Head-mounted display device and system

Abstract

The invention provides a head-mounted display device and system, and relates to the technical field of augmented reality. The method and the device are used for solving the problems of poor wearing comfort and the like caused by configuration of a large battery in the augmented reality display equipment. The head-mounted display device comprises a main system and a power supply circuit, the power supply circuit comprises a power interface, a voltage transformation circuit and an insertion detection circuit, and the power interface is used for being connected with an external power supply; the voltage transformation circuit is connected with the power supply interface and is also connected with the power supply end of the main system, and the voltage transformation circuit is used for transforming a power supply voltage provided by an external power supply into a working voltage of the main system so as to supply power to the main system; the insertion detection circuit is used for outputting a startup signal to a startup signal end of the main system when the power interface is connected with an external power supply.

Description

Technical Field

[0001] The present application relates to the field of extended reality technology, and in particular to a head-mounted display device and system. Background Art

[0002] Extended reality (XR) technology is a general term for augmented reality (AR) technology, virtual reality (VR) technology, mixed reality (MR) and other technologies. It refers to the combination of reality and virtuality through computers to create a virtual environment for human-computer interaction.

[0003] Due to the special nature of their use, XR devices need to be worn on the head. In order to increase product life, a large-capacity battery pack needs to be configured on the XR device, which results in the overall weight of the device being heavier. Users will feel uncomfortable after wearing it for a long time, which restricts the development of XR devices. Summary of the invention

[0004] This application provides a head-mounted display device and system to improve the problem that the configuration of a large battery in an XR display device affects the wearing comfort, and the configuration of a small battery affects the battery life of the XR device. The technical solution adopted by this application is as follows:

[0005] In a first aspect, a head-mounted display device is provided. The head-mounted display device includes a main system and a power supply circuit. The power supply circuit includes a power supply interface, a voltage transformation circuit and an insertion detection circuit. The power supply interface is used to connect an external power supply. The voltage transformation circuit is connected to the power supply interface and is also connected to the power supply end of the main system, and is used to transform the power supply voltage provided by the external power supply to the working voltage of the main system to provide power to the main system. The insertion detection circuit is used to output a power-on signal to the power-on signal end of the main system when the power supply interface is connected to the external power supply.

[0006] The head-mounted display device provided in the embodiment of the present application does not have a built-in battery, but uses a power interface to connect to an external power supply, and the transformer circuit transforms the external power supply to the working voltage of the main system, which improves the wearing comfort caused by the configuration of the battery and other problems. At the same time, because the external power supply is easy to replace, a large-capacity external power supply can be selected, so the battery life of the head-mounted display device can also be improved. Since the head-mounted display device needs to be connected to an external power supply to be used, in view of this usage feature, the head-mounted display device provided in the embodiment of the present application does not have a power button, but is provided with an insertion detection circuit. When the power interface is connected to the external power supply, the insertion detection circuit generates a power-on signal to trigger the main system to start up, which saves the cost of setting buttons on the device and improves the user experience.

[0007] In some embodiments, the insertion detection circuit is further configured to stop outputting a power-on signal to a power supply terminal of the main system in response to a control signal of the main system after the main system is powered on.

[0008] In some embodiments, the power interface includes a power pin, the insertion detection circuit includes a first transistor, a second transistor and a first resistor, the first end of the first transistor is connected to the power pin, the second end of the first transistor is grounded through the first resistor, and the control end of the first transistor is connected to the first input and output port of the main system; the first end of the second transistor is connected to the power pin, the second end of the second transistor is connected to the power supply end of the main system, and the control end of the second transistor is connected to the second end of the first transistor.

[0009] In some embodiments, the power supply circuit also includes a protocol chip, which is connected to the power interface; the protocol chip is used to communicate with an external power supply connected to the power interface, so as to output a first power supply voltage to a power pin of the power interface when the external power supply supports a fast charging mode, or to output a second power supply voltage to a power pin of the power interface when the external power supply does not support a fast charging mode, and the first power supply voltage is greater than the second power supply voltage.

[0010] The head-mounted display device provided in the embodiment of the present application is provided with a protocol chip, which can interact with an external power supply. When the external power supply supports the fast charging mode, the external power supply can be powered in the fast charging mode, thereby improving power efficiency and increasing battery life.

[0011] In some embodiments, the power supply circuit also includes a power-off detection circuit, which includes a third transistor, a second resistor, a third resistor and a fourth resistor; the first end of the second resistor is connected to the power interface, the second end of the second resistor and the first end of the third resistor are coupled to the first voltage dividing node, and the second end of the third resistor is grounded; the first voltage dividing node is connected to the shutdown signal end of the main system; the first end of the third transistor is connected to the first voltage dividing node, the second end of the third transistor is grounded through the fourth resistor, and the control end of the third transistor is used to turn on in response to a shutdown operation signal triggered by the user.

[0012] Since the head mounted display device provided in the embodiment of the present application does not have a power button, when the power interface is connected to an external power source, the insertion detection circuit generates a power-on signal to trigger the main system to start up. When the power is off, the power-off detection circuit generates a shutdown signal in response to a shutdown operation signal triggered by the user to notify the main system to shut down, thereby avoiding data loss or device damage caused by a sudden power outage of the system. For example, the above shutdown operation signal can be a signal triggered by a preparatory action of the user before disconnecting the power interface from the external power source, such as rotating the interface, disconnecting the connection buckle, etc.

[0013] In some embodiments, the transformer circuit includes a selection circuit, a first transformer sub-circuit and a second transformer sub-circuit; the selection circuit includes a fixed end, a first selection end and a second selection end, the fixed end of the selection circuit is connected to the power pin of the power interface, the first selection end of the selection circuit is connected to the input end of the first transformer sub-circuit, and the second selection end of the selection circuit is connected to the input end of the second transformer sub-circuit; the output end of the first transformer sub-circuit is connected to the power supply end of the main system, and the output end of the second transformer sub-circuit is connected to the power supply end of the main system; the selection circuit is configured to connect the fixed end and the first selection end when the voltage of the power pin is the first power supply voltage, and the first transformer sub-circuit is configured to transform the first power supply voltage to the working voltage of the main system; the selection circuit is also configured to connect the fixed end and the second selection end when the voltage of the power pin is the second power supply voltage, and the second transformer sub-circuit is configured to transform the second power supply voltage to the working voltage of the main system.

