CN112736860B

CN112736860B - Fault protection circuit of USB cable and USB cable thereof

Info

Publication number: CN112736860B
Application number: CN202110099906.3A
Authority: CN
Inventors: 谢仁践; 潘浩
Original assignee: Hynetek Semiconductor Co ltd
Current assignee: Hynetek Semiconductor Co ltd
Priority date: 2021-01-25
Filing date: 2021-01-25
Publication date: 2023-04-07
Anticipated expiration: 2041-01-25
Also published as: CN112736860A

Abstract

The embodiment of the invention relates to the technical field of USB, in particular to a fault protection circuit of a USB cable and the USB cable. The fault protection circuit includes: the overcurrent fault detection module is used for outputting an overcurrent fault signal when the level of the detection node is higher than a first reference voltage; the second voltage comparison unit is used for outputting the overcurrent fault signal when the level of the detection node is lower than a second reference voltage; the reference voltage and a preset over-current detection threshold value are added to form a first reference voltage, and the reference voltage and the preset over-current detection threshold value are subtracted to form a second reference voltage; and the circuit protection module is used for cutting off power supply to respond to the overcurrent fault signal. The fault protection circuit collects current information by using the voltage drop of the electric wire generated by the impedance of the ground wire, and can realize accurate detection of overcurrent faults without arranging an additional current sampling device.

Description

Fault protection circuit of USB cable and USB cable thereof

[ technical field ] A method for producing a semiconductor device

The invention relates to the technical field of USB (universal serial bus), in particular to a fault protection circuit of a USB cable and the USB cable.

[ background of the invention ]

A Serial Bus (USB) is a Serial Bus standard for connecting a computer system and an external device, and is also a technical specification of an input/output interface, and is widely applied to information communication products such as personal computers and mobile devices, and is extended to other related fields such as camera equipment, digital televisions (set top boxes), game machines, and the like.

With the increasingly stringent requirements of the mobile device on transmission rate, charging power and interface size, a new generation of USB interface USB Type-C is in force. USB Type-C, called Type-C or USB-C for short, is a hardware interface specification of Universal Serial Bus (USB). It has the advantages of small size, high transmission speed, support of double-sided insertion, and high power transmission power.

However, the charging current is continuously increased, so that the situation that the connector of the USB cable is heated and burnt is more and more frequent, and great potential safety hazards are caused to daily charging and use. Therefore, attention is focused on safety protection of USB cables in high-current operating scenarios such as charging.

The current safety protection of the USB cable mainly adopts a protection scheme of connecting a thermistor (PTC) in series on a VBUS bus of the USB cable. The PTC protector protects the cable at 80-100 ℃, so that the protection function can be realized before the rubber of the cable reaches the melting point, and the short-circuit protection function is also realized.

However, the PTC heating device has the defect of self-heating, which not only brings extra loss, but also causes certain potential safety hazard. Moreover, the PTC is a heat-sensitive element, mainly plays a role of over-temperature protection, and has low precision of over-current fault protection.

[ summary of the invention ]

The embodiment of the invention aims to provide a fault protection circuit of a USB cable and the USB cable thereof, which can overcome the defects of the existing protection scheme of serially connecting a thermistor on a VBUS bus.

In order to solve the above technical problems, embodiments of the present invention provide the following technical solutions: a fault protection circuit for a USB cable. The fault protection circuit includes:

an over-current fault detection module, the over-current fault detection module comprising: the USB cable comprises a detection node, a reference voltage unit, a first voltage comparison unit and a second voltage comparison unit, wherein the detection node takes the ground wire of the USB cable as a reference ground;

the first voltage comparison unit is used for outputting an overcurrent fault signal when the level of the detection node is higher than a first reference voltage; the second voltage comparison unit is used for outputting the overcurrent fault signal when the level of the detection node is lower than a second reference voltage;

the reference voltage and a preset over-current detection threshold value are added to form a first reference voltage, and the reference voltage and the preset over-current detection threshold value are subtracted to form a second reference voltage;

and the circuit protection module is used for cutting off power supply when the overcurrent fault signal appears.

