Display control circuits and devices

Abstract

The present application relates to a display control circuit and device, including a resistance adjustment component and at least two light-emitting units, wherein the first end of the resistance adjustment component is connected to an external power supply port, the second end of the resistance adjustment component is grounded, each light-emitting unit includes a switch tube and a light-emitting component, the control end of the switch tube is connected to the output end of the resistance adjustment component, the first end of the switch tube is grounded, the second end of the switch tube is connected to the negative electrode of the light-emitting component, and the positive electrode of the light-emitting component is connected to the external power supply port. The light-emitting unit is used to indicate the working state of the electrical appliance, and the resistance value connected to the display control circuit is adjusted by the resistance adjustment component to adjust the voltage to control the conduction of the switch tube of the light-emitting unit, thereby controlling the light-emitting component to emit light, so as to indicate the working state of the electrical appliance. The display control device does not need to add an MCU, and display control can be achieved through pure hardware, which can reduce costs.

Description

Technical Field

[0001] The present application relates to the field of display control technology, and in particular to a display control circuit and device. Background Art

[0002] The current controllers of household appliances are mostly a main control board plus a display control board. The main control board and the display board each have at least one MCU, which uses communication to transmit information to control the good operation of the appliance. This can reduce the number of connections between the two control boards, reduce costs and enhance anti-interference capabilities. The MCU on the main control board controls the working status of the product, including various load operations and load status detection functions; the MCU on the display control board is electrically connected to the MCU on the main control board for communication and exchange of status information. At the same time, the MCU on the display control board controls the display circuit on the board to display the working status of the household appliance. Therefore, even if there are only a few LEDs on the display control board, an MCU is needed to control it, resulting in a waste of cost. Summary of the invention

[0003] Based on this, it is necessary to provide a display control circuit and device that can reduce costs and does not require an MCU to control the display product status with pure hardware, in order to address the technical problem that the display control circuit in the controller of traditional household appliances also needs to be controlled by an MCU, which leads to high costs.

[0004] A display control circuit includes a resistance adjustment component and at least two light-emitting units, wherein the first end of the resistance adjustment component is connected to an external power supply port, the second end of the resistance adjustment component is grounded, each light-emitting unit includes a switch tube and a light-emitting component, the control end of the switch tube is connected to the output end of the resistance adjustment component, the first end of the switch tube is grounded, the second end of the switch tube is connected to the negative electrode of the light-emitting component, and the positive electrode of the light-emitting component is connected to the external power supply port.

[0005] In one embodiment, the resistance adjustment component includes a resistance adjuster and a voltage divider resistor, one end of the voltage divider resistor is connected to an external power port, the other end of the voltage divider resistor is connected to the output end of the resistance adjuster, the first input end of the resistance adjuster is connected to the output end of the resistance adjuster, the second input end of the resistance adjuster is grounded, and the output end of the resistance adjuster is connected to the control end of the switch tube in each light-emitting unit, wherein one end of the voltage divider resistor serves as the first end of the resistance adjustment component, the second input end of the resistance adjuster serves as the second end of the resistance adjustment component, and the output end of the resistance adjuster serves as the output end of the resistance adjustment component.

[0006] In one embodiment, the resistance adjustment component includes a resistance adjuster and a voltage divider resistor, the first input end of the resistance adjuster is connected to the external power supply interface, the second input end of the resistance adjuster is connected to one end of the voltage divider resistor and the output end of the resistance adjuster, the other end of the voltage divider resistor is grounded, and the output end of the resistance adjuster is connected to the control end of the switch tube in each light-emitting unit, wherein the first input end of the resistance adjuster serves as the first end of the resistance adjustment component, the other end of the voltage divider resistor serves as the second end of the resistance adjustment component, and the output end of the resistance adjuster serves as the output end of the resistance adjustment component.

[0007] In one embodiment, the at least two light-emitting units include a first light-emitting unit, a second light-emitting unit and a third light-emitting unit, and the switch tube in each light-emitting unit is a triode, and the light-emitting component in each light-emitting unit is a light-emitting diode.

[0008] In one embodiment, the first light-emitting unit also includes a first diode, the second light-emitting unit also includes a second diode, and the third light-emitting unit also includes a third diode, the anode of the first diode is connected to the output end of the resistance adjustment component, the cathode of the first diode is connected to the base of the transistor of the first light-emitting unit, the anode of the second diode is connected to the cathode of the first diode, the cathode of the second diode is connected to the base of the transistor of the second light-emitting unit, the anode of the third diode is connected to the cathode of the second diode, and the cathode of the third diode is connected to the base of the transistor of the third light-emitting unit.

