Display device
By employing a combination of a power module, USB interface, current limiting switch, and detection resistor in the display device, and utilizing the main control module to detect current and control the current limiting switch, the increased cost caused by current limiting integrated circuit chips in the prior art is solved, and effective current limiting and safe power supply of the USB interface are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2026-03-10
AI Technical Summary
In existing display devices, a separate current-limiting integrated circuit chip is usually used to limit the output current of the USB interface, which increases manufacturing costs.
It adopts a combination structure of power module, USB interface, current limiting switch and detection resistor. The main control module detects the current and controls the current limiting switch to turn on and off, so as to realize the current limiting function and avoid the use of additional current limiting integrated circuit chip.
This reduces the manufacturing cost of the display device while effectively limiting the current of the USB interface, ensuring electrical safety.
Smart Images
Figure CN223986409U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of display devices, and in particular to a display device that can limit the output current of a USB interface. Background Technology
[0002] Current display devices typically include a Universal Serial Bus (USB) interface to provide power and signal transmission capabilities. In terms of power supply, this allows for the provision of power to external electronic devices. However, to prevent damage to these devices due to excessive current, a dedicated current-limiting integrated circuit (IC) chip is usually included in the display device to limit the output current of the USB interface. This increases the cost of the display device.
[0003] Therefore, how to design a display device that can limit the current of the USB interface while reducing the manufacturing cost has become a new research topic. Utility Model Content
[0004] The present invention provides a display device that can limit the output current of a USB interface and can reduce the manufacturing cost of the display device.
[0005] An embodiment of this utility model provides a display device, comprising:
[0006] Power module;
[0007] USB interface;
[0008] A current limiting switch is connected in series between the power module and the USB interface;
[0009] A sensing resistor is connected in series between the power module and the current limiting switch, or in series between the current limiting switch and the USB interface; and
[0010] The main control module is used to receive and process video signals and drive the display panel of the display device to display the corresponding video image. The main control module includes a first voltage detection terminal, a second voltage detection terminal, and a second control terminal. The first voltage detection terminal is connected to the first end of the detection resistor, the second voltage detection terminal is connected to the second end of the detection resistor, and the second control terminal is connected to the first control terminal of the current limiting switch. The main control module is also used to detect the current flowing through the detection resistor and to control the current limiting switch to turn off when the current is greater than a preset value.
[0011] Preferably, a first voltage divider resistor is connected in series between the first voltage detection terminal and the first terminal of the detection resistor;
[0012] And / or, a second voltage divider resistor is connected in series between the second voltage detection terminal and the second terminal of the detection resistor.
[0013] Preferably, the current limiting switch further includes a first conductive terminal and a second conductive terminal, the first conductive terminal being coupled to the power supply voltage terminal of the power module, and the second conductive terminal being coupled to the USB voltage terminal of the USB interface.
[0014] More preferably, the current limiting switch is an N-channel MOS switch, which turns on when the level at the first control terminal is greater than a first level;
[0015] When the main control module detects that the current flowing through the detection resistor is greater than the preset value, the main control module adjusts the level of the first control terminal to be lower than the first level through the second control terminal to turn off the MOS switch.
[0016] More preferably, the current limiting switch is a P-channel MOS switch, which is turned on when the level at the first control terminal is lower than the second level;
[0017] When the main control module detects that the current flowing through the detection resistor is greater than the preset value, the main control module adjusts the level of the first control terminal to be greater than the second level through the second control terminal to turn off the MOS switch.
[0018] More preferably, the first conductive terminal is the source of the MOS switch, the second conductive terminal is the drain of the MOS switch, and the first control terminal is the gate of the MOS switch.
[0019] More preferably, the second control terminal of the main control module is a general-purpose input / output pin;
[0020] Specifically, the main control module raises the level of the first control terminal by raising the general-purpose input / output pin; or, the main control module lowers the level of the first control terminal by lowering the general-purpose input / output pin.
[0021] Preferably, the display panel is also used to display a display control menu, which is operated to adjust the preset value.
[0022] Preferably, the error in the resistance value of the sensing resistor is less than or equal to 1%.
[0023] Preferably, the USB interface is at least one of USB Type-A, USB Type-B and USB Type-C.
