Voltage protection circuit and medical device

Abstract

The application discloses a kind of voltage-withstanding protection circuit and medical equipment.The circuit includes network card interface, external network interface, industrial computer switching power supply, isolation transformer, shell ground protection and clamping circuit.Network card interface is used to connect network card;External network interface is used to connect external network cable, and industrial computer communicates with external network through the port;Industrial computer switching power supply is used to power supply industrial computer mainboard and network card;Isolation transformer is arranged between external power supply interface and industrial computer switching power supply;Shell ground protection connects the shell of industrial computer, connects the digital ground of industrial computer internal switching power supply, and the digital ground of industrial computer network card;Clamping circuit connects external network interface and shell ground protection, and clamping circuit is used to ensure that external network interface circuit and shell ground protection are in a safe voltage range, so as to protect the chip of network card.The application can stabilize the voltage between external network interface and shell ground protection in a safe range through clamping circuit.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, and in particular relates to a withstand voltage protection circuit and a medical device. Background Technology

[0002] Different types of existing medical equipment need to meet different testing specifications. Based on their protection against electric shock, they are classified into Type B, Type BF, and Type CF. Type F equipment has higher protection requirements (leakage current); Type B equipment is suitable for use on the body surface and in cavities, but the contact parts are not insulated; Type BF equipment represents equipment suitable for use on the body surface and in cavities, but with insulated contact parts. Type BF medical equipment needs to meet a 4000V withstand voltage requirement to prevent electric shock accidents to operators due to excessive mains voltage.

[0003] Industrial control computer motherboards for medical devices typically have a network interface card (NIC) and an external network interface. The NIC connects to the motherboard via the NIC interface, while the external network interface connects to an external network cable. However, NICs used in these interfaces are usually consumer or industrial products and lack high-voltage withstand capabilities. Therefore, the NIC and external network interface do not meet the voltage withstand requirements of medical devices.

[0004] To ensure the external network interface meets voltage withstand requirements, multiple Ethernet transformers are typically installed between the external network interface and the network card interface to achieve network communication while meeting the voltage withstand requirements. However, this solution requires multiple Ethernet transformers, increasing the manufacturing cost of medical equipment and affecting network communication transmission speed. Summary of the Invention

[0005] This application provides a voltage-resistant protection circuit and a medical device that can solve the technical problem of high additional costs required for the external network interface of medical devices to meet voltage resistance requirements.

[0006] In a first aspect, embodiments of this application provide a withstand voltage protection circuit for implementing withstand voltage protection between an external network interface and an external power supply interface. The circuit includes a network card interface, an external network interface, an industrial control computer switching power supply, an isolation transformer, a casing grounding protection, and a clamping circuit. The network card interface is used to connect a network card; the external network interface is used to connect an external network cable; the industrial control computer switching power supply is used to supply power to the industrial control computer motherboard and the network card interface; the isolation transformer is disposed between the external power supply interface and the switching power supply; the casing grounding protection is used to connect to the ground terminal of the external power supply interface, and the casing grounding protection is connected to the digital ground of the network card and the switching power supply; and the clamping circuit connects the external network interface and the casing grounding protection, and the clamping circuit is used to clamp the voltage between the external network interface and the casing grounding protection within a defined voltage range.

[0007] In some embodiments, the clamping circuit is connected in parallel with the network card interface.

[0008] In some embodiments, the clamping circuit includes a transient suppression diode that conducts at a predetermined high voltage to connect the external network interface to the housing ground protection.

[0009] In some embodiments, the clamping circuit includes a plurality of transient suppression diodes corresponding one-to-one with the signal lines of the external network interface, one end of the transient suppression diode being connected to the housing grounding protection and the other end being connected to the signal line.

[0010] In some embodiments, the clamping circuit further includes a capacitor disposed between the housing grounding protection and the transient suppression diode.

[0011] In some embodiments, the clamping circuit further includes a resistor connected in parallel with the capacitor.

[0012] In some embodiments, the enclosure grounding protection includes a digital ground and a protective ground, and the clamping circuit is connected to the protective ground.

[0013] In some embodiments, the network interface card and / or the switching power supply are connected to the digital ground.