[0009] In one embodiment, the switch tube of the first light-emitting unit is a first transistor, the light-emitting component of the first light-emitting unit is a first light-emitting diode, and the first light-emitting unit also includes a first current limiting resistor and a second current limiting resistor, one end of the first current limiting resistor is connected to the cathode of the first diode, the other end of the first current limiting resistor is connected to the base of the first transistor, one end of the second current limiting resistor is connected to an external power supply port, and the other end of the second current limiting resistor is connected to the anode of the first light-emitting diode.

[0010] In one embodiment, the switching tube of the second light-emitting unit is a second triode, the light-emitting component of the second light-emitting unit is a second light-emitting diode, and the second light-emitting unit also includes a third current limiting resistor and a fourth current limiting resistor, one end of the third current limiting resistor is connected to the cathode of the second diode, the other end of the third current limiting resistor is connected to the base of the second triode, one end of the fourth current limiting resistor is connected to the external power supply port, and the other end of the fourth current limiting resistor is connected to the anode of the second light-emitting diode.

[0011] In one embodiment, the transistor of the third light-emitting unit is a third transistor, the light-emitting component of the third light-emitting unit is a third light-emitting diode, and the third light-emitting unit also includes a fifth current limiting resistor and a sixth current limiting resistor, one end of the fifth current limiting resistor is connected to the cathode of the third diode, the other end of the fifth current limiting resistor is connected to the base of the third transistor, one end of the sixth current limiting resistor is connected to the external power supply port, and the other end of the sixth current limiting resistor is connected to the anode of the third light-emitting diode.

[0012] In one embodiment, a display control device includes a display control board and the above-mentioned display control circuit, and the display control circuit is arranged on the display control board.

[0013] In one of the embodiments, the display control device further includes a main control board and a main controller, the main controller is arranged on the main control board, and the output end of the resistance adjustment component is connected to the input and output port of the main controller.

[0014] The display control circuit and device described above include a resistance adjustment component and at least two light-emitting units. The first end of the resistance adjustment component is connected to an external power supply port, and the second end of the resistance adjustment component is grounded. Each light-emitting unit includes a switch tube and a light-emitting component. The control end of the switch tube is connected to the output end of the resistance adjustment component, the first end of the switch tube is grounded, and the second end of the switch tube is connected to the negative electrode of the light-emitting component. The positive electrode of the light-emitting component is connected to the external power supply port. The light-emitting unit is used to indicate the working state of the appliance. By adjusting the resistance value connected to the display control circuit through the resistance adjustment component, the voltage can be adjusted to control the conduction of the switch tube of the light-emitting unit, thereby controlling the light-emitting component to emit light, so as to indicate the working state of the appliance. The display control device does not need to add an MCU, and display control can be achieved through pure hardware, which can reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A circuit diagram showing a control circuit in one embodiment;

[0016] Figure 2 The following is a circuit diagram showing a control device in one embodiment. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0018] In one embodiment, Figure 1As shown, a display control circuit includes a resistance adjustment component 110 and at least two light-emitting units, the first end of the resistance adjustment component 110 is connected to an external power port, the second end of the resistance adjustment component 110 is grounded, each light-emitting unit includes a switch tube and a light-emitting component, the control end of the switch tube is connected to the output end of the resistance adjustment component 110, the first end of the switch tube is grounded, the second end of the switch tube is connected to the negative pole of the light-emitting component, and the positive pole of the light-emitting component is connected to the external power port.

[0019] Specifically, the switch tube acts as a switch. When the voltage applied between its control end and the first end is higher than a certain value, it is turned on, and when it is lower than a certain value, it is turned off. The light-emitting unit is used to indicate the working status of the electrical appliance. By adjusting the resistance connected to the display control circuit through the resistance adjustment component, the voltage can be adjusted to control the conduction of the switch tube of the light-emitting unit, thereby controlling the light-emitting component to emit light to indicate the working status of the electrical appliance. The display control device does not need to add an MCU, and display control can be achieved through pure hardware, which can reduce costs.