Optionally, the fault protection circuit further comprises:

the over-temperature detection module is used for detecting current circuit temperature information and outputting an over-temperature fault signal when the current circuit temperature information exceeds a temperature threshold value; the circuit protection module is also used for cutting off power supply when the over-temperature fault signal occurs.

Optionally, the reference voltage unit includes: providing a reference voltage source for stabilizing a preset voltage and a voltage dividing resistor network for dividing the voltage;

the voltage dividing resistor network consists of one or more voltage dividing resistors and is connected between the reference voltage source and the detection node;

the circuit protection module cuts off power supply by cutting off a power supply bus of the USB cable or sending an alarm signal to power supply equipment.

Optionally, the fault protection circuits are arranged in pairs at both ends of the USB cable;

the fault protection circuits arranged at two ends of the USB cable in pairs are connected through a single communication bus; the detection node is on the communication bus.

Optionally, the fault protection circuit further comprises: a signal transmitting unit and a signal receiving unit;

the signal sending unit is used for sending the overcurrent fault signal and the overtemperature fault signal to a fault protection circuit at the opposite end through the communication bus;

the signal receiving unit is used for receiving the over-current fault signal and the over-temperature fault signal sent by the signal sending unit from the opposite end.

Optionally, the fault protection circuits arranged at two ends of the USB cable in pairs communicate with each other by using BMC coding.

Optionally, the circuit protection module comprises: the MOS tube is arranged on a VBUS bus of the USB cable and used for unidirectionally blocking the VBUS bus; the blocking directions of the circuit protection modules of the fault protection circuits arranged in pairs are opposite;

the fault protection circuit is used for switching off the MOS tube to cut off the power supply current on the VBUS bus of the USB cable when receiving the over-current fault signal or the over-temperature fault signal from the fault protection circuit at the opposite end.

In order to solve the above technical problems, embodiments of the present invention further provide the following technical solutions: a USB cable. This USB cable includes: a number of Tpye-C connectors, a connection cable connecting said Tpye-C connectors, and a fault protection circuit as described above.

Optionally, the USB cable further includes an electronic tag unit for storing attribute information of the USB cable, the electronic tag unit being integrated in the fault protection circuit;

the fault protection circuit is powered by a VCONN pin of the USB cable, and communication of the electronic tag is achieved through a CC pin of the USB cable.

Optionally, the USB cable further includes an electronic tag unit for storing attribute information of the USB cable, the electronic tag unit is disposed separately from the fault protection circuit, and the fault protection circuit is powered by a VBUS bus of the USB cable.

Compared with the prior art, the fault protection circuit provided by the embodiment of the invention collects current information by using the voltage drop of the wire generated by the impedance of the ground wire of the USB cable, can realize accurate detection of overcurrent faults without arranging or using an additional current sampling device, and has the advantages of simple structure and low realization cost.

[ description of the drawings ]

One or more embodiments are illustrated by way of example in the accompanying drawings which correspond to and are not to be construed as limiting the embodiments, in which elements having the same reference numeral designations represent like elements throughout, and in which the drawings are not to be construed as limiting in scale unless otherwise specified.

FIG. 1 is a schematic diagram of a pin definition for a USB Type-C connector;

FIG. 2 is a schematic view of a USB Type-C cable;

fig. 3 is a schematic structural diagram of a fault protection circuit according to an embodiment of the present invention;

fig. 4 is a schematic diagram illustrating an operating principle of a fault protection circuit according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a fault protection circuit according to another embodiment of the present invention;

FIG. 6 is a schematic diagram of BMC encoding.

[ detailed description ] embodiments

In order to facilitate an understanding of the invention, the invention is described in more detail below with reference to the accompanying drawings and specific examples. It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. As used in this specification, the terms "upper," "lower," "inner," "outer," "bottom," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the invention and simplicity in description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

In order to fully explain the fault protection circuit and the working principle thereof provided by the embodiment of the invention, a USB cable (hereinafter referred to as USB Type-C cable) adopting a USB Type-C connector is taken as an example in the invention, and the specific implementation and the actual operation process of the fault protection circuit are described in detail.

