ONE ESD SELF-PROTECT METHOD FOR CONNECTOR

A system and method for efficient methods and systems for input/output port protection from electrostatic discharge events are described. In various implementations, an integrated circuit mounted on a printed circuit board includes a connector port that uses a first signal pin within a metal shell mounted on the printed circuit board and is electrically connected to a ground reference. The first signal pin is electrically connected to the ground reference though a spring pin located between itself and the shell. A user inserts a head contact of a cable into the connector port. The head contact includes a second signal pin that is floating, but becomes connected to the ground reference when brought into physical contact with the first signal pin. During later insertion, the head contact pushes the spring pin causing physical disconnection of the spring pin from the first signal pin allowing data transmission to begin.

BACKGROUND

Description of the Relevant Art

When two nodes have a different electrical potential, such as different electrical charge accumulation, and the two nodes are electrically connected, an electrostatic discharge (ESD) occurs. Current flows and seeks a low impedance path from the higher potential node to a ground reference voltage level. In one example, a user inserts a head contact of a cable into a connector port of an input/output interface of a computing system, and it is possible that electrical charge had accumulated on the skin, which causes the electrostatic discharge event. The circuitry of ESD protection components are used to provide a lowest impedance path to the ground reference voltage level, which protect circuits of an input/output interface and one or more functional blocks of an integrated circuit connected to the input/output interface. These ESD protection components are located near the input/output interface of the integrated circuit. However, as signal rates increase through the input/output interface, these ESD protection components increase transmission line loss and reduce signal integrity. It is desired to have a method to both provide ESD protection for circuit nodes without introducing insertion loss.

In view of the above, efficient methods and systems for input/output (I/O) port protection from electrostatic discharge events are desired.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, one having ordinary skill in the art should recognize that the invention might be practiced without these specific details. In some instances, well-known circuits, structures, and techniques have not been shown in detail to avoid obscuring the present invention. Further, it will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements.

Systems and methods for efficiently providing input/output port protection from electrostatic discharge events are contemplated. In various implementations, an integrated circuit mounted on a printed circuit board includes one or more functional blocks. The integrated circuit also includes an input/output interface with a connector port that communicates with a peripheral device through a link between the peripheral device and the connector port. The link includes a head contact of a cable that is inserted into the connector port by a user. The connector port uses multiple signal pins within a metal shell mounted on the printed circuit board. The multiple signal pins are connected to one or more of the functional blocks of the integrated circuit. The shell is electrically connected to a ground reference voltage level of the printed circuit board. At least a first signal pin of the multiple signal pins is electrically connected to the ground reference voltage level though a spring pin located between the shell and the first signal pin. Therefore, the first signal pin is not floating.

A user inserts the head contact of the cable into the connector port. The head contact of the cable is associated with a display connector, a Universal Serial Bus (USB) link, or other. The head contact includes multiple signal pins including a second signal pin that is floating. As the user inserts the head contact into the connector port, the second signal pin becomes physically connected to the first signal pin. As a result, the second signal pin is set to the ground reference voltage level and is no longer floating. If there is a difference in electrical potential between the first signal pin and the second signal pin, an electrostatic discharge occurs, and the corresponding current flows through the low impedance path provided by the first signal pin, the spring pin, and the shell connected to the ground reference voltage level. For example, as the second signal pin becomes physically connected to the first signal pin, if the second signal pin has a non-zero electrical potential, whereas, the first signal pin has the ground reference voltage level, then there is a difference in electrical potential that causes the electrostatic discharge to occur. The use of the spring pin provides ESD protection, though.

As the user continues to insert the head contact into the connector port, the head contact is configured to push the spring pin causing physical disconnection of the spring pin from the first signal pin. As a result, the first signal pin is disconnected from the metal shell of the connector port, and each of the first signal pin and the second signal pin remains at a same electrical potential. By being at the same electrical potential, a further electrostatic discharge is unable to occur. At this point in time, the head contact is fully inserted into the connector port, and each of the first signal pin and the second signal pin is available for transmitting data. In some implementations, the functional block that receives the first signal pin does not include electrostatic discharge protection circuitry.