[0020] In one embodiment, a resistance adjustment component includes a resistance adjuster and a voltage divider resistor, one end of the voltage divider resistor is connected to an external power port, the other end of the voltage divider resistor is connected to the output end of the resistance adjuster, the first input end of the resistance adjuster is connected to the output end of the resistance adjuster, the second input end of the resistance adjuster is grounded, and the output end of the resistance adjuster is connected to the control end of the switch tube in each light-emitting unit, wherein one end of the voltage divider resistor serves as the first end of the resistance adjustment component, the second input end of the resistance adjuster serves as the second end of the resistance adjustment component, and the output end of the resistance adjuster serves as the output end of the resistance adjustment component.

[0021] Specifically, in this embodiment, Figure 1 As shown, the voltage-dividing resistor is a resistor R0, and the resistance adjuster is an adjustable resistor Rn. Pin 1 of the resistor R0 is connected to the power supply VCC, and pin 2 of R0 is connected to the output end of the adjustable resistor Rn. The first input end of Rn is connected to its output end, and the second input end of Rn is grounded. The resistance adjuster can be an adjustable resistor or a potentiometer, or a dip switch or a coding switch, etc., and is not limited to the above devices. Any device that can be used to adjust the resistance value connected to the display control circuit can be used. When the resistance adjuster is an adjustable resistor or a potentiometer, the adjustable resistor or the potentiometer can be connected to a sliding bar or a knob, and the user can adjust the resistance value of the connected circuit by sliding or rotating.

[0022] In another embodiment, the resistance adjustment component includes a resistance adjuster and a voltage divider resistor, the first input end of the resistance adjuster is connected to the external power supply interface, the second input end of the resistance adjuster is connected to one end of the voltage divider resistor and the output end of the resistance adjuster, the other end of the voltage divider resistor is grounded, and the output end of the resistance adjuster is connected to the control end of the switch tube in each light-emitting unit, wherein the first input end of the resistance adjuster serves as the first end of the resistance adjustment component, the other end of the voltage divider resistor serves as the second end of the resistance adjustment component, and the output end of the resistance adjuster serves as the output end of the resistance adjustment component.

[0023] Specifically, the positions of the voltage-dividing resistor and the resistance adjuster are interchangeable, and Rn and R0 form a voltage-dividing circuit. When Rn is connected to different resistance values, the voltage at its output end will be different. The output end of Rn is connected to the main controller. The main controller detects different voltages, which is equivalent to being input with different instructions. The main controller MCU controls the household appliances to work with different functions or powers accordingly. For example, when the MCU detects that the voltage is 1V, the appliance is controlled to work with the porridge cooking function; when the voltage is detected to be 1.5V, the appliance is controlled to work with the hot pot function; or, when 1V is detected, it works with a power of 1000W; when 1.5V is detected, it works with a power of 1500W.

[0024] In one embodiment, Figure 1 As shown, at least two light-emitting units include a first light-emitting unit 120, a second light-emitting unit 130 and a third light-emitting unit 140, and the switch tube in each light-emitting unit is a triode, and the light-emitting component in each light-emitting unit is a light-emitting diode.

[0025] Specifically, in this embodiment, the number of light-emitting units is three as an example, and the switching tube in the light-emitting unit is a triode, that is, the control end of the switching tube is the base of the triode, the first end of the switching tube is the emitter of the triode, and the second end of the switching tube is the collector of the triode.

[0026] In one embodiment, the first light-emitting unit further includes a first diode, the second light-emitting unit further includes a second diode, and the third light-emitting unit further includes a third diode, the anode of the first diode is connected to the output end of the resistance adjustment component, the cathode of the first diode is connected to the base of the transistor of the first light-emitting unit, the anode of the second diode is connected to the cathode of the first diode, the cathode of the second diode is connected to the base of the transistor of the second light-emitting unit, the anode of the third diode is connected to the cathode of the second diode, and the cathode of the third diode is connected to the base of the transistor of the third light-emitting unit. Specifically, when the number of light-emitting units is more than three, the connection relationship between the light-emitting units is in accordance with the above description, and the first diode D1, the second diode D2, and the third diode D3 play a voltage dividing and clamping role.

[0027] In one embodiment, the switching tube of the first light-emitting unit is a first transistor, the light-emitting component of the first light-emitting unit is a first light-emitting diode, and the first light-emitting unit also includes a first current limiting resistor and a second current limiting resistor, one end of the first current limiting resistor is connected to the cathode of the first diode, the other end of the first current limiting resistor is connected to the base of the first transistor, one end of the second current limiting resistor is connected to the external power supply port, and the other end of the second current limiting resistor is connected to the anode of the first light-emitting diode.

