System and method for cable shield fault detection and protection

Abstract

System and method embodiments are described for shield fault detection that protect the cable, components, and other circuitry connected to the cable shield, and avoid high short circuit current flow from the power supply to ground during an unexpected event. A threshold voltage detector and a slope detector can be used to sense the voltage on a shield pin that is switchably coupled to ground via a shield ground. Method embodiments are also described for distinguishing between shield ground switch current caused by a shield fault and normal operation. In some cases, a weak ground path is first established to sense or identify a valid attachment on the cable before a strong ground path is established. The disclosed embodiments can effectively detect shield faults with improved performance, alone or in combination.

Description

[0001] Cross-reference to related applications

[0002] This invention claims priority to all common subject matter of U.S. Provisional Patent Application 63 / 017,630, filed April 29, 2020. The contents of that application are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to systems and methods for detecting cable shielding faults. Background Technology

[0004] Portable device cables (such as Universal Serial Bus (USB) Type-A, Type-C, Micro USB, and EMC cables) are widely used in a variety of applications. They can be used for device charging, data communication, and more. Typically, a portable device cable includes a power cord, a ground wire, one or more pairs of data wires, and shielding. During operation, one end of the portable device cable can be connected to a power source or electronic device, such as a car charging port, desktop computer, or laptop computer. The other end of the portable device cable can be connected to a portable electronic device.

[0005] In some situations, the shielding of a portable device cable may be accidentally shorted to voltage. For example, in automotive applications, if one connector of a portable device cable is connected to a vehicle's USB port, and the other connector of the portable device cable accidentally falls into a 12V cigarette lighter socket, a short-to-battery short to USB ground may occur. The connector shielding may come into contact with the 12V center terminal. As a result, a potentially damaging current may flow from the cigarette lighter connection through the portable device cable. A shielded grounding switch can be used on the USB port side to disconnect the port ground from the shielding to protect the USB port, cable, and cigarette lighter.

[0006] A threshold voltage detector has been used to sense the current through the grounding switch via a current-sensing amplifier (CSA). The output of the threshold voltage detector can be used to control the shielded grounding switch. However, this implementation has limitations. First, the shielded grounding switch may be incorrectly turned off during load transients because it may be impossible to distinguish the source of the current flowing through the shielded grounding switch from the load current to the ground short-circuit current. Furthermore, for shielded grounding switches using field-effect transistors (FETs), a high drain-source voltage (VDS) may be required to handle the high-voltage loop that occurs when the FET is rapidly turned off. Therefore, high-voltage protection is also required on the shielding pin.

[0007] Therefore, it is desirable to have systems and methods for detecting cable shielding faults in order to achieve improved performance and better protection. Summary of the Invention

[0008] Embodiments of systems and methods for shield fault detection and protection are described, which prevent high short-circuit currents from flowing from the power source to ground through the shield during unforeseen events. Threshold voltage detectors and slope detectors can be used to sense the voltage on a grounding switch connected between the shield and ground. Methods for distinguishing grounding switch currents caused by shield faults from those of normal operation are also illustrated. In some cases, a weak ground is first established to sense or identify valid attachments on the cable before connecting the actual strong ground. The disclosed embodiments can effectively detect shield faults with improved performance, individually or in combination, and can also help reduce system costs by using smaller shielded grounding switches with lower current capacity.

[0009] In one or more embodiments, the shield pin of the electronic device is grounded via a ground path including a shield grounding switch. When the shield of the portable device cable is shorted to a voltage source, the current flowing through the ground path generates a voltage at the shield pin. When the sensed voltage exceeds a threshold, a voltage comparator is triggered to report a fault condition to a fault control module, which then outputs a signal to close the shield grounding switch via a driver. In one or more embodiments, the shield grounding switch is reopened once the fault condition is cleared or after a predetermined time interval.

[0010] In one or more embodiments, both a threshold detector and a slope detector are used to achieve rapid detection. When a shield threshold detection triggers the shield grounding switch to close, the current in the cable may be high enough to cause some damage to the components. One way to reduce damage is to detect the fault before the threshold detector reaches a lower threshold. However, using a lower threshold for the threshold detector is challenging because such a lower threshold may be within the transient envelope of the load operation. In one or more embodiments, to achieve earlier detection at a lower threshold, a slope detector is implemented to compare the rate of voltage change on the shield with a reference slope. In the event of a fault (e.g., shorting to a battery), the slope detection can detect the fault even when the sensed voltage at the shield pin is less than a predetermined threshold. The slope detector triggers when the rate of voltage change is faster than the reference slope. In normal applications, the load current transient rate is typically less than the fault current transient rate, and therefore, a predetermined, fixed reference slope is sufficient.