FIG. 1 is a pin definition diagram of a USB Type-C connector. FIG. 2 is a schematic diagram of a USB cable employing a Tpye-C connector.

As shown in fig. 1, a CC pin (Configuration Channel) is a Configuration Channel. The USB interface is used as a newly-added channel in a USB Type-C standard and is used for detecting USB connection, detecting positive and negative insertion, data connection between USB devices, establishment and management of VBUS and the like.

The VBUS pin is a bus power channel for carrying current and outputting corresponding voltage to supply power to a bus power supply device (e.g., a mobile terminal such as a mobile phone being charged) connected to the USB cable.

The VCONN pin is a channel for providing a 5V power supply and supplying power to an electronic tag unit (e-Marker). The electronic tag unit (e-Marker) is a chip or a functional module in which attribute information related to the USB cable exists.

Through an electronic tag unit (e-Marker) packaged in a USB Type-C cable, devices (DFP or UFP) connected to two ends of the USB Type-C cable can read attribute information such as power transmission capacity, data transmission capacity and ID of the cable by using a USB PD protocol.

The USB PD protocol (USB Power Delivery Specification) is a protocol matched with USB Type-C. The intelligent self-adaptive charging device can bear 3A or 5A current, the output voltage is up to 20V, meanwhile, a special channel for power transmission protocol communication is defined in an interface, and intelligent self-adaptive charging adjustment can be completed between charging equipment and powered equipment.

As shown in fig. 2, the physical structure of the USB cable may include USB Type-C connectors P at both ends and a connection cable C connecting the USB Type-C connectors at both ends. Usually, a small PCB is welded in the USB Type-C connector. The connecting cable is also welded on the PCB, and the shell M made of plastic and the like wraps the USB Type-C connector and the welded PCB to form a complete cable structure.

The fault protection circuit 10 provided by the embodiment of the invention can be arranged on the small-sized PCB to realize fault detection and cut off power supply in time to ensure the safety of the USB Type-C connector. Specifically, in the USB Type-C cable shown in fig. 2, both USB Type-C connectors P1 and P2 at both ends may be provided with their own fault protection circuit 10. That is, in one USB cable, the fault protection circuits 10 have two, respectively provided at both ends of the USB Type-C cable.

For convenience of presentation, the fault protection circuits provided in pairs at both ends of the USB Type-C cable are referred to as a "first fault protection circuit" and a "second fault protection circuit" in this specification. It should be noted that the "first" and "second" are not used to limit specific fault protection circuits, but are used only to distinguish and illustrate fault protection circuits located at both ends.

In some embodiments, as shown in fig. 3, the first fault protection circuit 10a and the second fault protection circuit 10b may be connected by a single communication bus SW. It should be noted that in the drawings of this specification, the first fault protection circuit 10a and the second fault protection circuit 10b are adjacent for convenience of illustration. However, in the actual use process, the two cables are far away from each other and are respectively positioned at the joints at the two ends of the USB cable. In fig. 3, a connection cable between the first fault protection circuit 10a and the second fault protection circuit 10b is indicated by parallel double-oblique lines having a certain length.

On the basis of the single communication bus SW, the fault protection circuit 10 provided in the embodiment of the present invention can implement a data transmission function of digital signals and the like between the two and an analog signal detection function of overcurrent fault detection.

Fig. 3 is a schematic structural diagram of the fault protection circuit 10 according to the embodiment of the present invention. As shown in fig. 3, the fault protection circuit 10 includes an overcurrent fault detection module 11 for implementing overcurrent fault detection and a circuit protection module 12 for cutting off power supply when an overcurrent fault occurs.

The circuit protection module 12 may be any suitable type, and is a functional module capable of timely cutting off power supply in the case of overcurrent or over-temperature of the USB cable. The circuit protection module 12 can specifically achieve the purpose of cutting off the power supply in various ways, and has a corresponding circuit element structure based on the way of achieving the purpose of cutting off the power supply.

For example, in some embodiments, the circuit protection module 12 is a switching component disposed on the VBUS bus of the USB cable that cuts off power by cutting off the VBUS power bus. In other embodiments, the circuit protection module 12 may also be a component with signaling capability that shuts down the process by sending a corresponding alarm signal to a power supply device (e.g., a charger) to cause the power supply device to stop supplying power.