[0028] Specifically, the first current limiting resistor R1 plays a role in limiting current; the second current limiting resistor R11 mainly plays a role in limiting current to prevent the first light-emitting diode from being damaged by excessive current. The cathode of the first diode D1 is connected to the pin 1 of the resistor R1, the pin 2 of the resistor R1 is connected to the base (b) of the first transistor Q1, the emitter (e) of the first transistor Q1 is grounded, the collector (c) of the first transistor Q1 is connected to the cathode of the first light-emitting diode LED1, the anode of the first light-emitting diode LED1 is connected to the pin 2 of the second current limiting resistor R11, and the pin 1 of R11 is connected to the power supply VCC. D1, R1, Q1, LED1, and R11 together constitute a first light-emitting unit, such as Figure 1 As shown in , the first light emitting unit is 130, and the structures of the remaining light emitting units are consistent with the structure of the first light emitting unit.

[0029] In one embodiment, the switching tube of the second light-emitting unit is a second triode, the light-emitting component of the second light-emitting unit is a second light-emitting diode, and the second light-emitting unit also includes a third current limiting resistor and a fourth current limiting resistor, one end of the third current limiting resistor is connected to the cathode of the second diode, the other end of the third current limiting resistor is connected to the base of the second triode, one end of the fourth current limiting resistor is connected to the external power supply port, and the other end of the fourth current limiting resistor is connected to the anode of the second light-emitting diode.

[0030] Specifically, the third current limiting resistor R2 plays a role in limiting current; the fourth current limiting resistor R12 mainly plays a role in limiting current to prevent the second light emitting diode from being damaged by excessive current. The cathode of the second diode D2 is connected to the pin 1 of the resistor R2, the pin 2 of the resistor R2 is connected to the base (b) of the second triode Q2, the emitter (e) of the second triode Q2 is grounded, the collector (c) of the second triode Q2 is connected to the cathode of the second light emitting diode LED2, the anode of the second light emitting diode LED2 is connected to the pin 2 of the fourth current limiting resistor R12, the pin 1 of R12 is connected to the power supply VCC, and D2, R2, Q2, LED2, and R12 together form a second light emitting unit.

[0031] In one embodiment, the transistor of the third light-emitting unit is a third transistor, the light-emitting component of the third light-emitting unit is a third light-emitting diode, and the third light-emitting unit also includes a fifth current limiting resistor and a sixth current limiting resistor, one end of the fifth current limiting resistor is connected to the cathode of the third diode, the other end of the fifth current limiting resistor is connected to the base of the third transistor, one end of the sixth current limiting resistor is connected to the external power supply port, and the other end of the sixth current limiting resistor is connected to the anode of the third light-emitting diode.

[0032] Specifically, the fifth current-limiting resistor R3 plays a role in limiting current; the sixth current-limiting resistor R13 mainly plays a role in limiting current to prevent the third light-emitting diode from being damaged by excessive current. The cathode of the third diode D3 is connected to the pin 1 of the resistor R3, the pin 2 of the resistor R3 is connected to the base (b) of the third triode Q3, the emitter (e) of the third triode Q3 is grounded, the collector (c) of the third triode Q3 is connected to the cathode of the third light-emitting diode LED3, the anode of the third light-emitting diode LED3 is connected to the pin 2 of the sixth current-limiting resistor R13, the pin 1 of R13 is connected to the power supply VCC, and D3, R3, Q3, LED3, and R13 together form a third light-emitting unit.

[0033] Among them, each light-emitting unit is used to indicate a different working state of the electrical appliance. For example, when the first light-emitting unit is on, it indicates that the electrical appliance is in one working state; when the first light-emitting unit and the second light-emitting unit are on at the same time, it indicates that the electrical appliance is in another working state; when the three light-emitting units are on at the same time, it indicates that the electrical appliance is in yet another working state. By adjusting the resistance connected to the display control circuit and thus adjusting the voltage, different light-emitting units can be controlled to emit light to indicate different working states of the electrical appliance.

