TWI911712B - Displaying interface system and connection detecting method thereof - Google Patents

Abstract

A displaying interface system and a connection detecting method thereof are provided. The displaying interface system includes a transmission port, a control module, and a transmission wire. The transmission port is configured to be electrically connected to a monitor. The control module is configured to load a basic input/output system (BIOS) firmware and perform an operating system. The transmission wire is electrically connected between the transmission port and the control module, and the transmission wire has a hot-plugging channel. In response to the BIOS firmware switches a power state of the operating system, the control module generates a negative pulse according to the BIOS firmware to trigger the monitor to detect whether it is electrically connected to the transmission port, and the negative pulse is transmitted to the monitor via the hot-plugging channel and the transmission port. The power state is corresponding to a state of Advanced Configuration and Power Interface (ACPI) specification.

Description

Display Interface System and its Connection Detection Method

This case relates to displays and hot-plugging, and in particular to a display interface system and its connection detection method.

With the rapid development of image display technology, related electronic devices and products have also made significant progress. Among these advancements, the transmission interfaces used to transmit image signals have evolved from the previously common Video Graphics Array (VGA) and Digital Video Interface (DVI) interfaces to today's popular High Definition Multimedia (HDMI), DisplayPort (DP), and USB Type-C interfaces. Furthermore, display devices used to display images have also evolved into various designs, such as LCD screens, LED screens, and OLED screens.

However, some problems still exist between various types of transmission interfaces and various types of display devices. For example, when a user plugs one end of a transmission cable into the transmission interface of a host device (e.g., a desktop computer) and the other end into a display device to display a screen, the screen may disappear and cannot be restored due to compatibility or signal problems. In this case, the user can only restore the display screen by unplugging and replugging at least one end of the transmission cable to trigger the hot-swappable display device to re-detect the device.

In view of this, this application proposes a display interface system and a connection detection method thereof. In some embodiments, a display interface system includes a transmission interface, a control module, and a transmission line. The transmission interface is used for electrical connection to a display. The control module is used for loading a Basic Input/Output System (BIOS) firmware and executing an operating system. The transmission line is electrically connected between the transmission interface and the control module, and the transmission line has a hot-swappable channel. In response to a power state switch of the operating system by the BIOS firmware, the control module generates a negative pulse according to the BIOS firmware to trigger the display to detect whether it is electrically connected to the transmission interface, and the negative pulse is transmitted to the display via the hot-swappable channel and the transmission interface. The power status corresponds to the status in the Advanced Configuration and Power Interface (ACPI) specification.

In some embodiments, the display interface system further includes a power supply module electrically connected to the control module and used to provide a power supply to the control module.

In some implementations, the power supply module is also used to adjust the voltage value of the power supply according to the BIOS firmware.

In some embodiments, the transmission interface includes multiple transmission interfaces, the transmission lines include multiple transmission lines corresponding to the multiple transmission interfaces, and the multiple transmission interfaces are selected from High Definition Multimedia (HDMI) interface, DisplayPort (DP) interface, USB Type-C interface, and combinations thereof.

In some implementations, the width of the negative pulse is greater than one threshold.

In some embodiments, the display interface system further includes a power transmission module, and the transmission line includes a first sub-channel, a second sub-channel and a third sub-channel, wherein the first sub-channel is electrically connected between the control module and the power transmission module, and the second and third sub-channels are electrically connected between the power transmission module and the transmission interface.

In some embodiments, the power transmission module is used to transmit negative pulses to the transmission interface via a second or third sub-channel.

In some embodiments, a display connection detection method includes: a control module loading a basic input/output system (BIOS) firmware and executing an operating system; in response to a power state of the operating system switching in the BIOS firmware, the control module generating a negative pulse according to the BIOS firmware, wherein the power state corresponds to a state in the Advanced Configuration and Power Interface (ACPI) specification; and the control module transmitting the negative pulse to the display via a hot-swappable channel of a transmission line and a transmission interface to trigger the display to detect whether it is electrically connected to the transmission interface.

In some embodiments, the connection detection method further includes: the control module receiving a power supply from a power supply module; and the power supply module adjusting the voltage value of the power supply according to the BIOS firmware when switching the operating system power status.