Of course, the fault protection circuit 10 may also include more or less functional modules according to the actual requirements, so that the integration realizes more functions to meet different use requirements. For example, the fault protection circuit may include a control unit 14 as a control hub, as shown in fig. 3, or an electronic tag unit (e-Marker) integrated in the fault protection circuit, as shown in fig. 5.

The control unit 14 may be any suitable type of processor having logic operation capabilities. Which may collect or receive data information, perform one or more processes on the data information, or control the operation of other functional modules in response to the received data information. For example, as described above, the control circuit protection module may cut off the power supply bus of the USB cable or send a corresponding alarm signal to the power supply device to cut off the power supply according to the fault signal provided by the detection overcurrent fault detection module.

As shown in fig. 3, the overcurrent fault detection module 11 of the fault protection circuit may include: a detection node 111, a reference voltage unit 112, a first voltage comparison unit 113, and a second voltage comparison unit 114.

Wherein the detection node 111 is arranged on the communication bus SW. The ground reference of the detection node 111 is the ground GND with the USB Type-C cable. That is, the ground level of the detection node 111 is determined by the connection point of the corresponding fail-safe circuit and the ground GND.

The reference voltage unit 112 is a functional module for providing a reference voltage to the detection node 111. Which may be any suitable type of voltage or current source, as long as it is capable of providing a stable reference voltage at the sense node 111.

In particular, as shown in FIG. 3For example, the reference voltage unit 112 may include a reference voltage source V providing a stable preset voltage and a voltage dividing resistor network R for dividing the voltage _DIV . Wherein, the voltage dividing resistance network R _DIV Is a resistor network formed by connecting one or more divider resistors, for example, a plurality of resistors with specific resistance values connected in series. Which may be connected between the reference voltage source V and the sensing node 111, the voltage applied at the sensing node 111 may be adjusted by voltage division through a voltage dividing resistor network.

Thus, the reference voltage provided by the reference voltage unit 112 and the ground level determined by the ground GND of the USB cable define the level at the detection node 111.

The first voltage comparison unit 112 and the second voltage comparison unit 113 are functional components for determining or judging the level of the detection node 111, and outputting corresponding overcurrent fault signals. Wherein, the first voltage comparing unit 112 outputs an overcurrent fault signal when the level of the detection node is higher than the first reference voltage. And the second voltage comparing unit 113 outputs the over-current fault signal when the level of the detection node is lower than a second reference voltage.

Specifically, the first voltage comparing unit 112 and the second voltage comparing unit 113 may be implemented by any suitable type of comparator for comparing the level of the detection node 111 with the first reference voltage and the second reference voltage, respectively. As shown in fig. 3, one of the inputs of the comparator may be connected to the detection node 111, and the other input is connected to the first reference voltage and the second reference voltage, respectively. The output of the comparator is connected to the control unit 14. The two comparators are respectively flipped when the level of the detection node is higher than the first reference voltage or when the level of the detection node is lower than the second reference voltage, so that the control unit 14 detects the over-current fault signal.

In general, the first voltage comparing unit 112 and the second voltage comparing unit 113 may use the same circuit configuration completely. Of course, different comparator circuit configurations may be used for both based on actual demand differences.

In this embodiment, the first reference voltage V _ref1 Formed by adding the reference voltage and a preset over-current detection threshold. And a second reference voltage V _ref2 Then it is formed by subtracting the reference voltage from a preset over-current detection threshold.

The preset over-current detection threshold is a reference threshold of current sampling set by a technician according to the needs of actual conditions. That is, in the case where the reference threshold value is exceeded, it can be considered that there is an overcurrent fault condition.

The working principle of the overcurrent fault detection module 11 of the above embodiment for realizing overcurrent fault detection on the basis of the communication bus SW is described in detail below with reference to fig. 4:

on the one hand, when no current flows through the ground GND of the USB Type-C cable, the ground levels of the detection nodes 111 of the first and second

fault protection circuits

10a and 10b are the same.