Turning now toFIG.1, a generalized block diagram is shown of a computing system100. Computing system100includes at least one processing node110that is connected to peripheral devices170-172through links180-182. Processing node110includes communication fabric140, clients120, memory subsystem130, and interface (IF) units150and160. In some implementations, the components of processing node110are individual dies on an integrated circuit (IC), such as a system-on-a-chip (SOC). In other implementations, the components are individual dies in a system-in-package (SiP) or a multi-chip module (MCM), or semiconductor chips on a motherboard or card. This implementation does not include all examples of functional blocks, control logic, and interfaces required both within and outside processing node110. In other implementations, computing system100includes two or more processing nodes110. The implementation shown is for a simple illustrative purpose.

In the illustrated implementation, clients120include multiple processing units122-124. Examples of processing units122-124are a central processing unit (CPU) with circuitry used for processing instructions of a selected instruction set architecture (ISA), a graphics processing unit (GPU) with circuitry that implements a high parallel data microarchitecture, a Hub used for communicating with multimedia engine, and a multimedia engine with circuitry that processes audio data and visual data for multimedia applications. In another implementation, examples of the processing units122-124include one or more application specific integrated circuits (ASICs) or microcontrollers, one or more digital signal processors (DSPs), analog-to-digital converters (ADCs), and digital-to-analog converters (DACs). Other data processing semiconductor chip designs included within clients120are possible and contemplated. Further, physically, in other implementations, one or more of these data processing designs are implemented outside of processing unit110for interfacing reasons, on-die routing and signal integrity reasons, or other reasons.

In some implementations, a cache memory subsystem is implemented as a L1cache structure integrated within one or more of the processing units122-124that stores blocks of data. Memory subsystem130is implemented as a L2or L3cache structure and is directly coupled to clients120. In various implementations, communication fabric140transfers data back and forth between clients120, memory subsystem130, and other external devices via the IF units150-160. The data being transferred through fabric450includes data such as commands, messages, probes, interrupts, and data corresponding to the commands and messages. Interface units150-160include circuitry to receive packets and synchronize the packets to an internal clock used by the processing node110.

Processing node110is coupled to one or more peripheral devices170-172. Depending on the implementation of processing node110, peripheral devices170-172include one or more of portable storage devices, display screens, gamepads, smartphones, personal data assistants (PDAs), portable audio/video players, cameras, or other. The peripheral devices170-172consist of several logical sub-devices that are referred to as device functions. A single peripheral device is capable of providing several functions. For example, a portable DVD player has both a video device function and built-in speakers, which is an audio device function. Other devices are contemplated to also be within the scope of the present invention. The specific type of peripheral used does not limit the invention.

As shown, the interface unit150includes connector ports152-154. One or more of the links182-184are a cable with a head contact that inserts into a corresponding one of the connector ports152-154. The links182-184and the connector ports152-154support data transfer and a communication protocol based on the type of a corresponding one of the peripheral devices170-172. For example, the link180and the connector port152support the communication protocol of a serial data communications of a Universal Serial Bus (USB) when the peripheral device170is a USB device. Similarly, the link182and the connector port154support the communication protocol for transferring video data when the peripheral device172is a display screen or monitor. In such cases, the link182and the connector port154support the DisplayPort (DP) specification, the High-Definition Multimedia Interface (HDMI) specification, or other.

The peripheral devices170-172, the links182-184and the connector ports152-154typically operate at relatively low voltage levels. Should an overvoltage event occur, then it is possible that one or more of the connector ports152-154and the head contact of a cable of the links182-184becomes permanently damaged. As described earlier, the link182includes a head contact of a cable that is inserted into the connector port154by a user. The connector port154uses multiple signal pins within a metal shell mounted on a printed circuit board. The multiple signal pins are connected to circuitry of the interface unit150, which sends the corresponding data to clients120through the communication fabric140.