In summary, according to any of the above embodiments, the display interface system and its connection detection method can generate negative pulses to trigger the display driver chip to re-detect whether the display is electrically connected to the host device's transmission interface, thereby achieving an effect equivalent to hot-plugging to ensure the display can display images normally. Furthermore, since the BIOS system can automatically and frequently switch the operating system's power state, the display interface system and its connection detection method can periodically generate negative pulses to maintain the display function without manual operation.

In the description of this case, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise stated, "at least one" means one or more, and "plural" means two or more.

Please refer to Figure 1, which is a circuit block diagram of a first embodiment of the display interface system 10. The display interface system 10 includes a transmission interface 100, a control module 110, and a transmission wire 120, wherein the transmission wire 120 is electrically connected between the transmission interface 100 and the control module 110, and the transmission wire 120 has a hot-swappable channel (the function of the hot-swappable channel will be described later). In some embodiments, the display interface system 10 may be part of the motherboard of an electronic product; or, the display interface system 10 may be a separate expansion card or interface card in the electronic product. The electronic product may be, for example, a desktop computer, a laptop computer, an industrial computer, or a server host, but is not limited thereto.

The transmission interface 100 is used for electrical connection to an externally connected display 20. In some embodiments, the display 20 can be a device with screen display function, such as, but not limited to, a computer monitor, television, mobile phone screen, or flat panel screen. In some embodiments, a transmission line L1 is provided between the transmission interface 100 and the display 20, and the two ends of the transmission line L1 are respectively plugged into the transmission interface 100 and the display 20. In other words, the transmission interface 100 is electrically connected to the display 20 via the transmission line L1.

In some embodiments, the transmission interface 100 may be an interface for transmitting video signals and supporting hot-swapping, such as, but not limited to, an HDMI interface, a DisplayPort (DP) interface, or a USB Type-C interface. Hot-swapping is a function that enables the direct insertion or removal of the removable device (e.g., mouse, keyboard, USB flash drive, or computer monitor) between a host device (e.g., a desktop computer or laptop computer) and a removable device, allowing the host device to be directly inserted or removed while powered on without causing damage to either the host device or the removable device. Furthermore, the host device can detect the insertion/removal of the removable device in real time. Hot-swapping is well known to those skilled in the art and will not be described further.

Please refer to Figures 1 to 3. Figure 2 is a flowchart of the operation of the first embodiment of the display interface system 10 in Figure 1, and Figure 3 is a signal diagram of some embodiments of the display interface system 10 in Figure 1. As shown in Figures 1 and 2, when the display interface system 10 is electrically connected to an external power supply (not shown) to be powered on, the control module 110 first loads a basic input/output system (BIOS) firmware 111, and then executes an operating system 112 (step S100). In some embodiments, the BIOS firmware 111 and operating system 112 are stored in a storage module SM1 (e.g., but not limited to read-only memory or flash memory) of the display interface system 10, wherein the storage module SM1 is electrically connected to the control module 110. In other embodiments, the BIOS firmware 111 and operating system 112 are stored in a storage device (not shown) external to the display interface system 10.

In some embodiments, the control module 110 may be a system-on-chip (SoC), wherein the SoC includes a central processing unit (CPU) chip and a platform controller hub (PCH) chip. In other embodiments, the control module 110 may include a plurality of independent chips (e.g., but not limited to, a CPU chip and a PCH chip).

In some embodiments, the BIOS firmware 111 is used to initialize the hardware components in the display interface system 10 when the display interface system 10 is powered on, and to provide the operating system 112 with the hardware control functions required for its operation (i.e., controlling the hardware through the firmware). Here, in some embodiments of step S100, when the operating system 112 performs hardware-related operations or settings (e.g., power management), the control module 110 triggers a system management interrupt (SMI) mechanism to switch control module 110 to execute the BIOS firmware 111. At this time, the BIOS firmware 111 adjusts the parameters of the hardware components to implement the operations or settings on the operating system 112. Furthermore, after the control module 110 completes the task corresponding to the SMI mechanism, the control module 110 switches to run the operating system 112. In some embodiments, the operating system 112 is, for example, a Windows operating system, a Linux operating system, or an Apple operating system (macOS), but is not limited thereto.

