ARC PREVENTION AT A USB PORT

Abstract

The present disclosure relates to a circuit (200) comprising: a first terminal (202) connectable to an input terminal (206) and configured to receive a supply voltage; a second terminal (204) connectable to an input of a current collector circuit (230); an electrically conductive connection (212) for coupling the first terminal (202) to the second terminal (204); a switch (214) for selectively activating or deactivating the electrically conductive connection (212); and a monitoring circuit (220) configured for: determining a voltage across the electrically conductive connection (212); determining a slew rate of the voltage across the electrically conductive connection (212); determining whether the determined voltage meets a predetermined voltage criterion; and determining whether the determined slew rate meets a predetermined slew rate criterion.and sending a control signal to the switch (214) when the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion, wherein the control signal is configured to control the switch (214) to selectively deactivate the electrically conductive connection (212).

Description

Technical area

[0001] The present disclosure generally relates to a circuit configured to dynamically control an electrically conductive connection between a USB port and a power collector circuit to prevent arcing at the USB port, and to related methods (e.g., a method for dynamically controlling an electrically conductive connection between a USB port and a power collector circuit). background

[0002] In general, the Universal Serial Bus (USB) is an industry standard used to standardize an interface between different types of devices. For example, a USB interface can enable a connection between a peripheral device (e.g., a flash drive, a portable hard drive, a keyboard, etc.) and a device (e.g., a laptop, a desktop computer, etc.). A USB interface can also enable the transfer of power to certain devices, e.g., to power a smartphone or tablet, or to charge the battery of such devices. Recently, the so-called USB Type-C connectors have been developed, which offer improved capabilities compared to older generations of USB connectors, such as the ability to support display, power, and data in a single connector.Additionally, USB Type-C connectors are rotationally symmetrical, allowing a connector to be accepted regardless of the orientation in which it is inserted. Advances in USB interfaces, especially USB Type-C interfaces, can therefore be relevant for many technological applications. Brief description of the drawings

[0003] In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles disclosed herein. In the following description, various aspects disclosed herein are described with reference to the following drawings, in which: Fig. 1A shows an exemplary system according to the present disclosure having a source device and a sink device; Fig. 1B shows an exemplary USB device in a schematic representation according to the present disclosure; Fig. 2A shows an exemplary circuit in a schematic representation according to the present disclosure, which is configured to dynamically adjust an electrically conductive connection between an input terminal and a current collector circuit; Fig. 2B shows exemplary diagrams according to the present disclosure relating to a normal state of the circuit and a hot-unplug state of the circuit; Fig. 3A shows an exemplary circuit in a schematic representation according to the present disclosure, which is configured to dynamically adjust an electrically conductive connection between an input terminal and a current collector circuit; Fig. 3B shows an exemplary slew rate detection circuit in a schematic representation according to the present disclosure; Fig. 3C shows an exemplary disconnection detection circuit in a schematic representation according to the present disclosure; Fig. 4A shows an exemplary simulated circuit in a schematic representation according to the present disclosure, which is configured to dynamically adjust an electrically conductive connection between an input terminal and a current collector circuit; Fig. 4B and Fig. 4C show exemplary diagrams according to the present disclosure illustrating simulation results of operation of the simulated circuit; and Fig. 5 shows an exemplary computer system in a schematic representation according to the present disclosure. Description

[0004] The following detailed description refers to the accompanying drawings, which, by way of illustration, show specific details and implementations in which the aspects described herein may be practiced. These aspects are described in sufficient detail to enable those skilled in the art to practice the disclosed implementations. Other aspects may be utilized, and structural, logical, and electrical changes may be made without departing from the scope of the disclosed implementations. The various aspects are not necessarily mutually exclusive, as some aspects may be combined with one or more other aspects to form new aspects. Various aspects are described in connection with methods, and various aspects are described in connection with devices (e.g., a circuit, a processor, a computer system).It should be understood, however, that aspects described in connection with methods may similarly apply to the devices, and vice versa.

[0005] A common problem associated with USB interfaces is so-called "hot unplug events," in which a USB cable is unplugged while a device is drawing power. A "hot unplug event" can be defined as a scenario in which the USB cable supplying power to the device is unplugged while the corresponding USB ports are still receiving power (e.g., voltage). A "hot unplug" can lead to arcing at the USB connector, i.e., the formation of an arc between the contact pins of the cable's USB connector and the contact pins of the USB connector of the sink device. The arcing can damage the USB connector, impairing or destroying its functionalities, e.g., with regard to data transmission, power transmission, and the like.

[0006] For example, arcing at the terminals of a USB Type-C connector during a hot unplug event can melt the metal contacts and reduce its reliability. During the hot unplug event, the voltage at the adapter's plug pins is regulated to a constant high voltage, while the voltage at the receptacle pins drops rapidly according to the load current and capacitance (visually after the cable is unplugged).

[0007] According to the USB Type-C cable and connector specifications, a voltage difference of more than 12 V between the plug and the contact pins with a 20 µm air gap can generate an arc. The amount of power (energy) dissipated as heat across the contact pins is proportional to the load current. A current of less than 1 A does not generate enough heat to damage the plug's contact pins. Because the USB Type-C Power Delivery (PD) specifications allow sink currents to be increased up to 5 A, the amount of energy (heat) dissipated during a hot unplug also increases proportionally. Therefore, the problem of arcing is a major concern during hot unplugging, both at 20 V SPR (Standard Power Range) and 48 V EPR (Extended Power Range), which can generate a 12 V difference between the plug and receptacle contact pins at a 5 A load current.

[0008] The USB Type-C Cable and Connector Specification, Annex H, proposes two methods to prevent arcing: (1) reducing the discharge rate of the sink device by increasing the load capacitance so that the connector is displaced more than the safe distance when the difference between the plug and receptacle contact pins is 12 V; or (2) removing the load current when the voltage at the V bus below vSinkDisconnect / vSinkDisconnectPD. Therefore, the voltage at the outlet should drop very slowly to avoid arcing.

[0009] However, solution (1) has disadvantages in terms of area occupancy and cost. The cost, area, and height requirements for reducing the discharge rate of the sink device using backup capacitors are high, and the following limitations must be considered. For ceramic capacitors, for example, the capacitance value typically drops by more than 80% at a DC bias of SPR or EPR, so the effectively required capacitance is more than five times the value proposed in the standard. Ceramic capacitors are therefore not the right choice for backup capacitors. For aluminum capacitors, the required height is a major constraint that limits their use. Solid tantalum capacitors would be a better choice from an electrical point of view, but this approach also requires more area, and furthermore, the use of tantalum should be limited.In addition, according to the USB Type-C Cable and Connector Specification, Annex H, a backup capacitor of 135 µF for SPR and 194 µF for EPR is required to prevent arcing, which is larger than the 100 µF suggested in the USB Power Delivery specification. Therefore, an additional active inrush current limiting circuit is required on the sink side, which, in addition to the large capacitors, also incurs additional cost and area usage.

[0010] Regarding solution (2), the implementation of the load current cut-off when the voltage at V busHot unplugging, which falls under vSinkDisconnect / vSinkDisconnectPD, can be done using firmware. However, a firmware implementation has its own delay due to ADC sampling (ADC is an abbreviation for "analog-to-digital converter"), conversion, and control. Therefore, it is difficult to detect the hot unplug even in a time below 10 µs. These firmware delays, in turn, lead to an increase in overall capacitance.

[0011] The present disclosure relates to a mechanism for quickly detecting and implementing corrective action within a few microseconds to prevent and avoid the problem of arcing. The proposed approach is based on monitoring the voltage and slew rate at the electrically conductive connection on a USB port (e.g., in a sink device) and evaluating whether the behavior of the voltage and slew rate indicates the occurrence of a hot unplug event. Illustratively, the present disclosure is based on the finding that the voltage value and slew rate provide a reliable indication of a hot unplug and can be quickly detected to initiate corrective action before an arc occurs at the USB ports. The detection method proposed herein reduces the capacitance requirement at the V bus , which reduces the overall cost, area and height of the entire solution.

[0012] In an exemplary implementation, the method may enable rapid detection of a disconnection event (e.g., a disconnection event of a USB-C adapter from a USB-C receptacle) by monitoring whether the discharge rate at the V bus is greater than the set value according to the bulk capacity used in the system, and by monitoring whether the V bus-voltage is less than another set value (e.g., the vSinkDisconnect / vSinkDisconnectPD). When the above conditions are detected, the sink switch is deactivated for a predetermined short period of time, e.g., 1 ms, which is sufficient to prevent arcing. The proposed detection method is latch-free and is used to deactivate the sink switch only during a hot-unplug event, while during normal operation, a controller (e.g., a PD controller) controls the sink switch. The proposed mechanism quickly detects the hot-unplug event and opens the sink switch using an arc-avoidance method with optimal cost and area.

[0013] The proposed approach reduces the capacitor requirement at the V busand thus the cost, area, and height of the complete solution, which is one of the most important design constraints in laptops or mobile platforms. Illustratively, the used capacity is less in this implementation, so the overall size of the final implementation is smaller than other implementations. The proposed method also provides a single solution for both EPR and SPR, thus eliminating the need for any changes in the components for EPR and SPR. Another aspect is that the method can be implemented either using discrete on-board components or within the controller (e.g., the PD controller). Finally, the solution takes into account all existing requirements and has no impact on the products on the market.

[0014] According to the present disclosure, a circuit may comprise: a first terminal connectable to an input terminal (e.g., a USB port), the first terminal configured to receive a supply voltage; a second terminal connectable to an input of a current collector circuit (e.g., a voltage regulator); an electrically conductive connection configured to couple the first terminal to the second terminal; a switch configured to selectively activate or deactivate the electrically conductive connection between the first terminal and the second terminal; and a monitoring circuit configured to: determine a voltage at the electrically conductive connection; determine a slew rate of the voltage at the electrically conductive connection; determine whether the determined voltage meets a predetermined voltage criterion;Determining whether the determined slew rate meets a predetermined slew rate criterion; and sending a control signal to the switch when the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion, wherein the control signal is configured to control the switch to selectively deactivate the electrically conductive connection between the first terminal and the second terminal.

[0015] According to the present disclosure, a circuit may comprise: a monitoring circuit configured to: determine a voltage at an electrically conductive connection between a first terminal and a second terminal, wherein the first terminal is connectable to an input terminal and is configured to receive a supply voltage, wherein the second terminal is connectable to an input of a current collector circuit (e.g., a voltage regulator); determine a voltage value and a slew rate of the voltage at the electrically conductive connection; determine whether the determined voltage value fulfills a predetermined voltage criterion (e.g., whether the determined voltage value is less than a predetermined voltage threshold); determine whether the determined slew rate fulfills a predetermined slew rate criterion (e.g.,whether an absolute value of the slew rate is greater than a predetermined slew rate threshold); and transmitting a control signal to deactivate the electrically conductive connection if the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion.

[0016] The monitoring circuit described herein can therefore be configured to perform voltage sensing and slew rate sensing on the bus connecting the USB connector to the load (e.g., via a voltage regulator), and can be configured to selectively enable / disable the bus (e.g., by closing / opening a switch) depending on whether the sensed voltage and slew rate indicate a hot unplug event. Illustratively, the hot unplug event can be associated with a voltage on the bus that drops faster than during normal operation, resulting in a rapid reduction in the voltage value (with a high slew rate, e.g., in terms of absolute value). The proposed approach is therefore based on the realization that these two voltage parameters on the bus can be sensed in a simple and fast (but efficient) manner, enabling a rapid response to a hot unplug event.The proposed method can enable rapid decoupling of the load from the USB port, thus mitigating or preventing the arcing problem.

[0017] The strategy proposed herein may be particularly relevant in the USB Type-C context, e.g., for devices configured according to the USB Type-C specification (e.g., the "Universal Serial Bus Type-C Cable and Connector Specification," Release 2.2 of October 2022). USB Type-C may be associated with higher voltages compared to older standards for USB communication and may therefore be more susceptible to the arcing issue compared to connectors configured according to other USB specifications (e.g., USB 1.0, USB 2.0, etc.). Therefore, some terms related to the USB Type-C framework are used below. However, it should be understood that the strategy proposed herein is, in principle, applicable to any type of USB connector. A USB Type-C device (e.g., a USB Type-C port, connector, etc.) may also be referred to herein as a USB-C device (e.g., a USB-C port, connector, etc.).

