Low-cost control circuit for realizing brightness change of patterns displayed on display panel

Abstract

The utility model relates to a low-cost control circuit for realizing brightness change of patterns displayed on a display panel, which comprises an MCU (Microprogrammed Control Unit) main control chip for processing input signals, a touch key module for detecting user input, a display device for displaying information, and a display driving module for receiving control signals of the MCU main control chip and driving the display device, the MCU main control chip is electrically connected with the touch key module and the display driving module, and the display driving module is electrically connected with the display device; wherein the display driving module controls and drives the display equipment to display information and adjusts the display brightness of the display equipment through the MCU main control chip. The control circuit is simple, reliable and low in cost, different brightness display can be achieved by adjusting hardware according to customer requirements, meanwhile, existing mature components can be fully utilized, and the reliability of a system and the convenience of production are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to a control circuit for realizing light and dark changes of display patterns on a display panel at a low cost. Background Art

[0002] The display driver chip AiP1640 is a dedicated circuit for common cathode LED drive control. It has large driving capability, excellent product performance, and reliable quality. Although the display grayscale software is adjustable, the brightness of each independent display unit cannot be adjusted separately, and the brightness of the display pattern cannot be independently adjusted. At present, the solution to this problem is mostly to use a dedicated display driver chip that can independently adjust the display grayscale of each display unit to achieve the above functional requirements. The above disadvantages are: although the use of a dedicated display driver chip can achieve the functional requirements, there are two problems: first, the cost price is not advantageous, and second, due to the driving capability of the display driver chip, it is difficult to adjust the display effect that satisfies customers.

[0003] Therefore, further improvement is needed. Utility Model Content

[0004] Based on this, the purpose of the utility model is to provide a low-cost control circuit for realizing the brightness change of the display pattern on the display board to overcome the shortcomings of the prior art. By simply adjusting the hardware circuit, different display brightness can be achieved. While meeting customer requirements, the circuit is simple, reliable and low-cost.

[0005] A low-cost control circuit designed for this purpose to achieve light and dark changes in a display pattern on a display panel includes an MCU main control chip for processing input signals, a touch button module for detecting user input, a display device for displaying information, and a display driver module for receiving control signals from the MCU main control chip and driving the display device, wherein the MCU main control chip is electrically connected to the touch button module and the display driver module, and the display driver module is electrically connected to the display device; wherein the display driver module controls the display device to display information and adjust the display brightness of the display device through the MCU main control chip.

[0006] The display device includes multiple groups of LED display modules, the LED display modules include multiple light-emitting diodes and current-sharing resistors, the display driver module includes a display driver chip, a diode D1, a diode D2 and a current-limiting resistor R0, the cathode of each of the light-emitting diodes is connected to an output pin of the display driver chip through one of the current-sharing resistors, and the display driver chip is connected to the anodes of the multiple light-emitting diodes through the diode D1, the diode D2 and the current-limiting resistor R0.

[0007] The segment output SEG1 pin of the display driver chip is connected to the anode of the diode D1, the segment output SEG2 pin of the display driver chip is connected to one end of the current limiting resistor R0, the other end of the current limiting resistor R0 is connected to the anode of the diode D2, and the cathodes of the diode D1 and the diode D2 are connected to the anodes of the plurality of light-emitting diodes;

[0008] The display driver chip also includes an electrolytic capacitor EC2 and a capacitor C2, wherein the positive electrode of the electrolytic capacitor EC2 and one end of the capacitor C2 are connected to the positive electrode of a DC 5V power supply, and the negative electrode of the electrolytic capacitor EC2 and the other end of the capacitor C2 are connected to the negative electrode of the DC 5V power supply.