[0014] Since the power supply circuit of the head-mounted display device provided in the embodiment of the present application can support fast charging mode and slow charging mode, the external power supply provides a higher first power supply voltage in the fast charging mode, and provides a lower second power supply voltage in the slow charging mode. In order to improve the power efficiency, the transformer circuit is provided with a first transformer sub-circuit for transforming the first power supply voltage to the working voltage of the main system, and a second transformer sub-circuit is also provided for transforming the second power supply voltage to the working voltage of the main system, and a selection circuit selects switching according to the size of the power supply voltage provided by the external power supply to improve the power efficiency.

[0015] In some embodiments, the first voltage transformation sub-circuit is a charge pump circuit, and the second voltage transformation sub-circuit is a BUCK circuit.

[0016] In some embodiments, the selection circuit includes a fourth transistor, a fifth transistor, a sixth transistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a ninth resistor; the first end of the fifth resistor is connected to the fixed end of the selection circuit, the second end of the fifth resistor and the first end of the sixth resistor are coupled to the second voltage dividing node, and the second end of the sixth resistor is grounded; the first end of the fourth transistor is connected to the fixed end of the selection circuit, the second end of the fourth transistor is connected to the first selection end of the selection circuit, and the control end of the fourth transistor is connected to the second voltage dividing node; the first end of the seventh resistor is connected to the second end of the fourth transistor, the second end of the seventh resistor and the first end of the eighth resistor are coupled to the third voltage dividing node, and the second end of the eighth resistor is grounded; the first end of the sixth transistor is connected to the fixed end of the selection circuit, the second end of the sixth transistor is grounded through the ninth resistor, and the control end of the sixth transistor is connected to the third voltage dividing node; the first end of the fifth transistor is connected to the fixed end of the selection circuit, the second end of the fifth transistor is connected to the second selection end of the selection circuit, and the control end of the fifth transistor is connected to the second end of the sixth transistor.

[0017] In some embodiments, the power supply circuit also includes a plug-in detection circuit, and the output end of the plug-in detection circuit is connected to the power-off detection circuit; the plug-in detection circuit is used to detect the user's operation of disconnecting the external power supply, and outputs a shutdown operation signal to the power-off detection circuit when it detects that the user disconnects the external power supply.

[0018] In a second aspect, a head-mounted display system is also provided, the head-mounted display system comprising a head-mounted display device and an external power supply, the head-mounted display device is a head-mounted display device provided in any implementation manner of the first aspect, the head-mounted display device comprises a power interface, and the external power supply is used to be connected to the power interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of an XR display device provided in an embodiment of the present application;

[0020] Figure 2 A schematic diagram of an XR display device provided in an embodiment of the present application;

[0021] Figure 3 A schematic diagram of another XR display device provided in an embodiment of the present application;

[0022] Figure 4 A functional block diagram of a head mounted display device provided in an embodiment of the present application;

[0023] Figure 5 A schematic diagram of a power interface provided in an embodiment of the present application;

[0024] Figure 6 A schematic diagram of an insertion detection circuit provided in an embodiment of the present application;

[0025] Figure 7 A schematic diagram of a power-off detection circuit provided in an embodiment of the present application;

[0026] Figure 8 A schematic diagram of a plug-in detection circuit provided in an embodiment of the present application;

[0027] Fig. 9 A schematic diagram of a protocol chip provided in an embodiment of the present application;

[0028] Fig.10 A schematic diagram of a voltage conversion circuit provided in an embodiment of the present application;

[0029] Fig.11 A schematic diagram of the workflow of a head mounted display device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0031] In the following, the terms "first", "second", etc. are used only for convenience of description and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more. For example, a plurality of processing units refers to two or more processing units.

[0032] In addition, in the embodiments of the present application, "upper", "lower", "left" and "right" are not limited to being defined relative to the orientation of the components schematically placed in the drawings. It should be understood that these directional terms can be relative concepts, which are used for description and clarification relative to the components, and can change accordingly according to the change in the orientation of the components placed in the drawings. In the drawings, for the sake of clarity, the thickness of the layers and regions is exaggerated, and the size ratio relationship between the parts in the drawings does not reflect the actual size ratio relationship.

[0033] In the embodiments of the present application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. In addition, the term "electrical connection" can be a direct electrical connection or an indirect electrical connection through an intermediate medium.

[0034] In the embodiments of the present application, the term "module" is generally a functional structure divided according to logic, and the "module" can be implemented by pure hardware, or by a combination of software and hardware. In the embodiments of the present application, "and / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, B exists alone, and A and B exist at the same time.

[0035] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0036] In the embodiment of the present application, the transistor can adopt a metal-oxide-semiconductor field effect transistor (MOSFET), and the transistor is divided into two types: N (negative) type transistor and P (positive) type transistor. The transistor includes a source, a drain and a gate. The conduction or cutoff of the transistor can be controlled by controlling the level of the input transistor gate. When the transistor is turned on, the source and the drain are turned on to generate a conduction current, and when the gate level of the transistor is different, the magnitude of the conduction current generated between the source and the drain is also different; when the transistor is cut off, the source and the drain will not be turned on and no current will be generated. In the embodiment of the present application, the gate of the transistor is also called the control end, the source is called the first end, and the drain is called the second end; or, the gate is called the control end, the drain is called the first end, and the source is called the second end. In addition, when the level of the control terminal is high, the N-type transistor is turned on, the first terminal and the second terminal are turned on, and a conduction current is generated between the first terminal and the second terminal; when the level of the control terminal is low, the N-type transistor is turned off, the first terminal and the second terminal are not turned on, and no current is generated. When the level of the control terminal is low, the P-type transistor is turned on, the first terminal and the second terminal are turned on, and a conduction current is generated; when the level of the control terminal is high, the P-type transistor is turned off, the first terminal and the second terminal are not turned on, and no current is generated.

[0037] With the development of computer graphics technology, extended reality (XR) technology has gradually been applied to people's lives. XR technology is a general term for augmented reality (AR), virtual reality (VR), mixed reality (MR) and other technologies. VR uses computer simulation to generate a virtual world in three-dimensional space, providing users with simulated effects of vision and other senses, making users feel as if they are in the scene, and allowing users to interact with the simulated virtual world; AR is a technology that integrates real-world information and virtual-world information, and superimposes physical information that is difficult to experience within a certain time and space range in the real world, such as visual information, sound, touch, etc., into the real world through computer and other scientific and technological simulation, so that users can get a sensory experience beyond reality; MR mixes the real world and the virtual world to produce a new visualization environment, which contains both real-world information and virtual-world information, and the real world and virtual world can interact in real time.