[0018] It should also be understood that USB devices may be the most relevant use case for the proposed strategy and for a circuit configured as described herein. However, while some examples relate to specific USB technologies, the examples included herein may similarly be applied to various other power interfaces, both existing and not yet formulated, particularly in cases where such interface technologies have similar features as disclosed in the following examples. Various example USB technologies that may utilize the devices and methods described herein include operations according to various USB specifications, including: USB 2.0 Specification (08 / 10 / 2021), USB 2.0 Cable and Connector Class Document (01 / 08 / 2007), any USB 3.x baseline specification such as USB 3.2 rev 1.1 (03 / 06 / 2022), USB Power Delivery Specification (20 / 04 / 2023), USB Type-C Connector Specification Release 2.2 (18 / 10 / 2022), USB Type-C and Power Delivery Source Power Requirements (24 / 05 / 2021), USB Type-C Bridge Specification (23 / 10 / 2018), USB Type-C Locking Connector Specification (09 / 03 / 2016), USB4 Specification (28 / 10 / 2022), and other existing or future interface technologies. Please note that aspects may be implemented according to any version of the listed specifications, not just the specifications with the given release dates.

[0019] Fig. 1A shows an example system 100 including a source device 102 and a sink device 104 (also referred to as a sink device or a sink device). The system 100 may be an example configuration of a system enabling programmable power delivery. For example, USB devices, particularly those supporting USB Power Delivery (USB PD), may negotiate different voltage levels based on their current power requirements. In general, the system 100 may include a source device 102 and a sink device 104 coupled via an interface 106. For example, an output port 108 of the source device 102 may be coupled to an input port 110 of the sink device 104 via the interface 106.

[0020] The source device 102 may be configured to provide an electrical supply via its output (e.g., via the output terminal 108). The source device 102 may be configured to vary the electrical supply, e.g., by varying a current and / or a voltage. In an exemplary configuration, the power supply by the device 102 may be programmable. Illustratively, the level of the power supply may be negotiated between the source device 102 and the sink device 104, as explained in further detail below.

[0021] In an example configuration, the source device 102 may be connected to an external power source (e.g., an AC power source, such as a wall outlet) and convert the received electrical supply (e.g., AC power) into the variable electrical supply. In some examples, the source device 102 may include an energy storage device (e.g., a battery), and the source may provide the variable power supply based on the electrical energy stored in the energy storage device. In some examples, the source device 102 (e.g., a hub device) may receive electrical energy from another port of the source device 102.

[0022] In general, the source device 102 may be an external unit to the sink device 104. In other examples, the source device 102 may be a programmable power supply circuit of the sink device 104, such as a voltage regulator, a buck converter, a boost converter, a linear voltage regulator, a switching voltage regulator, a low-dropout regulator, a battery charger, and the like. In the USB context, the source device 102 may be, for example, a USB adapter configured to provide a variable power supply according to a USB specification (e.g., a USB protocol) and / or a USB host. In some examples, the source device 102 may be circuitry connectable to a converter 112 of the sink device 104 via the interface 106.

[0023] The sink device 104 may have an input terminal 110 that can be connected to the source device 102 via the interface 106. The input terminal 110 may be configured to receive the electrical supply provided by the source device 102 via the interface 106. The input terminal 110 may further be configured to feed the received electrical supply into a supply line 114 (e.g., an electrically conductive connection that may also be referred to as a supply terminal, power line, sink line, etc.). The sink device 104 may further have a current collector circuit, e.g., with a voltage regulator 112, e.g.with a converter for DC-to-DC conversion of the provided electrical supply to regulate the electrical supply received from the supply line 114 to supply a load 116 (illustratively, load circuitry) of the sink device 104. The load 116 may comprise any component, module, unit, or portion of the sink device 104 that is electrically powered by an output of the voltage regulator 112. In an exemplary configuration, the load 116 may comprise a battery configured to supply electrical energy to the sink device 104. It should also be noted that the voltage regulator 112 may also be a load of the sink device 104, but this is expressly illustrated here for the purpose of describing operation.As exemplary components, the load 116 may include at least one processor, a memory device, a communication circuit, a sensor, a display device, another voltage regulator, input and / or output devices, a battery charging circuit, and the like.

[0024] In the context of USB technology, the source device 102 may be a USB Power Delivery (PD)-enabled device (e.g., a PD source), such as a USB adapter or a USB host configured to supply power according to a USB PD specification. Accordingly, the output port 108 of the source device 102 may be a USB port, and the input port 110 of the sink device 104 may be a USB port. The interface 106 may be a USB interface, e.g., a USB cable or connector, such as a Type-C cable / connector. In this context, the source device 102 is a USB source that supplies power to a port, and the sink device 104 may be a USB sink that consumes the supplied power. It should be noted that a USB device can work as a sink device or as a source device in different modes as a USB dual-role power supply device according to the assigned role.

[0025] The sink device 104 may be any electronic device capable of consuming variable electrical supply power received from a source. In some examples, the sink device 104 may be a wireless station, a mobile device or non-mobile device, a user equipment (UE), a computing device such as a personal computer (PC), a desktop computer, a mobile computer, a laptop computer, a notebook computer, a tablet computer, a server, a wearable computing device, a wearable device such as a smart bracelet, a smart watch, smart glasses, a smart ring, etc.be an Internet of Things (IoT) device, a sensor, a mobile phone, any type of wireless accessory such as a headphone, a headset, a microphone, a speaker, a home automation device (smart home), a docking station, a medical device, an endoscope, a surgical robot, a hearing aid, a Bluetooth medical device, an audio communication device, a headset, an earphone, an earbud, an earplug, a true wireless earphone, a wireless speaker, etc.

[0026] To control the power supply from the source device 102, the sink device 104 may include a controller 118. The controller 118 may include any type of circuit for controlling the power supply. The sink device 104 may further include a switch 120 (illustratively a switching device, circuit, or component for performing switching operations). The switch 120 may be configured to establish a connection between the input terminal 110 and an input of the voltage regulator 112 via the supply line 114. When the switch 120 is turned off (off state), the switch 120 may prevent the electrical supply received from the input terminal 110 from being delivered to the input of the voltage regulator 112.When switch 120 is connected (connected state), switch 120 may enable the electrical supply received from input terminal 110 to be delivered to the input of voltage regulator 112. Controller 118 may control the operation of switch 120 to selectively enable or disable supply line 114. In other words, in a conducting state, switch 120 may couple supply line 114 to the input of voltage regulator 112, and in a non-conducting state, switch 120 may decouple supply line 114 from the input of voltage regulator 112. Switch 120 may be any type of controllable switch, e.g., a load switch or a transistor. Switch 120 may also be referred to herein as a sink switch.

[0027] In some aspects, the controller 118 may further communicate with the source device 120 to determine the electrical power supplied by the source device 102. The communication may occur via the interface 106, but it may also occur via another interface configured to exchange information for the determination. In the context of USB, the controller 118 may be a proportional derivative (PD) controller. The source device 102 and the sink device 104 may be configured to negotiate more or less power and / or higher or lower voltages via the interface 106. The controller 118 may include memory to store a particular voltage level, which may be a voltage level negotiated with the source device 102 in a negotiation operation.

[0028] The sink device 104 may further include a backup capacitor 122 connected to the supply line 114. The backup capacitor 122 may be configured to decouple the input terminal 110 from the rest of the circuitry of the sink device 104 (e.g., from the switch 120 and the voltage regulator 112), thus preventing a voltage drop when a device is coupled to the input terminal 110. The backup capacitor 122 may be configured (e.g., dimensioned) to limit the amplitude of the inrush current within a predetermined range.

[0029] Fig. 1B shows an exemplary USB device 150 in a schematic representation, according to the present disclosure. Fig. 1B may provide a schematic representation of components of a USB device 150 in which the strategy proposed herein may be implemented. For example, the USB device 150 may support USB PD ("Power Delivery").

[0030] In general, the USB device 150 may include an external power supply circuit 152 configured to receive electrical energy externally from an external power source (e.g., from a source device). The USB device may further include a power storage circuit 154 configured to store the (e.g., externally received) power. The USB device 150 may further include a communication circuit 156 configured to communicate with other devices (e.g., another USB device), e.g., via an interface such as a USB connector / cable. For example, the communication circuit 156 may include an upstream port and a downstream port for sending and receiving data.The USB device 150 may further include a processor 158 configured to implement one or more functions for which the USB device 150 is configured / adapted. The USB device 150 may further include memory (not shown) that stores instructions for the processor 158, data, and the like.

[0031] The USB device 150 can selectively operate as a sink (e.g., as sink device 104) or as a source (e.g., as source device 102), depending on a particular role assigned during manufacture or assigned during operation (e.g., in coordination with another USB device performing the complementary role). In an example configuration, the USB device 150 can operate as a sink or as a source in a port-based structure; for example, it can operate as a source for one USB port and as a sink for another USB port. As an example, the USB device can be a USB host, a USB hub, or a USB charger (illustratively, a USB adapter).

[0032] If the USB device 150 operates as a source, the USB device 150 may use the upstream port to supply electrical power. If the USB device 150 operates as a sink, the USB device 150 may use the downstream port to sink power. For example, the USB device 150 may power the power storage circuit 154 or power internal functions of the USB device 150 or another USB port using the downstream port. The USB device 150 may use the upstream port and the downstream port to communicate with another USB product. The communication may include communication for PD operation (e.g., SOP communication, in which power packets beginning with SOP are exchanged).

[0033] The processor 158 may include one or more processors dedicated to various operations of the USB device 150. As examples, the processor 158 may include a central processing unit, a graphics processing unit, a hardware acceleration unit (e.g., one or more dedicated hardware acceleration circuits (e.g., ASICs, FPGAs, and other hardware)), a neuromorphic chip, and / or a hardware controller (e.g., an embedded controller). In an example configuration, the processor 158 may be configured to control USB-related operations of the USB device 150 (e.g., as a controller). The processor 158 may be configured to implement the USB PD communication stack (e.g., as described in the USB PD specifications). The memory may store various types of information required by the processor 158 to operate according to various aspects of this disclosure.

[0034] As mentioned earlier, in systems with programmable power supplies, a problem can arise if the source device is disconnected from the sink device without properly shutting down the power. To illustrate, in the USB framework, a "hot unplug" can occur if the USB cable is disconnected from the sink device while the source device is sourcing power and the sink device's load is drawing power. This "hot unplug" can result in a large voltage difference between the cable pins and the sink device's input connector pins due to the high voltage on the bus. This large voltage difference can lead to the formation of an arc, which in extreme cases can melt the USB connector pins.

[0035] The present disclosure is based on the discovery that the supply line voltage and the supply line voltage slew rate can be monitored to detect the occurrence of a hot unplug event and trigger corrective action to prevent the arcing problem. Monitoring the voltage and slew rate enables rapid detection of a hot unplug, allowing rapid control of the switch to decouple the load from the input terminal to prevent the formation of an arc at the connector pins.

[0036] Fig. 2A illustrates an exemplary circuit 200 in a schematic view according to the present disclosure. The circuit 200 may be provided for use in an electronic device (e.g., in a sink device 104, e.g., in a USB device 150). For example, a computing device (e.g., a laptop, a tablet, a smartphone, and the like) may include the circuit 200. The circuit 200 may also be referred to as a circuit or circuit arrangement. The circuit 200 may include a first terminal 202 (e.g., an input terminal) and a second terminal 204 (e.g., an output terminal).

[0037] The first terminal 202 can be connected to an input terminal 206 (e.g., the input terminal of the electronic device). The input terminal 206 can be connected to a source device via a specific interface (e.g., via a USB interface, e.g., via a USB cable). The input terminal 206 can be supplied with electrical supply energy (e.g., a supply voltage) from the source (e.g., the source device 102). The electrical supply voltage can, for example, comprise a DC voltage. The electrical supply voltage can be variable and / or programmable. The first terminal 202 can be connected to the input terminal 206 such that the first terminal 202 receives the electrical supply voltage from the input terminal 206.

[0038] In a preferred configuration, the input port 206 may be a USB connector or may include a USB plug. The USB connector may be configured to receive a complementary / mating USB connector to enable a connection between a device including the circuit 200 and another device via a USB interface (e.g., via a USB cable). In an exemplary configuration, the USB connector may be configured as a USB receptacle to receive a mating USB connector (e.g., a USB plug). However, it should be understood that the USB port 102 may also be configured as a USB plug that can be coupled to a corresponding USB receptacle.

[0039] The USB connector may be configured according to any suitable USB configuration. In a preferred configuration, the USB connector may be a USB Type-C connector. However, it should be understood that the strategy proposed herein may also be applicable to other types of USB connectors, such as standard A connectors, standard B connectors, mini A connectors, mini B connectors, mini AB connectors, micro A connectors, micro B connectors, and micro AB connectors. In a preferred configuration, the USB connector may be board-mounted, i.e., it may be configured for integration into a printed circuit board (PCB), for example, a motherboard of a data processing device. In an exemplary configuration, a motherboard may include the circuitry 200, e.g., integrated into the motherboard.

