External interface short circuit detection circuit and electric equipment

Abstract

The external interface short circuit detection circuit comprises an auxiliary power supply, a first switch circuit, a second switch circuit and a sampling circuit, the first switch circuit is connected with a main power supply circuit and an anode of an external interface, and the second switch circuit is connected with the first switch circuit and the anode of the external interface. The sampling circuit is connected with the negative electrode of the external interface, a ground wire and the controller; the first switching circuit is used for disconnecting the main power supply from the external interface; and the second switching circuit is used for conducting the connection between the external interface and the auxiliary power supply when the first switching circuit is disconnected, and providing the auxiliary power supply for the external device. An additional auxiliary power supply is added, before the main power supply for supplying power to the outside is provided, the sampling circuit of the external device is detected through the sampling circuit, whether short circuit and overcurrent conditions exist or not is judged, the controller is informed, the main power supply is provided for supplying power to the external device after it is confirmed that the external device is not abnormal, and therefore the risk that equipment is damaged is reduced.

Description

Technical Field

[0001] This utility model relates to the field of circuit protection technology, and in particular to an external interface short-circuit detection circuit and electrical equipment. Background Technology

[0002] Medical equipment is generally equipped with external active accessories. The equipment interface needs to provide power to the external interface. When an accessory with a short circuit to ground is connected to the equipment, the current at the external interface increases abnormally, which may damage the circuit components at the interface and increase the workload of after-sales service. If the power supply to the external interface also supplies power to the system, it will cause system malfunction. Utility Model Content

[0003] The main purpose of this invention is to provide an external interface short circuit detection circuit and device, which aims to detect whether there are short circuits and overcurrents in external accessory devices.

[0004] To achieve the above objectives, this utility model proposes an external interface short-circuit detection circuit, which includes: an auxiliary power supply, a first switching circuit, a second switching circuit, and a sampling circuit, wherein...

[0005] The first switching circuit is connected to the positive terminal of the main power supply circuit and the external interface; the second switching circuit is connected to the positive terminal of the first switching circuit and the external interface; and the sampling circuit is connected to the negative terminal of the external interface, the ground wire, and the controller.

[0006] The first switching circuit is used to disconnect the main power supply and the external interface;

[0007] The second switching circuit is used to connect the external interface and the auxiliary power supply when the first switching circuit is disconnected, so as to provide low voltage power to the external device.

[0008] The sampling circuit is used to detect the current of the external device as the sampling current when the auxiliary power supply is on, and to generate and send a short-circuit signal to the controller when the sampling current is abnormal.

[0009] In one embodiment, the external interface short-circuit detection circuit further includes: a third switching circuit;

[0010] The third switching circuit is connected to the negative terminal of the sampling circuit and the external interface;

[0011] The third switching circuit is used to connect the power supply circuit of the sampling circuit and the external device.

[0012] The sampling circuit is used to detect the current of the sampling circuit as a sampling current when the auxiliary power supply is on and the third switching circuit is turned on.

[0013] In one embodiment, the external interface short-circuit detection circuit further includes: an amplifier circuit and a comparator circuit;

[0014] The amplifier circuit is connected to the sampling circuit, and the comparator circuit is connected to the amplifier circuit.

[0015] The sampling circuit is also used to transmit the sampling current to the amplification circuit;

[0016] The amplification circuit is used to amplify the sampled current to obtain an amplified current, and transmit it to the comparison circuit and the controller;

[0017] The comparison circuit is used to compare the amplified current with the threshold current and transmit the comparison result to the controller.

[0018] In one embodiment, the controller is connected to the first switching circuit, the second switching circuit, the third switching circuit, the comparator circuit, and the amplifier circuit;

[0019] The controller is configured to control the first switching circuit to remain open when the amplified current is greater than the threshold current.

[0020] The controller is also used to control the second switching circuit and the third switching circuit to conduct when the external device is connected.