[0038] XR technology is based on XR devices, especially display devices. XR display devices include XR head-mounted display devices, binocular omnidirectional displays, etc. Users can obtain visual effects by wearing XR display devices, such as Figure 1 As shown in a and b, commonly used XR display devices may include XR glasses, XR helmets, etc. XR display devices are usually equipped with one or more display screens, which consume a lot of power. In order to increase the battery life of XR display devices, it is necessary to set up a battery with a large capacity. However, due to the special nature of its use, XR display devices need to be worn on the head, and a battery with a large capacity is also heavy. Figure 2 As shown, if a large-capacity battery pack is configured on the XR device in order to increase the battery life of the XR display device, the overall weight of the device will become heavier, seriously affecting the user experience. However, if a battery with smaller capacity and lighter weight is configured on the XR display device, there will be a problem of insufficient battery life.

[0039] In order to improve the above problems, one possible implementation method is not to integrate the battery into the XR display device to reduce the overall weight of the device, see Figure 3 , use an external battery pack to power the XR display device, and the battery life of the XR display device can be improved by replacing the external battery pack. However, in such a solution, the battery of the XR display device needs to be customized, which is costly. For the XR product as a whole, including the XR display device and the battery, the inclusion of the battery in the XR product will limit the storage and transportation of the XR product.

[0040] In order to improve the above problems, the embodiments of the present application provide a head-mounted display device, which does not have a built-in battery, but can use a common mobile power supply, power bank or other electronic device with a discharge function on the market as an external power supply to power the head-mounted display device. It is plug-and-play, which can not only reduce the cost of product manufacturing, transportation and storage, but also, when the user uses the head-mounted display device, because the head-mounted display device does not have a built-in battery and is lighter in weight, the user experience is better than that of a head-mounted display device equipped with a large-capacity built-in battery. In addition, the user can reuse existing mobile power supplies or power banks and other devices to power the head-mounted display device, thereby reducing the cost of use and ensuring the battery life of the head-mounted display device.

[0041] For example, see Figure 4 , Figure 4The functional block diagram of the head mounted display device provided by the embodiment of the present application is shown, and the head mounted display device includes a main system 10 and a power supply circuit 20, wherein the main system 10 is the core of the head mounted display device, and is used to control the operation of the head mounted display device, and the power supply circuit 20 is used to connect an external power supply to supply power to the main system 10. For example, the main system 10 includes a power supply end, and the power supply circuit 20 includes a power supply interface 21, an insertion detection circuit 22, and a voltage conversion circuit 23, wherein the power supply interface 21 is used to connect an external power supply, for example, the power supply interface 21 can be a USB interface, a MicroUSB interface, a type-C interface, etc.; the insertion detection circuit 22 is used to output a power-on signal to the power supply end of the main system 10 when the power supply interface 21 is connected to an external power supply, and the voltage conversion circuit 23 is connected to the power supply interface 21 and also connected to the power supply end of the main system 10, and is used to convert the power supply voltage provided by the external power supply to the working voltage of the main system 10, so as to provide power to the main system 10.

[0042] For example, taking the power interface 21 as a type-C interface, a pin structure of the type-C interface is as follows: Figure 5 As shown, the type-c interface includes a GND1 pin, a VBUS1 pin, a CC pin, a D+ pin, a D- pin, a SUB pin, a VBUS2 pin, and a GND2 pin. Among them, the D+ pin, the D- pin, and the SUB pin are used as data pins for the head-mounted display device to exchange data with other devices, and the VBUS1 pin and the VBUS2 pin are used as power pins for powering the external power supply and the head-mounted display device. For a brief description, they are collectively referred to as power pins (VBUS) in the embodiment of the present application. The GND1 pin and the GND2 pin are used as ground pins. For a brief description, they are collectively referred to as ground pins (GND) in the embodiment of the present application. The CC pin is used as an identification pin for exchanging charging protocol data packets with an external power supply. When the power interface 21 is connected to an external power supply, and the external power supply provides power to the power interface 21, there will be a voltage on the VBUS pin. For example, the external power supply can provide a power supply voltage of 5V or other magnitudes to the VBUS pin.

[0043] When the power interface 21 is connected to an external power source, the transformer circuit 23 is used to transform the power voltage provided by the external power source into the working voltage of the main system 10 to provide power to the main system 10. For example, when the power interface 21 is connected to an external power source and the external power source provides power to the power interface 21, there will be a voltage on the VBUS pin. In some possible implementations, the external power source can provide a power supply with a voltage of 5V, 9V or other voltages to the VBUS pin. If the working voltage of the main system 10 is 4.5V, the transformer circuit 23 transforms the voltage on the VBUS pin to 4.5V and provides it to the main system 10.

[0044] In the aforementioned Figure 3In the head-mounted display device shown, although the head-mounted display device is not provided with a built-in battery, but is connected to an external battery pack for power supply, the head-mounted display device is still provided with a power button, which invisibly increases the cost of manufacturing and use. For example, adding a button to the device will increase the production and manufacturing costs. When the user uses the head-mounted display device, the head-mounted display device will not start up when the battery pack is not connected, and the power button can only be pressed to start up after the battery pack is connected, which increases the cost of use. In view of the use characteristics of the head-mounted display device powered by an external power source, that is, it can only be used after connecting to an external power source, and it cannot be used when the external power source is disconnected, the embodiment of the present application provides a plug-and-play head-mounted display device, the power supply circuit 20 of the head-mounted display device includes an insertion detection circuit 22, the head-mounted display device does not need to be provided with a power button, and automatically generates a power-on signal to start up the main system 10 when the power interface 21 is connected to an external power source.

[0045] Exemplarily, the insertion detection circuit 22 is used to send a start signal terminal P1 (see FIG. 1 ) of the main system 10 when the power interface 21 is connected to an external power source. Figure 6 ) output signal, triggering the main system 10 to start up. In some embodiments, the insertion detection circuit 22 includes a first transistor Q1 and a second transistor Q2, the first end Q1a of the first transistor Q1 is connected to the VBUS pin of the power interface 21, and the second end Q1b of the first transistor Q1 is grounded. In some possible implementations, the insertion detection circuit 22 also includes a first resistor R1, the second end Q1b of the first transistor Q1 can also be grounded through the first resistor R1, and the control end Q1c of the first transistor Q1 is connected to the first input and output port GPIO1 of the main system 10; the first end Q2a of the second transistor Q2 is connected to the power pin VBUS, the second end Q2b of the second transistor Q2 is connected to the start signal end P1 of the main system 10, and the control end Q2c of the second transistor Q2 is connected to the second end Q1b of the first transistor Q1. In the embodiment of the present application, the first transistor Q1 is an N-type transistor, which is turned on when the control end Q1c is at a high level, and the second transistor Q2 is a P-type transistor, which is turned on when the control end Q2c is at a low level.

