Key screen device suitable for lightning interface

Abstract

The utility model relates to a key screen device suitable for a thunder interface, which comprises a power supply module and a processor, the input of the power supply module is externally connected with a power supply, the power supply module is used as a power supply of the key screen suitable for the thunder interface and comprises a foldable display screen and a keyboard area, and the structure is similar to that of a notebook computer. The display screen and the keyboard area are respectively arranged on the inner surfaces of the two hinges, the keyboard area comprises a keyboard and a touch panel, the display screen and the keyboard area are respectively in signal connection with an interface module, and the interface module is used for being externally connected with a host. The pocket computer inherits the characteristic of being convenient to carry of a traditional screen, a keyboard, a mouse and sound equipment, solves the problem that in the prior art, when a pocket computer is used, various electronic devices need to be carried, and is very troublesome, has the characteristics of being convenient to use, portable and the like, and can meet more comprehensive use requirements.

Description

Technical Field

[0001] This utility model relates to the field of display technology, specifically to a keypad device with a Thunderbolt interface. Background Technology

[0002] In today's fast-paced life, laptops have become the go-to choice for frequent business travelers and tourists. While laptops offer increasing convenience, they also have significant limitations. The main issue is the limited internal space, leading to poor heat dissipation and preventing the CPU and GPU from operating at full capacity, often operating at reduced frequencies. While this might be manageable for basic typing and office work, demanding tasks like gaming or using AI programs can cause the CPU to easily exceed 90 degrees Celsius, a phenomenon known as "stress testing." The keyboard becomes increasingly hot, the fan noise grows louder, and the overall user experience deteriorates drastically.

[0003] The rapid development of chips and power supplies has brought us new choices.

[0004] Firstly, the integrated graphics performance of Intel's Ultra 7 and AMD's Ryzen 8000G series has been greatly improved, with overall performance reaching or exceeding that of a GTX 1650. The Ultra 9 and AMD's AI 300 series even surpass a GTX 1050. This is sufficient for most games and AI processing, eliminating the need for a dedicated graphics card and significantly reducing heat generation. Based on these chips, the main unit can be made smaller and smaller, ultimately achieving a "pocket computer."

[0005] Pocket-sized devices can become increasingly smaller while maintaining improved performance; mobile phone processors are also becoming more than capable of handling the demands of mobile devices. Currently, portable devices with separate screens and keyboards are all separate components. Moreover, the portable screen is mostly used only as a secondary display, a design that is very inconvenient for users on the go. Utility Model Content

[0006] This utility model proposes a keypad with a Thunderbolt interface and a power control circuit. The keypad with a Thunderbolt interface inherits the traditional features of a screen, keyboard, mouse, and speakers, offering portability and solving the problem of the inconvenience of carrying multiple electronic devices when using a pocket computer. It is convenient to use and portable, and can meet more comprehensive usage needs. The power control circuit addresses the potential for voltage instability or electromagnetic interference in complex environments or remote areas. Applying this invention can reduce electromagnetic interference and provide a stable DC power supply to the subsequent system.

[0007] The technical solution of this utility model is as follows:

[0008] A Thunderbolt-compatible keypad includes a power module and a processor. The power module is connected to an external power source and serves as the power supply for the Thunderbolt-compatible keypad. It includes a foldable display screen and a keyboard area, similar in structure to a laptop computer. The display screen and the keyboard area are located on the inner surfaces of two hinged panels. The keyboard area includes a keyboard and a touchpad. The display screen and the keyboard area are respectively signal-connected to an interface module for connecting to an external host.

[0009] As a further optimization of this solution, the interface module includes multiple USB ports and Thunderbolt 4 ports. Each port in the interface module is connected to the display screen, the keyboard, and the touchpad via a data exchange circuit signal. The power module is connected to the interface module for power supply.

[0010] As a further optimization of this solution, a camera module is also included. The camera module includes a camera control circuit and a camera electrically connected to the camera control circuit. The camera control circuit is connected to the interface module through the data exchange circuit.

[0011] As a further optimization of this solution, an audio module is also included. The audio module includes an audio control circuit and an audio speaker and a microphone electrically connected to the audio control circuit. The audio control circuit is connected to the interface module through the data exchange circuit.

[0012] A keypad compatible with a Thunderbolt interface is similar to that of a laptop computer, with only two differences: unlike a laptop computer, this keypad does not have a core processor and has a Thunderbolt 4 interface and the Thunderbolt 4 conversion circuit required for the Thunderbolt 4 interface; it is also compatible with mobile phone processors as the host and enables reverse charging of mobile phones.