[0021] In one embodiment, the first switching circuit includes: a first resistor, a second resistor, a third resistor, a first capacitor, a first MOSFET, and a first transistor;

[0022] One end of the first resistor is connected to the main power supply, one end of the first capacitor, and the source of the first MOSFET. The other end of the first resistor is connected to the other end of the first capacitor, the gate of the first MOSFET, and the collector of the first transistor. The drain of the first MOSFET is connected to the anode of the external interface and the second switching circuit. The base of the first transistor is connected to one end of the second resistor and one end of the third resistor. The other end of the second resistor is connected to the controller. One end of the third resistor and the emitter of the first transistor are grounded.

[0023] In one embodiment, the second switching circuit includes: a fourth resistor, a fifth resistor, a sixth resistor, a second capacitor, a first diode, a second diode, a second MOSFET, and a second transistor;

[0024] The anode of the first diode is connected to the auxiliary power supply. The cathode of the first diode is connected to one end of the fourth resistor, one end of the second capacitor, and the source of the second MOSFET. The other end of the fourth resistor is connected to the other end of the second capacitor, the gate of the second MOSFET, and the collector of the second transistor. The drain of the second MOSFET is connected to the anode of the second diode. The cathode of the second diode is connected to the anode of the external interface and the first switching circuit. The base of the second transistor is connected to one end of the fifth resistor and one end of the sixth resistor. The other end of the fifth resistor is connected to the controller. The other end of the sixth resistor and the emitter of the second transistor are grounded.

[0025] In one embodiment, the third switching circuit includes: a third MOSFET;

[0026] The drain of the third MOS transistor is connected to the cathode of the external interface, the gate of the third MOS transistor is connected to the controller, the source of the third MOS transistor is connected to one end of the sampling circuit and the amplification circuit, and the other end of the sampling circuit is grounded.

[0027] In one embodiment, the amplification circuit includes: an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a third capacitor, and the first operational amplifier;

[0028] One end of the eighth resistor is connected to the acquisition circuit, the other end of the eighth resistor is connected to one end of the ninth resistor and one end of the third capacitor, the other end of the ninth resistor is connected to the positive input terminal of the first operational amplifier, the negative input terminal of the first operational amplifier is connected to one end of the tenth resistor, the other end of the tenth resistor is connected to one end of the eleventh resistor and the output terminal of the first operational amplifier, and the other end of the eleventh resistor is connected to the comparator circuit and the controller.

[0029] In one embodiment, the comparator circuit includes: a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a second operational generator;

[0030] One end of the twelfth resistor is connected to the amplifier circuit and the controller, the other end of the twelfth resistor is connected to the positive input terminal of the second operational amplifier, the negative input terminal of the second operational amplifier is connected to one end of the thirteenth resistor and one end of the fourteenth resistor, the other end of the thirteenth resistor is connected to the auxiliary power supply, the other end of the fourteenth resistor is grounded, and the output terminal of the second operational amplifier is connected to the controller.

[0031] This utility model also proposes an electrical device, which includes an external interface short-circuit detection circuit as described above.

[0032] This utility model employs an external interface short-circuit detection circuit to detect whether an external device is short-circuited. The external interface short-circuit detection circuit includes: an auxiliary power supply, a first switching circuit, a second switching circuit, and a sampling circuit. The first switching circuit is connected to the main power supply circuit and the positive terminal of the external interface. The second switching circuit is connected to the first switching circuit and the positive terminal of the external interface. The sampling circuit is connected to the negative terminal of the external interface, ground, and controller. The first switching circuit disconnects the main power supply from the external interface. The second switching circuit, when the first switching circuit is disconnected, connects the external interface to the auxiliary power supply, providing auxiliary power to the external device. The sampling circuit detects the current of the external device as a sampling current when the auxiliary power supply is on. If the sampling current is abnormal, it generates and sends a short-circuit signal to the controller. This application adds an extra auxiliary power supply. Before providing the main power supply, the sampling circuit detects whether the external device is short-circuited or overcurrent and informs the control system of the status. Only after confirming that the external device is normal is the main power supply provided, thereby reducing the risk of equipment damage. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0034] Figure 1 A schematic diagram of the module of the first embodiment of the external interface short-circuit detection circuit provided by this utility model;

[0035] Figure 2 A circuit diagram of the second embodiment of the external interface short-circuit detection circuit provided by this utility model.