[0011] In certain situations, such as hot-plug events using non-Type C connectors, when the DC-DC converter's output voltage may be a fixed 5V, the non-faulty shield current transfer can be high enough to trigger a false fault report. In one or more embodiments, to prevent the slope detector from responding to such non-faulty shield current transfer, a current sensing circuit is used to detect the current from the DC-DC converter's output capacitor to distinguish the source of the shield grounding switch current. If no DC-DC converter inrush current is detected, the voltage rise at the shield pin is due to a fault event.

[0012] In a typical USB Type-C connection, the voltage drop across the CC pin caused by the internal resistance (RD) of the device (sink or portable device) can be used to determine if a device is connected to one end of the USB Type-C cable. During connection detection, grounding is required to allow current flow. The shield grounding switch should remain open while waiting for attachment to occur after system startup. However, a strong cable grounding via the shield grounding switch can be prone to shield short-circuit events to the battery. In one or more embodiments, a method for establishing a weak ground path is disclosed that establishes the weak ground path before connecting to the actual strong ground path to sense a valid attachment on the cable. This method provides protection by preventing high current flow through the strong ground path in the event of a shield short-circuit fault.

[0013] The further applicability of this disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are intended for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0014] Exemplary embodiments will be shown with reference to the accompanying drawings. These drawings are intended to be illustrative and not restrictive. Although this disclosure has been described in the context of these embodiments in general, it is not intended to limit the scope of this disclosure to the specific features of the depicted or described embodiments.

[0015] Figure 1 illustrates a prior art circuit with a grounding switch for shielded fault protection.

[0016] Figure 2 Circuits with various components for shielding fault detection and protection are described according to various embodiments.

[0017] Figure 3 Operational procedures for shielding fault detection and protection are described according to various embodiments.

[0018] Figure 4 The operational process for shielding fault protection by establishing a weak ground path before establishing a strong ground path is described according to various embodiments.

[0019] Those skilled in the art will recognize that various implementation methods and embodiments can be practiced based on the specification. All such implementation methods and embodiments are intended to be included within the scope of this disclosure. Detailed Implementation

[0020] In the following description, specific details are set forth for purposes of explanation in order to provide an understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without these details. Furthermore, those skilled in the art will recognize that the embodiments described below can be implemented in various ways, such as processes, apparatuses, systems, devices, or methods, on tangible computer-readable media.

[0021] The components or modules shown in the figures illustrate exemplary embodiments and are intended to avoid obscuring the invention. It should also be understood that throughout this discussion, a component can be described as a separate functional unit that may include subunits; however, those skilled in the art will recognize that various components or portions thereof may be divided into separate components or may be integrated together, including within a single system or component. It should be noted that the functions or operations discussed herein can be implemented as components. Components can be implemented in software, hardware, or a combination thereof.

[0022] Furthermore, the connections between components or systems shown in the accompanying drawings are not intended to be limited to direct connections. Instead, data between these components can be modified, reformatted, or otherwise altered via intermediate components. Moreover, additional connections or fewer connections may be used. It should also be noted that the terms "coupling," "connection," or "communicationally coupled" should be understood to include direct connections, indirect connections via one or more intermediate devices, and wireless connections.

[0023] In this specification, references to "one embodiment," "preferred embodiment," "embodiment," or "multiple embodiments" mean that a specific feature, structure, characteristic, or function described in connection with an embodiment is included in at least one embodiment of this disclosure and may be included in more than one embodiment. Furthermore, the above phrases appearing in different places in this specification do not necessarily refer to the same embodiment or multiple embodiments.

[0024] The use of certain terms in different places in this specification is illustrative and should not be construed as restrictive. A service, function, or resource is not limited to a single service, function, or resource; the use of these terms may refer to a group of related services, functions, or resources, whether discrete or aggregated. The terms “include,” “including,” “comprise,” and “comprising” should be understood as open-ended terms, and any listing items following them are illustrative and not intended to limit the scope of the listed items.