[0046] When the power interface 21 is not connected to an external power source, the main system 10 of the head mounted display device is not powered on and will not start, and the first input / output port GPIO1 does not output a control signal, and the control end Q1c of the first transistor Q1 is connected to the first input / output port GPIO1 of the main system 10. Therefore, in this case, the first transistor Q1 is turned off, and the voltage of the second end Q1b of the first transistor Q1 is 0, and the control end Q2c of the second transistor Q2 is connected to the second end Q1b of the first transistor Q1, so the voltage of the control end Q2c of the second transistor Q2 is also at a low level. The first end Q2a and the second end Q2b of the second transistor Q2 are turned on, and the first end Q2a of the second transistor Q2 is connected to the VBUS pin, and the second end Q2b of the second transistor Q2 is connected to the start signal terminal P1 of the main system 10, that is, the VBUS pin is connected to the start signal terminal P1 of the main system 10. Therefore, when the power interface 21 is connected to the external power supply, the VBUS pin has a voltage, for example, the voltage of the VBUS pin is 5V, and this voltage will be provided to the start signal terminal P1 of the main system 10. The main system 10 determines that this voltage signal is a power-on signal, and the main system 10 is turned on and started.

[0047] When the main system 10 is started, the first input-output port GPIO1 outputs a control signal. For example, the control signal is at a high level, that is, the control terminal Q1c of the first transistor Q1 is at a high level, the first transistor Q1 is turned on, and the first terminal Q1a of the first transistor Q1 is connected to the VBUS pin, and the second terminal Q1b of the first transistor Q1 is grounded through a first resistor. Therefore, when the first transistor Q1 is turned on, the second terminal Q1b of the first transistor Q1 is pulled up to a high level by the power supply of the VBUS pin, that is, the control terminal Q2c of the second transistor Q2 is at a high level, the first terminal Q2a and the second terminal of the second transistor Q2 are cut off, and the insertion detection circuit 22 stops outputting the power-on signal.

[0048] The head-mounted display device provided in the embodiment of the present application uses an external power supply and can only be started and used when the external power supply is connected. Based on such usage characteristics, when the user connects the head-mounted display device to the external power supply, the user intends to use the head-mounted display device; when the user intends to stop using the head-mounted display device, the external power supply can be disconnected. The head-mounted display device provided in the embodiment of the present application cancels the power button and instead sets an insertion detection circuit 22. When the power interface 21 is connected to the external power supply, the insertion detection circuit 22 outputs a signal to the main system 10 to trigger the main system 10 to start up. When the main system 10 is started, the insertion detection circuit 22 stops outputting signals. When using the head-mounted display device provided in the embodiment of the present application, the user will trigger the start-up after connecting the head-mounted display device to the external power supply, eliminating the process of pressing the power button to start the start-up, which can save the cost of setting buttons in the device and is more convenient to use.

[0049] The head-mounted display device does not have a power button and is plug-and-play, which can improve the convenience of use. The corresponding to plug-in startup is shutdown by powering off, but for electronic devices, sudden power outages may cause data loss and system damage. The head-mounted display device provided in the embodiment of the present application also includes a power-off detection circuit. The main system 10 includes a shutdown signal terminal. The power-off detection circuit is connected to the shutdown signal terminal of the main system 10. The power-off detection circuit is used to output a signal to the main system 10 in response to a shutdown operation signal triggered by the user, triggering the main system 10 to shut down and stop running.

[0050] For example, in Figure 4 Based on Figure 7 In Figure a, the power-off detection circuit 24 includes a third transistor Q3, a second resistor R2 and a third resistor R3, wherein the first end of the second resistor R2 is connected to the VBUS pin of the power interface 21, the second end of the second resistor R2 and the first end of the third resistor R3 are coupled to the first voltage dividing node F1, the second end of the third resistor R3 is grounded, the first voltage dividing node F1 is connected to the shutdown signal end P2 of the main system 10, the first end Q3a of the third transistor Q3 is connected to the first voltage dividing node F1, and the second end Q3b of the third transistor Q3 is grounded. In some examples, the power-off detection circuit 24 also includes a fourth resistor R4, the second end Q3b of the third transistor Q3 can be grounded through the fourth resistor R4, and the control end Q3c of the third transistor Q3 is used to receive a shutdown operation signal triggered by the user, and is cut off when the shutdown operation signal is not received, and is turned on when the shutdown operation signal is received.

[0051] In the circuit provided in the embodiments of the present application, nodes (such as the first voltage-dividing node F1 and subsequent other nodes in the aforementioned example) do not represent actual existing components, but represent the junction points of related electrical connections in the circuit diagram, that is, these nodes are nodes formed by the junction points of related electrical connections in the circuit diagram.

[0052] The voltage of the first voltage-dividing node F1 is the voltage of the VBUS pin divided by the voltage on the third resistor R3. When the shutdown operation signal triggered by the user is not received, the third transistor Q3 is turned off, and the first voltage-dividing node F1 pulls up the voltage of the shutdown signal terminal P2 of the main system 10, and the main system 10 works normally at this time. In the case of receiving the shutdown operation signal triggered by the user, the third transistor Q3 is turned on, the first voltage-dividing node F1 is grounded through the third transistor Q3 and the fourth resistor R4, and the voltage of the first voltage-dividing node F1 is pulled down to a low level, and the high level of the shutdown signal terminal P2 originally output to the main system 10 is pulled down to a low level, informing the main system 10 to prepare for shutdown, so that the main system 10 starts to shut down each functional module in turn, and saves user data to prevent the system from being powered off and shutting down suddenly.

[0053] For example, in order to prevent the voltage of the first voltage-dividing node F1 from being too high, refer to Figure 7 As shown in Figure b, the power-off detection circuit 24 may also include a transistor M1, a resistor Rs1, and a resistor Rs2. The first end of the resistor Rs1 is connected to the VBUS pin, the second end of the resistor Rs1 and the first end of the resistor Rs2 are coupled to the voltage dividing node Fs, and the second end of the resistor Rs2 is grounded. The first end M1a of the transistor M1 is connected to the VBUS pin, the second end M1b of the transistor M1 is connected to the first end of the second resistor R2, and the control end M1c of the transistor M1 is connected to the voltage dividing node Fs. In this example, when there is voltage on the VBUS pin, the voltage of the VBUS pin is divided by the resistors Rs1 and Rs2, the voltage of the voltage dividing node Fs1 is pulled up, and the transistor M1 is turned on when the voltage of the voltage dividing node Fs1 is at a high level. In this case, the voltage of the first voltage dividing node F1 is not the voltage divided by the voltage of the VBUS pin on the third resistor R3, but the voltage divided by the voltage of the turned-on transistor M1 on the third resistor R3, so that the voltage of the first voltage dividing node F1 can be reduced to avoid damaging the internal structure of the main system 10.