[0040] Accordingly, the USB connector may be compatible with any suitable USB standard. For example, a USB Type-C connector may be compatible with USB 2.0, USB 2.0 revised, USB 3.0, USB 3.1, USB 3.2, USB 4, and / or USB 4 v2.0. In other configurations, the USB connector 102 may be compatible with other USB standards, such as USB 1.0 and / or USB 1.1. It is also understood that the strategy proposed herein may also be adapted to USB connector configurations and USB standards that have not yet been formulated.

[0041] In general, the configuration of a USB connector is known in the art and can be adapted according to the specific USB type for which the USB connector is configured. In short, the USB connector may have a plurality of contacts to enable an electrically conductive connection with the complementary USB connector. The plurality of contacts may include a common power contact, a ground contact, and a plurality of differential signal contacts. For example, the USB connector may have at least four contacts, e.g., two data lines, a contact for a ground connection, and a contact for a power connection. In an exemplary configuration, e.g., if the USB connector is configured as a Type-C connector, the USB connector may have 24 contacts arranged in a rotationally symmetric manner. A "contact" of a USB connector may also be referred to herein as a "port" or "contact pin."Furthermore, the USB connector may have a shield, e.g. a metal shield, arranged around the contacts to provide shielding against electrical noise and interference.

[0042] The second terminal 204 may be connected to a current collector circuit 230. In general, the current collector circuit 230 may comprise any circuit that draws power, e.g., from an electrically conductive connection 212. Illustratively, the current collector circuit 230 may be any circuit of a sink device that receives power from the input terminal 206 via the electrically conductive connection 212. In a preferred configuration, the current collector circuit 230 may comprise a voltage regulator 208. e.g., the second terminal 204 may be connected to a voltage regulator 208, e.g., to the input terminal of the voltage regulator 208. The voltage regulator 208 may be configured as described with respect to Fig. 1A and may be configured to maintain a power level of the power supplied from the source to the circuit 200 at a predetermined level (e.g., a constant level). The voltage regulator 208 may have any suitable configuration, e.g., a linear configuration or a switching configuration. As examples, the voltage regulator 208 may include a low-dropout regulator, a step-down converter, a step-up converter, a buck-boost converter, or the like. In an example configuration, the current collector circuit 230 may additionally or alternatively include a battery charger, e.g., a battery charging circuit, configured to draw power from the electrically conductive connection to charge a battery.In the following, particular reference may be made to a configuration in which the second terminal 204 is connected / connectable to a voltage regulator 208, as an example, but the aspects discussed herein may also apply accordingly to other configurations of the current collector circuit 230. The current collector circuit 230 may illustratively be any circuit that consumes current and may also be referred to herein as a current sink circuit.

[0043] The current collector circuit 230 may further include a load 210. The voltage regulator 208 may further be coupled to a load 210 (e.g., configured as the load 116 in Fig. 1A), e.g., with a load circuitry 210. Illustratively, an output terminal of the voltage regulator 208 may be coupled to the load 210 to supply constant power (e.g., a constant voltage) to the load 210. The load 210 may include any type of circuitry that consumes the power received at the input terminal 206. As examples, the load 210 may include a processor, memory, communication circuitry, a sensor, a display device, and the like. The second terminal 204 of the circuit 200 may be connected to the load 210 via the voltage regulator 208. The circuit 200 may thus regulate the behavior of the connection between the load 210 and the input terminal 206, and accordingly, the power transfer, to mitigate or prevent the arcing problem, as will be explained in more detail below. In an exemplary configuration, the load 210 may include a battery.For example, load 210 may include a battery charging circuit configured to draw power from input terminal 206 (illustratively from an electrically conductive connection 212 coupled to input terminal 206) to charge a battery. As described with respect to FIG. Fig. 1A, the voltage regulator 208 itself can be considered part of a load, e.g., load 210, but is shown separately to illustrate its function.

[0044] In an example configuration, circuit 200 may include input terminal 206 and current collector circuit 230 (e.g., voltage regulator 208 and optionally load 210).

[0045] The circuit 200 may further comprise an electrically conductive connection 212 (e.g., a supply line) configured to couple the first terminal 202 and the second terminal 204 to one another. The electrically conductive connection 212 may thus connect the input terminal 206 to the current collector circuit 230 (e.g., to the voltage regulator 208 and the load 210). The electrically conductive connection 212 may be an electrically conductive line, e.g., a conductive trace made of metal (e.g., copper, gold, etc.), which provides an electrically conductive path coupling the input terminal 206 to the current collector circuit 230, e.g., to the voltage regulator 208. Illustratively, the electrically conductive connection 212 may be a bus to which the input terminal 206 and the current collector circuit 230 (e.g., the voltage regulator 208) are connected. The bus may comprise a power transmission (e.g., a voltage transmission, V bus) between the input terminal 206 and the current collector circuit 230, e.g. the voltage regulator 208 (and to the load 210).

[0046] The circuit 200 may further include a switch 214 (illustratively a switching device, a switching element, or a switchable element) configured to selectively activate or deactivate the electrically conductive connection 212 between the first terminal 202 and the second terminal 204 (and accordingly between the input terminal 206 and the voltage regulator 208). The switch 214 may be configured to enable or prevent current flow from the input terminal 206 to the current collector circuit 230 (e.g., to the voltage regulator 208). Illustratively, the switch 214 may be operable (e.g., controllable) to selectively provide a closed path or an open path between the first terminal 202 and the second terminal 204 to enable the supply of a voltage (Vbus ) to the current collector circuit 230 (e.g., to the voltage regulator 208). The switch 214 may generally be configured as shown in Fig. 1A described switch 120 and may also be referred to herein as a sink switch.

[0047] In a normal operating mode, the switch 214 may activate the electrically conductive connection 212 between the first port 202 and the second port 204 when the input port 206 is coupled to a complementary connector, e.g., a mating USB connector, and may deactivate the electrically conductive connection 212 when the input port 206 is not coupled to a complementary connector (e.g., after a disconnection). The switch 214 may thus be configured to establish an electrical connection between the first port 202 and the second port 204, providing a supply line 212. When the switch 214 is in a disconnection state (e.g., in a disconnect position, the switch is ON), the supply line 212 does not supply any received electrical supply current to the second port 204. When the switch 214 is in a connection state (e.g.,in a connection position or the switch is OFF), the supply line 212 supplies power to the second terminal 204. In other words, when the first terminal 202 is connected to the input terminal 206 and when the second terminal 204 is connected to a load (e.g., to the voltage regulator 208), the switch 214 can connect the terminal of the input terminal 206 that supplies the electrical supply power (e.g., V. bus ) to the load via the supply line 212, couple (in a connection state) or decouple (in a disconnection state).

[0048] In general, switch 214 may have any suitable configuration that enables switching time compatible with USB-related operations. As an exemplary configuration that enables ready integration into circuit 200 (e.g., as part of a printed circuit board), switch 214 may comprise a transistor, such as a metal-oxide-semiconductor field-effect transistor (MOSFET). In this configuration, one of the drain or source terminals of the MOSFET may be connected to the first terminal 202 (e.g., to the input terminal 206) via the electrically conductive connection 212, and the other of the drain or source terminals may be connected to the second terminal (e.g., to the voltage regulator) via the electrically conductive connection 212. A field-effect transistor may have higher switching speed and higher efficiency. In principle, other transistor types may also be used, e.g., bipolar transistors (BJTs).In an example configuration, switch 214 may be an integrated circuit (e.g., an integrated load switch).

[0049] The circuit 200 may further include a controller 216 configured to control the coupling and decoupling of the switch 214. The controller 216 may generally be configured as shown in Fig. 1A. The controller 216 may instruct the switch 214 to operate in the disconnected state during a time period when there is a transient in the electrical supply power (e.g., a voltage and / or current change). The controller 216 may cause the switch 214 to operate in the disconnected state to decouple the first terminal 202 and the second terminal 204 during a voltage transient of the electrical supply power. The controller 216 may further cause the switch 214 to operate in the connected state to couple the first terminal 202 and the second terminal 204 such that the electrical supply power received at the first terminal 202 is supplied to the second terminal 204 (and the load).

[0050] The controller 216 may include a set of one or more electronic components, a computer-related device, hardware, software (e.g., in execution), and / or firmware. The controller 216 may include circuitry to provide some or all of the described aspects and / or a processor (e.g., processor 158) to provide some or all of the described aspects. The controller 216 may include one or more logic circuits. The controller 216 may further include memory. In some aspects, particularly in examples where the circuitry is for a USB device, the controller 216 may be a PD controller.

[0051] The controller 216 may be further configured to communicate with the source connected to the input port 206 to negotiate a power supply option (e.g., a voltage level or a current level) for the received electrical power supply. The input port 206 may have at least one contact pin (e.g., configuration channel (CC) pins for USB Type-C) connected to the controller 216. The controller 216 may determine a power supply option representing a voltage level to be supplied as the electrical power supply. The controller 216 may indicate the determined power supply option to the source via specific signaling so that the source can provide the electrical power supply according to the determined power supply option by adjusting the received electrical power supply (causing a voltage transition resulting in the determined power supply option).In particular, the power supply option may have a specific voltage level. For example, the controller 216 may command voltage transitions according to fixed supply voltage transitions and / or according to voltage transitions of the programmable power supply (PPS) in the standard power range (SPR) and / or according to voltage transitions of the adjustable power supply (AVS) in the extended power range (EPR) and / or according to hard reset transitions.

[0052] In an example configuration, the controller 216 may send a message to the source device to request an operating mode associated with a particular power requirement. For example, the load 210 may require more or less power to operate (e.g., to charge a battery or to support certain functions), e.g., depending on available time, other parallel processes, and the like. Thus, the controller 216 may send a message to instruct the source device to supply electrical energy according to one of a plurality of operating modes. For example, the source device may have at least a first operating mode and a second operating mode.In the first mode of operation, the source device may supply a first voltage to the input terminal 206 (and accordingly to the electrically conductive connection 212), and in the second mode of operation, the source device may supply a second voltage to the input terminal 206. The second voltage may be different from the first voltage, e.g., the second voltage may be greater than the first voltage. For example, the first mode of operation may be a standard power range and the second mode of operation may be an extended power range. As a numerical example, the first voltage may be 20 V and the second voltage may be 48 V. However, it should be understood that the source device may support more than two modes of operation, e.g., to adjust the voltage supplied to the input terminal 206.

[0053] The circuit 200 may further include a monitoring circuit 220 configured to detect the occurrence of a hot unplug event at the input port 206. Illustratively, the monitoring circuit 220 may be configured to detect the occurrence of an unplug event at the input port 206 while the load 210 is drawing power from the electrically conductive connection 212. With respect to the USB framework, an unplug event may, for example, describe the unplugging (illustratively, the removal or disconnection) of a complementary / mating USB connector from the USB port 206. A hot unplug event may describe the unplugging of the complementary / mating USB connector while the USB connector 206 is still receiving power.The monitoring circuit 220 may be configured to initiate or trigger a corrective action upon detecting the hot unplug event to reduce or prevent the formation of an arc at the contact pins of the input connector 206. The monitoring circuit 220 may also be referred to as an arc prevention circuit.

[0054] In an example configuration, as in Fig. As shown in Figure 2A, the controller 216 may be located external to the monitoring circuit 220; for example, the two circuits may be separate circuits that implement the respective functions. In another exemplary configuration, the controller 216 may include the monitoring circuit 220; for example, the controller 216 may be configured to perform the function of the monitoring circuit 220.

[0055] In general, the monitoring circuit 220 may be configured to monitor a voltage at the electrically conductive connection 212, e.g., it may be configured to monitor the bus voltage V bus on the bus 212. The monitoring circuit 220 can be configured to detect the occurrence of a hot unplug event depending on the behavior of the bus voltage. Clearly, the monitoring circuit 220 can be electrically conductively coupled to the electrically conductive connection 212 (e.g., to the bus) and configured to determine a status and a temporal change in the voltage at the electrically conductive connection 212.