[0025] Furthermore, those skilled in the art should recognize that: (1) certain steps may be performed optionally; (2) the steps may not be limited to the specific order set forth herein; (3) certain steps may be performed in different orders; and (4) certain steps may be performed simultaneously. More specifically, for the purposes of this disclosure, “connecting a ground path” must be understood to include and be functionally equivalent to “keeping a ground path connected”; and similarly, “disconnecting a ground path” must be understood to include and be functionally equivalent to “keeping a ground path disconnected”. That is, descriptions or claims describing a connection, connecting, or connections should be interpreted to cover pre-existing connections. Similarly, descriptions or claims describing disconnections, disconnecting, or disconnects should be interpreted to cover pre-existing disconnections.

[0026] Figure 1 illustrates a prior art circuit with a grounding switch for shielded fault protection. A portable device 130 is coupled to a charger or DC-DC converter 110 via a cable 120, which may be a USB cable including at least a power line 121 and a ground line 122. In some cases, the cable shield may be accidentally shorted to a voltage. For example, in automotive applications, a USB ground short to the battery may occur when one connector of the portable device cable is connected to the vehicle's USB port, and the other connector of the portable device cable accidentally falls into a 12V cigarette lighter socket 140. The connector shield may contact the 12V center terminal. As a result, a potentially damaging current may flow from the cigarette lighter connection through the portable device cable. The charger (USB port) includes a shielded grounding switch 118 to disconnect the port ground from the shield, thereby protecting the USB port, cable, and cigarette lighter. For voltage control purposes, the shielded grounding switch 118 may be used in conjunction with a pull-up resistor. A current-sensing amplifier (CSA) 114 is used to sense the current through the grounding switch via a current-sensing resistor RSNS 113. The output of CSA 114 is fed into current limiting circuit 116 for comparison with a predetermined threshold. The comparison result is used to control shielded grounding switch 118.

[0027] This implementation has limitations. First, the shielded grounding switch may be incorrectly turned off during load transients because it may not be able to distinguish between ground short-circuit current and load currents that can be high in some normal transient events. Furthermore, for shielded grounding switches using field-effect transistors (FETs), high drain-source voltages (VDS) may be required to handle high-voltage loops that may occur when the FET turns off rapidly. Therefore, high-voltage protection is also required on the shielding pin. Additionally, to prevent communication disruption on the reference ground data line, an FET with low on-resistance RDSON must be used to limit DC voltage changes on ground. Therefore, a FET with high current capacity is required, which inevitably increases the cost of such a shielded grounding detection circuit.

[0028] Figure 2 Circuits with various components for shielding fault detection and protection, according to various embodiments, are depicted. For example... Figure 2As shown, a first device 210 is coupled to a second device 250 via a cable 230 comprising multiple wires. The first device 210 may be a USB port in a vehicle for charging and / or data communication. The second device 250 may be a portable device, such as a smartphone, tablet computer, etc. The cable 230 may be a Type-A, Type-B, Mini-B, or Type-C USB cable, or a Lightning cable, etc. The cable 230 may include at least a power line 232 and a shielding line 234, which connect the power pin (V-out) and shielding pin of the cable connection interface 221 at the first device to the corresponding pins of the cable connection interface 221 at the second device. In one or more embodiments, the cable connection interface 221 may be a Type-A USB port, a Type-B USB port, a Type-C USB port, a mini-USB port, a micro-USB port, a Lightning connector, or other multi-pin port of other types with shielded connections. Although lines 232, 234, and 236 of the cable 230 are shown as including an inductor (L-cable), those skilled in the art will understand that the inductance can be very small, substantially close to zero, or practically zero. Such variations should still fall within the scope of this disclosure.

[0029] In one or more embodiments, the first device 210 includes a first shielded ground switch 211 coupled to a shielded (SHLD) pin (or connector) to switchably establish a first ground path for the shielded pin. The first ground path is also referred to as a strong ground because the grounding resistance of the first ground path is the on-resistance of the first shielded ground switch 211, which is very small. The first device 210 may further include a threshold voltage detector 216 coupled to the shielded (SHLD) pin. The threshold voltage detector 216 senses the voltage of the shielded pin to compare it with a reference voltage (at... Figure 2The voltage comparison is shown as VREF1), and a voltage comparison signal 217 is output to the logic control module 224. In one or more embodiments, the threshold voltage detector 216 is a voltage comparator that may have hysteresis. When the voltage of the shield pin is higher than the reference voltage in a fault event where the shield is shorted to the power supply 240, the logic control module 224 receives the voltage comparison signal from the threshold voltage detector 216 and outputs a signal to turn off the first shield ground switch 211 via the first switch driver 220, thereby decoupling the shield pin from ground. In one or more embodiments, the first device 210 may operate as a charging port and includes a DC converter 214 coupled to the power supply pin to provide voltage to the second device 250 via cable 230. In this document, the logic control module 224 will be understood as having at least the physical structural components of transistor logic gates for providing computation and control. Furthermore, the logic control module 224 includes structural inputs and outputs that typically operate between zero and five volts. The logic control module 224 is envisioned to be based on a TTL or CMOS architecture, but may also include other logic families, such as RTL, DTL and ECL.