[0054] Exemplarily, the shutdown operation signal may be a shutdown operation signal generated by the user through interaction with the main system 10, or may be a preparation signal for the user to disconnect the power connection between the external power supply and the head mounted display device.

[0055] For example, in some embodiments, see Figure 8 The power supply circuit 20 also includes a plug-in detection circuit 26, which is connected to the power-off detection circuit 24. The plug-in detection circuit 26 is used to detect the user's operation of disconnecting the external power supply, and generates the above-mentioned shutdown operation signal when the user's operation of disconnecting the external power supply is detected, and the shutdown operation signal is output to the power-off detection circuit 24. For example, the interface of the external power supply can be connected to the power interface 21 of the head-mounted display device by rotation or snapping, etc. Before disconnecting the connection between the interface of the external power supply and the power interface 21 of the head-mounted display device, it is necessary to rotate the interface or release the snap, etc. When the user rotates the interface or releases the snap, etc., the plug-in detection circuit can be triggered to generate the above-mentioned shutdown operation signal. The power-off detection circuit 24 sends a shutdown signal to the main system 10 in response to the shutdown operation signal, notifying the main system 10 to shut down, so as to avoid data loss or system failure caused by sudden power failure.

[0056] In addition, in the above example, the power supply terminal (VCC), the start signal terminal (P1), and the shutdown signal terminal (P2) of the main system are different terminals or pins. In some other possible implementations, some or all of them can be combined on the same terminal to play corresponding functions by identifying different signals. For example, when the signal lasts for a first time, it can be determined as a start signal, and when the signal lasts for a second time, it can be determined as a shutdown signal.

[0057] For example, in some embodiments, the start signal terminal (P1) and the power supply terminal (VCC) of the main system 10 of the head-mounted display device are the same terminal. Taking the power-on signal as an example, the insertion detection circuit 22 is connected to the power supply terminal (VCC) of the main system 10. When the power interface 21 is connected to an external power supply, the voltage of the VBUS pin generates a voltage signal to the power supply terminal of the main system 10 through the transistor Q2 of the insertion detection circuit 22. After the signal lasts for a first period of time (for example, 3 seconds), the main system 10 recognizes it as a power-on signal and starts to start. After the main system 10 is started, it will control the transistor Q1 of the insertion detection circuit 22 to turn on through the input and output port (for example, GPIO1), thereby controlling the transistor Q2 to turn on, and the insertion detection circuit 22 stops outputting (power-on) signals to the power supply terminal of the main system 10.

[0058] External power sources such as power banks and power banks can output a voltage of 5V. In order to quickly charge mobile phones, tablets or other electronic devices, power banks or power banks can often support fast charging protocols and charge mobile phones and other electronic devices in fast charging mode. For example, when working in fast charging mode, the power bank or power bank can output a voltage of 9V or higher. Relatively speaking, working in fast charging mode, the power bank or power bank is more efficient and has a longer battery life.

[0059] For example, please combine Figure 4 , Figure 5 and Fig. 9 In order to improve the power supply efficiency and battery life of the head-mounted display device provided in the embodiment of the present application, the power supply circuit includes a protocol chip 25, and the protocol chip 25 is connected to the power interface 21. When the power interface 21 is connected to the external power supply, the protocol chip 25 is used to communicate with the external power supply connected to the power interface 21, so that the external power supply outputs a first power supply voltage to the power pin of the power interface 21 when the fast charging mode is supported, or outputs a second power supply voltage to the power pin of the power interface 21 when the fast charging mode is not supported. The first power supply voltage is greater than the second power supply voltage. For example, the first power supply voltage is 9V and the second power supply voltage is 5V.

[0060] For example, the protocol chip 25 includes pins such as VIN, EN, CC, PSEL, TABLE_SLE and GND. The VIN pin of the protocol chip 25 is an input pin, which is connected to the VBUS pin of the power interface 21. The EN pin of the protocol chip 25 is an enable pin, which is in working state by default. The CC pin of the protocol chip 25 is connected to the CC pin of the power interface 21, which is used to exchange charging protocol data packets with the external power supply. When the external power supply is connected to the power interface 21, the protocol chip 25 will communicate with the external power supply through the CC pin to determine whether the external power supply supports the fast charging mode. If supported, the voltage of the VBUS pin will be raised from the second power supply voltage to the first power supply voltage; otherwise, if not supported, the voltage of the VBUS pin will be kept at the first power supply voltage. By configuring the resistors on the PSEL pin and the TABLE_SEL pin, the output configuration of the protocol chip 25 can be adjusted to meet the load requirements of the system.

[0061] In the solution provided in the embodiment of the present application, in order to reduce the cost of production, transportation, storage and use of the head-mounted display device and improve the battery life of the head-mounted display device, the head-mounted display device is not provided with a built-in battery, but an external power supply is used to power the head-mounted display device. The external power supply can be a mobile power supply or a power bank, or other devices that can discharge power to the outside. Some external power supplies can support fast charging mode and slow charging mode, and can provide a first power supply voltage in fast charging mode, or provide a second power supply voltage in slow charging mode, while some external power supplies only support slow charging mode and can provide a second power supply voltage.

[0062] Since the operating voltage of the head-mounted display device may be different from the voltage provided by the external power supply, the power supply circuit 20 of the head-mounted display device is provided with a voltage conversion circuit 23, the input end of the voltage conversion circuit 23 is connected to the VBUS pin of the power interface 21, and the output end of the voltage conversion circuit 23 is connected to the power supply end of the main system 10. The voltage conversion circuit 23 is used to convert the power supply voltage provided by the external power supply to the operating voltage of the main system 10 of the head-mounted display device. In some embodiments, the operating voltage of the main system 10 of the head-mounted display device is 4.5V, so no matter whether the external power supply provides the first power supply voltage or the second power supply voltage, it needs to be converted before it can be provided to the main system 10 of the head-mounted display device for power supply.