[0009] The multiple light-emitting diodes include light-emitting diode L1, light-emitting diode L2, light-emitting diode L3, light-emitting diode L4, light-emitting diode L5, light-emitting diode L6, light-emitting diode L7 and light-emitting diode L8; the light-emitting diode L1, the light-emitting diode L2, the light-emitting diode L3 and the light-emitting diode L4 are combined to form a group of the LED display modules, and the light-emitting diode L5, the light-emitting diode L6, the light-emitting diode L7 and the light-emitting diode L8 are combined to form another group of the LED display modules.

[0010] The current-sharing resistors include resistors R1, R2, R3, R4, R5, R6, R7 and R8. The cathode of the light-emitting diode L1 is connected to the resistor R1, the cathode of the light-emitting diode L2 is connected to the resistor R2, the cathode of the light-emitting diode L3 is connected to the resistor R3, and the cathode of the light-emitting diode L4 is connected to the resistor R4. The other ends of the resistors R1, R2, R3 and R4 are connected to the bit output GR5 pin of the display driver chip; the cathode of the light-emitting diode L5 is connected to the resistor R5, the cathode of the light-emitting diode L6 is connected to the resistor R6, and the cathode of the light-emitting diode L7 is connected to the resistor R8. To the resistor R7, the cathode of the light emitting diode L8 is connected to the resistor R8, the resistor R5, the resistor R6, the resistor R7 and the other end of the resistor R8 are connected to the bit output GR6 pin of the display driver chip, when the bit output pin of the display driver chip is at a high level, the light emitting diode is in an off state; when the bit output pin of the display driver chip is at a low level and the segment output pin SEG1 of the display driver chip is at a high level, the light emitting diode is in a high-bright state; when the bit output pin of the display driver chip is at a low level, the segment output pin SEG1 of the display driver chip is at a low level and the segment output pin SEG2 of the display driver chip is at a high level, the light emitting diode is in a dim state.

[0011] The control circuit also includes a power communication module electrically connected to the MCU main control chip, and the power communication module includes a wiring terminal CN1, a resistor R11 and a resistor R12. Pin 1 of the wiring terminal CN1 inputs the negative pole of a DC 5V power supply, and pin 2 of the wiring terminal CN1 inputs the positive pole of a DC 5V power supply. Pin 3 of the wiring terminal CN1 is connected to one end of the resistor R11, and the other end of the resistor R11 is connected to pin 22 of the MCU main control chip. Pin 4 of the wiring terminal CN1 is connected to one end of the resistor R12, and the other end of the resistor R12 is connected to pin 21 of the MCU main control chip.

[0012] The MCU main control chip also includes an electrolytic capacitor EC1 and a capacitor C1. The positive electrode of the electrolytic capacitor EC1 and one end of the capacitor C1 are connected to the positive electrode of a DC 5V power supply, and the negative electrode of the electrolytic capacitor EC1 and the other end of the capacitor C1 are connected to the negative electrode of a DC 5V power supply.

[0013] The touch button module includes a connection terminal CN2, a resistor R9 and a resistor R10, wherein pin 1 of the connection terminal CN2 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to pin 1 of the MCU main control chip, and pin 2 of the connection terminal CN2 is connected to one end of the resistor R10, and the other end of the resistor R10 is connected to pin 2 of the MCU main control chip.

[0014] The display device also includes a digital screen, wherein pin 7 of the display driver chip is connected to pin 17 of the MCU main control chip, and pin 8 of the display driver chip is connected to pin 18 of the MCU main control chip; pin 1 of the digital screen is connected to pin 13 of the display driver chip; pin 2 of the digital screen is connected to pin 12 of the display driver chip; pin 3 of the digital screen is connected to pin 16 of the display driver chip; pin 4 of the digital screen is connected to pin 11 of the display driver chip; pin 7 ... Pin 15 of the digital display chip is connected, pin 6 of the digital screen is connected to pin 21 of the display driver chip; pin 7 of the digital screen is connected to pin 10 of the display driver chip; pin 8 of the digital screen is connected to pin 20 of the display driver chip; pin 9 of the digital screen is connected to pin 19 of the display driver chip; pin 10 of the digital screen is connected to pin 14 of the display driver chip; pin 11 of the digital screen is connected to pin 9 of the display driver chip, and pin 12 of the digital screen is connected to pin 18 of the display driver chip.