[0036] Explanation of icon numbers:

[0037]

[0038]

[0039] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0040] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0041] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0042] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0043] Medical equipment is generally equipped with external active accessories. The equipment interface needs to provide power to the external interface. When an accessory with a short circuit to ground is connected to the equipment, the current at the external interface increases abnormally, which may damage the circuit components at the interface and increase the workload of after-sales service. If the power supply to the external interface also supplies power to the system, it will cause system malfunction.

[0044] This utility model proposes an external interface short-circuit detection circuit.

[0045] Please see Figure 1 , Figure 1 This is a schematic diagram of a module of an embodiment of the external interface short-circuit detection circuit proposed in this utility model.

[0046] In this embodiment, the technical solution of this utility model uses an external interface short-circuit detection circuit to detect whether the external device is short-circuited. The external interface short-circuit detection circuit includes: an auxiliary power supply 40, a first switching circuit 10, a second switching circuit 20, and a sampling circuit 60. The first switching circuit 10 is connected to the main power supply circuit and the positive terminal of the external interface. The second switching circuit 20 is connected to the first switching circuit 10 and the positive terminal of the external interface 50. The sampling circuit is connected to the negative terminal of the external interface, the ground wire, and the controller 70. The first switching circuit 10 is used to disconnect the connection between the main power supply and the external interface. The second switching circuit is used to connect the external interface and the auxiliary power supply when the first switching circuit 10 is disconnected, providing auxiliary power 40 to the external device. The sampling circuit 60 is used to detect the current of the external device as a sampling current when the auxiliary power supply is powered, and to generate and send a short-circuit signal to the controller 70 when the sampling current is abnormal.

[0047] It should be noted that the auxiliary power supply (low voltage Vcc_Aux, 2~5V) checks for short circuits and overcurrents in external devices connected to the external interface before the main power supply provides the operating voltage. This is to prevent equipment from burning out due to short circuits when the operating voltage (high voltage) is reduced.

[0048] This invention relates to skin electrical devices, such as radiofrequency electrical devices. Before powering the treatment head, it checks whether the handle and the treatment head are electrically short-circuited, and relies on the controller to control the first switching circuit 10 to disconnect the connection between the main power supply and the external interface; or, if the active accessory device is a heating film for heating a refrigerant source, before outputting the refrigerant for treatment, it checks whether the heating film and the device are electrically short-circuited, and relies on the controller to control the first switching circuit 10 to disconnect the electrical connection between the main power supply in the device and the active accessory device.

[0049] In this embodiment, an additional auxiliary power supply is added. Before providing the main power supply to the external device, a sampling circuit detects whether there is a short circuit or overcurrent in the external device and informs the control system of the status. The main power supply is then provided to the external device only after confirming that there are no abnormalities in the external device, thereby reducing the risk of equipment damage.

[0050] like Figure 2 The diagram shown is a circuit diagram of the second embodiment of the external interface short-circuit detection circuit proposed in this utility model.

[0051] Based on the first embodiment described above, a second embodiment of the external interface short-circuit detection circuit of this utility model is proposed.

[0052] The external interface short-circuit detection circuit further includes: a third switch circuit 100; the third switch circuit 100 is connected to the sampling circuit 60 and the negative terminal of the external interface; the third switch circuit 100 is used to conduct the power supply circuit of the sampling circuit and the external device; the sampling circuit 60 is used to detect the current of the sampling circuit 60 as the sampling current when the auxiliary power supply is on and the third switch circuit is on.

[0053] The third switching circuit 100 includes: a third MOS transistor Q3; the drain of the third MOS transistor is connected to the cathode of the external interface, the gate of the third MOS transistor is connected to the controller, the source of the third MOS transistor is connected to one end of the sampling circuit and the amplification circuit, and the other end of the sampling circuit is grounded.