[0056] According to the strategy proposed herein, the monitoring circuit 220 may be configured to detect a hot unplug event using an amplitude of the voltage at the electrically conductive connection 212 and a magnitude of a temporal change in such voltage. The monitoring circuit 220 may thus be configured to determine (e.g., measure) the voltage at the electrically conductive connection 212 and the slew rate of the voltage at the electrically conductive connection 212. For example, the monitoring circuit 220 may determine an absolute value of the voltage and / or an absolute value of the slew rate of the voltage. For example, the monitoring circuit 220 may be configured to perform a differentiation of the voltage at the electrically conductive connection 212 to derive the slew rate of the voltage.

[0057] The term "slew rate" may be used herein in the usual manner to indicate a change in an electrical quantity (e.g., the voltage across the electrically conductive connection 212) per unit of time. Below, some values ​​for the slew rate are expressed in millivolts per microsecond (mV / µs), but it should be understood that the slew rate may be determined and expressed in any suitable unit.

[0058] The monitoring circuit 220 may further be configured to determine whether the determined voltage meets a predetermined voltage criterion and to determine whether the determined slew rate meets a predetermined slew rate criterion. Illustratively, the monitoring circuit 220 may be configured to evaluate the behavior of the voltage and the slew rate with respect to a predetermined behavior to determine whether a hot unplug event is occurring. For example, the predetermined voltage criterion and the predetermined slew rate criterion may be indicative of a hot unplug event, such that fulfillment of the criteria may indicate that a hot unplug event is occurring.It is understood that a "complementary" configuration may also be provided, where the specified voltage criterion and the specified slew rate criterion may indicate normal operation (or safe unplugging), so that a "complementary" detection process may be provided, where fulfillment of the criteria indicates that no corrective action is required.

[0059] If the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion, the monitoring circuit 220 may send a control signal 218 to the switch 214. The control signal 218 may be configured to control the switch 214 to selectively deactivate the electrically conductive connection 212 between the first terminal 202 and the second terminal 204 (thus decoupling the load from the input terminal 206). Illustratively, the monitoring circuit 220 may instruct the switch 214 to interrupt (or prevent) current flow from the input terminal 206 to the load (e.g., to the voltage regulator 208) if the monitoring circuit 220 determines that the voltage at the electrically conductive connection 212 and the corresponding slew rate are attributable to a hot unplug event. The control signal 218 may also be referred to herein as an enable / disable signal.

[0060] In the exemplary configuration where switch 214 is a transistor, monitoring circuit 220 may provide control signal 218 to the gate terminal of switch 214 to control the electrical behavior of the source terminal and the drain terminal, e.g., to prevent current flow in the channel between the source terminal and the drain terminal.

[0061] The control signal 218 may be configured to control the switch 214 to selectively deactivate the electrically conductive connection 212 for a predetermined period of time, e.g., a period of time selected to ensure that the formation of an electrical arc does not occur. Illustratively, given the USB framework, the predetermined period of time may be selected to ensure that the USB connector is sufficiently far away from the input port 206 before the electrically conductive connection 212 is reactivated. As a numerical example, the predetermined period of time may be greater than 0 seconds and less than 10 milliseconds; for example, the predetermined period of time may be approximately 1 millisecond.

[0062] In an exemplary implementation, control signal 218 may comprise a pulse having a duration corresponding to the predetermined time period. Control signal 218 may comprise a voltage pulse (or, equivalently, a current pulse) delivered to switch 214 to interrupt the flow of current between input terminal 206 and the load for the duration of the pulse. The pulse may have a pulse width corresponding to the predetermined time period and a pulse amplitude suitable to trigger a change in state of switch 214 (e.g., a change in state of the transistor).

[0063] In principle, the monitoring circuit 220 may be configured to evaluate the voltage and slew rate behavior in any suitable manner that allows for rapid detection of a hot unplug event. In a preferred configuration (see also Fig. 3A to Fig. 3C), the monitoring circuit 220 may be configured to compare the detected voltage to a corresponding voltage threshold (also referred to as a voltage value threshold) and to compare the detected slew rate to a corresponding slew rate threshold. This approach may enable detection of hot unplug conditions in a manner that can be easily implemented in the circuit 200 (e.g., using simple analog components, for example). For example, the monitoring circuit 220 may be configured to continuously monitor the voltage and the slew rate of the voltage at the electrically conductive connection 212 and perform detection of a hot unplug event based on an instantaneous voltage value and an instantaneous slew rate value (compared to a corresponding threshold).

[0064] However, it is understood that monitoring circuit 220 may also use other approaches, e.g., analog and / or digital, to determine the behavior of the voltage and slew rate. As another example, monitoring circuit 220 may be configured to determine a time series of voltage values ​​and / or slew rate values ​​and detect a hot unplug event according to a temporal evolution of the voltage and / or slew rate.

[0065] In the preferred configuration, monitoring circuit 220 may determine the voltage value at electrically conductive connection 212 and whether the voltage value is less than a voltage value threshold. Illustratively, monitoring circuit 220 may compare the voltage value to the voltage value threshold to determine whether a hot unplug event is occurring. A voltage value below the voltage value threshold may indicate a sudden voltage drop, which may be associated with a disconnection event rather than an adjustment of the power supply during normal operation of circuit 200 (e.g., an adjustment after a negotiation). As previously mentioned, monitoring circuit 220 may compare an instantaneous voltage value (at a particular point in time) to the corresponding voltage value threshold.As another example, the monitoring circuit 220 may compare an average of a number N of consecutive voltage values ​​(determined at N consecutive times) with the voltage value threshold, where N is equal to or greater than 2.

[0066] Accordingly, the monitoring circuit 220 may determine whether the slew rate is greater than a slew rate threshold. Illustratively, the monitoring circuit 220 may compare the slew rate to the slew rate threshold to determine whether a hot unplug event is occurring. A slew rate greater than the slew rate threshold may indicate a voltage drop that is faster than a drop during normal operation of the circuit 200 (e.g., faster than a negotiated voltage swing). As mentioned above, the monitoring circuit 220 may compare an instantaneous value of the slew rate (e.g., at the same time as the voltage value) to the corresponding slew rate threshold.As another example, the monitoring circuit 220 may compare an average of a number M of consecutive slew rate values ​​(determined at M consecutive times) with the slew rate threshold, where M is equal to or greater than 2.

[0067] In general, the monitoring circuit 220 may perform the comparison with respect to absolute values, e.g., an absolute value of the voltage at the electrically conductive connection 212 compared to an absolute voltage value of the threshold. This allows a hot unplug event to be detected regardless of the "sign" of the voltage. In this context, the monitoring circuit 220 may determine whether the absolute value of the voltage is below the absolute voltage value of the voltage threshold. If the sign of the voltage has been taken into account, the comparison may be adjusted accordingly, e.g., to determine whether a positive / negative voltage value is closer to a reference value (e.g., 0 V) ​​than a respective positive / negative threshold.

[0068] Accordingly, the monitoring circuit 220 may additionally or alternatively determine whether the absolute value of the slew rate is greater than the absolute voltage value of the slew rate threshold. The slew rate with respect to an unplug event may be a negative value, indicating a decrease in voltage per unit time. In this context, the slew rate being greater than the slew rate threshold may indicate that the slew rate is more negative than the slew rate threshold, e.g., that the slew rate is farther from a reference value (e.g., 0 mV / µs) than the slew rate threshold.

[0069] In this configuration, the voltage at the electrically conductive connection 212 may satisfy the predetermined voltage criterion (and thus contribute to the deactivation of the connection 212) if the voltage value is less than the corresponding voltage threshold. Similarly, the slew rate may satisfy the predetermined slew rate criterion (and thus contribute to the deactivation of the connection 212) if the slew rate is greater than the corresponding slew rate threshold.

[0070] If the voltage value is less than the voltage value threshold and the slew rate is greater than the slew rate threshold, this may be an indication of a hot unplug event. Illustratively, such conditions may indicate a variation in the voltage at the electrically conductive connection 212 that is too steep and of a magnitude too high to be compatible with normal operation of the circuit 200, e.g., a variation in the voltage due to a different power demand. The monitoring circuit 220 may therefore be configured to transmit the control signal 218 to the switch 214 to deactivate the electrically conductive connection 212 if the voltage value is less than the voltage value threshold and the slew rate is greater than the slew rate threshold.

[0071] The voltage threshold and the slew rate threshold can be set to any suitable value to distinguish a hot unplug event from a normal adjustment of the voltage at the electrically conductive connection 212. Illustratively, the voltage threshold and the slew rate threshold can be set to mimic a plug unplug event rather than an actual voltage reduction request. As a numerical example proven suitable in the context of USB Type-C, the slew rate threshold can be in the range of -30 mV / µs to -50 mV / µs (e.g., an absolute value of the slew rate threshold can be in the range of 30 mV / µs to 50 mV / µs). For example, the slew rate threshold can be -31.5 mV / µs. As another example, the slew rate threshold can be -40 mV / µs.It should be understood that these numerical values ​​are exemplary and that the slew rate threshold can be set to higher or lower values ​​depending on circuit considerations.

[0072] In principle, the monitoring circuit 220 may be implemented in any suitable manner compatible with the operation of the circuit 200. In a preferred configuration (see also Fig. 3A to Fig. 3C), the monitoring circuit 220 may be implemented in an analog manner, e.g., it may include analog components to perform the detection of the voltage and slew rate and to perform the corresponding control of the switch 214. An analog implementation may enable a simple but efficient configuration for rapid corrective action in the event of a hot-unplug event. However, it should be understood that the operation of the monitoring circuit 220 may also be implemented digitally; e.g., the monitoring circuit 220 may include an analog-to-digital converter to convert the monitored voltage into a digital representation and perform digital processing. As another example, the operation of the monitoring circuit 220 may be implemented using software, e.g., as part of firmware of the circuit 200 (e.g., the controller 216).As another example, the operation of the monitoring circuit 220 may be implemented as a combination of hardware and software components and / or as a combination of analog and digital components.

[0073] As described above, the controller 216 may be configured to communicate with the source device coupled to the input port 206 to negotiate a voltage value and a slew rate at the electrically conductive connection 212. As an example, the controller 216 may be configured to perform the negotiation with a USB adapter plugged into the USB receptacle 206. The negotiation may include negotiating a voltage value and a slew rate for the power supply to the load 210 (and, accordingly, to the input port 206). Illustratively, the USB specification (e.g., the Type-C specification) may enable dynamic adjustment of the power supply to the requirements of the connected device, e.g., to charge a battery of the device more quickly or to support a resource-intensive process.

[0074] The negotiated values ​​can be used to adjust the criteria for detecting a hot unplug event. In other words, the negotiated values ​​can provide an indication of what to expect during normal operation of the circuit 200, e.g., regarding the load requirements, so that the criteria for detecting operation deviating from this normal operation can be adjusted accordingly.

[0075] The monitoring circuit 220 may therefore be configured to receive an indication of a negotiated voltage value and / or a negotiated slew rate for a power supply at the input terminal 206, and may be configured to set or change the voltage criterion and / or the slew rate criterion depending on the negotiated voltage value or the negotiated slew rate. In the example configuration in which thresholds are used to detect a hot unplug event, the monitoring circuit 220 may be configured to set or change (e.g., increase or decrease) the voltage value threshold depending on the negotiated voltage value. Similarly, the monitoring circuit 220 may be configured to set or change (e.g., increase or decrease) the slew rate threshold depending on the negotiated slew rate.In an example configuration, a user can select the slew rate threshold (also referred to herein as a rate reference) based on a supported power supply mode at input terminal 206, e.g., Fixed PDO (Power Delivery Objects), PPS (Programmable Power Supply), or AVS (Adjustable Voltage Supply), and the actual backup capacitors used in the circuit.

[0076] In an example configuration, monitoring circuit 220 may be further configured to adjust the voltage threshold and / or the slew rate threshold to account for normal fluctuations that occur during operation of circuit 200 due to losses or dips within the system. For example, monitoring circuit 220 may be configured to adjust or change the voltage threshold such that the voltage threshold corresponds to a sum of a predetermined percentage of the negotiated voltage and a predetermined adjustment value.The predetermined percentage and the predetermined adjustment value may be selected to account for system-internal variations that may cause the voltage at the electrically conductive connection 212 to deviate from the negotiated value while still being within the limits of normal operation of the circuit 200.

[0077] As a numerical example, the predetermined percentage may range from 90% of the negotiated voltage value to 97.5% of the negotiated voltage value, e.g., the predetermined percentage may be 95% of the negotiated voltage value. As another numerical example, the predetermined adjustment value may range from -0.5 V to -1 V, e.g., the predetermined adjustment value may be -0.75 V. These parameters may be consistent with the USB Type-C PD specification, which specifies that for all negotiated voltage levels, a V BusA voltage at the sink end that is greater than the sum of 95% of the negotiated value of -0.75 V (due to cable drop) is considered a normal voltage level. However, it should be understood that the predetermined percentage and the predetermined adjustment value may take any suitable value depending on the circuit, e.g., the USB specification according to which the circuit 200 is configured or operates.