[0015] The model of the MCU main control chip is CBM7320A4S2D.

[0016] A low-cost control circuit for realizing the light and dark change of the display pattern of the display panel in the above embodiment includes an MCU main control chip for processing input signals, a touch key module for detecting user input, a display device for displaying information, and a display driver module for receiving the control signal of the MCU main control chip and driving the display device, the MCU main control chip is electrically connected to the touch key module and the display driver module, and the display driver module is electrically connected to the display device; wherein the display driver module controls the display device to display information and adjust the display brightness of the display device through the MCU main control chip. Specifically, the MCU main control chip is responsible for receiving and processing the input signal from the touch key module. When the user inputs an instruction through the touch key module, the MCU main control chip parses the signal and generates a corresponding control instruction. The MCU main control chip sends a control signal to the display driver module according to the parsed instruction. The display driver module controls the current and voltage of the display device according to the received control signal to realize the light and dark change of the display pattern; the control circuit is simple and reliable, low-cost, and can realize different brightness displays by adjusting the hardware according to customer needs. At the same time, it can make full use of existing mature components and improve the reliability of the system and the convenience of production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and the description thereof are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a block diagram of a display board circuit control system in one embodiment of the utility model.

[0020] Figure 2 This is a circuit diagram of an LED display module in one embodiment of the utility model.

[0021] Figure 3 This is a circuit diagram of a power communication module in one embodiment of the utility model.

[0022] Figure 4 This is a circuit diagram of the MCU main control chip in one embodiment of the utility model.

[0023] Figure 5 This is a circuit diagram of a touch key module in one embodiment of the utility model.

[0024] Figure 6 It is a circuit diagram of a display driving module in one embodiment of the utility model.

[0025] Figure 7 This is a circuit diagram of a digital screen in one embodiment of the utility model. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0027] like Figure 1 As shown, a low-cost control circuit for realizing light and dark changes of a display pattern on a display panel is provided, comprising an MCU main control chip 1 for processing input signals, a touch button module 2 for detecting user input, a display device 3 for displaying information, and a display driver module 4 for receiving a control signal of the MCU main control chip 1 and driving the display device 3. The MCU main control chip 1 is electrically connected to the touch button module 2 and the display driver module 4, and the display driver module 4 is electrically connected to the display device 3; wherein the display driver module 4 controls the display device 3 to display information and adjust the display brightness of the display device 3 through the MCU main control chip 1.

[0028] Specifically, the MCU main control chip 1 is responsible for receiving and processing input signals from the touch button module 2. When the user inputs instructions through the touch button module 2, the MCU main control chip 1 parses the signal and generates corresponding control instructions. The MCU main control chip 1 sends a control signal to the display driver module 4 according to the parsed instructions. The display driver module 4 controls the current and voltage of the display device 3 according to the received control signal to achieve light and dark changes in the display pattern. The control circuit is simple and reliable, with low cost. Different brightness displays can be achieved by adjusting the hardware according to customer needs. At the same time, it can make full use of existing mature components, thereby improving the reliability of the system and the convenience of production.

[0029] Further, if Figure 2 As shown, the display device 3 includes multiple groups of LED display modules 301, the LED display module 301 includes multiple light-emitting diodes and current-sharing resistors, the display driver module 4 includes a display driver chip, a diode D1, a diode D2 and a current-limiting resistor R0, the cathode of each light-emitting diode is connected to an output pin of the display driver chip through a current-sharing resistor, and the display driver chip is connected to the anodes of multiple light-emitting diodes through the diode D1, the diode D2 and the current-limiting resistor R0.