[0054] It is understood that the sampling circuit includes a seventh resistor R7. When an external device is connected to the external interface, the first switching circuit 10 is disconnected, the second switching circuit 20 is turned on, and the auxiliary power supply VCC2 supplies power to the external device. However, the negative terminal of the external device is connected to the third switching circuit 100. When the protection enable signal provided by the controller to the third MOSFET Q3 is high, the third MOSFET Q3 is turned on, and the power supply circuit of the external device is turned on. The current flowing through the seventh resistor R7 is the sampling current, which is also the current of the external device. When the external device is short-circuited, the sampling current will be greater than the preset current. The magnitude of the sampling current is detected to determine whether the external device is short-circuited, and the sampling current is transmitted to the controller. When the sampling circuit detects that the sampling current is normal, the controller 70 controls the third switching circuit 10 to turn on, and the main power supply normally supplies power to the external device. When the sampling circuit detects that the sampling current is abnormal, the controller 70 controls the third switching circuit 10 to turn on, the auxiliary power supply supplies power to the external device, and the sampling circuit continuously collects the sampling current and sends it to the controller.

[0055] The controller is connected to the first switching circuit 10, the second switching circuit 20, the third switching circuit 100, the comparator circuit 300, and the amplifier circuit 200; the controller is also used to control the second switching circuit and the third switching circuit to conduct when the external device is connected; the controller is used to control the first switching circuit to remain disconnected when the amplified current is greater than the threshold current.

[0056] Understandably, the controller 70 provides a power enable signal to the first switching circuit. When an external device is connected to the external interface 50, the controller 70 controls the first switching circuit 10 to disconnect, thus disconnecting the main power supply from the external interface. When the sampling circuit detects that the sampling current is normal, the controller 70 controls the first switching circuit 10 to conduct, thus supplying power to the external device normally. When the sampling circuit detects that the sampling current is abnormal, the controller 70 controls the first switching circuit 10 to remain disconnected.

[0057] It should be noted that the controller 70 provides an auxiliary power enable signal to the second switching circuit. When the external device is connected to the external interface 50, the controller 70 controls the second switching circuit 10 to be turned on. When the sampling circuit detects that the sampling current is normal, the controller 70 controls the second switching circuit 10 to be turned off, and the auxiliary power supply stops supplying power to the external device. When the sampling circuit detects that the sampling current is abnormal, the controller 70 controls the second switching circuit 10 to be turned on continuously, the auxiliary power supply 40 provides low-voltage power to the external device, the sampling circuit 60 continuously collects the sampling current, and sends it to the controller.

[0058] The first switching circuit includes: a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, a first MOSFET Q1, and a first transistor M1; one end of the first resistor R1 is connected to the main power supply VCC1, one end of the first capacitor C1, and the source of the first MOSFET Q1; the other end of the first resistor is connected to the other end of the first capacitor, the gate of the first MOSFET, and the collector of the first transistor M1; the drain of the first MOSFET Q1 is connected to the anode of the external interface and the second switch 20 circuit; the base of the first transistor is connected to one end of the second resistor and one end of the third resistor; the other end of the second resistor R2 is connected to the controller; and one end of the third resistor R3 and the emitter of the first transistor M1 are grounded.

[0059] Understandably, the controller 70 provides a power enable signal to the first switching circuit. When an external device is connected to the external interface 50, the power enable signal is low, the first transistor M1 is turned off, and the first MOSFET Q1 is also turned off, so the main power supply VCC1 does not supply power to the external device. When the sampling current is normal, the power enable signal is high, the first transistor M1 is turned on, the base of the first MOSFET Q1 is grounded, so the base voltage of the first MOSFET Q1 is less than the source voltage, Q1 is also turned on, and the main power supply VCC1 normally supplies power to the external device.

[0060] It should be noted that the first MOSFET Q1 is a PMOS transistor, and a relay or a chip with the same function can also be used to replace the first MOSFET Q1.