[0030] In one or more embodiments, the first device 210 may further include a slope detector 218 coupled to a shielded (SHLD) pin for detecting the rate of voltage change on the shielded pin. The slope detector 218 compares the detected rate with a reference slope (in... Figure 2The slope comparison signal 219, shown as VREF2, is output to the logic control module 224. The rate of change of voltage on the shield pin is also an indicator of the rate of change of current through the shield ground switch, since the voltage at the shield pin is substantially linearly related to the current through the shield ground switch when the shield ground switch is open, with the slope being the on-resistance of the switch. In one or more embodiments, the slope detector 218 includes a hysteresis for the slope comparison. When the rate detected in a fault event where the shield is shorted to the power supply 240 is higher than a reference slope, the logic control module 224 receives the slope comparison signal from the slope detector 218 and outputs a signal to close the first shield ground switch 211 via the first switch driver 220, thereby decoupling the shield pin from ground. Compared to threshold voltage detection, slope detection can provide a faster response to shield fault events because the current in the cable may be high enough to cause some damage to the components when threshold detection triggers the shield ground switch to close. Using a lower threshold for the threshold detector can be challenging because such a lower threshold may be within the transient envelope of the load operation. In the event of a fault (e.g., shorting to the battery), slope detection can detect the fault when the sensed voltage at the shielded pin is even less than a predetermined threshold. The slope detector triggers when the rate of voltage change exceeds a reference slope. In normal applications, the load current transient rate is typically less than the fault current transient rate, and therefore, a fixed reference slope is sufficient. In this document, the slope detector 218 will be understood as a physical component including physical structures such as switching elements, amplifiers, differentiators, resistors, or capacitors.

[0031] In one or more embodiments, the threshold voltage detector 216 and the slope detector 218 can be used individually or in combination for masking fault detection. Accordingly, the logic control module 224 can be triggered individually (e.g., as an OR gate) or jointly (e.g., as an AND gate) by the threshold voltage detector 216 and the slope detector 218.

[0032] In certain situations, such as hot-plug events using non-Type C connectors, when the output voltage of the DC-DC converter 214 within the first device 210 is a fixed 5V, the non-faulty shield current transfer may be high enough to trigger a false fault report. In one or more embodiments, to prevent the slope detector 218 from responding to such non-faulty shield current transients, a current sensing circuit 215 is used to detect the current from the DC-DC converter and through the power pin via a sensing resistor (RS) coupled between the DC converter and the power pin for differentiation. That is, the current sensing circuit detects the presence of current flowing through the power pin of the cable connection interface. The logic control module 224 is coupled to receive the output from the current sensing circuit 215, thereby aiding in shield fault detection. If no DC-DC converter inrush current is detected, or the rate of change of the inrush current is less than the rate of change of the current detected through the shield grounding switch, the rise in voltage at the shield pin is due to a fault event. Combining output current sensing with slope detection effectively prevents false fault reports and thus improves the reliability of fault detection. In this paper, the current sensing circuit 215 will be understood as a physical structural component having at least structural input connections and structural output connections. However, many forms of current sensing circuits are envisioned, including Hall effect linear sensors, electrically isolated sensors, or GMR-based sensors. Other forms are also envisioned, including fluxgate sensors, shunt resistors, and even sensors based on fiber optic interferometers.

[0033] In one or more embodiments, the first device 210 further includes a clamp 260 coupled to the first shielded ground switch 211 for limiting peak voltage on the shield pin. The clamp may include a first Zener diode (D1) connected between the gate and drain of the first shielded ground switch 211 and a second Zener diode (D2) connected between the gate and ground. In one or more embodiments, a parallel resistor (R1) may be coupled to D2 in parallel. When the first shielded ground switch 211 is open, the clamp helps limit the drain voltage. Once the drain voltage reaches the Zener diode voltage limit, the clamp automatically closes the first shielded ground switch 211 to dissipate remaining energy in the cable 230 and thus protect the switch 211 and the first device 210.