[0013] As a further optimization of this solution, the Thunderbolt-compatible keypad is similar to that of a laptop with a touchpad.

[0014] As a further optimization of this solution, the difference from laptops is that this Thunderbolt-compatible keypad does not have a display adapter.

[0015] A power control circuit is disclosed, wherein the input of the power control circuit is connected to an external voltage source for supplying power to a downstream system. The circuit includes a noise reduction unit, a rectifier unit, a boost unit, a drive unit, and secondary-side output, tertiary-side output, and quaternary-side output. The input of the noise reduction unit is connected to an external AC power source. The output of the noise reduction unit is connected to the input of the rectifier unit. The output of the rectifier unit is connected to the input of the boost unit. The output of the boost unit is connected to the input of the drive unit. The output of the drive unit serves as the primary input of a transformer. The secondary-side output, tertiary-side output, and quaternary-side output are located on the secondary, tertiary, and quaternary sides of the transformer, respectively.

[0016] As a further optimization of this solution, the noise reduction unit includes inductors L1 and L2 and a common-mode inductor L8. The input of inductor L1 is connected to an external power supply via a fuse. A filter capacitor and a voltage divider resistor are provided between inductors L1 and L2. A capacitor C4 and a thermistor R5 are provided between inductor L2 and common-mode inductor L8. The output of common-mode inductor L8 is connected to the rectifier BD1 of the voltage regulator module. The input of rectifier BD1 is also connected to the thermistor R8. The output of rectifier BD1 is connected to the boost unit. The boost unit includes... The system includes an inductor group, a switching module, and a capacitor module. The input of the boost unit is connected to the positive output of the rectifier BD1. One end of the inductor group serves as the input of the boost unit, and the other end of the inductor group is connected to the positive terminal of the diode D1 via a resistor R9. The series connection point of the resistor R9 and the diode D1 is connected to the drain of the switching transistor Q1 between the power supply ground and the source of the switching transistor Q1 is grounded. The gate of the switching transistor Q1 is externally connected to a PWM control signal via an amplifier. The negative terminal of the diode D1 serves as the output of the boost unit via a capacitor module connected in parallel with the power supply ground.

[0017] As a further optimization of this solution, the driving unit includes a switch Q3 and a switch Q6. The drain of the switch Q3 serves as the input of the driving unit, the source of the switch Q3 is connected to the drain of the switch Q6, the source of the switch Q6 is grounded, the gates of the switch Q3 and the switch Q6 are connected to PWM signals with opposite waveforms, and the drain of the switch Q3 serves as the output of the driving unit and is connected to the positive terminal of the primary side of the transformer T1.

[0018] The working principle and beneficial effects of this utility model are as follows:

[0019] This solution integrates a traditional screen, keyboard, and audio equipment into one unit. When paired with a pocket host, it can perform all the functions of a traditional laptop; when paired with a mobile phone, it can reuse the phone's performance to handle complex tasks. While the structure of this application is similar to a laptop, the absence of a CPU and graphics card results in very low heat generation, ensuring the pocket host's performance and maintaining a satisfactory user experience. Furthermore, this technical solution is also compatible with using a mobile phone processor as the host and enables reverse charging of the mobile phone.

[0020] In this application, L1, L2, and L8 in the power control circuit can filter noise and block unstable current. The input of the switch Q1 in the boost circuit is driven by an amplifier, which can enhance the anti-interference capability. Attached Figure Description

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] Figure 1 This is a schematic diagram of the keypad with a Thunderbolt interface used in this application.

[0023] Figure 2 This is a schematic diagram of the appearance of this application;

[0024] Figure 3 This is a schematic diagram of one embodiment of the present application;

[0025] Figure 4 This is a schematic diagram of the interface unit in this application;

[0026] Figure 5 This refers to the primary side of the transformer in the power control circuit.

[0027] Figure 6 This is the output from the secondary side of the transformer in the power control circuit.

[0028] Figure 7 The output of the transformer on the third side of the power control circuit;

[0029] Figure 8 This is the output from the fourth side of the transformer in the power control circuit;

[0030] Figure 9 This is an example of square wave driving in the embodiments. Detailed Implementation

[0031] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this utility model.

[0032] In the following description of the embodiments, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0033] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of a described feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or a collection thereof. It should also be understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations. As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0034] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. References to "one embodiment" or "some embodiments" in this application mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0035] As per the instruction manual Figure 1 As shown, a Thunderbolt-compatible keypad includes a power module and a processor. The power module is connected to an external power source and serves as the power supply for the Thunderbolt-compatible keypad. It includes a foldable display screen and a keyboard area, similar in structure to a laptop computer. The display screen and keyboard area are located on the inner surfaces of two hinged panels. The keyboard area includes a keyboard and a touchpad. The display screen and keyboard area are each signal-connected to an interface module for connecting to an external host. The interface modules include Type-A, Type-C, and Thunderbolt 4 interfaces. The keyboard area in this application operates on the same principle as laptops with touchpads, such as the ThinkPad series.