[0061] The second switching circuit includes: a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a second capacitor C2, a first diode D1, a second diode D2, a second MOSFET Q2, and a second transistor M2; the anode of the first diode D1 is connected to the auxiliary power supply, the cathode of the first diode D1 is connected to one end of the fourth resistor R4, one end of the second capacitor C2, and the source of the second MOSFET Q2, the other end of the fourth resistor R4 is connected to the other end of the second capacitor C2, the gate of the second MOSFET Q2, and the collector of the second transistor M2, the drain of the second MOSFET Q2 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to the anode of the external interface and the first switching circuit, the base of the second transistor M2 is connected to one end of the fifth resistor R5 and one end of the sixth resistor R6, the other end of the fifth resistor R5 is connected to the controller 70, and the other end of the sixth resistor R6 and the emitter of the second transistor M2 are grounded.

[0062] Understandably, the controller 70 provides an auxiliary power enable signal to the first switching circuit. When an external device is connected to the external interface 50, the auxiliary power enable signal is at a high level, the second transistor M2 is turned on, which in turn turns on the second MOSFET Q2, and the auxiliary power supply VCC2 provides a low voltage to the external device. When the sampling current is normal, the auxiliary power enable signal is at a low level, the second transistor M2 is turned off, which in turn turns off the second MOSFET Q2, and the auxiliary power supply VCC2 stops supplying power to the external device.

[0063] It should be noted that the second MOSFET Q2 is a PMOS transistor, and a relay or a chip with the same function can also be used to replace the second MOSFET Q2. The first diode D1 is to protect the second switching circuit from overcurrent surges or high-voltage main power supply inflow, and the second diode D2 is to protect the auxiliary power supply from overcurrent surges.

[0064] Optionally, the first transistor M1 and the second transistor M2 can be replaced by MOSFETs or relays.

[0065] In this embodiment, when the external device is connected to the external interface 50, the controller sends an enable signal to disconnect the main power supply and the external interface through the first switching circuit, and connect the auxiliary power supply and the external interface through the second switching circuit. The low-voltage auxiliary power supply supplies power to the external device, and at the same time, the power supply circuit of the external device is connected through the third switching circuit. The sampling current in the circuit is collected through the sampling circuit, and the magnitude of the sampling current is used to determine whether the external device is short-circuited or overcurrent.

[0066] like Figure 2The diagram shown is a circuit diagram of the third embodiment of the external interface short-circuit detection circuit proposed in this utility model.

[0067] Based on the first and / or second embodiments described above, a third embodiment of the external interface short-circuit detection circuit of this utility model is proposed.

[0068] The external interface short-circuit detection circuit further includes an amplifier circuit 200 and a comparator circuit 300; wherein the amplifier circuit 200 is connected to the sampling circuit 60, and the comparator circuit 300 is connected to the amplifier circuit 200; the sampling circuit 60 is also used to transmit the sampled current to the amplifier circuit 200; the amplifier circuit 200 is used to amplify the sampled current to obtain an amplified current, and transmit it to the comparator circuit 300 and the controller 70; the comparator circuit 300 is used to compare the amplified current with a threshold current, and transmit the comparison result to the controller 70.

[0069] Understandably, the auxiliary power supply provides a low-voltage power supply. The sampling current collected by the sampling circuit 60 is too small to be directly detected and compared. It needs to be amplified by the amplifier circuit 200. The amplified current is then transmitted to the controller 70 and the comparison circuit 300. The amplifier circuit 200 outputs a current detection signal to the controller. The comparison circuit 300 compares the amplified current with a preset current and transmits the comparison result to the controller. The comparison circuit 300 also outputs a short-circuit detection signal to the controller 70. If the detected amplified current is greater than the preset current, the comparison circuit 300 outputs a high-level short-circuit detection signal to notify the MCU controller that there is a power short circuit in the external device.