Following step S100, in response to a power state switch of the operating system 112 by the BIOS firmware 111, the control module 110 generates a negative pulse NP according to the BIOS firmware 111 (step S110), and transmits the negative pulse NP to the corresponding display 20 via the hot-swappable channel of the transmission line 120 and the transmission interface 100 (step S120). In some embodiments, the control module 110 sends the negative pulse NP via pin 1 corresponding to the hot-swappable channel, and the display 20 receives the negative pulse NP via a pin (not shown) corresponding to the hot-swappable channel.

In some embodiments, the power status of the operating system 112 corresponds to the status in the Advanced Configuration and Power Interface (ACPI) specification. ACPI is a power management interface specification jointly developed and proposed by Intel, Microsoft, and Toshiba, designed to provide the operating system 112 with a hardware configuration interface for managing hardware power status. In other words, when both the BIOS firmware 111 and the operating system 112 support the ACPI specification, the operating system 112 can adjust the power status of the corresponding hardware components through the BIOS firmware 111, thereby switching the power status of the operating system 112.

Please refer to Table 1, which shows the various power states defined by the ACPI specification. As shown in Table 1, in some embodiments, the ACPI specification defines four power states G0 to G3, where power state G0 can also be called power state S0, power state G1 can be subdivided into power states S1 to S4, and power state G2 can also be called power state S5. Therefore, the operating system 112 can switch between the seven power states S0 to S5 and G3 according to different usage scenarios. In some embodiments, the operating system 112 can automatically switch its power state (for example, the Windows operating system automatically adjusts its power options to power-saving mode when idle to conserve power). In other embodiments, the operating system 112 can also manually switch its power status (for example, the user manually adjusts the power options in the Windows operating system to power saving mode). [Table 1] Power status instruction S0 (G0) The operating status when the device is powered on. S1 (G1) Power on Suspend (POS). At this time, the CPU and memory are continuously powered, and non-used hardware is not powered. S2 (G1) At this time, the CPU stops supplying power, the memory continues to be powered, and non-used hardware is not powered. S3 (G1) Suspend to RAM (STR), also known as sleep mode in Windows systems, means that only the memory continues to receive power, while all other hardware stops receiving power. S4 (G1) Suspend to Disk (STD) is the hibernation mode in Windows. In this mode, only the hard drive continues to receive power, while all other hardware stops receiving power. S5 (G2) The power-off state when the external power supply is on. G3 The power-off state when the external power supply is turned off.

It should be noted that in some embodiments, the power state G3 shown in Table 1 requires the external power supply electrically connected to the display interface system 10 to be turned off (e.g., manually unplugging the external power supply). Therefore, the operating system 112 cannot switch its power state to the power state G3 shown in Table 1 through the BIOS firmware 111. Furthermore, ACPI is well known to those skilled in the art. Therefore, the description of the power states in Table 1 is merely an example in the ACPI specification, and Table 1 is not intended to limit the power states in the ACPI specification. In other words, any modifications or changes to the power states based on known ACPI specifications are within the scope of this invention.

In some embodiments, in response to the switching of the power state of the operating system 112 by the BIOS firmware 111, the control module 110 generates a signal Shp with a negative pulse NP (as shown in Figure 3). In some embodiments, the potential of the signal Shp switches from a high logic level representing logic "1" to a low logic level representing logic "0" and maintains it for a period of time, and then switches from the low logic level back to the high logic level to form a negative pulse NP. In some embodiments, the voltage values for high logical levels are, for example, 1 volt (V), 3V, or 5V, without limitation; and the voltage values for low logical levels are, for example, 0V, 0.1V, or 0.5V, without limitation.

In some embodiments, when the display 20 receives a low-logic-level signal Shp (i.e., negative pulse NP), the driver chip (not shown) of the display 20 detects that the display 20 is not electrically connected to any transmission interface 100 (i.e., at least one end of the transmission line L1 is not plugged into the transmission interface 100 or the display 20). Furthermore, when the display 20 receives a high-logic-level signal Shp again, the driver chip of the display 20 detects that the display 20 is electrically connected to the transmission interface 100 and can display the image normally (i.e., both ends of the transmission line L1 are plugged into the transmission interface 100 and the display 20, respectively). In other words, the hot-swap channel is used to transmit signals (e.g., negative pulses NP) so that the display 20 can detect whether it is electrically connected to the transmission interface 100. In addition, the display interface system 10 can simulate the action of replugging either end of the transmission line L1 through the negative pulse NP (in fact, neither end of the transmission line L1 is replugged), thereby producing the same effect as hot-swapping.