[0030] Specifically, by controlling the output of the display driver chip, the LED display module 301 can be controlled to achieve the display effect of highlighting, dimming, switching on and off the display mask;

[0031] Adjusting the size of the current limiting resistor R0 can change the brightness of the display mask when it is dark or bright, while not changing the brightness of the digital screen;

[0032] The current-sharing resistor is used to balance the current passing through the LEDs, and will not affect the service life of individual LEDs due to individual differences in the LEDs.

[0033] Diode D1 and diode D2 are used to isolate the two segment outputs so that the change of the level on one segment output will not affect the display circuit on the other segment output.

[0034] Further, if Figure 2 As shown, the segment output SEG1 pin of the display driver chip is connected to the anode of the diode D1, the segment output SEG2 pin of the display driver chip is connected to one end of the current limiting resistor R0, the other end of the current limiting resistor R0 is connected to the anode of the diode D2, and the cathodes of the diodes D1 and D2 are connected to the anodes of multiple light-emitting diodes.

[0035] Further, if Figure 6 As shown, the display driver chip also includes an electrolytic capacitor EC2 and a capacitor C2, the positive electrode of the electrolytic capacitor EC2 and one end of the capacitor C2 are connected to the positive electrode of the DC 5V power supply, and the negative electrode of the electrolytic capacitor EC2 and the other end of the capacitor C2 are connected to the negative electrode of the DC 5V power supply.

[0036] Specifically, the electrolytic capacitor EC2 and the capacitor C2 play a filtering role to improve the anti-interference performance of the system.

[0037] Further, if Figure 2 As shown, the multiple light-emitting diodes include light-emitting diode L1, light-emitting diode L2, light-emitting diode L3, light-emitting diode L4, light-emitting diode L5, light-emitting diode L6, light-emitting diode L7 and light-emitting diode L8; light-emitting diode L1, light-emitting diode L2, light-emitting diode L3 and light-emitting diode L4 are combined to form a group of LED display modules 301, and light-emitting diode L5, light-emitting diode L6, light-emitting diode L7 and light-emitting diode L8 are combined to form another group of LED display modules 301.

[0038] Further, if Figure 2As shown, the current-sharing resistor includes resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7 and resistor R8, the cathode of the light-emitting diode L1 is connected to the resistor R1, the cathode of the light-emitting diode L2 is connected to the resistor R2, the cathode of the light-emitting diode L3 is connected to the resistor R3, the cathode of the light-emitting diode L4 is connected to the resistor R4, and the other ends of the resistors R1, R2, R3 and R4 are connected to the bit output GR5 pin of the display driver chip; the cathode of the light-emitting diode L5 is connected to the resistor R5, the cathode of the light-emitting diode L6 is connected to the resistor R6, and the cathode of the light-emitting diode L7 is connected to Resistor R7, the cathode of the light-emitting diode L8 is connected to resistor R8, and the other ends of resistors R5, R6, R7 and R8 are connected to the bit output GR6 pin of the display driver chip. When the bit output pin of the display driver chip is at a high level, the light-emitting diode is in an off state; when the bit output pin of the display driver chip is at a low level and the segment output pin SEG1 of the display driver chip is at a high level, the light-emitting diode is in a high-bright state; when the bit output pin of the display driver chip is at a low level, the segment output pin SEG1 of the display driver chip is at a low level and the segment output pin SEG2 of the display driver chip is at a high level, the light-emitting diode is in a dim state.

[0039] Further, if Figure 4 As shown, the control circuit also includes a power communication module 5 electrically connected to the MCU main control chip 1, and the power communication module 5 includes a wiring terminal CN1, a resistor R11 and a resistor R12. Pin 1 of the wiring terminal CN1 inputs the negative pole of a DC 5V power supply, and pin 2 of the wiring terminal CN1 inputs the positive pole of a DC 5V power supply. Pin 3 of the wiring terminal CN1 is connected to one end of the resistor R11, and the other end of the resistor R11 is connected to pin 22 of the MCU main control chip 1. Pin 4 of the wiring terminal CN1 is connected to one end of the resistor R12, and the other end of the resistor R12 is connected to pin 21 of the MCU main control chip 1.