[0014] Secondly, embodiments of this application provide a medical device, which includes the industrial control computer as described above.

[0015] Compared with existing technologies, the withstand voltage protection circuit provided in this application embodiment, by setting a clamping circuit between the external network interface and the protective ground, can limit the voltage across the network card interface when the input voltage is too high, keeping the voltage drop across the network card interface at a predetermined voltage and preventing damage to the network card interface due to excessive input voltage. By setting the predetermined voltage of the clamping circuit to be lower than the withstand voltage value of the network card, the clamping circuit can ensure that the voltage across the network card interface is always lower than its withstand voltage value when the voltage is too high. This ensures the normal operation of the network card when it is inserted into the network card interface, preventing high voltage from damaging the network card and the network card interface, and achieving withstand voltage protection between the external network interface and the external power interface. During withstand voltage testing, the network card interface can also pass the withstand voltage index test of the BF type medical device, meeting the withstand voltage index requirements. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a topology diagram of a withstand voltage protection circuit provided in an embodiment of this application;

[0018] Figure 2 yes Figure 1 In the embodiment, a schematic diagram of the voltage drop of the circuit when the isolation transformer is equivalent to a capacitor during the withstand voltage test is shown.

[0019] Figure 3 This is a schematic diagram of the circuit structure of a clamping circuit provided in another embodiment of this application.

[0020] Figure descriptions: 10, Isolation transformer; 20, Switching power supply; 30, Network card interface; 40, Clamping circuit; 50, External network interface; SC, Shell grounding protection; AC1, First voltage; PE, Protective ground; GND, Digital ground; Z1, Transient suppression diode; C, Capacitor; R, Resistor. Detailed Implementation

[0021] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples of this application.

[0022] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The embodiments will now be described in detail with reference to the accompanying drawings.

[0024] The applicant noted that different types of medical devices require different withstand voltage tests to protect operators and prevent electric shock accidents. However, the network cards (NICs) in the industrial control computer motherboards of existing medical devices are typically consumer-grade products and lack withstand voltage capabilities. Therefore, medical devices equipped with NICs and external network interfaces cannot meet the withstand voltage requirements.

[0025] To address the aforementioned technical problems identified by the applicant, this application provides a withstand voltage protection circuit. The withstand voltage protection circuit provided in this application is described below.

[0026] Please see Figure 1 , Figure 1 This application illustrates a withstand voltage protection circuit according to one embodiment. The circuit includes a network interface card 30, an external network interface 50, a switching power supply 20, an isolation transformer 10, a casing grounding protection SC, and a clamping circuit 40.

[0027] The network interface card (NIC) 30 can connect to a NIC, and the connection method can be plug-and-play. The external network interface 50 connects to the NIC interface 30 and enables signal transmission. The external network interface 50 can connect to an external network cable, allowing the NIC to communicate over the network. The switching power supply 20 connects to the NIC interface 30 and supplies power to it. An isolation transformer 10 is located between the external power interface and the switching power supply 20, converting the external AC voltage output from the external power interface into the operating voltage and outputting it to the switching power supply 20. The enclosure grounding protection SC is connected to the ground terminal of the external power interface and is also connected to the NIC interface 30 and the switching power supply 20.

[0028] The clamping circuit 40 is connected to the external network interface 50 and the casing grounding protection SC, respectively. The clamping circuit 40 conducts when the voltage applied to its two ends exceeds a predetermined voltage, thus connecting the external network interface 50 and the casing grounding protection SC through the clamping circuit 40. When the voltage between the external power interface and the external network interface 50 is too high, the clamping circuit 40 conducts at a predetermined voltage. The two ends of the network card interface 30 are connected to the two ends of the clamping circuit 40. When the clamping circuit 40 is conducting, it can short-circuit the network card interface 30, thereby preventing damage to the network card interface 30 from high voltage.

[0029] It is understandable that the clamping circuit 40 mentioned above can be a TVS (Transient Voltage Suppressor). A TVS can provide an ultra-low resistance path for transient current when the transient voltage exceeds its breakdown voltage, allowing the transient current to flow directly to the enclosure grounding protection SC without passing through the network interface 30. The breakdown voltage of the TVS is a predetermined voltage. When the input voltage is higher than the breakdown voltage, the voltage across the network interface 30 remains at the predetermined voltage, thus achieving the withstand voltage protection of the network interface 30.