[0063] In order to adapt to different power supply voltages, combined Figure 4 and Fig.10The voltage transformation circuit 23 provided in the embodiment of the present application includes a selection circuit 231, a first voltage transformation sub-circuit 232 and a second voltage transformation sub-circuit 233. When the external power supply provides the first power supply voltage or the second power supply voltage to the head-mounted display device, the selection circuit 231 controls the working state of the corresponding voltage transformation sub-circuit. For example, when the external device provides the first power supply voltage to the head-mounted display device, the selection circuit 231 selects the first voltage transformation sub-circuit 232 to work, and the second voltage transformation sub-circuit 233 does not work; when the external device provides the second power supply voltage to the head-mounted display device, the selection circuit 231 selects the second voltage transformation sub-circuit 233 to work, and the first voltage transformation sub-circuit 232 does not work.

[0064] Since the power supply voltages provided by the external power supply to the head mounted display device are different, the selection circuit 231 needs to select a voltage transformation sub-circuit matching the voltage provided by the external power supply to the head mounted display device according to the voltage.

[0065] Exemplarily, the selection circuit 231 includes a fixed end S1, a first selection end S2 and a second selection end S3. The fixed end S1 of the selection circuit 231 is connected to the VBUS pin of the power interface 21, the first selection end S2 of the selection circuit 231 is connected to the input end IN1 of the first transformer sub-circuit 232, and the second selection end S3 of the selection circuit 231 is connected to the input end IN2 of the second transformer sub-circuit 233. The output terminal OUT1 of the first transformer subcircuit 232 is connected to the power supply terminal VCC of the main system 10, and the output terminal OUT2 of the second transformer subcircuit 233 is connected to the power supply terminal VCC of the main system 10. The selection circuit 231 is configured to conduct the fixed terminal S1 and the first selection terminal S2 when the voltage of the VBUS pin is the first power supply voltage, so that the input terminal IN1 of the first transformer subcircuit 232 has a voltage, and the first transformer subcircuit 232 transforms the first power supply voltage into the working voltage of the main system 10 and outputs it to the main system 10 of the head-mounted display device; the selection circuit 231 is also configured to conduct the fixed terminal S1 and the second selection terminal S3 when the voltage of the VBUS pin is the second power supply voltage, so that the input terminal IN2 of the second transformer subcircuit 233 has a voltage, and the second transformer subcircuit 233 transforms the second power supply voltage into the working voltage of the main system 10 and outputs it to the main system 10 of the head-mounted display device.

[0066] Taking the first power supply voltage as 9V and the working voltage of the main system 10 of the head-mounted display device as 4.5V as an example, the first voltage transformation subcircuit 232 may be a charge pump circuit with a transformation ratio of 2:1, which is used to transform the first power supply voltage into a working voltage of 4.5V in proportion to supply the main system 10 of the head-mounted display device. Taking the second power supply voltage as 5V and the working voltage of the main system 10 of the head-mounted display device as an example, the second voltage transformation subcircuit 233 may be a BUCK (step-down) circuit, which transforms the second power supply voltage into a working voltage of 4.5V to supply the main system 10 of the head-mounted display device.

[0067] Exemplary, combined Fig.10 The selection circuit 231 further includes a fourth transistor Q4, a fifth transistor Q5, a sixth transistor Q6, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8. A first end of the fifth resistor R5 is connected to the fixed end S1 of the selection circuit 231, a second end of the fifth resistor R5 and a first end of the sixth resistor R6 are coupled to the second voltage-dividing node F2, and a second end of the sixth resistor R6 is grounded; a first end Q4a of the fourth transistor Q4 is connected to the fixed end S1 of the selection circuit 231, a second end Q4b of the fourth transistor Q4 is connected to the first selection end S2 of the selection circuit 231, and a control end Q4c of the fourth transistor Q4 is connected to the second voltage-dividing node F2; a first end of the seventh resistor R7 is connected to the second end Q4b of the fourth transistor Q4, a second end of the seventh resistor R7 and a first end of the eighth resistor R8 are coupled to the third voltage-dividing node F3, and a second end of the eighth resistor R8 is connected to the third voltage-dividing node F4. 8 is grounded; the first end Q6a of the sixth transistor Q6 is connected to the fixed end S1 of the selection circuit 231, and the second end Q6b of the sixth transistor Q6 is grounded. In some examples, the selection circuit 231 also includes a ninth resistor R9, and the second end Q6b of the sixth transistor Q6 can also be grounded through the ninth resistor R9, and the control end Q6c of the sixth transistor Q6 is connected to the third voltage dividing node F3; the first end Q5a of the fifth transistor Q5 is connected to the fixed end S1 of the selection circuit 231, the second end Q5b of the fifth transistor Q5 is connected to the second selection end S3 of the selection circuit 231, and the control end Q5c of the fifth transistor Q5 is connected to the second end Q6b of the sixth transistor Q6.

[0068] In the embodiment of the present application, the fourth transistor Q4 and the sixth transistor Q6 are N-type transistors, which are turned on when the control terminal is at a high level and turned off when the control terminal is at a low level; the fifth transistor Q5 is a P-type transistor, which is turned on when the control terminal is at a low level and turned off when the control terminal is at a high level.

[0069] In order to improve the power efficiency of the power supply system, the selection circuit 231 can control the switching transformation path through the voltage of the VBUS pin, for example, selecting the first transformation subcircuit 232 to work or selecting the second transformation subcircuit 233 to work. Exemplarily, the working principle of the selection circuit 231 is described below by taking the first power supply voltage as 9V and the second power supply voltage as 5V as an example.

[0070] When the voltage of the VBUS pin is 5V, after the 5V voltage of the VBUS pin is divided by the fifth resistor R5 and the sixth resistor R6, the voltage of the second voltage-dividing node F2 is relatively low, the control terminal Q4c of the fourth transistor Q4 is at a low level, and the fourth transistor Q4 is in a cut-off state; when the fourth transistor Q4 is cut off, there is no voltage at the third voltage-dividing node F3, and the control terminal Q6c of the sixth transistor Q6 is also at a low level, so that the sixth transistor Q6 is also in a cut-off state, at this time, the second terminal Q6b of the sixth transistor Q6 is grounded at a low level, that is, the control terminal Q5c of the fifth transistor Q5 is at a low level, and the fifth transistor Q5 is in a conducting state. That is, when the voltage of the VBUS pin is 5V, the sixth transistor Q6 and the fourth transistor Q4 of the selection circuit 231 are cut off, and the fifth transistor Q5 is turned on, and the fixed terminal S1 of the selection circuit 231 is turned on with the second selection terminal S3 of the selection circuit 231 through the fifth transistor Q5, that is, the second voltage-converting sub-circuit 233 is selected to work, and at this time, the fourth transistor Q4 is in a cut-off state, and the input of the first voltage-converting sub-circuit 232 is turned off.