[0024] Compared with the prior art, the embodiments of this utility model provide a display device, including a power module, a USB interface, a current limiting switch, a sensing resistor, and a main control module. The current limiting switch is connected in series between the power module and the USB interface, and the sensing resistor is connected in series between the power module and the current limiting switch, or in series between the current limiting switch and the USB interface. The main control module is used to receive and process video signals and drive the display panel of the display device to display corresponding video images. The main control module includes a first voltage detection terminal, a second voltage detection terminal, and a second control terminal. The first voltage detection terminal is connected to a first end of the sensing resistor, the second voltage detection terminal is connected to a second end of the sensing resistor, and the second control terminal is connected to the first control terminal of the current limiting switch. The main control module is also used to detect the current flowing through the sensing resistor and to control the current limiting switch to turn off when the current exceeds a preset value. Attached Figure Description
[0025] Figure 1 This is a circuit structure block diagram of a display device in one embodiment of the present invention, showing a limitable output current of the USB interface;
[0026] Figure 2 This is a schematic diagram of the working steps of a circuit that can limit the output current of a USB interface in one embodiment of the present invention. Detailed Implementation
[0027] To provide a better understanding of the purpose, structure, features, and functions of this utility model, detailed descriptions are provided below with reference to specific embodiments.
[0028] Certain terms are used in the specification and claims to refer to specific elements. It will be understood by those skilled in the art that manufacturers may use different names to refer to the same element. This specification and claims do not distinguish elements by differences in name, but rather by differences in function. The term "comprising" throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to".
[0029] Please see Figure 1This is a circuit block diagram of a display device in one embodiment of the present invention, showing a device for limiting the output current of a Universal Serial Bus (USB) interface. The display device includes a main control module 4 and a display panel 5. The main control module 4 is, for example, a microcontroller unit (MCU), typically including a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), and input / output interfaces. The display panel 5 is, for example, a liquid crystal display (LCD) panel or an organic light-emitting diode (OLED) panel. The main control module 4 can be coupled to a display adapter and the display panel 5, and is used to receive and process video signals from the display adapter. For example, it can scale the video signal to match the resolution of the display panel 5 and drive the display panel 5 to display the corresponding video image.
[0030] The display device also includes a power module 1, a current limiting switch 2, a sensing resistor 31, and a USB interface 6. In a preferred embodiment, the USB interface 6 is at least one of USB Type-A, USB Type-B, and USB Type-C; however, practical applications are not limited to this. External power devices can be plugged into the USB interface 6 to connect to the power (Voltage Bus, V_BUS) pin in the USB interface 6. The current limiting switch 2 is connected in series between the power module 1 and the USB interface 6. In one embodiment, the sensing resistor 31 is connected in series between the power module 1 and the current limiting switch 2; in another embodiment, the sensing resistor 31 is connected in series between the current limiting switch 2 and the USB interface 6; however, practical applications are not limited to this. In a preferred embodiment, the resistance value error of the sensing resistor 31 is less than or equal to 1%, that is, the actual resistance value of the sensing resistor 31 has an error of ≤ ±1% relative to its calibrated resistance value, in order to improve the accuracy of current detection. The specific resistance value of the sensing resistor 31 must be designed by a technician according to the actual situation, and this utility model is not limited thereto. The main control module 4 includes a first voltage detection terminal V1, a second voltage detection terminal V2, and a second control terminal IO. The first voltage detection terminal V1 is connected to the first end of the detection resistor 31, the second voltage detection terminal V2 is connected to the second end of the detection resistor 31, and the second control terminal IO is connected to the first control terminal G of the current limiting switch. The main control module 4 is also used to detect the current flowing through the detection resistor 31 and to control the current limiting switch 2 to turn off when the detected current flowing through the detection resistor 31 is greater than a preset value. In this embodiment, the main control module 4 specifically detects the voltage values across the detection resistor 31 through the first voltage detection terminal V1 and the second voltage detection terminal V2, calculates the current value flowing through the detection resistor 31 based on the voltage values and resistance value of the detection resistor 31, and then compares the current value with the preset value to determine whether to turn off the current limiting switch 2. If the current value is greater than the preset value, a control signal is sent to the current limiting switch 2 to control its shutdown. It is understandable that after the current limiting switch 2 is turned on, the power module 1 and the external power device plugged into the USB interface 6 will form a circuit loop. The current flowing through the detection resistor 31 is the current that will subsequently flow from the USB interface 6 to the external power device. As mentioned above, the current value of the USB interface 6 can be limited, ensuring electrical safety. This utility model utilizes the function of the main control module 4 to calculate the current value and determine whether the current value is greater than the limit, in conjunction with the current limiting switch 2 to achieve the purpose of current limiting. There is no need to add an additional integrated circuit (IC) chip specifically for current limiting, which helps to reduce the manufacturing cost of the display device.