[0040] Specifically, the DC 5V power supply provides power for the entire control system, while pins 21 and 22 of the MCU main control chip and the circuits connected thereto constitute a serial communication system, which is responsible for receiving the real-time status of the touch button module 2, the display driver chip and the digital screen 302 and controlling the operation of the action execution component.

[0041] Further, if Figure 4 As shown, the MCU main control chip 1 also includes an electrolytic capacitor EC1 and a capacitor C1. The positive electrode of the electrolytic capacitor EC1 and one end of the capacitor C1 are connected to the positive electrode of a DC 5V power supply, and the negative electrode of the electrolytic capacitor EC1 and the other end of the capacitor C1 are connected to the negative electrode of the DC 5V power supply.

[0042] Specifically, the electrolytic capacitor EC1 and the capacitor C1 play a filtering role to improve the anti-interference performance of the system. The 28th pin of the main control chip is connected to the positive pole of the DC 5V power supply, the 27th pin of the main control chip is connected to the negative pole of the DC 5V power supply, and the other pins are connected to the devices of the corresponding functional units.

[0043] Further, if Figure 5 As shown, the touch button module 2 includes a wiring terminal CN2, a resistor R9 and a resistor R10, pin 1 of the wiring terminal CN2 is connected to one end of the resistor R9, the other end of the resistor R9 is connected to pin 1 of the MCU main control chip 1, pin 2 of the wiring terminal CN2 is connected to one end of the resistor R10, and the other end of the resistor R10 is connected to pin 2 of the MCU main control chip 1.

[0044] Specifically, when the user touches the key area of ​​the touch membrane, the MCU main control chip detects the corresponding key value and controls other components in the system to perform corresponding actions.

[0045] Further, if Figure 7 As shown, the display device 3 also includes a digital screen 302, the 7th pin of the display driver chip is connected to the 17th pin of the MCU main control chip 1, and the 8th pin of the display driver chip is connected to the 18th pin of the MCU main control chip 1; the 1st pin of the digital screen 302 is connected to the 13th pin of the display driver chip; the 2nd pin of the digital screen 302 is connected to the 12th pin of the display driver chip; the 3rd pin of the digital screen 302 is connected to the 16th pin of the display driver chip; the 4th pin of the digital screen 302 is connected to the 11th pin of the display driver chip; the 7th pin of the digital screen 302 is connected to the display driver chip Pin 15 of the digital screen 302 is connected to pin 21 of the display driver chip, pin 6 of the digital screen 302 is connected to pin 21 of the display driver chip; pin 7 of the digital screen 302 is connected to pin 10 of the display driver chip; pin 8 of the digital screen 302 is connected to pin 20 of the display driver chip; pin 9 of the digital screen 302 is connected to pin 19 of the display driver chip; pin 10 of the digital screen 302 is connected to pin 14 of the display driver chip; pin 11 of the digital screen 302 is connected to pin 9 of the display driver chip, and pin 12 of the digital screen 302 is connected to pin 18 of the display driver chip.

[0046] Specifically, the digital screen 302 is a white light common cathode digital screen. The digital screen 302 is controlled by the MCU main control chip 1 through the display driver chip 7, and is used to display the time, temperature and other information in the system; the MCU main control chip controls the display driver chip through pins 17 and 18 to perform corresponding actions, and drives the digital screen 302 and the light-emitting diode to display corresponding patterns as required.

[0047] Furthermore, the model of the display driver chip is AiP1640.

[0048] Specifically, the model of the MCU main control chip 1 is CBM7320A4S2D.