Therefore, the level of the detection node 111 located on the communication bus SW is the average voltage of the reference voltages of the first and second

fault protection circuits

10a and 10 b. As shown in equation (1) below, when the first fault protection circuit 10a and the second fault protection circuit 10b are set to have the same reference voltage, the level of the detection node 111 (i.e., the level of the communication bus SW) is equal to the reference voltage V _REF 。

V _SW ＝(V _REF +V _REF )/2＝V _REF (1)

Wherein, V _SW To detect the level of node 111, V _REF Is the reference voltage of the fault protection circuit.

On the other hand, the current I flows through the USB Type-C cable _BUS In the meantime, since the ground GND is usually implemented by a copper wire or the like, there is a line impedance R itself _GND . Therefore, there is a voltage difference between the ground levels of the detection nodes 111 of the first and second

fault protection circuits

10a and 10b located at both ends of the cable. The voltage difference is the line impedance R between the two

fault protection circuits

10a and 10b _GND And current I _BUS The product of (a).

Taking the current direction shown in fig. 4 as an example, the ground level of the detection node 111 of the first fault protection circuit 10a is lower than the ground level of the detection node 111 of the second fault protection circuit 10 b.

At this time, the level of the detection node 111 of the first fault protection circuit 10a can be calculated by the following equation (2):

V _SW ＝(V _REF +V _REF +R _GND *I _BUS )/2＝V _REF +0.5*R _GND *I _BUS (2)

wherein, V _SW To detect the level of node 111, V _REF Is a reference voltage of a fault protection circuit, R _GND Is the line impedance, I, between two sensing nodes 111 _BUS Is the current flowing through the USB Type-C cable.

The level of the detection node 111 of the second fault protection circuit 10b can be calculated by the following equation (3):

V _SW ＝(V _REF +V _REF -R _GND *I _BUS )/2＝V _REF -0.5*R _GND *I _BUS (3)

wherein, V _SW To detect the level of node 111, V _REF Is a reference voltage of a fault protection circuit, R _GND Is the line impedance, I, between two

fault protection circuits

10a and 10b _BUS Is the current flowing through the USB Type-C cable.

As can be seen by comparison, if the voltage difference R is small _GND *I _BUS If the voltage level of the detection node 111 of the first fault protection circuit 10a is greater than the twice of the preset overcurrent detection threshold, the voltage level will be higher than the first reference voltage, so that the first voltage comparison unit of the first fault protection circuit 10a will be turned over, and an overcurrent fault signal will be output and detected by the control unit 14. Meanwhile, the level of the detection node 111 of the second fault protection circuit 10b will be lower than the second reference voltage, so that the second voltage comparison unit of the second fault protection circuit 10b is turned over, outputs an overcurrent fault signal, and is detected by the control unit of the second fault protection circuit 10 b.

Therefore, a technician can adjust and set a proper over-current detection threshold value to control the over-current I _BUS ExceedanceAnd under the condition of safety limit, triggering the first or second voltage comparison unit to output a corresponding overcurrent fault signal.

Of course, during actual use, the direction of current flowing through the USB Type-C cable is not uniquely determined, and it may flow in either a forward direction (i.e., from the first fault protection circuit to the second fault protection circuit) or a reverse direction (i.e., from the second fault protection circuit to the first fault protection circuit). Therefore, the first voltage comparing unit 112 and the second voltage comparing unit 113 need to be provided in the fault protection circuit at the same time to satisfy the overcurrent fault detection when the current flows in the reverse direction.

Specifically, when the current flows in the reverse direction, the roles of the first fault protection circuit 10a and the second fault protection circuit 10b are interchanged. At this time, if the voltage difference R _GND *I _BUS Greater than twice the preset overcurrent detection threshold, the second voltage comparison unit of the first fault protection circuit 10a will output an overcurrent fault signal while the first voltage comparison unit of the second fault protection circuit 10b outputs an overcurrent fault signal.

The overcurrent fault detection module 11 provided by the embodiment of the invention realizes overcurrent fault detection by using cable impedance of the USB cable on the premise of not depending on an additional current sampling device, and can realize more accurate overcurrent protection.