[0070] The amplification circuit includes: an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a third capacitor C3, and a first operational amplifier A; one end of the eighth resistor R8 is connected to the acquisition circuit, the other end of the eighth resistor is connected to one end of the ninth resistor R9 and one end of the third capacitor, the other end of the ninth resistor R9 is connected to the positive input terminal of the first operational amplifier, the negative input terminal of the first operational amplifier is connected to one end of the tenth resistor R10, the other end of the tenth resistor is connected to one end of the eleventh resistor R11 and the output terminal of the first operational amplifier, and the other end of the eleventh resistor R11 is connected to the comparator circuit and the controller.

[0071] It is understood that by detecting the sampled voltage value across the seventh resistor R7, the sampled current I = U / R is calculated, the first operational amplifier amplifies the sampled voltage to obtain an amplified voltage, and the amplified voltage is transmitted to the controller and the comparison circuit.

[0072] The comparator circuit includes: a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, and a second operational amplifier B; one end of the twelfth resistor R12 is connected to the amplifier circuit 200 and the controller, the other end of the twelfth resistor is connected to the positive input terminal of the second operational amplifier, the negative input terminal of the second operational amplifier is connected to one end of the thirteenth resistor and one end of the fourteenth resistor, the other end of the thirteenth resistor is connected to the auxiliary power supply, the other end of the fourteenth resistor is grounded, and the output terminal of the second operational amplifier is connected to the controller.

[0073] It should be noted that the thirteenth resistor R13 and the fourteenth resistor R14 are voltage divider resistors connected to the auxiliary power supply and used to set the preset voltage value. The preset voltage U = VCC2 * R14 / (R13 + R14). By setting the resistance values ​​of the thirteenth resistor R13 and the fourteenth resistor R14, the preset voltage is adjusted. If the amplified voltage is detected to be greater than this preset voltage, a short-circuit detection signal is output at a high level to notify the MCU controller that there is a power short circuit in the external device. If the amplified voltage is detected to be less than this preset voltage, a short-circuit detection signal is output at a low level to notify the MCU controller that the external device is normal and there is no power short circuit.

[0074] In this embodiment, the sampling circuit collects the sampling current of the external device, amplifies it through the amplification circuit to obtain the amplified current, and transmits the amplified current to the controller and the comparison circuit respectively. The comparison circuit compares the amplified current with a preset current, and the comparison circuit 300 transmits the comparison result to the controller. If the amplified current is detected to be greater than the preset current, the comparison circuit 300 outputs a high-level short-circuit detection signal to notify the MCU controller that there is a power short circuit in the external device.

[0075] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system 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 system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0076] This utility model also proposes an electrical device, which includes an external interface short-circuit detection circuit. The specific structure of the external interface short-circuit detection circuit is as described in the above embodiments. Since the overcurrent protection device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0077] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. An external interface short-circuit detection circuit, characterized in that, include: The system comprises an auxiliary power supply, a first switching circuit, a second switching circuit, and a sampling circuit, among which... The first switching circuit is connected to the main power supply circuit and the positive terminal of the external interface; the second switching circuit is connected to the first switching circuit and the positive terminal of the external interface; and the sampling circuit is connected to the negative terminal of the external interface, the ground wire, and the controller. The first switching circuit is used to disconnect the main power supply and the external interface; The second switching circuit is used to connect the external interface and the auxiliary power supply when the first switching circuit is disconnected, so as to provide low voltage power to the external device. The sampling circuit is used to detect the current of the external device as the sampling current when the auxiliary power supply is on, and to generate and send a short-circuit signal to the controller when the sampling current is abnormal.

2. The external interface short-circuit detection circuit as described in claim 1, characterized in that, The external interface short-circuit detection circuit also includes: a third switch circuit; The third switching circuit is connected to the negative terminal of the sampling circuit and the external interface; The third switching circuit is used to connect the power supply circuit of the sampling circuit and the external device. The sampling circuit is used to detect the current of the sampling circuit as a sampling current when the auxiliary power supply is on and the third switching circuit is turned on.