The metal shell of the connector port154is electrically connected to a ground reference voltage level of the printed circuit board. At least one signal pin of the multiple signal pins is electrically connected to the ground reference voltage level though the spring pin155located between the shell and the first signal pin. Therefore, this signal pin is not floating. As the head contact of the cable of the link182is inserted by the user, the spring pin155a signal pin of the head contact physically connects to the signal pin of the connector port154and becomes electrically shorted to the ground reference voltage level. Shortly afterwards, the spring pins disconnects from the signal pin of the connector port154. Since the two signal pins are at a same electrical potential, such as the ground reference voltage level, no electrostatic discharge occurs. In various implementations, the connector port152also includes at least one spring pin153to prevent a corresponding signal pin from being a floating signal.

Referring toFIG.2, a generalized block diagram is shown of a printed circuit board200. The printed circuit board220is representative of one of a variety of printed circuit boards and cards used in a computing system. The connector port210is one example of multiple connector ports placed on the printed circuit board220. The metal shell of the connector port210is electrically connected to a ground reference voltage level of the printed circuit board220.

Turning now toFIG.3, a generalized block diagram is shown of an input/output interface300. The metal shell of a connector port310is shown without the printed circuit board or card for ease of illustration. Inside the connector port310are multiple signal pins used to transfer data based on a particular communication protocol. The head contact320and the cable330provide a link between the connector port310and a peripheral device (not shown). Similar to the connector port310, the head contact320also includes multiple signal pins used to transfer data based on a particular communication protocol. A user inserts the head contact320into the connector port310when connecting the peripheral device to a computing system. The metal shell of the connector port310is electrically connected to a ground reference voltage level of the printed circuit board. At least one signal pin of the multiple signal pins of the connector port310is electrically connected to the ground reference voltage level though a spring pin inside the connector port310. The spring pin is located between the metal shell and the signal pin. Therefore, this signal pin is not floating. In some implementations, each of the signal pins of the connector port310has a corresponding spring pin.

Referring toFIG.4, a generalized block diagram is shown of an input/output interface400. Components, structures, and circuits described earlier are numbered identically. The input/output interface400includes the head contact320being partially inserted in the connector port310. The connector port310includes the metal shell414that is connected to the ground reference voltage level of the printed circuit board (not shown). The connector port also includes at least the signal pin410. Although a single signal pin is shown, the connector port310includes any number of signal pins in various implementations. The remainder of the connector port is a body used for physical support and electrical isolation for the signal pins. For example, one of a variety of types of plastics is used.

The connector port310additionally includes the spring pin412. Similar to the signal pin410, although a single signal pin is shown, the connector port310includes any number of spring pins in various implementations. For example, in an implementation, each signal pin of the connector port310has a corresponding spring pin. The spring pin412is physically connected to each of the metal shell414and the signal pin410. Since the spring pin412conducts, the signal pin410is electrically connected to the ground reference voltage level of the printed circuit board through the spring pin412and the metal shell414. Therefore, the signal pin410is not floating.

The head contact320also has a signal pin420. It is possible and contemplated that the head contact320has a same number of signal pins as the connector port310. In contrast to the signal pin410, there is no spring pin used with the signal pin420of the head contact320. Therefore, the signal pin420is a floating signal. In some implementations, the signal pins410and420use copper metal or a mixture of copper and other conductive metals. The spring pin412uses stainless steel. In one implementation, the spring pin412uses the Society of Automotive Engineers (SAE) steel grade304, which is equivalent to the Asian steel grade of SUS 304. As shown, the head contact320is partially inserted in the connector port310, and the signal pin420has not yet made physical contact with the signal pin410.