[0034] In one or more embodiments, the shielded pin of the electronic device may be grounded via a second ground path including a second shielded ground switch 212 and a series resistor 213. A logic control module 224 is coupled to the second shielded ground switch 212 via a second switch driver or logic circuit 222 for switching control. In one or more embodiments, the logic control module 224 may selectively open either the first shielded ground switch 211 or the second shielded ground switch 212 to select a desired ground path between the first ground path and the second ground path. In one or more embodiments, the logic control module 224 may open both the first shielded ground switch 211 and the second shielded ground switch 212 to enable both ground paths simultaneously. The logic control module 224 utilizes a comparator 227 to enable the first ground path through the first shielded ground switch 211 based on determining that a device is connected, and the logic control module 224 disables the second ground path through the second shielded ground switch 212 based on determining that the device is connected. In one or more embodiments, the first shielded ground switch 211 and the second shielded ground switch 212 may be opened together, selectively opened, or closed together. In one or more embodiments, the second grounding path may include a second shielded grounding switch 212 without a series resistor 213, the on-resistance of the second shielded grounding switch 212 being greater than that of the first shielded grounding switch 211, such that the second grounding path is still a weak grounding path compared to the first grounding path.

[0035] When the shield of a portable device cable is shorted to a voltage source, the current flowing through the ground path generates a voltage at the shield pin. When the sensed voltage exceeds a threshold, a voltage comparator is triggered to report a fault condition to a fault control module, which then outputs a signal to close the shield grounding switch via a driver. In one or more embodiments, the shield grounding switch is reopened once the fault condition is cleared or after a predetermined time interval.

[0036] In one or more embodiments, for a typical USB Type-C connection, the connection interface or socket 221 includes two configuration channel (CC) pins, which, along with the CC line 236 on the cable 230, are used to establish and manage the source-to-sink connection. The connection of the second device 250 to the first device 210 via a USB Type-C cable can be determined by the voltage drop across the CC pins, caused by an internal resistance or pull-down resistor (RD) 252 within the device 250, which can act as a sink or portable device. Comparator 227 determines the voltage drop across the CC pins caused by the internal resistance within the device. For simplicity, Figure 2 Only the CC pin of the connection is shown. Those skilled in the art should understand the wiring for a Type-C USB connection.

[0037] During connection detection, grounding is required to allow current from current source 226 to flow through the connected CC pin to resistor 252. The first device uses two comparators 227 (for simplicity, Figure 2 Only one comparator is shown in the diagram to monitor these two pins to detect voltages less than the unterminated voltage. In one or more embodiments, voltages greater than or equal to 2.75V are considered unterminated (e.g., no valid insertion). Once such a voltage drop is detected, comparator 227 sends the result to logic control module 224 to indicate that the sink, energized cable, or sink connected via an energized cable has been attached to the first device. That is, comparator 227 uses the second shielded grounding switch 212 of the second grounding path to determine that the device is connected to the cable connection interface. In one or more embodiments, the current source 226 is removed from operation to save power after attachment detection is complete. The shielded grounding switch should remain open while waiting for the second device to connect after system startup and during connection detection. However, the strong grounding path through the first shielded grounding switch 211 may be prone to shield short-circuiting to the battery. In one or more embodiments, a second grounding path through the second shielded grounding switch 212 is first established to sense a valid attachment on the cable. The second grounding path can also be referred to as a weak ground because its grounding resistance is the sum of the on-resistance of the second shielded grounding switch 212 and the series resistor 213. The grounding resistance of the second grounding path is greater than that of the first grounding path. After the connection is established, the second shielded grounding switch 212 is closed, and a strong ground is established through the first shielded grounding switch 211. This grounding configuration provides protection by preventing high current from flowing from the battery shorted to the cable to the strong shielded FET ground.

[0038] The first shielding grounding switch 211 or the second shielding grounding switch 212 can disconnect the grounding path of the shielding pin based on the rate of voltage change being higher than or greater than the reference slope VREF2 and no current is detected through the power supply pin, and the first shielding grounding switch 211 or the second shielding grounding switch 212 can connect the grounding path based on the rate of voltage change being higher than or greater than the reference slope VREF2 and a current is detected through the power supply pin.