[0071] When the external power supply supports the fast charging protocol, the protocol chip communicates with the external power supply to increase the voltage output by the external power supply to the VBUS pin to 9V. At this time, after the 9V voltage of the VBUS pin is divided by the fifth resistor R5 and the sixth resistor R6, the voltage of the second voltage-dividing node F2 is relatively high, so that the control terminal Q4c of the fourth transistor Q4 is at a high level, and the fourth transistor Q4 is turned on. When the fourth transistor Q4 is turned on, the 9V voltage of the VBUS pin is divided by the seventh resistor R7 and the eighth resistor R8, and the voltage of the third voltage-dividing node F3 is relatively high, so that the control terminal Q6c of the sixth transistor Q6 is at a high level, and the sixth transistor Q6 is turned on. When the sixth transistor Q6 is turned on, the sixth transistor Q6c is turned on. The voltage of the second end Q6b of the selection circuit 231 is pulled up, so that the control end Q5c of the fifth transistor Q5 is at a high level, and the fifth transistor Q5 is turned off. That is, when the voltage of the VBUS pin is 9V, the sixth transistor Q6 and the fourth transistor Q4 of the selection circuit 231 are turned on, and the fifth transistor Q5 is turned off. The fixed end S1 of the selection circuit 231 is turned on with the first selection end S2 of the selection circuit 231 through the fourth transistor Q4, that is, the first voltage transformation sub-circuit 232 is selected to work, and the first voltage transformation sub-circuit 232 will step down the voltage and output it to the power supply end VCC of the main system 10 at a ratio of 2:1 for power supply, and at this time, the fifth transistor Q5 is in a cut-off state, and the input of the second voltage transformation sub-circuit 233 is turned off.

[0072] The transformer circuit 23 of the head-mounted display device provided in the embodiment of the present application is provided with a selection circuit 231, and the selection circuit 231 selects a suitable transformer sub-circuit to work according to the size of the power supply voltage provided by the external power supply. For example, when the external power supply provides the first power supply voltage in the fast charging mode, it selects to output a signal to the first transformer sub-circuit 232 and at the same time closes the input of the second transformer sub-circuit 233; when the external power supply provides the power supply voltage in the slow charging mode, it selects to output a signal to the second transformer sub-circuit 233 and at the same time closes the input of the first transformer sub-circuit 232. The transformer path can be switched according to the different power supply voltages provided by the external power supply, thereby greatly improving the power supply efficiency and increasing the battery life.

[0073] In some embodiments, the first voltage transformation sub-circuit 232 may be a charge pump circuit, for example, a circuit combining Fig.10 The first transformer subcircuit 232 includes a charge pump chip U1, a resistor R10, a capacitor C1, a capacitor C2, and a capacitor C3, etc. The charge pump chip U1 includes pins such as VIN, VOUT, EN, SCL, CF1, SDA, CF2, and GND, wherein the VIN pin is an input pin, and the VIN pin of the charge pump chip U1 is connected to the VBUS pin of the power interface 21, the VOUT pin is an output pin, and is connected to the power supply terminal VCC of the main system 10 of the head-mounted display device, and the EN pin is used to control whether the chip is working, and is in a working state by default. There is a flying capacitor between the CF1 pin and the CF2 pin, and the capacitors C1, C2, and C3 are connected between the CF1 pin and the CF2 pin, and are used to charge and discharge during the voltage conversion process to achieve voltage conversion, and the SCL and SDA pins are used to communicate with the main system 10, for example, the SCL pin is connected to the second input and output port GPIO2 of the main system 10, and the SDC pin is connected to the third input and output port GPIO3 of the main system 10, and the charge pump circuit can effectively improve the working efficiency of the power supply and reduce system losses.

[0074] In some embodiments, the second transformer sub-circuit 233 may be a BUCK circuit, see Fig.10As shown, the second transformer subcircuit 233 includes a BUCK chip U2, a resistor R11 and a resistor R12. The BUCK chip U2 includes pins such as VIN, VOUT, EN, FB, and GND, wherein the VIN pin of the BUCK chip U2 is an input pin, the VIN pin of the BUCK chip U2 is connected to the VBUS pin of the power interface 21, the VOUT of the BUCK chip U2 is an output pin, connected to the power supply end VCC of the main system 10 of the head mounted display device, the EN pin of the BUCK chip U2 is used to control whether the chip is working, and is in a working state by default; FB is an output feedback pin, used to set the output voltage, the first end of the resistor R11 is connected to the VOUT pin of the BUCK chip U2, the second end of the resistor R11 and the first end of the resistor R12 are coupled to the fourth voltage dividing node F4, the second end of the resistor R12 is grounded, and the voltage dividing node F4 is connected to the FB pin of the BUCK chip U2. The output voltage of the BUCK circuit can be expressed as:

[0075] VOUT = V CON *(R 11 +R 12 ) / R 12

[0076] Where VOUT is the output voltage of the BUCK circuit, R 12 is the resistance value of resistor R12, R 11 is the resistance value of resistor R11, V CON This is the constant set for the BUCK chip. By adjusting V CON When the voltage of the VBUS pin is 5V, the BUCK circuit can step down 5V to 4.5V and output it to the main system 10 of the head mounted display device.

[0077] Combine the following Fig.11, the example introduces the working process of the head-mounted display device. After the power interface is connected to the external power supply, on the one hand, the insertion detection circuit generates a power-on signal to trigger the main system to start up. On the other hand, the protocol chip communicates with the external power supply to determine whether the external power supply supports the fast charging mode. If the fast charging mode is supported, the external power supply will increase the 5V voltage provided to the head-mounted display device to 9V. The selection circuit of the voltage conversion circuit selects the voltage conversion sub-circuit according to the size of the VBUS voltage. If the voltage of the VBUS pin is 9V, the first voltage conversion sub-circuit is selected to work. The first voltage conversion sub-circuit can be a charge pump circuit. The charge pump circuit converts the 9V voltage to 4.5V and provides it to the main system, and closes the input of the second voltage conversion sub-circuit; if the external power supply does not support the fast charging mode and provides a 5V voltage to the head-mounted display device, the selection circuit will select the second voltage conversion sub-circuit to work. The second voltage conversion sub-circuit can be a BUCK circuit. The BUCK circuit converts the 5V voltage to 4.5V and provides it to the main system, and closes the first voltage conversion sub-circuit. The power-off detection circuit detects whether the user triggers the shutdown operation signal, and generates a shutdown signal when the user triggers the shutdown operation signal to notify the main system to shut down.