[0036] As per the instruction manual Figure 4 As shown, the interface module includes multiple USB ports and a Thunderbolt 4 port. Each port in the interface module is connected to the display screen, the keyboard, and the touchpad via a data exchange circuit. The power module is connected to the interface module to supply power. This module is similar to a docking station, and the processor enables the keyboard, mouse, and external host and monitor to work together in the data exchange circuit.

[0037] As per the instruction manual Figure 1 As shown, it also includes a camera module, which comprises a camera control circuit and a camera electrically connected to the camera control circuit. The camera control circuit is connected to the interface module via the data exchange circuit. The camera control circuit is externally connected to a camera, and its principle is the same as that of the camera and internal camera control circuit in a laptop. It also includes an audio module, which comprises an audio control circuit and a speaker and microphone electrically connected to the audio control circuit. The audio control circuit is connected to the interface module via the data exchange circuit. The audio control circuit is connected to a speaker, and its principle is the same as that of the speaker and audio control circuit in a laptop or television.

[0038] Example 1: A keypad with a Thunderbolt interface. The keypad with a Thunderbolt interface is similar to that of a laptop computer. The difference between the keypad with a Thunderbolt interface and a laptop computer is that the keypad with a Thunderbolt interface does not have a core processor, but has a Thunderbolt 4 interface and the Thunderbolt 4 conversion circuit required for the Thunderbolt 4 interface.

[0039] The Thunderbolt-enabled keyboard and screen are similar to those on laptops with touchpads. You could refer to ThinkPad laptops and remove the graphics card and CPU, making them external in a pocket-sized form factor, or simply externalize the CPU in a pocket-sized form factor and eliminate the dedicated graphics card.

[0040] Example 2 differs from a laptop in that the Thunderbolt-compatible keypad does not have a display adapter.

[0041] This application, when combined with a pocket host or desktop host, is equivalent to a complete computer function.

[0042] Pocket PCs or mobile devices can be exemplified by ZeroTech, which has already achieved a very small size. With the use of an external power supply and new materials, they can be made even more compact, fitting perfectly into a pocket and featuring a full-fledged Thunderbolt 4 port. Many mobile phone brands now also have full-fledged Tape-C ports.

[0043] On the other hand, V-Feng launched a USB4 converter chip in 2022. It features one USB4 or Thunderbolt 4 upstream port, five downstream ports, and one DP port. The DP port supports 32.4 Gbit / s bandwidth and up to 8K / 60Hz HDR video output. The hardware supports digitally signed firmware security features, PWM-driven LED indicators, and firmware upgrades via USB or I2C bus. The USB ports support charging protocols such as BC1.2, Apple 2.4A, and Samsung, allowing charging of connected devices. It also includes a built-in USB 3.2 hub, supporting four USB 3.2 ports and one USB 2.0 port, as well as one DP 1.4a port. The DP port can also be converted to an HDMI port using other adapter chips. Combined with V-Feng's VL103 and VL105 chips, it supports PD, enabling laptops to power via USB-C, expand USB ports, and extend display interfaces.

[0044] This utility model provides a lightning key screen as shown in the attached figure. Figure 1 As shown, to cater to user habits, it still adopts the form of a laptop, retaining only the screen, speakers, keyboard, and camera functions.

[0045] The screen, speaker, and camera components are integrated together.

[0046] Keyboard and screen combination method 1: Using a physical keyboard and monitor. This solution has lower requirements for the screen and is easy to implement.

[0047] Keyboard Combination Option Two: This option uses a touch-sensitive foldable screen. When folded, the upper screen functions as a monitor, and the lower screen serves as a virtual keyboard, suitable for office work scenarios. When unfolded, the two screens combine to form a large display, suitable for scenarios such as watching movies. This solution requires the design of an additional hidden stand.

[0048] The main external interfaces are Thunderbolt 4, Type-C, and USB. The Thunderbolt 4 interface can be used as a standalone power connector or as a combined power and data connector. The Type-C interface supports interconnection with mobile phones, tablets, and other devices. The USB interface can be used as an expansion port or as a source of other audio and video content.