[0030] When performing withstand voltage tests between the external network interface 50 and the external power interface, a first voltage AC1 that meets the withstand voltage requirements can be applied between the live wire terminals of the external network interface 50 and the external power interface. At this time, the voltage across the clamping circuit 40 is greater than the predetermined voltage, and the clamping circuit 40 changes from the cutoff state to the conduction state. At this time, the voltage across the network card interface 30 is equal to the breakdown voltage of the TVS. When the breakdown voltage of the TVS is less than the normal withstand voltage value of the network card, the voltage across the network card can always be kept below the withstand voltage value, thereby enabling the network card to maintain normal operation.

[0031] Please refer to Figure 2 It should be noted that during the withstand voltage test, when the first applied voltage AC1 is Vtotal, the isolation transformer module can be considered as an equivalent capacitor. At this time, the voltage across the equivalent capacitor is V1, the voltage between the switching power supply 20 and the casing grounding protection SC is V2, and the voltage across the network interface 30 is V3. Therefore, Vtotal = V1 + V2 + V3. Because the switching power supply 20 contains a large number of energy storage electrolytic capacitors, the voltage drop it generates in the circuit is relatively small, i.e., V2 is relatively small. The clamping circuit 40 keeps the voltage across the network interface 30 at a predetermined value, i.e., V3 always remains at the predetermined voltage value of the clamping circuit 40. Therefore, the voltage drop V1 across the isolation transformer 10 is most of the high voltage applied during the withstand voltage test. If the voltage V1 across the isolation transformer 10 is too large, it may damage the isolation transformer 10, causing the medical equipment to malfunction. Therefore, the isolation transformer 10 can be configured as a high-voltage resistant isolation transformer 10. For example, in BF-type medical equipment, to meet the 4000V withstand voltage requirement, the isolation transformer 10 can be a 4000V withstand transformer 10. That is, the withstand voltage between the live wire, neutral wire and the transformer's grounding wire is greater than or equal to 4000V, and the withstand voltage between the live wire, neutral wire and the transformer's output terminal is greater than or equal to 4000V.

[0032] In this embodiment, by setting a clamping circuit 40, when the input voltage is too high, such as during a withstand voltage test on the external network interface 50 and network card interface 30 in the withstand voltage protection circuit, the clamping circuit 40 can limit the voltage across the network card interface 30, keeping the voltage drop across the network card interface 30 at a predetermined voltage, thus preventing damage to the network card interface 30 due to excessive input voltage. By setting a predetermined voltage for the clamping circuit 40, which is lower than the withstand voltage value of the network card interface 30, the clamping circuit 40 can conduct when the voltage is too high, ensuring that the voltage across the network card interface 30 is always lower than its withstand voltage value. This ensures the normal operation of the network card when it is inserted into the network card interface 30, preventing damage to the network card and network card interface 30 from high voltage, and achieving withstand voltage protection between the external network interface 50 and the external power interface.

[0033] It should be noted that the main method for achieving withstand voltage protection currently involves setting up multiple Ethernet transformers between the external network interface 50 and the network card interface 30. However, setting up Ethernet transformers not only increases equipment manufacturing costs but also reduces network communication transmission speed. Furthermore, the voltage that the multiple Ethernet transformers can withstand is actually unknown. Compared to the above withstand voltage protection scheme, this application uses a clamping circuit 40 to clamp and limit the voltage across the network card interface 30. This not only reduces the cost of withstand voltage protection but also avoids the impact of Ethernet transformers on communication transmission speed, thereby improving communication transmission speed.

[0034] In BF-type medical devices, a 4000V withstand voltage requirement is required. Therefore, when the first voltage AC1 applied between the external network interface 50 and the live wire of the external power interface is 4000V, the clamping circuit 40 ensures that the voltage across the network card interface 30 remains below its withstand voltage value. This allows the network card interface 30 to maintain normal operation when connected to the network card interface 30, enabling it to pass the withstand voltage test of the BF-type medical device and meet the withstand voltage requirement.