Specifically, as shown in fig. 3, the circuit protection module 112 specifically includes: and the switching tube Q is arranged on the VBUS bus. The switching tube Q may be a MOS tube, and its gate is connected to the control unit 14 of the fault protection circuit, and is turned off or turned on under the control of the MOS tube Q to perform a switching effect.

For convenience of presentation, the switching tubes of the first and second

fault protection circuits

10a and 10b are labeled as Q1 and Q2, respectively.

The reverse body diode contained in the MOS transistor is always conducting. Therefore, the switch realized based on the MOS tube has the characteristic of unidirectional blocking. That is, only a specific direction of current flow is blocked and a reverse direction of current flow is not blocked.

However, in an actual use scenario, the direction of current flowing through the USB Type-C cable is not exclusive, and it may flow in either the forward or reverse direction. Cutting off the bus supply of the USB cable requires the use of switching devices with bidirectional blocking capabilities.

In the present embodiment, the switching tubes Q1 and Q2 having opposite blocking directions may be combined in the first and second

fault protection circuits

10a and 10b to satisfy the bidirectional blocking requirement for the USB cable.

As shown in fig. 4, when the current direction of the USB cable is shown by an arrow, the second fault protection circuit 10b may transmit an overcurrent fault signal or an overtemperature fault signal to the first fault protection circuit 10a at the opposite end. After receiving the overcurrent fault signal or the overtemperature fault signal, the control unit of the first fault protection circuit 10a turns off the switching tube Q1 to cut off the supply current on the VBUS bus of the USB cable.

When the current direction of the USB cable is opposite to that shown in fig. 4, the control unit 14 of the second fault protection circuit 10b may turn off the switch Q2 by itself to cut off the supply current on the VBUS bus of the USB cable.

The mutual cooperation of the switching tube Q1 of the first fault protection circuit 10a and the switching tube Q2 of the second fault protection circuit 10b realizes bidirectional blocking based on data transmission and communication between the two fault protection circuits.

Thus, to meet the data communication requirements between the first and second

fault protection circuits

10a and 10b described above, the fault protection circuit 10 may further include a signal transmitting unit Tx and a signal receiving unit Rx.

Wherein the signal transmitting unit Tx is configured to transmit the over-current fault signal and the over-temperature fault signal to a fault protection circuit at an opposite end through the communication bus SW. And the signal receiving unit Rx is configured to receive the over-current fault signal and the over-temperature fault signal sent by the signal sending unit at the opposite end.

In other words, in one fault protection circuit, the signal transmitting unit Tx and the signal receiving unit Rx are connected to the control unit 14, and the control unit 14 may receive the signal transmitted from the communication bus SW through the signal transmitting unit Tx and the signal receiving unit Rx.

The signal transmitting unit Tx and said signal receiving unit Rx may be implemented by any suitable type of data transmitting and data receiving circuit in the prior art, only need to be able to meet the requirements of use or be adapted to the data transmission form or protocol of the communication bus.

In a preferred embodiment, the first fault protection circuit 10a and the second fault protection circuit 10b may communicate using BMC coding based on a single communication bus SW.

The BMC coding belongs to a coding technology of phase modulation. Which is an encoding method that mixes a clock and data together for transmission. As shown in fig. 6, the BMC coding is characterized by: if the data is 1, the level is inverted in the middle of the bit and at the boundary of each data transmission bit. By using the BMC coding, the transmission end and the receiving end can transmit and receive data correctly only by one data line, and the method has the advantage of keeping good synchronism at the transmitting end and the receiving end.

The fault protection circuit provided by the embodiment of the invention can realize the detection of an analog signal (overcurrent fault signal) and the communication of a digital signal on the basis of a single communication bus SW by using the BMC code and a special overcurrent fault detection circuit, and has the advantages of simple structure and low realization cost.

Preferably, in addition to the overcurrent fault protection, as shown in fig. 5, the fault protection circuit 10 may further include an over-temperature detection module 13 for detecting a temperature, so as to implement the function of the over-temperature protection.

The over-temperature detection module 13 may specifically employ any suitable type of temperature detection circuit for signaling an over-temperature fault when the circuit temperature is too high and providing the over-temperature fault to the control unit 14.