[0049] The motherboard mainly consists of a Thunderbolt 4 interface conversion circuit, a data exchange circuit, a processor, an audio control circuit, a camera control circuit, and a power control circuit. The Thunderbolt 4 interface conversion circuit separates the power and signal lines of the Thunderbolt 4 interface; the signal lines are connected to the data exchange circuit, and the power lines are connected to the power control circuit. The power control circuit provides appropriate voltage and power to all components of the motherboard. The data exchange circuit performs two main functions: converting data packets of different protocols and routing data packets. The audio control circuit drives the audio equipment. The camera control circuit controls the camera module. The processor is the core of the entire motherboard, running the device's operating system, internally controlling all components of the motherboard, and externally providing interactive content to the user through the display.

[0050] The outer shell of the device is made of new materials such as carbon fiber, achieving an extremely thin and light design while also protecting the screen.

[0051] It has a built-in rechargeable battery and only works when the phone is connected.

[0052] The pocket computer + Thunderbolt keyboard design achieves a cool and noise-free keyboard environment while ensuring performance, making it a promising solution for various applications.

[0053] As per the instruction manual Figure 5-8As shown, a power control circuit has an external voltage source connected to its input for powering subsequent systems. It includes a noise reduction unit, a rectifier unit, a boost unit, a drive unit, and secondary, tertiary, and quaternary outputs. The noise reduction unit's input is connected to external AC power. Its output is connected to the input of the rectifier unit, which in turn is connected to the input of the boost unit. The boost unit's output is connected to the input of the drive unit, which serves as the primary input of a transformer. The secondary, tertiary, and quaternary outputs are located on the secondary, tertiary, and quaternary sides of the transformer, respectively. On the primary side of transformer T1, an external voltage source is input. After being filtered by a three-pole inductor, the alternating current is converted into varying DC by a rectifier bridge. Then, the voltage is boosted to the required range by a boost circuit, and finally converted into varying current by the drive unit. The period and duty cycle of the square wave input in the boost unit can be determined according to the required voltage. The transformer converts the current into three voltage sources, namely Vout, Vs, and VCC, which can be used as three independent voltage sources.

[0054] As per the instruction manual Figure 5 As shown, the noise reduction unit includes inductors L1 and L2 and a common-mode inductor L8. The input of inductor L1 is connected to an external power supply via a fuse. A filter capacitor and a voltage divider resistor are provided between inductors L1 and L2. A capacitor C4 and a thermistor R5 are provided between inductor L2 and common-mode inductor L8. The output of common-mode inductor L8 is connected to the rectifier BD1 of the voltage regulator module. The input of rectifier BD1 is also connected to the thermistor R8. The output of rectifier BD1 is connected to the boost unit. The boost unit includes an inductor bank, The system includes a switching module and a capacitor module. The input of the boost unit is connected to the positive output of the rectifier BD1. One end of the inductor group serves as the input of the boost unit, and the other end of the inductor group is connected to the positive terminal of the diode D1 via resistor R9. The series connection point of resistor R9 and diode D1 is connected to the drain of the switching transistor Q1 between the power supply ground and the source of the switching transistor Q1. The gate of the switching transistor Q1 is externally connected to a PWM control signal via an amplifier. The negative terminal of the diode D1 serves as the output of the boost unit via a capacitor unit connected in parallel with the power supply ground. The three inductors in the front stage act as filters, while thermistors R3 and R5 protect the power supply. When the current is too high or the temperature is too high, the thermistors will short-circuit and blow the fuse, ensuring the stability of the subsequent circuit. In the boost unit, when the switching transistor Q1 is turned on or off, current flows through inductors L3 and L4, and capacitors C6 and C7 are charged. When the switching transistor Q1 is turned on, inductors L3 and L4 store current, and capacitors C6 and C7 discharge. When Q1 is turned off, inductors L3 and L4 discharge the stored current and raise the potential of the positive terminal of the capacitor, thereby achieving voltage boost.

[0055] The driving unit includes switching transistors Q3 and Q6. The drain of Q3 serves as the input of the driving unit, and the source of Q3 is connected to the drain of Q6. The source of Q6 is grounded. PWM signals with opposite waveforms are externally connected to the gates of Q3 and Q6. The drain of Q3 serves as the output of the driving unit and is connected to the positive terminal of the primary side of transformer T1. In the diagram, GATEL and GATEH are out of phase. When Q6 is on, Q3 is off, and the output voltage is grounded. When Q6 is off, Q3 is on, and the output voltage is pulled to the output potential of the boost unit. This drives the secondary coil through the transformer. The driving of GATEL and GATEH can be found in [reference needed]. Figure 8 .