[0078] The head-mounted display device provided in the embodiment of the present application does not have a built-in battery, but uses an external power supply for power supply, which can reduce the cost of production, transportation, storage and use of the head-mounted display device, solve the safety and limitation problems of the battery in the transportation of the product, and also avoid the problem that the battery may be depleted due to the product being in the warehouse for a long time. The user can use the existing mobile power supply or power bank to power the head-mounted display device, and the user does not need to use a customized battery pack to use the product, so as to realize the battery-free product, thereby reducing the weight of the product and improving the wearing comfort. In addition, the head-mounted display device provided in the embodiment of the present application is provided with a protocol chip, a selection circuit and a plurality of transformer sub-circuits, which can be compatible with fast-charging or slow-charging external power supplies, can improve the power supply efficiency of the external power supply, and increase the power supply endurance. The user can choose a large-capacity mobile power supply or power bank, or directly replace the external power supply when the external power supply is exhausted to increase the endurance. In view of the fact that the head-mounted display device does not have a built-in battery, the head-mounted display device provided in the embodiment of the present application cancels the power button, but automatically triggers the power on when the power interface is connected to an external power source, and automatically triggers the power off when the user is about to disconnect the power interface. On the one hand, it can reduce production costs, and on the other hand, it can improve user experience.

[0079] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A head mounted display device, characterized in that: It includes a main system and a power supply circuit, and the power supply circuit includes: Power interface, used to connect an external power source; A voltage conversion circuit, connected to the power interface and also connected to the power supply end of the main system, for converting the power supply voltage provided by the external power supply to the working voltage of the main system to provide power to the main system; The insertion detection circuit is used to output a power-on signal to the power-on signal terminal of the main system when the power interface is connected to an external power source.

2. The head mounted display device according to claim 1, characterized in that: The insertion detection circuit is further configured to stop outputting the power-on signal to the power supply end of the main system in response to a control signal of the main system after the main system is powered on.

3. The head mounted display device according to claim 2, characterized in that: The power interface includes a power pin, the insertion detection circuit includes a first transistor and a second transistor, a first end of the first transistor is connected to the power pin, a second end of the first transistor is grounded, and a control end of the first transistor is connected to a first input / output port of the main system; A first end of the second transistor is connected to the power pin, a second end of the second transistor is connected to the power supply end of the main system, and a control end of the second transistor is connected to the second end of the first transistor.

4. The head mounted display device according to claim 1, characterized in that: The power supply circuit also includes a protocol chip, and the protocol chip is connected to the power interface; The protocol chip is used to communicate with the external power supply connected to the power interface to output a first power supply voltage to the power pin of the power interface when the external power supply supports fast charging mode, or to output a second power supply voltage to the power pin of the power interface when the external power supply does not support fast charging mode, and the first power supply voltage is greater than the second power supply voltage.

5. The head mounted display device according to any one of claims 1 to 4, characterized in that: The power supply circuit further includes a power-off detection circuit, and the power-off detection circuit includes a third transistor, a second resistor and a third resistor; The first end of the second resistor is connected to the power interface, the second end of the second resistor and the first end of the third resistor are coupled to the first voltage division node, and the second end of the third resistor is grounded; The first voltage dividing node is connected to a shutdown signal terminal of the main system; The first end of the third transistor is connected to the first voltage dividing node, the second end of the third transistor is grounded, and the control end of the third transistor is used to be turned on in response to a shutdown operation signal triggered by a user.

6. The head mounted display device according to any one of claims 1 to 5, characterized in that: The voltage transformation circuit includes a selection circuit, a first voltage transformation subcircuit and a second voltage transformation subcircuit; The selection circuit includes a fixed end, a first selection end and a second selection end, the fixed end of the selection circuit is connected to the power pin of the power interface, the first selection end of the selection circuit is connected to the input end of the first transformer subcircuit, and the second selection end of the selection circuit is connected to the input end of the second transformer subcircuit; The output end of the first transformer subcircuit is connected to the power supply end of the main system, and the output end of the second transformer subcircuit is connected to the power supply end of the main system; The selection circuit is configured to conduct the fixed terminal with the first selection terminal when the voltage of the power pin is the first power voltage, and the first voltage transformation subcircuit is configured to transform the first power voltage to the working voltage of the main system; The selection circuit is further configured to conduct the fixed end and the second selection end when the voltage of the power pin is the second power voltage, and the second transformation subcircuit is configured to transform the second power voltage to the working voltage of the main system.

7. The head mounted display device according to claim 6, characterized in that: The first voltage transformation sub-circuit is a charge pump circuit, and the second voltage transformation sub-circuit is a BUCK circuit.

8. The head mounted display device according to claim 6 or 7, characterized in that: The selection circuit includes a fourth transistor, a fifth transistor, a sixth transistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor; The first end of the fifth resistor is connected to the fixed end of the selection circuit, the second end of the fifth resistor and the first end of the sixth resistor are coupled to the second voltage division node, and the second end of the sixth resistor is grounded; The first end of the fourth transistor is connected to the fixed end of the selection circuit, the second end of the fourth transistor is connected to the first selection end of the selection circuit, and the control end of the fourth transistor is connected to the second voltage dividing node; The first end of the seventh resistor is connected to the second end of the fourth transistor, the second end of the seventh resistor and the first end of the eighth resistor are coupled to the third voltage dividing node, and the second end of the eighth resistor is grounded; A first end of the sixth transistor is connected to a fixed end of the selection circuit, a second end of the sixth transistor is grounded, and a control end of the sixth transistor is connected to the third voltage dividing node; The first end of the fifth transistor is connected to the fixed end of the selection circuit, the second end of the fifth transistor is connected to the second selection end of the selection circuit, and the control end of the fifth transistor is connected to the second end of the sixth transistor.

9. The head mounted display device according to claim 5, characterized in that: The power supply circuit further includes a plug-in detection circuit, and an output end of the plug-in detection circuit is connected to the power-off detection circuit; The plug-in detection circuit is used to detect the operation of disconnecting the external power supply by the user, and output the shutdown operation signal to the power-off detection circuit when the operation of disconnecting the external power supply by the user is detected.

10. A head mounted display system, characterized in that: The head-mounted display system includes a head-mounted display device and an external power supply. The head-mounted display device is the head-mounted display device according to any one of claims 1 to 9. The head-mounted display device includes a power interface, and the external power supply is used to be connected to the power interface.

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