[0049] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 present invention.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0051] In the present invention, unless otherwise clearly defined and specified, the terms "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, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0053] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0054] It should also be understood that when explaining the connection relationship or positional relationship of elements, although not explicitly described, the connection relationship and positional relationship are interpreted as including an error range, which should be within the acceptable deviation range of a specific value determined by those skilled in the art. For example, "approximately", "approximately" or "substantially" may mean within one or more standard deviations, which are not limited here.

[0055] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0056] The above embodiments only express several implementation methods of the utility model, and the descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A control circuit for realizing light and dark changes of display patterns on a display panel at low cost, characterized in that: The invention comprises an MCU main control chip (1) for processing input signals, a touch key module (2) for detecting user input, a display device (3) for displaying information, and a display driver module (4) for receiving control signals from the MCU main control chip (1) and driving the display device (3), wherein the MCU main control chip (1) is electrically connected to the touch key module (2) and the display driver module (4), and the display driver module (4) is electrically connected to the display device (3); wherein the display driver module (4) controls the display device (3) to display information and adjusts the display brightness of the display device (3) through the MCU main control chip (1).

2. The control circuit for realizing light and dark changes of display patterns on a display panel at low cost according to claim 1, characterized in that: The display device (3) comprises a plurality of groups of LED display modules (301), the LED display modules (301) comprising a plurality of light emitting diodes and a current-sharing resistor, the display driver module (4) comprising a display driver chip, a diode D1, a diode D2 and a current-limiting resistor R0, the cathode of each light emitting diode being connected to an output pin of the display driver chip via one of the current-sharing resistors, and the display driver chip being connected to the anodes of the plurality of light emitting diodes via the diode D1, the diode D2 and the current-limiting resistor R0.

3. The control circuit for realizing light and dark changes of display patterns on a display panel at low cost according to claim 2, characterized in that: The segment output SEG1 pin of the display driver chip is connected to the anode of the diode D1, the segment output SEG2 pin of the display driver chip is connected to one end of the current limiting resistor R0, the other end of the current limiting resistor R0 is connected to the anode of the diode D2, and the cathodes of the diode D1 and the diode D2 are connected to the anodes of the plurality of light-emitting diodes; The display driver chip also includes an electrolytic capacitor EC2 and a capacitor C2, wherein the positive electrode of the electrolytic capacitor EC2 and one end of the capacitor C2 are connected to the positive electrode of a DC 5V power supply, and the negative electrode of the electrolytic capacitor EC2 and the other end of the capacitor C2 are connected to the negative electrode of the DC 5V power supply.

4. The control circuit for realizing light and dark changes of display patterns on a display panel at low cost according to claim 2, characterized in that: The plurality of light-emitting diodes include a light-emitting diode L1, a light-emitting diode L2, a light-emitting diode L3, a light-emitting diode L4, a light-emitting diode L5, a light-emitting diode L6, a light-emitting diode L7 and a light-emitting diode L8; the light-emitting diode L1, the light-emitting diode L2, the light-emitting diode L3 and the light-emitting diode L4 are combined to form a group of the LED display modules (301), and the light-emitting diode L5, the light-emitting diode L6, the light-emitting diode L7 and the light-emitting diode L8 are combined to form another group of the LED display modules (301).

5. The control circuit for realizing light and dark changes of display patterns on a display panel at low cost according to claim 4, characterized in that: The current-sharing resistors include resistors R1, R2, R3, R4, R5, R6, R7 and R8. The cathode of the light-emitting diode L1 is connected to the resistor R1, the cathode of the light-emitting diode L2 is connected to the resistor R2, the cathode of the light-emitting diode L3 is connected to the resistor R3, and the cathode of the light-emitting diode L4 is connected to the resistor R4. The other ends of the resistors R1, R2, R3 and R4 are connected to the bit output GR5 pin of the display driver chip; the cathode of the light-emitting diode L5 is connected to the resistor R5, the cathode of the light-emitting diode L6 is connected to the resistor R6, and the cathode of the light-emitting diode L7 is connected to the resistor R8. To the resistor R7, the cathode of the light emitting diode L8 is connected to the resistor R8, the resistor R5, the resistor R6, the resistor R7 and the other end of the resistor R8 are connected to the bit output GR6 pin of the display driver chip, when the bit output pin of the display driver chip is at a high level, the light emitting diode is in an off state; when the bit output pin of the display driver chip is at a low level and the segment output pin SEG1 of the display driver chip is at a high level, the light emitting diode is in a high-bright state; when the bit output pin of the display driver chip is at a low level, the segment output pin SEG1 of the display driver chip is at a low level and the segment output pin SEG2 of the display driver chip is at a high level, the light emitting diode is in a dim state.