[0031] In a preferred embodiment, the current limiting switch 2 includes a first conductive terminal S and a second conductive terminal D. The first conductive terminal S is coupled to the power supply voltage terminal 11 of the power module 1, and the second conductive terminal D is coupled to the USB voltage terminal 61 of the USB interface 6. When the current limiting switch 2 is turned on, a circuit is formed from the power supply voltage terminal 11 to the external electrical device plugged into the USB interface 6. The current generated by the voltage drop flows into the current limiting switch 2 from the first conductive terminal S and flows out of the current limiting switch 2 from the second conductive terminal D. Preferably, the current limiting switch 2 is a MOS switch. It should be noted that a MOS switch generally includes a gate (G) used as a control terminal, a source (S) used as an input terminal, and a drain (D) used as an output terminal. The first control terminal G of the current limiting switch 2 is the gate G, used to receive external control signals to control the on / off state of the conductive channel in the MOS switch; the first conductive terminal S of the current limiting switch 2 is the source S; and the second conductive terminal D of the current limiting switch 2 is the drain D. In some preferred embodiments, the current limiting switch 2 is an N-channel MOS switch, which is turned on when the gate G level is greater than a first level. When the microprocessor of the main control module 4 detects that the current flowing through the detection resistor 31 is greater than the preset value, the main control module 4 adjusts the gate G level of the N-channel MOS switch to be less than or equal to the first level via the second control terminal IO, thereby turning off the conductive channel of the N-channel MOS switch. In other preferred embodiments, the current limiting switch 2 is a P-channel MOS switch, which is turned on when the gate G level is less than a second level. The second level may be the same as or different from the first level, and this invention is not limited thereto. When the microprocessor of the main control module 4 detects that the current flowing through the detection resistor 31 is greater than the preset value, the main control module 4 adjusts the gate G level of the P-channel MOS switch to be greater than or equal to the first level via the second control terminal IO, thereby turning off the conductive channel of the P-channel MOS switch. Preferably, the second control terminal IO of the main control module 4 is a general purpose input / output (GPIO) pin. The main control module 4 pulls the GPIO pin high to correspondingly pull the level of the first control terminal G high; or, the main control module 4 pulls the GPIO pin low to correspondingly pull the level of the first control terminal G low.Specifically, taking the current limiting switch 2 as an N-channel MOS switch as an example, when the microprocessor of the main control module 4 detects that the current flowing through the detection resistor 31 is not greater than the preset value, the microprocessor controls the general-purpose input / output pin to output a high level, thereby pulling up the level of the gate G of the N-channel MOS switch. That is, at this time, the gate G of the N-channel MOS switch is at a high level greater than the first level, making the conductive channel of the N-channel MOS switch conduct. When the microprocessor of the main control module 4 detects that the current flowing through the detection resistor 31 is greater than the preset value, the microprocessor controls the general-purpose input / output pin to output a low level, thereby pulling down the level of the gate G of the N-channel MOS switch. That is, at this time, both the general-purpose input / output pin and the gate G of the N-channel MOS switch are at a low level less than the first level, making the conductive channel of the N-channel MOS switch turn off. The embodiment where the current limiting switch 2 is a P-channel MOS switch is similar and will not be described in detail.
[0032] In a preferred embodiment, a first voltage divider resistor 32 is connected in series between the first voltage detection terminal V1 and the first terminal of the detection resistor 31; and / or, a second voltage divider resistor 33 is connected in series between the second voltage detection terminal V2 and the second terminal of the detection resistor 31. In a preferred embodiment, the resistance value of the first voltage divider resistor 32 is much larger than the resistance value of the detection resistor 31, and the error of the resistance value of the first voltage divider resistor 32 is less than or equal to 1%; and the resistance value of the second voltage divider resistor 33 is much larger than the resistance value of the detection resistor 31, and the error of the resistance value of the second voltage divider resistor 33 is less than or equal to 1%, to ensure the accuracy of current detection. For example, the first voltage divider resistor 32 and the second voltage divider resistor 33 can be selected as resistors that are more than 10,000 times larger than the detection resistor 31, but practical applications are not limited to this. Preferably, the first voltage detection terminal V1 and the second voltage detection terminal V2 are, for example, analog-to-digital conversion (ADC) input terminals of the microprocessor coupled to the main control module 4. These two ADC input terminals can convert the analog voltage values across the detection resistor 21 into digital signals, and then the microprocessor calculates the corresponding current value and determines whether the current value is greater than the preset value. Alternatively, the analog voltage difference across the detection resistor 21 can be directly converted into a digital signal, so that the microprocessor can calculate the corresponding current value and determine whether the current value is greater than the preset value. However, the actual application is not limited to this.
[0033] In a preferred embodiment, the display panel 5 is also used to display an on-screen display (OSD) menu. For example, the on-screen display menu can be operated by using adjustment buttons on the display device or other external adjustment devices, thereby adjusting the preset value of the allowable current. Users can adjust the current limiting value according to the specifications of the external power device, improving the versatility of the current limiting function. In addition, the on-screen display menu displayed on the display panel 5 is intuitive and easy for users to operate.
[0034] Based on the above, the operating steps of the circuit that can limit the output current of the USB interface are as follows: Figure 2 As shown, the details are as follows:
[0035] Step S10: The user can operate the on-screen control menu according to the specifications of the external power device plugged into the USB interface 6 to adjust the current limiting of the USB interface 6 to match the external power device.
