatible embedded motherboard circuitry of claim 2 further comprising a TFT bias power generation circuit comprising: The single-inductor boost converter is used for generating a first positive bias voltage; A first charge pump circuit and a second charge pump circuit, each of the first and second charge pump circuits multiplexing a high frequency switching node within the boost converter for operation, for generating a second positive bias voltage higher than the first positive bias voltage, and a negative bias voltage, respectively; And the output ends of the second positive bias voltage and the negative bias voltage are respectively connected with a zener diode in parallel for realizing overvoltage or undervoltage clamping protection.
7. The multi-screen compatible embedded motherboard circuitry of claim 2 further comprising an LED backlight driving circuit comprising: a constant current driving chip for driving the LED backlight; the current sampling network is connected to the feedback pin of the constant current driving chip and is composed of at least two parallel precise resistors and used for distributing the total current flowing through the network, so that the power stress of the single resistor is reduced and the balanced distribution of heat is realized.
8. The multi-screen compatible embedded motherboard circuitry of claim 7 wherein the LED backlight driver circuitry further comprises an analog dimming conversion circuit comprising: The RC low-pass filter is composed of a resistor and a capacitor and is used for converting a PWM dimming signal from the main control chip into a stable direct-current voltage; The stable direct current voltage is injected into the feedback pin of the constant current driving chip, and constant direct current flowing through the LED backlight is changed smoothly by adjusting a feedback reference, so that noise-free analog dimming is realized.
9. The multi-screen compatible embedded motherboard circuitry of claim 2 further comprising an adaptive level shifting backlight control interface, said adaptive level shifting backlight control interface comprising: the input end of the level conversion chip receives a backlight control signal which is from the main control chip and works in a first voltage domain, and the output end of the level conversion chip outputs a backlight control signal which works in a second voltage domain; And the output enabling control circuit comprises a pull-up resistor connected between the power supply of the first voltage domain and an output enabling pin of the level conversion chip, wherein the pull-up resistor provides a hardware default high level for the output enabling pin and simultaneously allows the main control chip to actively pull the output enabling pin low so as to realize software gating.
10. A display self-adapting method of a multi-screen compatible embedded motherboard circuit system, applied to the embedded motherboard circuit system as claimed in any one of claims 1 to 9, comprising the steps of: according to the specification of the display screen to be connected and conforming to the second display standard, selecting a matched working voltage for a power supply pin of the second display interface by plugging or shorting a physical device on the power supply selection interface; Setting the state of the controller node corresponding to the second display interface to be enabled and simultaneously setting the state of the controller node corresponding to the first display interface to be disabled by modifying a device tree file in an operating system; powering up and starting the embedded main board circuit system so that the kernel of the system configures the set of reusable signal pins of the main control chip into the second working mode according to the configuration of the equipment tree file, and loads a corresponding driver program to light the display screen.

Description

Multi-screen compatible embedded main board circuit system and display self-adaption method thereof Technical Field The invention relates to the technical field of electronics related to display driving printed circuits, in particular to a multi-screen compatible embedded main board circuit system and a display self-adaptation method thereof. Background The embedded main board is used as a core component of industrial control, commercial display terminals and Internet of things equipment, and one of the functions of the embedded main board is to drive a display screen to realize man-machine interaction. In practical applications, the variety of display screens is wide, and the physical interfaces and electrical standards are also diversified, and the mainstream interface standards include high-definition multimedia interface (HDMI), mobile industry processor interface (MIPI-DSI), low voltage differential signaling interface (LVDS), and the like. In addition, even the same interface standard (such as LVDS), the required operating voltage may be different for different sizes or different suppliers of screen modules, and there are various specifications of 3.3 v, 5 v, 12 v, etc. in general. Currently, in order to enable a single type of embedded motherboard to adapt to different specifications of display screens, the following technical means are generally adopted by those skilled in the art. The first way is to use an external protocol conversion chip. For example, when the main control chip only provides MIPI-DSI output and the application needs to connect with LVDS screen, a bridge chip of MIPI-to-LVDS is integrated on the main board. This approach, while capable of solving the interface mismatch problem, significantly increases hardware cost and PCB design complexity while introducing additional power consumption and potential signal integrity risk points. The second way is to design a dedicated motherboard model for different interfaces, respectively. For example, a type A motherboard is designed for the MIPI screen market and a type B motherboard is designed for the LVDS screen market. The method causes the product line to be bloated, and the research and development, production, material management and inventory costs are greatly increased, which is unfavorable for large-scale production and quick response to market change. In addition, in terms of screen powering, conventional motherboards typically only provide a fixed operating voltage for the display interface. When a screen with different power supply specifications needs to be replaced, the main board hardware is often required to be modified, for example, voltage is regulated by a flying lead or component replacement mode, and the operation is low in efficiency and seriously affects the reliability and consistency of products. Therefore, how to realize the wide compatibility of a single hardware platform to multiple main stream display interfaces and power supply specifications in a low-cost, high-integration and high-reliability mode under the condition of limited main control chip pin resources and PCB area is a technical problem to be solved in the current embedded main board circuit system design field. Disclosure of Invention In order to help solve the technical problems in the prior art, the invention provides a multi-screen compatible embedded main board circuit system and a display self-adapting method thereof, which can make a single main board hardware platform compatible with display screens with different interface standards and power supply specifications by utilizing a pin multiplexing function built in a main control chip and combining a hardware configurable power supply scheme under the condition of not adding an external protocol conversion chip. The invention discloses a multi-screen compatible embedded main board circuit system, which comprises: a main control chip; the display interface module comprises at least one first display interface and at least one second display interface, and the first display interface and the second display interface are respectively used for connecting display screens conforming to a first display standard and a second display standard; The main control chip comprises a first display interface, a second display interface, a first multiplexing signal pin, a second multiplexing signal pin, a first control module and a second control module, wherein the first multiplexing signal pin is electrically connected to the signal end of the first display interface and the signal end of the second display interface at the same time, and is configured to respond to software configuration and selectively work in a first working mode or a second working mode so as to respectively output display signals conforming to the first display standard or the second display standard, thereby directly driving the first display interface or the second display interface; The system also comprises a configurable screen power