Taking Figure 3 as an example, in this embodiment, state ST1 represents the operating state of display 20. When state ST1 is On, it means display 20 is displaying the image normally; when state ST1 is Off, it means display 20 is not displaying the image. As shown in Figure 3, at time t1, display 20 may stop displaying the image due to a signal problem. At this time, BIOS firmware 111 has not yet switched the power state of operating system 112, causing signal Shp to remain at a high logic level. At time t2, BIOS firmware 111 switches the power state of operating system 112, causing control module 110 to generate a signal Shp with a negative pulse NP according to BIOS firmware 111. Between time points t2 and t3, because the driver chip of display 20 receives a low-logic-level signal Shp, the driver chip of display 20 detects that display 20 is not electrically connected to any transmission interface 100. At time point t3, the signal Shp switches from a low-logic-level to a high-logic-level. At this time, the driver chip of display 20 receives a high-logic-level signal Shp and detects that display 20 is electrically connected to transmission interface 100. Therefore, at time point t4, display 20 can display the image normally.

In some embodiments, the time difference between time point t3 and time point t4 depends on the clock speed of the driver chip of the display 20. Specifically, the faster the clock speed of the driver chip of the display 20, the shorter the time difference between time point t3 and time point t4; the slower the clock speed of the driver chip of the display 20, the longer the time difference between time point t3 and time point t4.

In some embodiments, when the pulse width PW1 of the negative pulse NP is too short, the driver chip of the display 20 treats the negative pulse NP as noise and does not perform any detection. Therefore, in some embodiments, the pulse width PW1 of the negative pulse NP is greater than a threshold value (e.g., 0.5 seconds or 1 second, not limited thereto) to ensure that the driver chip of the display 20 performs detection operations. In some embodiments, the threshold value can be set by the user; in other embodiments, the threshold value can be adjusted according to the type of driver chip of the display 20.

In some embodiments, the display interface system 10 further includes a power supply module 130 (as shown in FIG. 1), wherein the power supply module 130 is electrically connected to the control module 110 and is used to provide a power supply Vsp to the control module 110. In other words, the power supply module 130 is used to convert the voltage value of the aforementioned external power supply into the voltage value of the power supply Vsp applicable to the control module 110, wherein the voltage value of the external power supply is, for example, 100V, 110V or 220V, and is not limited thereto; and the voltage value of the power supply Vsp is, for example, 1V, 3V, 5V or 12V, and is not limited thereto. In some embodiments, when the display interface system 10 is powered on, the control module 110 first receives a power supply Vsp with an appropriate voltage value (step S90), and then loads the BIOS firmware 111 and executes the operating system 112 (step S100).

Following step S100, in some embodiments, in response to the BIOS firmware 111 switching the power state of the operating system 112, the power supply module 130 first adjusts the voltage value of the power supply Vsp according to the BIOS firmware 111 (step S105), and then the control module 110 generates a negative pulse NP according to the BIOS firmware 111. In other words, when the power state of the operating system 112 is switched, the change in the voltage value of the power supply Vsp is controlled by the power supply module 130. Taking Table 1 as an example, in this embodiment, when the power state of the operating system 112 switches from power state S0 to power state S2, the power supply module 130 adjusts the voltage value of the power supply Vsp from 12V to 3V.

Please refer to Figures 4 and 5. Figure 4 is a circuit block diagram of a second embodiment of the display interface system 10, and Figure 5 is a signal diagram of some embodiments of the display interface system 10 in Figure 4. As shown in Figure 4, in some embodiments, the transmission interface 100 is a USB Type-C interface. The USB Type-C interface is a hardware interface form of Universal Serial Bus (USB), characterized by its support for and compatibility with multiple transmission standards, such as, but not limited to, the Thunderbolt 3 data transmission standard, the DP2.0 video transmission standard, or the USB-PD power transmission standard. The Type-C interface supports high-wattage power transmission (e.g., but not limited to 36 watts, 65 watts, or 100 watts).