The control unit 14 controls the circuit protection module 200 to cut off power supply in time in a manner similar to the above-mentioned over-current fault detection when the circuit temperature is too high based on the over-temperature fault signal provided by the over-temperature detection module 13. For example, the power supply is cut off by cutting off the VBUS bus power supply of the USB cable, or sending related alarm information to the power supply apparatus.

In addition, an electronic tag unit packaged in the USB cable may be provided independently of the fault protection circuit 10. The independently arranged electronic tag units are powered by the VCONN pin and communicate through the CC pin. The fault protection circuit 10 is connected to the VBUS bus of the USB cable and simply draws power from the VBUS bus.

In some embodiments, an electronic tag unit (e-Marker) 15 may also be integrated in the fault protection circuit 10, as shown in fig. 5. That is, the fault protection circuit 10 includes a functional module for storing attribute information of the USB cable.

At this time, the fault protection circuit 10 may be powered by the VCONN pin of the USB cable and implement communication of the electronic tag unit through the CC pin of the USB cable, so as to implement a function of an electronic tag unit (e-Marker).

It will be understood by those skilled in the art that, based on the fault protection circuit and the working principle thereof disclosed in the embodiments of the present invention, all technical solutions obtained by adapting, replacing or changing the specific implementation of the fault protection circuit to any other Type of USB cable having the same or similar function as the USB Type-C connector are within the protection scope of the present invention.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fault protection circuit for a USB cable, comprising:

an over-current fault detection module, the over-current fault detection module comprising: the USB cable comprises a reference ground detection node, a reference voltage unit, a first voltage comparison unit and a second voltage comparison unit, wherein the reference ground detection node is arranged on a ground wire of the USB cable;

the fault protection circuits are arranged at two ends of the USB cable in pairs;

the fault protection circuits arranged at two ends of the USB cable in pairs are connected through a single communication bus; the detection node is on the communication bus;

and the circuit protection module is used for cutting off power supply by cutting off a power supply bus of the USB cable or sending an alarm signal to power supply equipment when the overcurrent fault signal appears.

2. The fault protection circuit of claim 1, further comprising:

the over-temperature detection module is used for detecting current circuit temperature information and outputting an over-temperature fault signal when the current circuit temperature information exceeds a temperature threshold value;

the circuit protection module is also used for cutting off power supply by cutting off a power supply bus of the USB cable or sending an alarm signal to power supply equipment when the over-temperature fault signal appears.

3. The fault protection circuit of claim 2, wherein the reference voltage unit comprises:

providing a reference voltage source for stabilizing a preset voltage and a voltage dividing resistor network for dividing the voltage;

the voltage dividing resistor network consists of one or more voltage dividing resistors and is connected between the reference voltage source and the detection node.

4. The fault protection circuit of claim 3, further comprising: a signal transmitting unit and a signal receiving unit;

5. The fault protection circuit of claim 3, wherein the fault protection circuits paired across the USB cable communicate using BMC coding.

6. The fault protection circuit of claim 3, wherein the circuit protection module comprises: the MOS tube is arranged on a VBUS bus of the USB cable and used for unidirectionally blocking the VBUS bus; the blocking directions of the circuit protection modules of the fault protection circuits arranged in pairs are opposite;

the fault protection circuit is used for switching off the MOS tube to cut off the bus power supply of the USB cable when receiving the overcurrent fault signal or the overtemperature fault signal from the fault protection circuit at the opposite end.

7. A USB cable, comprising: a number of Tpye-C connectors, a connection cable connecting said Tpye-C connectors and a fault protection circuit according to any of claims 1-6.

8. The USB cable of claim 7, further comprising an electronic tag unit for storing attribute information of the USB cable, the electronic tag unit being integrated in the fault protection circuit;

the fault protection circuit is powered by a VCONN pin of the USB cable, and communication of the electronic tag unit is achieved through a CC pin of the USB cable.

9. The USB cable of claim 7, further comprising an electronic tag unit for storing attribute information of the USB cable, the electronic tag unit being provided separately from the fault protection circuit, the fault protection circuit being powered by the VBUS bus of the USB cable.