[0039] Figure 3Operational procedures for shielded fault detection and protection according to various embodiments are described. For a first device 210 having a cable connection interface including a shielded pin grounded via a shielded grounding switch, in step 305, a slope detector detects the rate of voltage change on the shielded pin. In step 310, the slope detector compares the detected rate of voltage change to a reference slope. In step 315, in response to a detected rate greater than the reference slope, a current sensing circuit reads (e.g., senses) the current through the power supply pin for verification or differentiation. In step 320, in response to no current being detected through the power supply pin or the rate of change of the current through the power supply pin being less than the detected rate of change of the current through the shielded grounding switch, a logic control module outputs a signal to turn off the shielded grounding switch to decouple the shielded pin from ground. In one or more embodiments, the shielded grounding switch is turned back on once the fault condition is cleared or after a predetermined time interval.

[0040] Figure 4 The process for shield fault protection, according to various embodiments, of establishing a weak ground path before establishing a strong ground path is described. In step 405, a first shield ground switch is closed to disable the first ground path, and a second shield ground switch is opened to establish a second ground path for the shield pin. The grounding resistance of the second ground path is greater than that of the first ground path. In step 410, after the second device is connected to the first device via a connection cable, the second device is verified for connection detection. In one or more embodiments, the verification for connection detection may include the process described above, determining the voltage drop on the CC pin when current flows from current source 226 through resistor 252 within the second device 250. While the first device is powered on and awaiting connection of the second device, and during connection detection, in step 415, one or more of the methods described above, including threshold detection, slope detection, current sensing, etc., are used to monitor the shield pin for shield fault detection. In step 420, if connection detection is completed and no shield fault is detected, the second shield ground switch is closed to disable the second ground path or the second shield ground switch remains open, and the first shield ground switch is opened to establish a first ground path for the shield pin. In one or more embodiments, the second shield ground can always be enabled so that the ground path is available even during transition phases. In step 425, the first and second devices can begin power and / or data communication with the first ground path of the enabled shield pin.

[0041] It will be understood by those skilled in the art that the foregoing examples and embodiments are exemplary and not limited to the scope of this disclosure. It is intended that all arrangements, enhancements, equivalents, combinations, and modifications thereof that will be apparent to those skilled in the art upon reading this specification and studying the accompanying drawings are included within the true spirit and scope of this disclosure. It should also be noted that the elements of any claim can be arranged in different ways, including having multiple dependencies, configurations, and combinations.

Claims

1. A method for detecting shielding faults, the method comprising: Detect the rate of voltage change on the shielded pins of the cable connection interface; The rate of change of this voltage is compared with a reference slope; Detect whether there is current flowing through the power pin of the cable connection interface; The ground path of the shield pin is disconnected because the rate of voltage change is higher than the reference slope and no current is detected through the power supply pin. as well as The ground path is connected based on the fact that the rate of voltage change is higher than the reference slope and the current through the power supply pin is detected.

2. The method of claim 1, further comprising connecting a ground path to the shield pin based on the fact that the rate of voltage change is lower than the reference slope.

3. The method as described in claim 1, wherein, Comparing the rate of change of the voltage to the reference slope includes comparing the rate of change of the voltage to a linear reference slope.

4. The method of claim 1, wherein, Detecting the rate of voltage change on the shielded pins of the cable connector includes detecting the rate of voltage change on the shielded pins of a Type A USB port, Type B USB port, Type C USB port, mini USB port, micro USB port, or Lightning connector.

5. The method of claim 1, wherein, Disconnecting the grounding path involves using a logic control module to provide a signal to disconnect the switch between the shield pin and ground.

6. A shielding fault detection system, the system comprising: A slope detector that detects the rate of voltage change on the shielded pin of the cable connection interface and compares the rate of voltage change with a reference slope. A current sensing circuit that detects whether there is current flowing through the power pin of the cable connection interface; as well as A switch that disconnects the ground path of the shield pin based on the rate of voltage change being higher than the reference slope and no current is detected through the power pin, and connects the ground path based on the rate of voltage change being higher than the reference slope and current is detected through the power pin.

7. The system of claim 6, wherein, The switch connects the shield pin to the ground path based on the fact that the rate of voltage change is lower than the reference slope.

8. The system of claim 6, wherein, The slope detector compares the rate of change of the voltage with a linear reference slope.

9. The system of claim 6, wherein, This slope detector detects the rate of voltage change on the shielded pins of a USB Type-A port, USB Type-B port, USB Type-C port, mini USB port, micro USB port, or Lightning connector.

10. The system of claim 6, further comprising a logic control module that provides a signal to disconnect the switch between the shield pin and ground.

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