In some embodiments, the display interface system 10 further includes a power transmission module 140, which is disposed between the transmission interface 100 and the control module 110 to enable the transmission interface 100 to support power transmission functionality. Furthermore, the transmission line 120 needs to conform to the hardware specifications of the USB Type-C interface to transmit signals correctly. In some embodiments, the transmission line 120 includes a first sub-channel C1, a second sub-channel C2, and a third sub-channel C3. The first sub-channel C1 is electrically connected between pin 1 of the control module 110 and the power transmission module 140 and has a hot-swappable channel, while the second sub-channel C2 and the third sub-channel C3 are electrically connected between the power transmission module 140 and the transmission interface 100.

In some embodiments, the second sub-channel C2 corresponds to the first configuration channel (CC1) in the hardware specification of the USB Type-C interface, and the third sub-channel C3 corresponds to the second configuration channel (CC2) in the hardware specification of the USB Type-C interface. CC1 and CC2 are used to manage communication between the master device (corresponding to the control module 110) and the slave device (corresponding to the display 20), such as connection detection or USB Type-C cable insertion orientation identification. The hardware specification of the USB Type-C interface is well known to those skilled in the art and will not be described in detail here.

In some embodiments, when the control module 110 transmits a signal Shp with a negative pulse NP to the power transmission module 140, the power transmission module 140 transmits the negative pulse NP to the transmission interface 100 via the second sub-channel C2 or the third sub-channel C3. Taking Figure 5 as an example, in this embodiment, signal Sc1 is the signal on the first sub-channel C1 (corresponding to signal Shp in Figure 3), signal Sc2 is the signal on the second sub-channel C2, and signal Sc3 is the signal on the third sub-channel C3. As shown in Figure 5, at time t1, the display 20 may stop displaying the image due to a signal problem. At this time, the BIOS firmware 111 has not yet switched the power state of the operating system 112, causing signals Sc1, Sc2, and Sc3 to all remain at a high logic level. At time t2, the BIOS firmware 111 switches the power state of the operating system 112, causing the control module 110 to generate a signal Sc1 with a negative pulse NP according to the BIOS firmware 111, and causing signal Sc2 to receive the negative pulse NP from the power transmission module 140. Between time t2 and time t3, since the driver chip of the display 20 receives the low logic level signal Sc2, the driver chip of the display 20 detects that the display 20 is not electrically connected to any transmission interface 100. At time t3, signal Sc2 switches back from a low logic level to a high logic level. At this time, the driver chip of display 20 receives the high logic level signal Sc2 and detects that display 20 is electrically connected to transmission interface 100. Therefore, at time t4, display 20 can display the screen normally.

It should be noted that in some embodiments, the USB Type-C interface lines (e.g., transmission line 120) actually contain multiple channels, and the functions of each channel are different. Therefore, Figures 4 and 5 are illustrative of the relationship between sub-channels C1, C2, and C3 in transmission line 120, and are not intended to limit the appearance of transmission line 120. In other words, any lines or channels modified based on conventional Type-C interface hardware specifications are within the scope of this invention.

Please refer to Figure 6, which is a circuit block diagram of a third embodiment of the display interface system 10. In some embodiments, the transmission interface 100 includes a plurality of transmission interfaces 100, the transmission line 120 includes a plurality of transmission lines 120 corresponding to the plurality of transmission interfaces 100, and the plurality of transmission interfaces 100 are selected from HDMI interface, DP interface, USB Type-C interface, and combinations thereof. Taking Figure 6 as an example, in this embodiment, the display interface system 10 includes three transmission interfaces 101, 102, and 103 (corresponding to transmission interface 100) and three transmission lines 121, 122, and 123 (corresponding to transmission line 120) corresponding to transmission interfaces 101, 102, and 103. Each transmission line 121, 122, and 123 is electrically connected to pins Pin1, Pin2, and Pin3 of the control module 110, where pins Pin1, Pin2, and Pin3 correspond to hot-swappable channels. In some embodiments, transmission interfaces 101 and 102 can be HDMI or DP interfaces, and transmission interface 103 is a USB Type-C interface. Therefore, when the display interface system 10 is connected to multiple displays 20 simultaneously via multiple transmission lines L1 to L3, the display interface system 10 can send negative pulses NP to each display 20 individually to ensure that each display 20 continuously displays the screen.

In summary, according to any of the above embodiments, the display interface system and its connection detection method can generate negative pulses to trigger the display driver chip to re-detect whether the display is electrically connected to the host device's transmission interface, thereby achieving an effect equivalent to hot-plugging to ensure the display can display images normally. Furthermore, since the BIOS system can automatically and frequently switch the operating system's power state, the display interface system and its connection detection method can periodically generate negative pulses to maintain the display function without manual operation.