[0036] Step S20: The microprocessor of the control module 4 obtains a preset value based on the current limit of the adjusted USB interface 6, and calculates the current value flowing through the detection resistor 31 based on the voltage value across the detection resistor 31, and determines whether the current value flowing through the detection resistor 31 is greater than the preset value.
[0037] If the current flowing through the detection resistor 31 is not greater than the preset value, the conductive channel of the current limiting switch 2 remains open, and the USB interface 6 supplies power to the external device.
[0038] If the current flowing through the detection resistor 31 is greater than the preset value, then step S30 is executed: the control module 4 controls the conductive channel of the current limiting switch 2 to turn off, and the USB interface 6 stops supplying power to the external electrical device.
[0039] In summary, embodiments of this utility model provide a display device, including a power module, a USB interface, a current limiting switch, a sensing resistor, and a main control module. The current limiting switch is connected in series between the power module and the USB interface, and the sensing resistor is connected in series between the power module and the current limiting switch, or in series between the current limiting switch and the USB interface. The main control module receives and processes video signals and drives the display panel of the display device to display corresponding video images. The main control module includes a first voltage detection terminal, a second voltage detection terminal, and a second control terminal. The first voltage detection terminal is connected to a first end of the sensing resistor, the second voltage detection terminal is connected to a second end of the sensing resistor, and the second control terminal is connected to the first control terminal of the current limiting switch. The main control module also detects the current flowing through the sensing resistor and controls the current limiting switch to turn off when the current exceeds a preset value.
[0040] This utility model has been described by the above-described embodiments; however, these embodiments are merely examples for implementing this utility model. It must be noted that the disclosed embodiments do not limit the scope of this utility model. Conversely, any modifications and refinements made without departing from the spirit and scope of this utility model are within the scope of patent protection of this utility model.
Claims
1. A display device, characterized by comprising: The application relates to a display device, comprising: a power module; a USB interface; a current-limiting switch connected between the power module and the USB interface; a detection resistor connected between the power module and the current-limiting switch or connected between the current-limiting switch and the USB interface; and a main control module for receiving and processing a video signal and driving a display panel of the display device to display a corresponding video image, the main control module comprising a first voltage detection terminal, a second voltage detection terminal and a second control terminal, the first voltage detection terminal being connected to a first end of the detection resistor, the second voltage detection terminal being connected to a second end of the detection resistor, and the second control terminal being connected to a first control terminal of the current-limiting switch; wherein the main control module is further configured to detect a current flowing through the detection resistor and control the current-limiting switch to be turned off when the current is greater than a preset value. A first voltage dividing resistor is connected between the first voltage detection terminal and the first end of the detection resistor.
2. The display device according to claim 1, wherein A second voltage dividing resistor is connected between the second voltage detection terminal and the second end of the detection resistor. The current-limiting switch further comprises a first conductive terminal and a second conductive terminal, the first conductive terminal being coupled to a power voltage terminal of the power module, and the second conductive terminal being coupled to a USB voltage terminal of the USB interface.
3. The display device according to claim 1, wherein The current-limiting switch is an N-channel MOS switch, which is turned on when a level of the first control terminal is greater than a first level.
4. The display device according to claim 3, wherein When the main control module detects that the current flowing through the detection resistor is greater than the preset value, the main control module adjusts the level of the first control terminal to be less than the first level through the second control terminal to turn off the MOS switch. The current-limiting switch is a P-channel MOS switch, which is turned on when a level of the first control terminal is less than a second level.
5. The display device according to claim 3, wherein When the main control module detects that the current flowing through the detection resistor is greater than the preset value, the main control module adjusts the level of the first control terminal to be greater than the second level through the second control terminal to turn off the MOS switch. The first conductive terminal is a source electrode of the MOS switch, the second conductive terminal is a drain electrode of the MOS switch, and the first control terminal is a gate electrode of the MOS switch.
6. The display device according to claim 4 or 5, characterized by The second control terminal of the main control module is a general-purpose input / output pin.
7. The display device according to claim 4 or 5, wherein The main control module pulls up the level of the first control terminal by pulling up the general-purpose input / output pin, or the main control module pulls down the level of the first control terminal by pulling down the general-purpose input / output pin. The display panel is further configured to display a screen control menu, which is operated to adjust the preset value.
8. The display device according to claim 1, wherein An error of a resistance value of the detection resistor is less than or equal to 1%.
9. The display device according to claim 1, wherein The USB interface is at least one of a USB Type-A, a USB Type-B and a USB Type-C.
10. The display device according to claim 1, wherein The USB interface is at least one of a USB Type-A, a USB Type-B and a USB Type-C.