[0034] Furthermore, the anode of the first diode D1 in the first light-emitting unit is connected to the output end of the adjustable resistor Rn, the anode of the second diode D2 in the second light-emitting unit is connected to the cathode of the first diode D1 in the first light-emitting unit, and the anode of the third diode D3 in the third light-emitting unit is connected to the cathode of the second diode D2 in the second light-emitting unit. Because each diode needs a certain voltage value to be turned on, in this circuit, lighting the first light-emitting unit requires a voltage that turns on one diode, lighting the second light-emitting unit requires a voltage that turns on two diodes, and so on. Therefore, if Figure 2 In the circuit shown, as the resistance of Rn increases, the voltage at its output terminal becomes higher and higher, and the first light-emitting unit, the second light-emitting unit and the third light-emitting unit are lit in sequence.

[0035] The display control circuit uses a pure hardware method to control each light-emitting component to display the product status while keeping the number of inter-board connections unchanged, thereby saving MCU resources of the display control board and reducing circuit costs.

[0036] In one embodiment, Figure 2As shown, a display control device includes a display control board and the above-mentioned display control circuit, and the display control circuit is arranged on the display control board.

[0037] In one embodiment, it also includes a main control board and a main controller, the main controller is arranged on the main control board, and the output end of the resistance adjustment component is connected to the input and output port of the main controller.

[0038] Specifically, the display control circuit is located on the display control board, and the display control board is electrically connected to the main control board through inter-board connections. The two are installed inside the household appliance. The main control board is equipped with a main controller MCU to control the operation of the household appliance. The output end of the resistance adjustment component in the display control circuit is also connected to the I / O port of the MCU of the main control board through the inter-board connection. When the resistance adjustment component is adjusted to different access resistance values, its output voltage changes accordingly. The MCU controls the household appliance to work in different states according to the changes in the collected voltage signal. At the same time, the change in the output voltage of the resistance adjustment component can control different light-emitting units to emit light to indicate different working states of the household appliance.

[0039] In a detailed embodiment, Figure 2As shown, a display control circuit is located on a display control board, and the display control board is electrically connected to the main control board through an inter-board connection line. Both are installed inside a household appliance, and a main controller MCU is installed on the main control board to control the operation of the household appliance. The display control circuit includes a resistor adjuster Rn, a number of resistors, diodes, triodes and light-emitting diodes. The resistance adjuster Rn can be connected to a slide bar or a knob, and the user can adjust the resistance value of the connected circuit by sliding or rotating; Pin 1 of the voltage divider resistor R0 is connected to the power supply VCC, Pin 2 of R0 is connected to the output end of the adjustable resistor Rn, the first input end of Rn is connected to its output end, the second input end of Rn is grounded, the cathode of the first diode D1 is connected to Pin 1 of the first current limiting resistor R1, Pin 2 of R1 is connected to the base (b) of the first transistor Q1, the emitter (e) of Q1 is grounded, the collector (c) of Q1 is connected to the cathode of the first light-emitting diode LED1, the anode of LED1 is connected to Pin 2 of the resistor R11, and Pin 1 of the second current limiting resistor R11 is connected to the power supply VCC; D1, R1, Q1, LED1, and R11 together constitute a first light-emitting unit; similarly, D2, R2, Q2, LED2, and R12 constitute a second light-emitting unit; D3, R3, Q3, LED3, and R13 constitute a third light-emitting unit. The anode of D1 in the first light-emitting unit is connected to the output end of the adjustable resistor Rn, the anode of D2 in the second light-emitting unit is connected to the cathode of the first light-emitting unit D1, the anode of D3 in the third light-emitting unit is connected to the cathode of the second light-emitting unit D2, and so on. The output end of Rn is also connected to the I / O port of the MCU of the main control board through the inter-board connection. When Rn is adjusted to different access resistance values, its output voltage changes accordingly. The MCU controls the household appliance to work in different states according to the changes in the collected voltage signal. At the same time, the change in the output voltage of Rn can control different light-emitting units to emit light to indicate different working states of the household appliance.

[0040] The above display control device uses a pure hardware method to control a small number of LED display product states while keeping the number of inter-board connections unchanged, saving MCU resources of the display control circuit on the display control board and reducing circuit costs.

[0041] 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.