Although the present invention has been disclosed above with examples, it is not intended to limit the creation of the present invention. Anyone with ordinary knowledge in the art may make some modifications and changes without departing from the spirit and scope of the disclosure, but such modifications and changes shall still be within the scope of the patent application of the present invention.

10: Display Interface System 100~103: Transmission Interface 110: Control Module 111: Basic Input/Output System (BIOS) Firmware 112: Operating System (OS) 120~123: Transmission Lines 130: Power Supply Module 140: Power Transmission Module 20: Display C1, C2, C3: Channels NP: Negative Pulse L1, L2, L3: Transmission Lines Pin1, Pin2, Pin3: Pins PW1: Pulse Width S90, S100, S105, S110, S120: Steps Sc1, Sc2, Sc3, Shp: Signals SM1: Storage Module ST1: Status t1, t2, t3, t4: Time points Vsp: Power supply

Figure 1 is a circuit block diagram of a first embodiment of the display interface system. Figure 2 is a flowchart of the operation of the first embodiment of the display interface system in Figure 1. Figure 3 is a signal diagram of some embodiments of the display interface system in Figure 1. Figure 4 is a circuit block diagram of a second embodiment of the display interface system. Figure 5 is a signal diagram of some embodiments of the display interface system in Figure 4. Figure 6 is a circuit block diagram of a third embodiment of the display interface system.

10: Display Interface System 100: Transmission Interface 110: Control Module 111: Basic Input/Output System (BIOS) Firmware 112: Operating System (OS) 120: Transmission Line 130: Power Supply Module 20: Display L1: Transmission Line Pin1: Pin SM1: Storage Module Vsp: Power Supply

Claims (10)

A display interface system includes: a transmission interface for electrically connecting to a display; a control module for loading a Basic Input/Output System (BIOS) firmware and executing an operating system; and a transmission line electrically connected between the transmission interface and the control module, wherein the transmission line has a hot-swappable channel; wherein, in response to the BIOS firmware switching a power state of the operating system, the control module generates a negative pulse according to the BIOS firmware to trigger the display to detect whether it is electrically connected to the transmission interface, and the negative pulse is transmitted to the display via the hot-swappable channel and the transmission interface, wherein the power state corresponds to a state in the Advanced Configuration and Power Interface (ACPI) specification. The display interface system as described in claim 1 further includes a power supply module electrically connected to the control module and used to provide a power supply to the control module. The display interface system as described in claim 2, wherein the power supply module is further used to adjust the voltage value of the power supply according to the BIOS firmware. The display interface system as described in claim 1, wherein the transmission interface includes a plurality of transmission interfaces, the transmission lines include a plurality of transmission lines corresponding to the plurality of transmission interfaces, and the plurality of transmission interfaces are selected from a high-definition multimedia (HDMI) interface, a displayPort (DP) interface, a USB Type-C interface, and combinations thereof. The display interface system as described in claim 1, wherein the pulse width of the negative pulse is greater than a threshold value. The display interface system as described in claim 1 further includes a power transmission module, and the transmission line includes a first sub-channel, a second sub-channel and a third sub-channel, wherein the first sub-channel is electrically connected between the control module and the power transmission module, and the second sub-channel and the third sub-channel are electrically connected between the power transmission module and the transmission interface. The display interface system as described in claim 6, wherein the power transmission module is used to transmit the negative pulse to the transmission interface via the second sub-channel or the third sub-channel. A display connection detection method includes: A control module loads a Basic Input/Output System (BIOS) firmware and executes an operating system; In response to the BIOS firmware switching a power state of the operating system, the control module generates a negative pulse according to the BIOS firmware, wherein the power state corresponds to a state in the Advanced Configuration and Power Interface (ACPI) specification; and The control module transmits the negative pulse to the display via a hot-swappable channel of a transmission line and a transmission interface to trigger the display to detect whether it is electrically connected to the transmission interface. The connection detection method as described in claim 8 further comprises: the control module receiving a power supply from a power supply module; and in response to the BIOS firmware switching the power state of the operating system, the power supply module adjusting the voltage value of the power supply according to the BIOS firmware. The connection detection method as described in claim 8, wherein the pulse width of the negative pulse is greater than a threshold.