Referring toFIG.5, a generalized block diagram is shown of an input/output interface500. Components, structures, and circuits described earlier are numbered identically (as well as forFIGS.6-8). The input/output interface500includes the head contact320being partially inserted in the connector port310. The signal pin420has not yet made physical contact with the signal pin410. In this view, it is shown that connector port310also includes the signal pin510below signal pin410. The signal pin510is physically disconnected from the signal pin410. Therefore, the signal pin510is able to transfer separate data than data being transferred by signal pin410. Likewise, the head contact320also includes the signal pin520below the signal pin420. When physically connected and data transmission has begun, the signal pin420of the head contact320transfers data with the signal pin410of the connector port310. Similarly, the signal pin520of the head contact320is able to transfer data with the signal pin510of the connector port310.

The connector port310also includes the spring pin512. The spring pin512is equivalent to the spring pin412. For example, the spring pin512is physically connected to each of the metal shell414and the signal pin510. Since the spring pin512conducts, the signal pin510is electrically connected to the ground reference voltage level of the printed circuit board through the spring pin512and the metal shell414. Therefore, the signal pin510is not floating.

Turning now toFIG.6, a generalized block diagram is shown of an input/output interface600. The input/output interface600includes the head contact320being further inserted in the connector port310. For example, the signal pins of the head contact320and the connector port310are able to be physically connected to one another.

Referring toFIG.7, a generalized block diagram is shown of an input/output interface700. The input/output interface700includes the head contact320being more fully inserted in the connector port310. The signal pin420has made physical contact with the signal pin410. Similarly, the signal pin520has made physical contact with the signal pin510. As a result, the signal pin420is electrically connected to the ground reference voltage level of the printed circuit board through the signal pin410, the spring pin412, and the metal shell414. The signal pin420is no longer floating. Similarly, the signal pin520is electrically connected to the ground reference voltage level of the printed circuit board through the signal pin510, the spring pin512, and the metal shell414. The signal pin520is no longer floating.

Referring toFIG.8, a generalized block diagram is shown of an input/output interface800. The input/output interface800includes the head contact320being fully inserted in the connector port310. The signal pin420has made physical contact with the signal pin410, and the body or housing of the head contact320has pushed the spring pin412causing the spring pin412to be physically disconnected from the signal pin410. Therefore, each of the signal pins410and420is at a same electrical potential, but is no longer electrically connected to the metal shell414. Similarly, the body or housing of the head contact320has pushed the spring pin512causing the spring pin512to be physically disconnected from the signal pin510. The dashed box shows an opening in the housing of the connector port, which allows a view of the spring pin512being physically disconnected from the signal pin510. Therefore, the signal pins510and520are set at a same electrical potential as a corresponding one of the signal pins410and412, but is no longer electrically connected to the metal shell414. At this point in time, each of the signal pins,410,420,510and520is available for transmitting data. In some implementations, one or more of the interface unit and functional blocks in a chip on the printed circuit that transmits data with the signal pins410and510do not include electrostatic discharge protection circuitry. Therefore, the data transmission loss is not reduced and significantly high data rates are achieved.

FIG.9is a generalized diagram of one implementation of a method900for efficiently providing input/output port protection from electrostatic discharge events. For purposes of discussion, the steps in this implementation (as well as inFIG.10) are shown in sequential order. However, in other implementations some steps occur in a different order than shown, some steps are performed concurrently, some steps are combined with other steps, and some steps are absent.

A voltage level of a shielding (or metal shell) of a connector port is set to a ground reference voltage level of a computing system (block902). For example, the connector port is embedded in an edge of the printed circuit board and a ground reference voltage level is routed to the shielding of the connector port. A voltage level of a first signal pin of the connector port is set to the ground reference voltage level via a spring pin between the shielding and the first signal pin (block904). A user inserts, into the connector port, a head contact of a cable with a second signal pin that is floating (block906). For example, the head contact and the cable are a link between the connector port and a peripheral device. The link is used to connect a display monitor, a Universal Serial Bus (USB) data storage device, or other.