[0042] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A display control circuit, characterized in that: It includes a resistance adjustment component and at least two light-emitting units, wherein the first end of the resistance adjustment component is connected to an external power supply port, the second end of the resistance adjustment component is grounded, each light-emitting unit includes a switch tube and a light-emitting component, the control end of the switch tube is connected to the output end of the resistance adjustment component, the first end of the switch tube is grounded, the second end of the switch tube is connected to the cathode of the light-emitting component, and the anode of the light-emitting component is connected to the external power supply port; The at least two light-emitting units include a first light-emitting unit, a second light-emitting unit and a third light-emitting unit, and the switch tube in each of the light-emitting units is a triode, and the light-emitting component in each of the light-emitting units is a light-emitting diode; the first light-emitting unit also includes a first diode, the second light-emitting unit also includes a second diode, and the third light-emitting unit also includes a third diode, the anode of the first diode is connected to the output end of the resistance adjustment component, the cathode of the first diode is connected to the base of the triode of the first light-emitting unit, the anode of the second diode is connected to the cathode of the first diode, the cathode of the second diode is connected to the base of the triode of the second light-emitting unit, the anode of the third diode is connected to the cathode of the second diode, and the cathode of the third diode is connected to the base of the triode of the third light-emitting unit.

2. The display control circuit according to claim 1, characterized in that: The resistance adjustment component includes a resistance adjuster and a voltage divider resistor, one end of the voltage divider resistor is connected to an external power port, the other end of the voltage divider resistor is connected to the output end of the resistance adjuster, the first input end of the resistance adjuster is connected to the output end of the resistance adjuster, the second input end of the resistance adjuster is grounded, and the output end of the resistance adjuster is connected to the control end of the switch tube in each of the light-emitting units, wherein one end of the voltage divider resistor serves as the first end of the resistance adjustment component, the second input end of the resistance adjuster serves as the second end of the resistance adjustment component, and the output end of the resistance adjuster serves as the output end of the resistance adjustment component.

3. The display control circuit according to claim 1, characterized in that: The resistance adjustment component includes a resistance adjuster and a voltage divider resistor, wherein the first input end of the resistance adjuster is connected to an external power supply interface, the second input end of the resistance adjuster is connected to one end of the voltage divider resistor and the output end of the resistance adjuster, the other end of the voltage divider resistor is grounded, and the output end of the resistance adjuster is connected to the control end of the switch tube in each of the light-emitting units, wherein the first input end of the resistance adjuster serves as the first end of the resistance adjustment component, the other end of the voltage divider resistor serves as the second end of the resistance adjustment component, and the output end of the resistance adjuster serves as the output end of the resistance adjustment component.

4. The display control circuit according to claim 1, characterized in that: The switching tube of the first light-emitting unit is a first triode, the light-emitting component of the first light-emitting unit is a first light-emitting diode, and the first light-emitting unit also includes a first current limiting resistor and a second current limiting resistor, one end of the first current limiting resistor is connected to the cathode of the first diode, the other end of the first current limiting resistor is connected to the base of the first triode, one end of the second current limiting resistor is connected to the external power supply port, and the other end of the second current limiting resistor is connected to the anode of the first light-emitting diode.

5. The display control circuit according to claim 1, characterized in that: The switching tube of the second light-emitting unit is a second triode, the light-emitting component of the second light-emitting unit is a second light-emitting diode, and the second light-emitting unit also includes a third current limiting resistor and a fourth current limiting resistor, one end of the third current limiting resistor is connected to the cathode of the second diode, and the other end of the third current limiting resistor is connected to the base of the second triode, one end of the fourth current limiting resistor is connected to the external power supply port, and the other end of the fourth current limiting resistor is connected to the anode of the second light-emitting diode.

6. The display control circuit according to claim 1, characterized in that: The transistor of the third light-emitting unit is a third transistor, the light-emitting component of the third light-emitting unit is a third light-emitting diode, and the third light-emitting unit also includes a fifth current-limiting resistor and a sixth current-limiting resistor, one end of the fifth current-limiting resistor is connected to the cathode of the third diode, the other end of the fifth current-limiting resistor is connected to the base of the third transistor, one end of the sixth current-limiting resistor is connected to the external power supply port, and the other end of the sixth current-limiting resistor is connected to the anode of the third light-emitting diode.

7. A display control device, characterized in that: It comprises a display control board and a display control circuit as claimed in any one of claims 1 to 6, wherein the display control circuit is arranged on the display control board.

8. The display control device according to claim 7, characterized in that: It also includes a main control board and a main controller, wherein the main controller is arranged on the main control board, and the output end of the resistance adjustment component is connected to the input and output port of the main controller.

Images