6. The control circuit for realizing light and dark changes of display patterns on a display panel at low cost according to claim 1, characterized in that: The control circuit further comprises a power communication module (5) electrically connected to the MCU main control chip (1), the power communication module (5) comprising a wiring terminal CN1, a resistor R11 and a resistor R12, pin 1 of the wiring terminal CN1 inputting a negative electrode of a DC 5V power supply, pin 2 of the wiring terminal CN1 inputting a positive electrode of a DC 5V power supply, pin 3 of the wiring terminal CN1 connected to one end of the resistor R11, the other end of the resistor R11 connected to pin 22 of the MCU main control chip (1), pin 4 of the wiring terminal CN1 connected to one end of the resistor R12, the other end of the resistor R12 connected to pin 21 of the MCU main control chip (1).

7. The control circuit for realizing light and dark changes of display patterns on a display panel at low cost according to claim 1, characterized in that: The MCU main control chip (1) further comprises an electrolytic capacitor EC1 and a capacitor C1, wherein the positive electrode of the electrolytic capacitor EC1 and one end of the capacitor C1 are connected to the positive electrode of a DC 5V power supply, and the negative electrode of the electrolytic capacitor EC1 and the other end of the capacitor C1 are connected to the negative electrode of the DC 5V power supply.

8. The control circuit for realizing light and dark changes of display patterns on a display panel at low cost according to claim 1, characterized in that: The touch key module (2) comprises a connection terminal CN2, a resistor R9 and a resistor R10, wherein pin 1 of the connection terminal CN2 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to pin 1 of the MCU main control chip (1), pin 2 of the connection terminal CN2 is connected to one end of the resistor R10, and the other end of the resistor R10 is connected to pin 2 of the MCU main control chip (1).

9. The control circuit for realizing light and dark changes of display patterns on a display panel at low cost according to claim 2, characterized in that: The display device (3) further comprises a digital screen (302), wherein pin 7 of the display driver chip is connected to pin 17 of the MCU main control chip (1), and pin 8 of the display driver chip is connected to pin 18 of the MCU main control chip (1); pin 1 of the digital screen (302) is connected to pin 13 of the display driver chip; pin 2 of the digital screen (302) is connected to pin 12 of the display driver chip; pin 3 of the digital screen (302) is connected to pin 16 of the display driver chip; pin 4 of the digital screen (302) is connected to pin 11 of the display driver chip; pin 7 ... The 15th pin of the display driver chip is connected, the 6th pin of the digital screen (302) is connected to the 21st pin of the display driver chip; the 7th pin of the digital screen (302) is connected to the 10th pin of the display driver chip; the 8th pin of the digital screen (302) is connected to the 20th pin of the display driver chip; the 9th pin of the digital screen (302) is connected to the 19th pin of the display driver chip; the 10th pin of the digital screen (302) is connected to the 14th pin of the display driver chip; the 11th pin of the digital screen (302) is connected to the 9th pin of the display driver chip, and the 12th pin of the digital screen (302) is connected to the 18th pin of the display driver chip.

10. The control circuit for realizing light and dark changes of display patterns on a display panel at low cost according to claim 1, characterized in that: The model of the MCU main control chip (1) is CBM7320A4S2D.

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