[0056] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0057] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0058] In the embodiments provided by this utility model, it should be understood that the disclosed apparatus / terminal devices and methods can be implemented in other ways. For example, the apparatus / terminal device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms. Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0059] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A keypad device with a Thunderbolt interface, comprising a power module and a processor, wherein the power module is connected to an external power source, and the power module serves as the power supply for the keypad with the Thunderbolt interface, characterized in that, It includes a foldable display screen and keyboard area, a structure similar to that of a laptop computer. The display screen and keyboard area are located on the inner surfaces of two hinged panels. The keyboard area includes a keyboard and a touchpad. The display screen and keyboard area are respectively connected to an interface module for connecting to an external host.

2. A keypad device with a Thunderbolt interface according to claim 1, characterized in that, The interface module includes multiple USB ports and Thunderbolt 4 ports. Each port in the interface module is connected to the display screen, the keyboard, and the touchpad via a data exchange circuit. The power module is connected to the interface module for power supply.

3. A keypad device with a Thunderbolt interface according to claim 2, characterized in that, It also includes a camera module, which includes a camera control circuit and a camera electrically connected to the camera control circuit. The camera control circuit is connected to the interface module through the data exchange circuit.

4. A keypad device with a Thunderbolt interface according to claim 2, characterized in that, It also includes an audio module, which includes an audio control circuit and an audio speaker and a microphone electrically connected to the audio control circuit. The audio control circuit is connected to the interface module through the data exchange circuit.

5. A keypad device with a Thunderbolt interface according to claim 1, characterized in that, This Thunderbolt-compatible keypad does not have a core processor compared to a laptop, but it does have a Thunderbolt 4 interface and the Thunderbolt 4 conversion circuit required for the Thunderbolt 4 interface; it is also compatible with mobile phone processors as the host and can realize reverse charging of mobile phones.

6. A keypad device with a Thunderbolt interface according to claim 5, characterized in that, The Thunderbolt-enabled keypad is similar to that of a laptop with a touchpad.

7. A keypad device with a Thunderbolt interface according to claim 5, characterized in that, The difference from laptops is that this Thunderbolt-compatible keyboard does not have a display adapter.

8. A keypad device with a Thunderbolt interface according to any one of claims 1-5, further comprising a built-in power control circuit, wherein the input of the power control circuit is an external voltage source for supplying power to the downstream system, characterized in that, It includes a noise reduction unit, a rectifier unit, a boost unit, a drive unit, and secondary-side output, tertiary-side output, and quaternary-side output. The input of the noise reduction unit is connected to an external AC power source. The output of the noise reduction unit is connected to the input of the rectifier unit. The output of the rectifier unit is connected to the input of the boost unit. The output of the boost unit is connected to the input of the drive unit. The output of the drive unit serves as the input of the primary side of the transformer. The secondary-side output, tertiary-side output, and quaternary-side output are located on the secondary, tertiary, and quaternary sides of the transformer, respectively.

9. A keypad device with a Thunderbolt interface according to claim 8, characterized in that, The noise reduction unit includes inductors L1 and L2 and a common-mode inductor L8. The input of inductor L1 is connected to an external power supply via a fuse. A filter capacitor and a voltage divider resistor are provided between inductors L1 and L2. A capacitor C4 and a thermistor R5 are provided between inductor L2 and common-mode inductor L8. The output of common-mode inductor L8 is connected to the rectifier BD1 of the voltage regulator module. The input of rectifier BD1 is also connected to the thermistor R8. The output of rectifier BD1 is connected to the boost unit. The boost unit includes an inductor bank and an open circuit. The boost unit consists of a switching module and a capacitor module. The input of the boost unit is connected to the positive output of the rectifier BD1. One end of the inductor group serves as the input of the boost unit, and the other end of the inductor group is connected to the positive terminal of the diode D1 through a resistor R9. The series connection point of the resistor R9 and the diode D1 is connected to the drain of the switching transistor Q1 between the power supply ground and the source of the switching transistor Q1 is grounded. The gate of the switching transistor Q1 is externally connected to a PWM control signal through an amplifier. The negative terminal of the diode D1 serves as the output of the boost unit through a capacitor unit connected in parallel with the power supply ground.

10. A keypad device with a Thunderbolt interface according to claim 8, characterized in that, The driving unit includes a switch Q3 and a switch Q6. The drain of the switch Q3 serves as the input of the driving unit, the source of the switch Q3 is connected to the drain of the switch Q6, the source of the switch Q6 is grounded, the gates of the switch Q3 and the switch Q6 are connected to PWM signals with opposite waveforms, and the drain of the switch Q3 serves as the output of the driving unit and is connected to the positive terminal of the primary side of the transformer T1.

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