[0035] In some embodiments, the clamping circuit 40 can be connected in parallel with the network interface 30. The two ends of the network interface 30 are connected to the external network interface 50 and the housing grounding protection SC, respectively. The clamping circuit 40 can connect the external network interface 50 and the housing grounding protection SC, that is, the clamping circuit 40 is connected in parallel with the network interface 30. When the clamping circuit 40 is turned on at a predetermined voltage, it can limit the voltage across the parallel network interface 30 to the predetermined voltage, thereby achieving voltage withstand protection for the network interface 30.

[0036] In some embodiments, the clamping circuit 40 may include a transient suppression diode Z1, which conducts when the voltage between its negative and positive terminals is a predetermined high voltage or above, thereby connecting the external network interface 50 to the housing grounding protection SC.

[0037] Please refer to Figure 2 In some embodiments, the clamping circuit 40 described above may include:

[0038] Transient voltage suppressor diode Z1, the cathode of transient voltage suppressor diode Z1 is connected to the external network interface 50, and the anode of transient voltage suppressor diode Z1 is connected to the casing grounding protection SC.

[0039] When a high voltage is applied between the live wire of the external network interface 50 and the external power interface, the transient voltage suppressor diode Z1 breaks down in reverse under the high voltage, directing the high voltage pulse to the casing grounding protection SC, thus maintaining the voltage across the transient voltage suppressor diode Z1 at a predetermined voltage, which is the breakdown voltage of the transient voltage suppressor diode Z1. Since the transient voltage suppressor diode Z1 is connected in parallel with the network interface 30, the voltage across the network interface also remains at the predetermined voltage.

[0040] like Figure 3 As shown, in some embodiments, the clamping circuit 40 may include a plurality of transient suppression diodes Z1 corresponding one-to-one with the signal lines of the external network interface 50. One end of the transient suppression diode Z1 is connected to the housing ground protection SC, and the other end is connected to the corresponding signal line. It is understood that the positive terminal of the transient suppression diode Z1 is connected to the housing ground protection SC, and the negative terminal is connected to the corresponding signal line. When the voltage on the signal line of the external network interface 50 exceeds a predetermined voltage, the transient suppression diode Z1 conducts, thereby limiting the voltage between the signal line and the housing ground protection SC to the predetermined voltage.

[0041] It is understandable that J1 is the external network interface 50, and J2 is the network card interface 30. When the network card is inserted into the network card interface 30, multiple pins of the network card interface 30 can be connected to multiple pins of the external network interface 50 respectively to achieve network communication. Each signal line connecting the network card interface 30 and the external network interface 50 is equipped with a transient voltage suppression diode Z1. Through multiple transient voltage suppression diodes Z1, the voltage between all signal lines and the casing ground protection SC can be limited to a predetermined voltage, thereby allowing the network card inserted into the network card interface 30 to continue to operate normally and preventing the voltage from exceeding the withstand voltage of the pins, which would damage the network card interface 30.

[0042] When a high voltage is generated between the external network interface 50 and the live wire of the external power interface, each transient voltage suppressor diode Z1 can clamp the voltage of the corresponding connection line between the pins. By using multiple transient voltage suppressor diodes Z1, the voltage between the external network interface 50 and the casing ground protection SC can be limited to the predetermined voltage of the transient voltage suppressor diode Z1, preventing the voltage of a certain connection line between the external network interface 50 and the network card interface 30 from being too high and causing damage to the network card interface 30.

[0043] In some embodiments, the clamping circuit 40 may further include:

[0044] Capacitor C can be placed between the casing grounding protection SC and the transient suppression diode Z1.

[0045] When the number of transient suppression diodes Z1 corresponds to the number of pins of the external network interface 50, the anode of each transient suppression diode Z1 is connected to the casing grounding protection SC through the capacitor C. The capacitor C can block DC in the clamping circuit 40, converting the DC component in the clamping circuit 40 into charge for accumulation.

[0046] In some embodiments, the clamping circuit 40 may further include:

[0047] The resistor R is connected in parallel with the capacitor C.

[0048] In the clamping circuit 40, the resistor R can be used as a discharge resistor for the capacitor C to discharge the charge accumulated on the capacitor C.