[0078] It goes without saying that Fig. 2A may be simplified for illustrative purposes and the circuit 200 may include additional components, such as one or more resistors, one or more capacitors, and / or the like. For example, the circuit 200 may be as described with respect to Fig. 1A, a backup capacitor (also referred to as a bulk capacitor or decoupling capacitor) coupled to the electrically conductive connection 212. As a numerical example, the backup capacitor may have a capacitance in the range of 5 microfarads (µF) to 50 microfarads; for example, the backup capacitor may have a capacitance of 10 microfarads. The turn-off time of the switch 214 may be considered when dimensioning the backup capacitor. By providing a fast gate discharge circuit on the external sink switches (MOSFETs), the sink switch can be deactivated in a few µs.

[0079] In an exemplary configuration, the monitoring circuit 220 can be configured to adapt the voltage criterion and the slew rate criterion depending on the capacitance value of the backup capacitor. Clearly, the conditions for identifying a "hot unplug event" can vary depending on the properties of the backup capacitor, and the monitoring circuit 220 can take such properties into account when defining the criteria for evaluating the monitored voltage and slew rate. As an example, the monitoring circuit 220 can be configured to set the threshold for the voltage value and / or the slew rate depending on the capacitance value of the backup capacitor. This can increase the reliability of the monitoring by adapting the evaluation to the actual properties of the circuit 200.In an exemplary implementation, monitoring circuit 220 may set the slew rate threshold based on the simple formula I=C*dv / dt. Where I is the maximum current of the platform, C is the capacitance of the backup capacitor, and dv / dt is the slew rate.

[0080] In an exemplary configuration, the components of circuit 200 may be integrated on the same substrate, e.g., on the same printed circuit board, e.g., on a motherboard. For example, input terminal 206, switch 214, monitoring circuit 220, controller 216, and current collector circuitry (e.g., voltage regulator 208 and load 210) may be integrated on the same substrate.

[0081] Fig. 2B shows two diagrams 250a, 250b that illustrate an exemplary application of the strategy proposed herein. The first diagram 250a illustrates a scenario of normal operation (a normal state) of the circuit 200 and the switch 214 (e.g., in the absence of a hot-unplug event), and the second diagram 250b illustrates a scenario with a hot-unplug state. The diagrams 250a, 250b illustrate a temporal change (t) of the voltage at the electrically conductive connection 212 (V to V bus ) in both scenarios. Diagrams 250a and 250b show the decrease in V bus during normal operation (Diagram 250a) and the hot unplug event (Diagram 250b).

[0082] During normal operation, the voltage 252a at the electrically conductive connection 212 may remain constant until an event 254a occurs in which the voltage 252a changes (e.g., decreases) in a controlled manner. For example, the event 254a may involve a negotiation of V bus to a new negotiated value. In this scenario, the voltage 252a may change smoothly without a sudden drop that could cause arcing. Illustratively, the slew rate of the voltage 252a (for illustration: the slope of the change in graph 250a) may be below the slew rate threshold 256. As a numerical example, the slew rate threshold 256 may be -31.5 mV / µs, and the slew rate of the voltage 252a may be below this threshold, i.e., an absolute value of the slew rate of the voltage 252a may be less than 30 mV / µs.

[0083] During a hot unplug, the voltage 252b at the electrically conductive connection 212 may remain constant until the hot unplug event 254b (e.g., unplugging a Type-C connector), at which time the voltage 252b changes suddenly and steeply (e.g., drops). In this scenario, the voltage 252b may change rapidly, with a sudden drop that could cause arcing. Illustratively, the slew rate of the voltage 252b (for illustration, the slope of the change in graph 250b) may be greater than the slew rate threshold 256. As a numerical example, an absolute value of the slew rate of the voltage 252b may be greater than 31.5 mV / µs.

[0084] As mentioned above, the fast detection of a hot unplug event (e.g. a USB-C adapter unplug event) is achieved by a slew rate detection function and a disconnection detection function that detects the V busSuch a monitoring function may be implemented in any suitable manner, e.g. based on a hardware implementation, a software implementation, or a combination of hardware and software. With regard to Fig. 3A to Fig. 3C shows an example configuration of a monitoring circuit. The example configuration in Fig. 3A to Fig. Figure 3C has proven to be a simple yet efficient implementation of the strategy proposed herein (e.g., for integration into a motherboard). However, it is understood that the monitoring circuit can also be implemented with additional, fewer, or alternative components than those shown.

[0085] According to various aspects, the monitoring circuit may comprise one or more hardware logics. Each hardware logic may be configured to provide its function for implementing the above-mentioned operation. In some examples, the monitoring circuit may comprise one or more hardware logics and one or more logics including software components. In particular, the one or more hardware logics may comprise comparison logic for comparing the voltage and slew rate with associated threshold values. In an implementation that comprises comparison logic independent of other software-dependent operations (i.e., firmware) of the monitoring circuit (and the control unit), the above-mentioned control of the electrically conductive connection may occur in real time, possibly at the microsecond level.

[0086] Fig. 3A shows an exemplary circuit 300 having a monitoring circuit 302 in a schematic representation according to the present disclosure. The circuit 300 may be an exemplary implementation of the circuit 200, and the monitoring circuit 302 may be an exemplary implementation of the monitoring circuit 220. In the exemplary representation in Fig. 3A, the load of circuit 300 is represented by load 320 (e.g., 5 A, as a numerical example) and a corresponding capacitor 322 (e.g., with a capacitance of less than 100 microfarads, e.g., a capacitance of less than 90 microfarads). Load 320 may be a representation of current collector circuit 230 (e.g., load 210 and voltage regulator 208) that is connected with respect to Fig. 2A was described.

[0087] The monitoring circuit 302 may include a slew rate detection circuit 304 configured to determine whether the slew rate of the voltage at the electrically conductive connection 212 satisfies the predetermined slew rate criterion, e.g., whether the slew rate is greater than the slew rate threshold. The slew rate detection circuit 304 may also be referred to herein as a "falling slew rate detection circuit." The monitoring circuit 304 may further include a disconnection detection circuit 306 configured to determine whether the voltage at the electrically conductive connection 212 satisfies the predetermined voltage criterion, e.g., whether the voltage value of the voltage at the electrically conductive connection 212 is less than the voltage value threshold. The disconnection detection circuit 306 may also be referred to as a "V bus -voltage isolation circuit”.

[0088] The slew rate detection circuit 304 and the disconnection detection circuit 306 may be coupled to the electrically conductive terminal 212. In an analog implementation (see also Fig. 3B and Fig. 3C), the slew rate detection circuit 304 and the disconnection detection circuit 306 may directly receive the voltage at the electrically conductive connection 212. In a digital or partially digital implementation, the monitoring circuit 302 may include one or more analog-to-digital converters to provide the slew rate detection circuit 304 and / or the disconnection detection circuit 306 with a digital representation of the voltage at the electrically conductive connection 212.

[0089] The slew rate detection circuit 304 may be configured to provide (e.g., deliver) a (first) output signal 314 indicating whether the slew rate meets the predetermined slew rate criterion. Similarly, the disconnection detection circuit 306 may be configured to provide a (second) output signal 316 indicating whether the voltage at the electrically conductive connection 212 meets the predetermined voltage criterion. If both criteria are met, the monitoring circuit 302 may deliver a control signal 218 to the switch 214 to deactivate the electrically conductive connection 212, as described above.

[0090] In an example configuration, as in Fig. 3A, the monitoring circuit 302 may include a logic gate 308 configured to receive the first output signal 314 from the slew rate detection circuit 304 and the second output signal 316 from the disconnection detection circuit 306. The logic gate 308 may be configured to provide a (third) output signal 318 representing whether both criteria are met (e.g., representative of whether both the slew rate is greater than the corresponding threshold and the voltage value is less than the corresponding threshold). The logic gate 308 may, for example, be an AND gate or configured according to any other suitable logic function or combination of logic functions to provide the desired output signal.

[0091] As with regard to Fig. 2A, the control signal 218 for controlling the switch 214 may include a pulse to selectively deactivate the electrically conductive connection 212 for a predetermined period of time defined by the duration of the pulse. In the exemplary configuration in Fig. 3A, the monitoring circuit 302 may include a pulse generator 310 configured to generate the pulse of the control signal 218 in response to a signal indicating that the detected voltage meets the voltage criterion and the slew rate meets the slew rate criterion. For example, the pulse generator 310 may be configured to generate the pulse based on the output signal 318 of the logic gate 308. As an example, the high switching of the output signal 318 may be an indication that both criteria are met and trigger the generation of the pulse at the pulse generator 310.

[0092] The output signal 218 of the monitoring circuit 302 (e.g., the pulse output of the pulse generator 310) can be supplied directly to the switch 214. In another configuration, as in Fig. 3A, the output signal 218 of the monitoring circuit 302 may be selectively combined with an output signal (e.g., a control signal) from the controller 216 to ensure that at least one control signal is provided to the switch 214. In such an example configuration, the circuit 300 may further include a second logic gate 312 configured to receive the output signal of the monitoring circuit 302 (e.g., the pulse from the pulse generator 310) and the output signal from the controller 216. The second logic gate 312 may be configured to provide a control signal to the switch 214 to deactivate the electrically conductive connection 212 when either the output signal of the monitoring circuit 302 or the output signal of the controller 216 includes an indication of an instruction to deactivate the connection 212.The second logic gate 312 may, for example, be an OR gate or configured according to any other suitable logic function or combination of logic functions to provide the desired output.

[0093] As mentioned above, voltage and slew rate detection can be performed in any suitable manner to ensure rapid correction in case of a hot unplug event. Fig. 3B and Fig. 3C show exemplary configurations of a slew rate detection circuit ( Fig. 3B) and a disconnection detection circuit ( Fig. 3C). The configurations in Fig. 3B and Fig. 3C uses simple and readily available components to implement the proposed strategy, but it is understood that other implementations are also possible.

[0094] Fig. 3B shows an exemplary slew rate detection circuit 330 in a schematic representation according to the present disclosure. The slew rate detection circuit 330 may be an exemplary implementation of the slew rate detection circuit 304 described with respect to Fig. 3A. According to the exemplary configuration in Fig. 3B, the slew rate detection circuit 330 may include a differentiator 332 and a comparator 334.

[0095] The differentiator 332 may be configured to receive a voltage representing the voltage at the electrically conductive connection 212. For example, an input of the differentiator 332 may be electrically conductively connected to the electrically conductive connection 212, or the differentiator 332 may receive a voltage from another source representing the voltage at the electrically conductive connection 212. The differentiator 332 may be configured to provide (e.g., supply) a (first) output signal 336 representing a rate of change of the voltage at the electrically conductive connection 212 over time. The output signal 336 may thus represent the slew rate of the voltage at the electrically conductive connection 212. The differentiator 332 may be configured in an analog or digital manner. As an exemplary implementation, the differentiator 332 may be an operational amplifier differentiator, e.g.,a practical differentiator circuit based on an operational amplifier.

[0096] The comparator 334 may be configured to compare the slew rate of the voltage at the electrically conductive connection 212 with a reference voltage representing the slew rate threshold. Considering the exemplary configuration in Fig. 3B, the comparator 334 may be configured to compare the output signal 236 of the differentiator 332 with a reference signal 338 and provide a (second) output signal 340 based on the comparison result. The (second) output signal 340 may be similar to the output signal 314 in Fig. 3A, or the slew rate detection circuit 330 may generate the output signal 314 provided to the logic gate 312 based on the output signal 340 of the comparator 334.

[0097] For example, the output signal 336 of the differentiator 332 may be a (first) output voltage, and the comparator 334 may be configured to compare the (first) output voltage 336 with a reference voltage 338. The reference signal 338 (e.g., the reference voltage) may represent the slew rate threshold. As an example, the slew rate detection circuit 330 may include a voltage source configured to generate the reference voltage corresponding to the slew rate threshold (e.g., 31.5 mV / µs as a numerical example). For example, the comparator 334 may receive the output signal 336 of the differentiator 332 at the positive terminal (non-inverting terminal) and the reference signal 338 at the negative terminal (inverting terminal). In an exemplary implementation, the comparator 334 may be an open collector output comparator.