3. The external interface short-circuit detection circuit as described in claim 2, characterized in that, The external interface short-circuit detection circuit also includes: an amplifier circuit and a comparator circuit; The amplifier circuit is connected to the sampling circuit, and the comparator circuit is connected to the amplifier circuit. The sampling circuit is also used to transmit the sampling current to the amplification circuit; The amplification circuit is used to amplify the sampled current to obtain an amplified current, and transmit it to the comparison circuit and the controller; The comparison circuit is used to compare the amplified current with the threshold current and transmit the comparison result to the controller.

4. The external interface short-circuit detection circuit as described in claim 3, characterized in that, The controller is connected to the first switching circuit, the second switching circuit, the third switching circuit, the comparator circuit, and the amplifier circuit; The controller is configured to control the first switching circuit to remain open when the amplified current is greater than the threshold current. The controller is also used to control the second switching circuit and the third switching circuit to conduct when the external device is connected.

5. The external interface short-circuit detection circuit as described in claim 4, characterized in that, The first switching circuit includes: a first resistor, a second resistor, a third resistor, a first capacitor, a first MOSFET, and a first transistor; One end of the first resistor is connected to the main power supply, one end of the first capacitor, and the source of the first MOSFET. The other end of the first resistor is connected to the other end of the first capacitor, the gate of the first MOSFET, and the collector of the first transistor. The drain of the first MOSFET is connected to the anode of the external interface and the second switching circuit. The base of the first transistor is connected to one end of the second resistor and one end of the third resistor. The other end of the second resistor is connected to the controller. One end of the third resistor and the emitter of the first transistor are grounded.

6. The external interface short-circuit detection circuit as described in claim 5, characterized in that, The second switching circuit includes: a fourth resistor, a fifth resistor, a sixth resistor, a second capacitor, a first diode, a second diode, a second MOSFET, and a second transistor; The anode of the first diode is connected to the auxiliary power supply. The cathode of the first diode is connected to one end of the fourth resistor, one end of the second capacitor, and the source of the second MOSFET. The other end of the fourth resistor is connected to the other end of the second capacitor, the gate of the second MOSFET, and the collector of the second transistor. The drain of the second MOSFET is connected to the anode of the second diode. The cathode of the second diode is connected to the anode of the external interface and the first switching circuit. The base of the second transistor is connected to one end of the fifth resistor and one end of the sixth resistor. The other end of the fifth resistor is connected to the controller. The other end of the sixth resistor and the emitter of the second transistor are grounded.

7. The external interface short-circuit detection circuit as described in claim 6, characterized in that, The third switching circuit includes: a third MOSFET; The drain of the third MOS transistor is connected to the cathode of the external interface, the gate of the third MOS transistor is connected to the controller, the source of the third MOS transistor is connected to one end of the sampling circuit and the amplification circuit, and the other end of the sampling circuit is grounded.

8. The external interface short-circuit detection circuit as described in claim 7, characterized in that, The amplifier circuit includes: an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a third capacitor, and a first operational amplifier; One end of the eighth resistor is connected to the sampling circuit, the other end of the eighth resistor is connected to one end of the ninth resistor and one end of the third capacitor, the other end of the ninth resistor is connected to the positive input terminal of the first operational amplifier, the negative input terminal of the first operational amplifier is connected to one end of the tenth resistor, the other end of the tenth resistor is connected to one end of the eleventh resistor and the output terminal of the first operational amplifier, and the other end of the eleventh resistor is connected to the comparator circuit and the controller.

9. The external interface short-circuit detection circuit as described in claim 8, characterized in that, The comparator circuit includes: a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a second operational amplifier; One end of the twelfth resistor is connected to the amplifier circuit and the controller, the other end of the twelfth resistor is connected to the positive input terminal of the second operational amplifier, the negative input terminal of the second operational amplifier is connected to one end of the thirteenth resistor and one end of the fourteenth resistor, the other end of the thirteenth resistor is connected to the auxiliary power supply, the other end of the fourteenth resistor is grounded, and the output terminal of the second operational amplifier is connected to the controller.

10. An electrical appliance, characterized in that, The electrical equipment includes the external interface short-circuit detection circuit as described in any one of claims 1 to 9.

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