[0049] In some embodiments, the clamping circuit 40 described above can also be a network signal adapter board. Each connection line between the external network interface 50 and the network card interface 30 on the network signal adapter board is equipped with a transient suppression diode Z1. One end of the transient suppression diode Z1 is connected to the connection line, and the other end is connected to the casing grounding protection SC. It is understood that a capacitor C and a resistor R can also be provided on the network signal adapter board to discharge the charge generated by the transient suppression diode Z1.

[0050] like Figure 2 As shown, in some embodiments, the aforementioned enclosure grounding protection SC may include digital ground GND and protective ground PE, which is connected to the ground terminal of the external power interface. The clamping circuit 40 may be connected to the protective ground PE, thereby conducting when there is a high voltage between the external network interface 50 and the protective ground PE, and providing withstand voltage protection for the network card interface 30.

[0051] In some embodiments, the network interface 30 can be connected to digital ground (GND), and the switching power supply 20 can also be connected to digital ground (GND). When the withstand voltage protection circuit is installed in the industrial control computer, the digital ground (GND) can be connected to the protective ground (PE) through the industrial control computer's casing.

[0052] This application also provides an industrial control computer, which includes a withstand voltage protection circuit. The structure of the withstand voltage protection circuit can be referred to in the above embodiments, and will not be repeated here. Accordingly, since the industrial control computer of this embodiment adopts the above-described withstand voltage protection circuit technical solution, it has all the beneficial effects of the above-described withstand voltage protection circuit.

[0053] This application also provides a medical device that includes an industrial control computer. Naturally, the medical device of this embodiment possesses all the beneficial effects of the aforementioned industrial control computer.

[0054] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0055] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A withstand voltage protection circuit for implementing withstand voltage protection between an external network interface and an external power supply interface, characterized in that, include: Network interface card (NIC) is used to connect to the network card of an industrial control computer. External network interface, used to connect to external network cables; Industrial PC switching power supply, used to power the industrial PC motherboard and network card; An isolation transformer is installed between the external power interface and the switching power supply; The casing grounding protection is used to connect the ground wire of the industrial control computer casing and the external power interface, and to connect it to the digital ground of the network card; A clamping circuit is connected to the external network interface and the aforementioned housing grounding protection. The clamping circuit is used to clamp the voltage between the external network interface and the housing grounding protection within a defined voltage range. When performing withstand voltage tests on the external network interface and the external power interface, the voltage between the external network interface and the external power interface is equal to the sum of the voltage across the isolation transformer, the voltage between the input terminal of the switching power supply and the casing grounding protection, and the voltage across the network card interface. The clamping circuit is used to clamp the voltage at both ends of the network card interface to a predetermined voltage value lower than the network card's withstand voltage value.

2. The withstand voltage protection circuit according to claim 1, characterized in that, The clamping circuit is connected in parallel with the network card interface.

3. The withstand voltage protection circuit according to claim 1, characterized in that, The clamping circuit includes a transient suppression diode, which conducts at a predetermined high voltage to connect the external network interface to the housing grounding protection.

4. The withstand voltage protection circuit according to claim 3, characterized in that, The clamping circuit includes multiple transient suppression diodes that correspond one-to-one with the signal lines of the external network interface. One end of each transient suppression diode is connected to the grounding protection of the outer casing, and the other end is connected to the signal line.

5. The withstand voltage protection circuit according to claim 4, characterized in that, The clamping circuit also includes a capacitor, which is disposed between the housing grounding protection and the transient suppression diode.

6. The withstand voltage protection circuit according to claim 5, characterized in that, The clamping circuit also includes a resistor connected in parallel with the capacitor.

7. The withstand voltage protection circuit according to claim 1, characterized in that, The enclosure grounding protection includes a digital ground and a protective ground, and the clamping circuit is connected to the protective ground.

8. The withstand voltage protection circuit according to claim 7, characterized in that, The network card interface and / or the switching power supply are connected to the digital ground.

9. A medical device, characterized in that, The medical device includes an industrial control computer, which includes a withstand voltage protection circuit as described in any one of claims 1 to 8.

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