[0098] For example, the comparator 334 may be configured to provide the output signal 340 with a first level (e.g., a low level) if the comparison indicates that the slew rate is less than the slew rate threshold, and to provide the output signal 340 with a second level (e.g., a high level) if the comparison indicates that the slew rate is greater than the slew rate threshold. The output signal 340 of the comparator 334 may be a (second) output voltage, and the voltage value of the output signal 340 may represent whether the slew rate is less than / greater than the corresponding threshold.

[0099] In an exemplary analog implementation, the differentiator 332 may include RC timing components configured (e.g., dimensioned) such that the (first) output voltage 336 of the differentiator 332 is greater than the reference voltage 338 when the time rate of change of the voltage at the electrically conductive connection 212 is greater than the slew rate threshold. In such an exemplary configuration, the slew rate detection may be implemented using a timing capacitor. The slew rate detection function is used to determine the discharge rate at the V bus to detect, taking into account that it should be able to detect the actual interruption event to avoid arcing and should also be able to determine the slew rate of the V busduring normal operation. In general, the user can select the rate reference for this slew rate detection circuit 330 based on the total support capacitance used and the load current.

[0100] For fixed PDO applications, the user can set the rate reference to 21.8 mV / µs, dvmax = 5.45 V (according to the USB Type-C specification, Appendix D), and dt (time to reach safe distance) = 250 µs (according to the USB Type-C specification, Appendix D), resulting in dv / dt = 21.8 mV / µs. For PPS or AVS-compatible systems, the maximum slew rate according to the USB Type-C PD specifications is -30 mV / µs. Similarly, the discharge rate at the V bus at SPR or EPR.

[0101] For the 48 V EPR case (assuming the following worst-case condition), taking into account a backup capacitor at V busof 100 µF (max. according to USB-PD specification), a charging current of 5 A (max. according to USB-PD specification) and a dv max of 5.45 V (according to the USB Type-C specification, Annex D) The following dt=charging current*dv max total support capacity=109 μs dvdt=50 mV / μs

[0102] Similarly, for the 20 V SPR case (assuming the following worst-case condition), taking into account a backup capacitor at V bus of 100 µF (max. according to USB-PD specification), a charging current of 5 A (max. according to USB-PD specification) and a dv max of 8.25 V (according to the USB Type-C specification, Annex D) The following dt=charging current*dv max total support capacity=165μs dvdt=50mV / μs

[0103] The value of the backup capacitor is always less than 100 µF in the actual implementation, therefore the slew rate of V busalways greater than 50 mV / µs in both the EPR and SPR cases. Therefore, a suitable threshold for the slew rate is 31.5 mV / µs (e.g., -31.5 mV / µs) to detect the hot unplug event.

[0104] In general, there are many possible approaches to implementing this rate detector. One possibility that offers a simple but efficient implementation is a practical op-amp-based differentiator circuit that can be used for rate detection, followed by an open-collector output comparator, as in Fig. 3B. The RC timing components of the differentiator 332 can be chosen so that whenever the slew rate of V bus is greater than the set threshold, e.g., (-)31.5 mV / µs, the output of the differentiator exceeds the reference threshold of the comparator.

[0105] Fig. 3C shows an exemplary disconnection detection circuit 350 in a schematic representation according to the present disclosure. The disconnection detection circuit 350 may be an exemplary implementation of the disconnection detection circuit 306 described with respect to Fig. 3A. According to the exemplary configuration in Fig. 3C, the disconnection detection circuit 350 may be a comparator-based circuit.

[0106] In general, the disconnection detection circuit 350 in the exemplary configuration may be Fig. 3C, a comparator 352 configured to compare the voltage at the electrically conductive connection 212 with a reference voltage 354 (e.g., at the negative terminal) and to provide an output signal 356 based on the result of the comparison. The output signal 356 may be an exemplary implementation of the output signal 316 in Fig. 3A, or the disconnection detection circuit 350 generates the output signal 316 provided to the logic gate 312 based on the output of the comparator 352. For example, an input of the comparator 352 (e.g., the positive terminal) may be electrically connected to the supply line 212 to receive the voltage 260 on the supply line 212, or the comparator 352 may receive a voltage from another source that represents the voltage on the electrically conductive connection 212.

[0107] For example, the comparator 352 may be configured to provide the output signal 356 with a first level (e.g., a low level) when the comparison indicates that the voltage value at the connection 212 is greater than the reference voltage 354, and to provide the output signal 356 with a second level (e.g., a high level) when the comparison indicates that the voltage value at the connection 212 is less than the reference voltage 354. The output signal 356 of the comparator 352 may be an output voltage, and the voltage value of the output signal 356 may represent whether the voltage value is less than / greater than the corresponding threshold value. In an example implementation, the comparator 352 may be an open-drain comparator.

[0108] The disconnection detection circuit 350 may be configured to change the voltage value of the reference voltage 354 used for comparison based on a variation in the requirements of a power supply at the electrically conductive connection 212, e.g., based on a variation in the requirements of a power supply from a source coupled to the input terminal 206. Illustratively, the disconnection detection circuit 350 may be configured to change the voltage value of the reference voltage 354 based on the negotiated voltage value for the voltage at the electrically conductive connection 212. This configuration may enable dynamic adjustment of the criteria to be met to avoid "false positive" results in detecting hot unplug events.

[0109] In this regard, the disconnection detection circuit 350 may be configured to set the voltage value of the reference voltage 354 to a predetermined fraction of the negotiated voltage value (e.g., 95% of the negotiated voltage value, optionally with an adjustment value added). The disconnection detection circuit 350 may be configured to determine a peak value of the voltage at the electrically conductive connection 212 (during normal operation, e.g., before unplugging) and provide a predetermined fraction of the peak value as the reference voltage 354 to the comparator 352.

[0110] In an exemplary implementation, the disconnection detection circuit 350 may include a peak hold and ratiometric circuit 358. The peak hold and ratiometric circuit 358 may be configured to hold a peak value of the voltage at the electrically conductive connection 212. For example, the peak hold and ratiometric circuit 358 may include a capacitor that stores a charge corresponding to or representing the peak value of the voltage at the electrically conductive connection 212.

[0111] The peak hold and ratiometric circuit 358 may further be configured to provide a predetermined fraction of the peak value to the comparator 352 as a reference voltage 354. For example, the peak hold and ratiometric circuit 358 may include a voltage divider configured (e.g., dimensioned) to divide the peak value by a predetermined amount to provide the reference voltage 354 as an output. By way of example, the voltage divider may include a plurality of resistors coupled to the capacitor to provide a voltage at an output node that corresponds to a predetermined fraction of the peak value (see also Fig. 4A).

[0112] In an analog implementation, the ratiometric circuit can be understood as an analog circuit configured to adjust the threshold 354 of the disconnect detection circuit 350 based on each voltage available on the supply line 212. As a numerical example, for a ratio of 95%, the threshold 354 can be set to 19 V if 20 V is agreed (or 18.25 V with an adjustment of -0.75 V), if 15 V is agreed, then 14.25 V (or 13.5 V), and so on. The proposed circuit complies with the PD specification and only turns off the sink switch when the voltage drops below the voltage specified in the PD specification.

[0113] Fig. 4A, Fig. 4B and Fig. 4C show a simulated circuit 400 ( Fig. 4A) and corresponding simulation results ( Fig. 4B and Fig. 4C) for the proposed concept. The circuit 400 in Fig. 4A may be an exemplary implementation of the circuit 200, 300, which may be related to Fig. 2A and Fig. 3A. Illustratively, the circuit 400 can represent an exemplary implementation of the monitoring circuit 220, 302. For better representation, the focus is Fig. 4 to the components of the monitoring circuit 402, but it is understood that the circuit 400 may include additional components, as described with respect to Fig. 2A and Fig. 3A, e.g., a current collector circuit such as a voltage regulator, a load, and the like. For example, circuit 400 may include a current source 410, e.g., a voltage source configured, for example, to provide 5 V to power the controller (e.g., the PD controller) (not shown). As another example, circuit 400 may include one or more decoupling capacitors, hysteresis around a comparator, a pulse generator, etc.

[0114] The circuit 400 may include a monitoring circuit 402 to monitor the voltage (V bus ) on a supply line 408 and initiate corrective action in the event of a hot unplug event. As described in relation to Fig. 3A, the monitoring circuit 402 may include a slew rate detection circuit 404 and a disconnection detection circuit 406. In an example configuration, the slew rate detection circuit 404 and the disconnection detection circuit 406 may be comparator-based circuits to detect a hot unplug event based on a comparison of the slew rate and the voltage on the supply line 408 to respective thresholds.

[0115] The slew rate detection circuit 404 can detect the voltage V bus received and configured to determine the slew rate of the voltage and to perform a comparison with a reference voltage representing the slew rate threshold. The slew rate detection circuit 404 may include a differentiator 412 configured to determine the slew rate of the voltage V busTo feed the differentiator 412, the slew rate detection circuit 404 may include a voltage divider 414 having a first resistor 416 (e.g., 90 kΩ) and a second resistor 418 (e.g., 5 kΩ) configured to provide an output voltage (at an output node) that is a fraction of the input voltage V bus The output voltage of the voltage divider 414 can be supplied to an operational amplifier 420 with negative feedback. The negative feedback can ensure that the voltage at the output of the operational amplifier 420 closely follows the voltage at the input of the operational amplifier 420, thereby ensuring stable and reliable determination of the slew rate.

[0116] The output voltage of the operational amplifier 420 can be supplied to the differentiator 412 (e.g., via a third resistor 422). In an exemplary configuration, the differentiator 412 can be an operational amplifier differentiator. Illustratively, the differentiator 412 can be configured such that the voltage output of the differentiator represents a time rate of change of the input voltage of the differentiator 412. In the exemplary configuration in Fig. 4A, the differentiator 412 may include a first capacitor 424 (e.g., having a capacitance of 0.01 µF) coupled to the inverting terminal of an operational amplifier 426. The non-inverting terminal of the operational amplifier 426 may be connected to a reference potential, e.g., ground. The output of the operational amplifier 426 may be coupled to the non-inverting terminal, e.g., via a path including a second capacitor 428 (e.g., having a capacitance of 10 pF) and a fourth resistor 430 (e.g., 151.5 kΩ).

[0117] The output of the differentiator 412 (illustratively, the output of the amplifier 426) may be provided to a comparator 432. In an example implementation, the comparator 432 may be an operational amplifier, and the output of the differentiator 412 may be provided to the non-inverting terminal of the operational amplifier. The slew rate detection circuit 404 may be configured to provide a reference voltage to the inverting terminal of the amplifier, and the reference voltage may represent the slew rate threshold. For example, the slew rate detection circuit 404 may include a voltage source that provides the reference voltage to the inverting terminal of the amplifier (e.g., via a fifth resistor 434).The comparator 432 may compare the slew rate of the voltage on the supply line 408 with the reference voltage and provide an output signal indicating whether the slew rate is greater than the slew rate threshold.

[0118] The disconnection detection circuit 406 may include a comparator 436 configured to determine the voltage value of V bus to compare with a reference voltage (representing the voltage threshold). As an example implementation, comparator 436 may be an operational amplifier, and the voltage of supply line 408 may be supplied to the inverting terminal of the operational amplifier (e.g., via a sixth resistor 438, for example, with a resistance of 90 kSZ).

[0119] The disconnection detection circuit 406 may further include a peak hold and ratiometric circuit 440. The peak hold and ratiometric circuit 440 may include a capacitor 442 to store a peak value of the voltage on the supply line 408. For example, the peak hold and ratiometric circuit 440 may be coupled to the supply line 408, e.g., via a first diode 446 and a second diode 448. The peak hold and ratiometric circuit 440 may further include a voltage divider consisting of a seventh resistor 450 (e.g., 100 kΩ) and an eighth resistor 452 (e.g., 10.5 kΩ). The voltage divider may be connected in parallel with the capacitor 442 to provide a reference voltage corresponding to a fraction of the stored peak value to the non-inverting terminal of the comparator 436. The peak hold and ratiometric circuit 440 may further include a ninth resistor 454 (e.g.10 kΩ) connected to the non-inverting terminal of comparator 436.

[0120] For illustrative purposes, the operation of the disconnection detection circuit 406 can be described as follows. Initially, the output of comparator 436 is low (and also the output of comparator 432 of the slew rate detection circuit 404). The ratiometric comparator operates by comparing two versions of V bus A first version is fed to the inverting terminal of comparator 436 (via the sixth resistor 438) and drops immediately as soon as a disconnection event occurs. The second version of V bus does not drop immediately because it is held by capacitor 442 when an interruption has occurred. When the first version of V busby a certain ratio to its original value (represented by the peak value stored by capacitor 442), the comparator output is triggered and goes high. When the outputs of both comparator 432 of slew rate detection circuit 404 and comparator 436 of disconnection detection circuit 406 are high by pull-up on a tenth resistor 456 (e.g., 10 kΩ), the sink switch is deactivated to stop the arc.

[0121] Fig. Figure 4B shows a diagram 450b illustrating the simulation results at a slew rate of -31 mV / µs at EPR 48 V. The proposed method deactivates the switch in 120 µs and the maximum voltage between the contact pins of the plug and the socket is limited to less than 8.8 V (50.4 V - 41.59 V), which is less than 12 V to trigger an arc. Fig. Figure 4C shows a graph 450c illustrating the simulation results at a slew rate of -30 mV / µs under EPR conditions. It can be observed that the proposed method effectively detects 30 mV / µs during normal operation with -30 mV / µs as the slew rate of PPS or AVS and does not disable the sink switch during normal operation.

[0122] The proposed method can reduce the total capacitance on the drain side to mitigate arcing. It is estimated that when the total capacitance of the drain is less than 33 µF, the proposed method eliminates connector damage due to arcing for all load current ranges up to 5 A for both EPR and SPR scenarios.

[0123] In general, the aspects described with respect to the strategy proposed herein may be implemented using a generic processor, illustratively a generic processing means (e.g., a generic processing circuit). The processor may be arranged to perform the various functions described above with respect to the monitoring circuit, the controller, etc.

[0124] In this context, Fig.5 illustrates a computer system 500 for monitoring the voltage on a utility line and prompting corrective action in the event of a hot unplug event, in accordance with the present disclosure. The computer system includes a processor 502 coupled to a memory 504. The memory 504 may store instructions and data for operation of the processor 502. Illustratively, the processor 502 and the memory 504 may be communicatively coupled, and the processor 502 may be configured to execute instructions or commands stored in the memory 504. The instructions / commands, when executed by the processor 502, may cause the processor 502 to perform detection of a hot unplug event according to the strategy described herein.Illustratively, the instructions may cause the processor 502 to perform a method 510 for monitoring the voltage on a power line and prompting corrective action in the event of a hot unplug event.

[0125] The processor 502 may be configured to determine (512) a voltage value of a voltage at an electrically conductive connection (e.g., a supply line) between a first terminal and a second terminal of a circuit. The first terminal may be connected (or be connected) to an input terminal to which a supply voltage is applied. For example, the input terminal may be a USB Type-C port. The second terminal may be connectable (or be connected) to an input of a current collector circuit, e.g., to an input of a voltage regulator (illustratively, to a load).

[0126] The processor 502 may be further configured to determine a slew rate of the voltage at the electrically conductive connection (514). For example, the processor 502 may be configured to perform a differentiation of the voltage at the electrically conductive connection to derive the rate of change of the voltage over time.

[0127] The processor 502 may be further configured to determine whether the determined voltage value meets a predetermined voltage criterion (e.g., whether the voltage value is less than a predetermined voltage threshold) and to determine whether the determined slew rate meets a predetermined slew rate criterion (e.g., whether an absolute value of the slew rate is greater than a predetermined slew rate threshold) (516).

[0128] The processor 502 may be further configured to transmit a control signal to deactivate the electrically conductive connection when the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion (518). For example, the processor 502 may be configured to transmit the control signal to a switch configured to selectively activate / deactivate the electrically conductive connection.

[0129] In the following, various examples are given which relate to the circuit 200, 300, 400, the computer system 500 and the method 510, wherein the examples which relate to the devices can also apply to the method in a corresponding manner and vice versa.

[0130] Example 1 is a circuit comprising: a first terminal connectable to an input terminal (e.g., a USB port), the first terminal configured to receive a supply voltage; a second terminal connectable to an input of a current collector circuit (e.g., a voltage regulator or a battery charging circuit); an electrically conductive connection configured to couple the first terminal to the second terminal; a switch configured to selectively activate or deactivate the electrically conductive connection between the first terminal and the second terminal; and a monitoring circuit configured to: determine a voltage at the electrically conductive connection; determine a slew rate of the voltage at the electrically conductive connection; determine whether the determined voltage meets a predetermined voltage criterion;Determining whether the determined slew rate meets a predetermined slew rate criterion; and sending a control signal to the switch when the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion, wherein the control signal is configured to control the switch to selectively deactivate the electrically conductive connection between the first terminal and the second terminal.

[0131] In Example 2, the circuit according to Example 1 can optionally further comprise that determining the voltage at the electrically conductive connection comprises determining a voltage value of the voltage at the electrically conductive connection; and that determining whether the determined voltage meets a predetermined voltage criterion comprises determining whether the determined voltage value is less than a voltage value threshold.

[0132] In Example 3, the circuit according to Example 1 or 2 may optionally further comprise that determining whether the determined slew rate satisfies a predetermined slew rate criterion comprises determining whether the determined slew rate is greater than a slew rate threshold.

[0133] In Example 4, the circuit according to Examples 2 and 3 may optionally further comprise sending a control signal to the switch when the determined voltage satisfies the predetermined voltage criterion and the determined slew rate satisfies the predetermined slew rate criterion, comprising sending the control signal when the determined voltage value is less than the voltage value threshold and the determined slew rate is greater than the slew rate threshold.

[0134] In Example 5, the circuit according to any one of Examples 1 to 4 may optionally further comprise that the control signal is configured to control the switch to selectively deactivate the electrically conductive connection between the first terminal and the second terminal for a predetermined period of time of more than 0 s.

[0135] In Example 6, the circuit according to Example 5 may optionally further comprise that the control signal comprises a pulse with a pulse width corresponding to the predetermined time period.

[0136] In Example 7, the circuit according to Example 6 may optionally further comprise that the monitoring circuit comprises a pulse generator configured to generate the pulse of the control signal in response to a signal indicating that the determined voltage satisfies the voltage criterion and the slew rate satisfies the slew rate criterion.

[0137] In Example 8, the circuit according to Example 7 can optionally further comprise that the signal is representative of the determined voltage value being less than the voltage value threshold and the determined slew rate being greater than a slew rate threshold.

[0138] In Example 9, the circuit according to any one of Examples 5 to 8 can optionally further comprise that the predetermined period of time is about 1 millisecond.

[0139] In Example 10, the circuit according to any one of Examples 1 to 9 can optionally further comprise that the monitoring circuit is configured to receive an indication of a negotiated voltage value for a supply voltage at the input terminal; and that the monitoring circuit is configured to set or change the voltage criterion as a function of the negotiated voltage value.

[0140] In Example 11, the circuit according to Example 10 may optionally further comprise that the monitoring circuit is configured to set or change the voltage value threshold as a function of the negotiated voltage value.

[0141] In Example 12, the circuit according to Example 11 may optionally further comprise that the monitoring circuit is configured to adjust or change the voltage value threshold such that the voltage value threshold corresponds to a sum of a predetermined percentage of the negotiated voltage value and a predetermined adjustment value.

[0142] In Example 13, the circuit according to any one of Examples 1 to 12 can optionally further comprise that the monitoring circuit is configured to receive an indication of a negotiated slew rate for a supply voltage at the input terminal; and that the monitoring circuit is configured to set or change the slew rate criterion as a function of the negotiated slew rate.

[0143] In Example 14, the circuit according to Example 13 can optionally further comprise that the monitoring circuit is configured to set or change the slew rate threshold as a function of the negotiated slew rate.

[0144] In Example 15, the circuit according to any one of Examples 1 to 14 may optionally further comprise that the monitoring circuit is configured to receive the voltage at the electrically conductive connection and to perform a differentiation of the received voltage to derive the slew rate of the voltage at the electrically conductive connection.

[0145] In Example 16, the circuit according to any one of Examples 3 to 15 may optionally further comprise that the monitoring circuit comprises a slew rate detection circuit configured to determine whether the slew rate of the voltage at the electrically conductive connection is greater than the slew rate threshold.

[0146] In Example 17, the circuit according to Example 16 can optionally further comprise that the slew rate detection circuit comprises: a differentiator configured to receive a voltage corresponding to the voltage at the electrically conductive connection and to provide a first output signal representing a rate of change over time of the voltage at the electrically conductive connection; and a comparator configured to compare the first output voltage with a reference voltage representing the slew rate threshold, wherein the comparator is further configured to provide a second output signal representing a result of the comparison.

[0147] In Example 18, the circuit according to Example 17 may optionally further comprise that the differentiator is a practical differentiator circuit based on an operational amplifier.

[0148] In Example 19, the circuit according to any one of Examples 2 to 18 may optionally further comprise that the monitoring circuit comprises a disconnection detection circuit configured to determine whether the voltage value of the voltage at the electrically conductive connection is below the voltage value threshold.

[0149] In Example 20, the circuit according to Example 19 can optionally further comprise that the disconnection detection circuit is configured to: determine a ratio between a peak value of the voltage at the electrically conductive connection and a predetermined voltage value; use the determined ratio as a reference value representing the voltage value threshold; and compare the voltage value of the voltage at the electrically conductive connection with the reference value.

[0150] In Example 21, the circuit of Example 20 may optionally further comprise that the predetermined voltage value is a predetermined fraction of a negotiated voltage value for a power supply of the input terminal

[0151] In Example 22, the circuit according to Example 20 or 21 may optionally further comprise that the disconnection detection circuit comprises a peak hold circuit configured to hold a peak value of the voltage at the electrically conductive connection.

[0152] In Example 23, the circuit according to Example 22 can optionally further comprise that the disconnection detection circuit comprises a voltage divider configured to provide a voltage at an output node that corresponds to a fraction of the peak value of the voltage at the electrically conductive connection.

[0153] In Example 24, the circuit according to any one of Examples 19 to 23 may optionally further comprise that the disconnection detection circuit comprises a comparator configured to compare the voltage value of the voltage at the electrically conductive connection with the reference value and to provide an output voltage representing a result of the comparison.

[0154] In Example 25, the circuit according to Example 23 or 24 may optionally further comprise that the comparator is coupled to the output node of the voltage divider.

[0155] In Example 26, the circuit according to any one of Examples 1 to 25 may optionally further comprise that the monitoring circuit is electrically conductively coupled to the electrically conductive connection.

[0156] In Example 27, the circuit according to any one of Examples 1 to 26 can optionally further comprise that the circuit has the input terminal, and that the input terminal is a USB port.

[0157] In Example 28, the circuit according to Example 27 can optionally further comprise that the input port is a USB Type-C port.

[0158] In Example 29, the circuit according to any one of Examples 1 to 28 may optionally further comprise that the switch comprises a transistor (eg, a MOSFET), and that the monitoring circuit is configured to supply the control signal to a gate terminal of the transistor.

[0159] In example 30, the circuit according to any one of examples 1 to 29 may optionally further comprise a backup capacitor connected to the electrically conductive connection; and that the monitoring circuit is configured to adjust the slew rate criterion as a function of a capacitance value of the backup capacitor.

[0160] In Example 31, the circuit according to Example 30 may optionally further comprise that the monitoring circuit is configured to adjust the slew rate threshold value depending on a capacitance value of the backup capacitor.

[0161] In Example 32, the circuit according to any one of Examples 1 to 31 can optionally further comprise that the fulfillment of the voltage criterion from the determined voltage and the fulfillment of the slew rate criterion from the determined slew rate are representative of a hot unplug event at the input port (e.g., a hot unplug of a USB adapter from the USB port).

[0162] In Example 33, the circuit according to Example 32 can optionally further comprise that the fact that the determined voltage is less than the voltage value threshold and the determined slew rate is greater than the slew rate threshold is representative of a hot unplug event at the input port (e.g., a hot unplug of a USB adapter from the USB port).

[0163] Example 34 is a system comprising the circuit of any one of Examples 1 to 33; and a source device (e.g., a USB adapter) plugged into the input port.

[0164] Example 35 is a device comprising: a first terminal for coupling to an input terminal (e.g., a USB port) for receiving a (variable) supply voltage; a second terminal for coupling to an input of a current collector circuit (e.g.,a voltage regulator or a battery charging circuit); a supply line connecting the first terminal and the second terminal; a switch for selectively activating or deactivating the supply line; and processing means for: determining a voltage on the supply line; determining a slew rate of the voltage on the supply line; determining whether the determined voltage meets a predetermined voltage criterion; determining whether the determined slew rate meets a predetermined slew rate criterion; and transmitting a control signal to the switch to deactivate the supply line if the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion.

[0165] In Example 36, the device of Example 35 may further include one or more features of any of Examples 1 to 33.

[0166] Example 37 is a computer system including a processor coupled to a memory, the memory configured to store instructions, the instructions, when executed by the processor, causing the processor to: determine a voltage at an electrically conductive connection between a first terminal and a second terminal, the first terminal connectable to an input terminal and configured to receive a supply voltage, the second terminal connectable to an input of a current collector circuit (e.g., a voltage regulator or a battery charging circuit); determine a slew rate of the voltage at the electrically conductive connection; determine whether the determined voltage value meets a predetermined voltage criterion (e.g.,B, determine whether the determined voltage value is less than a predetermined voltage threshold value); determine whether the determined slew rate meets a predetermined slew rate criterion (e.g., whether an absolute value of the slew rate is greater than a predetermined slew rate threshold value); and transmit a control signal to deactivate the electrically conductive connection if the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion.

[0167] In Example 38, the computer system of Example 37 may further include one or more features of any of Examples 1 to 33.

[0168] Example 39 is a method for controlling an electrically conductive connection, the method comprising: determining a voltage at an electrically conductive connection between a first terminal and a second terminal, the first terminal being connectable to an input terminal for receiving a (variable) supply voltage and the second terminal being connectable to an input of a current collector circuit (e.g.a voltage regulator or battery charging circuit); determining a voltage and a slew rate of the voltage at the electrically conductive connection; determining whether the determined voltage meets a predetermined voltage criterion; determining whether the determined slew rate meets a predetermined slew rate criterion; and deactivating the electrically conductive connection (to decouple the first terminal from the second terminal) if the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion.

[0169] In Example 40, the method of Example 39 can optionally further comprise that determining the voltage at the electrically conductive connection comprises determining a voltage value of the voltage at the electrically conductive connection; and that determining whether the determined voltage meets a predetermined voltage criterion comprises determining whether the determined voltage value is less than a voltage value threshold.

[0170] In example 41, the method of example 39 or 40 may optionally further comprise determining whether the determined slew rate satisfies a predetermined slew rate criterion comprising determining whether the determined slew rate is greater than a slew rate threshold.

[0171] In example 42, the method according to examples 40 and 41 may optionally further comprise deactivating the electrically conductive connection if the determined voltage satisfies the predetermined voltage criterion and the determined slew rate satisfies the predetermined slew rate criterion, comprising deactivating the electrically conductive connection if the determined voltage value is less than the voltage value threshold and the determined slew rate is greater than the slew rate threshold.

[0172] In example 43, the method according to any one of examples 39 to 43 can optionally further comprise deactivating the electrically conductive connection for a predetermined period of time greater than 0 s.

[0173] In Example 44, the method of Example 43 may optionally further include the predetermined period of time being about 1 millisecond.

[0174] In Example 45, the method of any of Examples 39 to 44 may optionally further comprise setting or changing the voltage criterion as a function of a negotiated voltage value for a supply voltage at the input terminal.

[0175] In Example 46, the method of Example 45 can optionally further comprise setting or changing the voltage value threshold as a function of a negotiated voltage value for a supply voltage at the input terminal.

[0176] In Example 47, the method of Example 46 may optionally further comprise setting or changing the voltage value threshold such that the voltage value threshold corresponds to a sum of a predetermined percentage of the negotiated voltage and a predetermined adjustment value.

[0177] In Example 48, the method of any of Examples 39 to 47 may optionally further comprise setting or changing the slew rate criterion as a function of a negotiated slew rate for a supply voltage at the input terminal.

[0178] In Example 49, the method of Example 48 may optionally further comprise setting or changing the slew rate threshold as a function of the negotiated slew rate.

[0179] In example 50, the method of any of examples 39 to 49 may optionally further comprise performing a differentiation of the received voltage to derive the slew rate of the voltage at the electrically conductive connection.

[0180] In Example 51, the method according to any one of Examples 39 to 50 can optionally further comprise determining a ratio between a peak value of the voltage at the electrically conductive connection and a predetermined voltage value; using the determined ratio as a reference value representing the voltage value threshold; and comparing the voltage value of the voltage at the electrically conductive connection with the reference value.

[0181] In Example 52, the method of Example 51 can optionally further include the predetermined voltage value being a predetermined fraction of a negotiated voltage value for a power supply of the input port.

[0182] In example 53, the method according to any one of examples 39 to 52 can optionally further comprise the input port being a USB port, e.g., a USB Type-C port.

[0183] In example 54, the method according to any one of examples 39 to 53 may optionally further comprise setting the slew rate criterion as a function of a capacitance value of a backup capacitor.

[0184] In example 55, the method according to example 54 may optionally further comprise setting the slew rate threshold value depending on a capacitance value of the backup capacitor.

[0185] In example 56, the method according to any one of examples 39 to 55 can optionally further comprise that the fulfillment of the voltage criterion from the determined voltage and the fulfillment of the slew rate criterion from the determined slew rate are representative of a hot unplug event at the input port (e.g., a hot unplug of a USB adapter from the USB port).

[0186] In example 57, the method according to example 56 can optionally further comprise that the fact that the determined voltage is less than the voltage value threshold and the determined slew rate is greater than the slew rate threshold is representative of a hot unplug event at the input port (e.g., a hot unplug of a USB adapter from the USB port).

[0187] Example 58 is a computer program product (e.g., a non-transitory computer-readable medium) comprising instructions that, when executed by a computer, cause the computer to perform the method of any of Examples 39 to 57.

[0188] The term "processor" as used herein can be understood as any type of technical unit that enables the processing of data. The data can be processed according to one or more specific functions that the processor can perform. Furthermore, a processor as used herein can be understood as any type of circuit, e.g. any type of analog or digital circuit. A processor can therefore be an analog circuit, a digital circuit, a mixed-signal circuit, a logic circuit (e.g., a hard-wired logic circuit or a programmable logic circuit), a microprocessor (e.g.a CISC (Complex Instruction Set Computer) processor or a RISC (Reduced Instruction Set Computer) processor), a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), an integrated circuit, an ASIC (Application Specific Integrated Circuit), etc., or any combination thereof. A "processor" can also be a logic-implementing unit that executes software, e.g., any kind of computer program, e.g., a computer program that uses virtual machine code such as Java. Any other way of implementing the respective functions can also be understood as a processor.It is understood that two (or more) of the processors described herein may be implemented as a single unit with equivalent functionality or the like, and conversely, that a single processor described herein may be implemented as two (or more) separate units with equivalent functionality or the like.

[0189] As used herein, the term "system" can be understood as a set of interacting elements, where the elements can be, by way of example and without limitation, one or more physical components (e.g., processors, transmitters, and / or receivers) and / or one or more digital components (e.g., code segments, instructions, protocols). In general, the system can have one or more operable functions (also referred to as "operational functions"), each of which can be controlled for the operation of the entire system.

[0190] The term "memory" as used herein can be understood as a computer-readable medium (e.g., a non-transitory computer-readable medium) in which data or information can be stored for retrieval. References herein to "memory" can therefore be understood to refer to volatile or non-volatile memory, including random access memory (RAM), read-only memory (ROM), flash memory, solid-state memory, magnetic tape, hard disk drive, optical drive, 3D XPoint™, and others, or any combination thereof. In addition, registers, shift registers, processor registers, data buffers, and others are also subsumed herein under the term memory. A single component referred to as "memory" or "a memory" may consist of more than one different type of memory and thus refer to an overall component that has one or more types of memory.

[0191] The term “software” refers to all types of executable instructions, including firmware.

[0192] The term "communicate" or "communication" encompasses both sending and receiving, i.e., unidirectional or bidirectional communication in one or both directions, i.e., inbound and outbound. In general, the term "communicate" can encompass the exchange of data, e.g., a unidirectional or bidirectional exchange in one or both directions, i.e., inbound and outbound.

[0193] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs.

[0194] The terms "at least one" and "one or more" may be understood to have a numerical quantity greater than or equal to one (e.g., one, two, three, four, [...], etc.). The phrase "at least one of" with respect to a group of elements may be used herein to mean at least one element from the group of elements. For example, the phrase "at least one of" with respect to a group of elements may be used herein to mean a selection of: one of the listed elements, a plurality of one of the listed elements, a plurality of individual listed elements, or a plurality of a multiple of individual listed elements.

[0195] It is understood that implementations of the methods described herein are demonstrative in nature and may therefore be implemented in a corresponding device. Likewise, it is contemplated that implementations of devices described herein may be implemented as a corresponding method. It is understood that a device corresponding to a method described herein may include one or more components configured to perform each aspect of the corresponding method.

[0196] All acronyms defined in the above description also apply to all claims contained herein.

[0197] While various implementations have been particularly shown and described with reference to specific aspects, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope as defined by the appended claims. The scope is thus indicated by the appended claims, and all changes which come within the meaning and range of equivalence of the claims are therefore intended to be embraced.

Claims

[1] A circuit (200) comprising: a first terminal (202) connectable to an input terminal (206), the first terminal (202) being configured to receive a supply voltage; a second terminal (204) connectable to an input of a current collector circuit (230); an electrically conductive connection (212) configured to couple the first terminal (202) to the second terminal (204); a switch (214) configured to selectively activate or deactivate the electrically conductive connection (212) between the first terminal (202) and the second terminal (204); and a monitoring circuit (220) which is arranged to: Determining a voltage at the electrically conductive connection (212); Determining a slew rate of the voltage at the electrically conductive connection (212); Determine whether the measured voltage meets a predetermined voltage criterion; Determining whether the determined slew rate meets a predetermined slew rate criterion; and Sending a control signal to the switch (214) when the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion, wherein the control signal is configured to control the switch (214) to selectively deactivate the electrically conductive connection (212) between the first terminal (202) and the second terminal (204). [2] Circuit (200) according to claim 1, wherein determining the voltage at the electrically conductive connection (212) comprises determining a voltage value of the voltage at the electrically conductive connection (212); wherein determining whether the determined voltage satisfies a predetermined voltage criterion comprises determining whether the determined voltage value is less than a voltage value threshold; and wherein determining whether the determined slew rate satisfies a predetermined slew rate criterion comprises determining whether the determined slew rate is greater than a slew rate threshold. [3] The circuit (200) of claim 2, wherein sending a control signal to the switch (214) when the determined voltage satisfies the predetermined voltage criterion and the determined slew rate satisfies the predetermined slew rate criterion comprises sending the control signal when the determined voltage value is less than the voltage value threshold and the determined slew rate is greater than the slew rate threshold. [4] Circuit (200) according to one of claims 1 to 3, wherein the monitoring circuit (220) is configured to receive an indication of a negotiated voltage value for a supply voltage at the input terminal (206); and wherein the monitoring circuit (220) is arranged to set or change the voltage criterion as a function of the negotiated voltage value. [5] Circuit (200) according to claim 4, wherein the monitoring circuit (220) is configured to set or change the voltage value threshold as a function of the negotiated voltage value; and wherein the monitoring circuit (220) is configured to set or change the voltage value threshold such that the voltage value threshold corresponds to a sum of a predetermined percentage of the negotiated voltage value and a predetermined adjustment value. [6] Circuit (200) according to one of claims 1 to 5, wherein the monitoring circuit (220) is arranged to receive an indication of a negotiated slew rate for a supply voltage at the input terminal (206); and wherein the monitoring circuit (220) is configured to set or change the slew rate criterion as a function of the negotiated slew rate. [7] The circuit (200) of any one of claims 1 to 6, wherein the monitoring circuit (220) is configured to receive the voltage at the electrically conductive connection (212) and to perform a differentiation of the received voltage to derive the slew rate of the voltage at the electrically conductive connection (212). [8] Circuit (200) according to one of claims 1 to 7, wherein the circuit (200) has the input terminal (206), and wherein the input connector (206) is a USB Type-C connector. [9] The circuit (200) of any one of claims 1 to 8, wherein the voltage criterion being met by the determined voltage and the slew rate criterion being met by the determined slew rate are representative of a hot unplug event at the input terminal (206). [10] A computer system (500) comprising a processor (502) coupled to a memory (504), the memory (504) being configured to store instructions, the instructions, when executed by the processor (502), causing the processor (502) to: Determining (512) a voltage at an electrically conductive connection between a first terminal and a second terminal, wherein the first terminal is connectable to an input terminal and is configured to receive a supply voltage, wherein the second terminal is connectable to an input of a current collector circuit; Determining (514) a slew rate of the voltage at the electrically conductive connection; Determining (516) whether the determined voltage value meets a predetermined voltage criterion; Determining (516) whether the determined slew rate meets a predetermined slew rate criterion; and Sending (518) a control signal to block the electrically conductive connection when the determined voltage meets the predetermined voltage criterion and the determined slew rate meets the predetermined slew rate criterion.

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