If the second signal pin does not physically connect to the first signal pin (“no” branch of the conditional block908), then the second signal pin of the head contact remains as a floating signal (block910), and control flow of method900returns to conditional block908. However, if the second signal pin becomes physically connected to the first signal pin (“yes” branch of the conditional block908), then the first signal pin sets a voltage level of the second signal pin to the ground reference voltage level (block912.) For example, due to the physical connection with the first signal pin, the second signal pin is electrically connected to the ground reference voltage level of the printed circuit board through the first signal pin, the spring pin, and the metal shell shielding of the connector port.

If the body or housing of the head contact does not push the spring pin causing physical disconnection from the first signal pin (“no” branch of the conditional block914), then control flow of method900returns to block912where the first signal pin sets the voltage level of the second signal pin to the ground reference voltage level. Otherwise, if the body or housing of the head contact pushes the spring pin causing physical disconnection from the first signal pin (“yes” branch of the conditional block914), then each of the first signal pin and the second signal pin remains at the ground reference voltage level until data is transmitted (block916).

FIG.10is a generalized diagram of one implementation of a method1000for efficiently providing input/output port protection from electrostatic discharge events. Data is transmitted between a first signal pin of a connector port and a second signal pin of a head contact of a cable (block1002). For example, an external peripheral device transfers data with a processing unit on a printed circuit board or card. Examples of the peripheral device are a display monitor, a USB device, or other. The connector port and the head contact have signal pins that transfer the data while interface circuitry supports the corresponding communication protocol. In various implementations, the interface circuitry does not include electrostatic discharge protection circuitry, which allows higher data rates to be achieved.

If a user does not begin removing the head contact from the connector port (“no” branch of the conditional block1004), then control flow of method1000returns to block1002where the head contact and the connector port transfer data between using their signal pins. However, if the user begins removing the head contact from the connector port (“yes” branch of the conditional block1004), then the head contact releases pressure on a spring pin of the connector port (block1006). If the release of pressure does not allow the spring pin to physically contact the first signal pin (“no” branch of the conditional block1008), then control flow of method1000returns to the block1006where the head contact releases pressure on the spring pin of the connector port. Otherwise, if the release of pressure does allow the spring pin to physically contact the first signal pin (“yes” branch of the conditional block1008), then the spring pin sets a voltage level of each of the first signal pin and the second signal pin to the ground reference voltage level (block1012). For example, the spring pin is now physically connected to each of the first signal pin and the metal shielding of the connector port. The metal shielding of the connector port is physically connected to a route on the printed circuit board that is electrically connected to the ground reference voltage level.

If the removal of the head contact has not yet caused physical connection to be removed between the first signal pin and the second signal pin (“no” branch of the conditional block1014), then control flow of method1000returns to the block1012where the spring pin sets the voltage level of each of the first signal pin and the second signal pin to the ground reference voltage level. Otherwise, if the removal of the head contact has caused physical connection to be removed between the first signal pin and the second signal pin (“yes” branch of the conditional block1014), then the ground reference voltage level on the first signal pin is maintained via the spring pin as the second signal pin becomes floating (block1016).

It is noted that one or more of the above-described implementations include software. In such implementations, the program instructions that implement the methods and/or mechanisms are conveyed or stored on a computer readable medium. Numerous types of media which are configured to store program instructions are available and include hard disks, floppy disks, CD-ROM, DVD, flash memory, Programmable ROMs (PROM), random access memory (RAM), and various other forms of volatile or non-volatile storage. Generally speaking, a computer accessible storage medium includes any storage media accessible by a computer during use to provide instructions and/or data to the computer. For example, a computer accessible storage medium includes storage media such as magnetic or optical media, e.g., disk (fixed or removable), tape, CD-ROM, or DVD-ROM, CD-R, CD-RW, DVD-R, DVD-RW, or Blu-Ray. Storage media further includes volatile or non-volatile memory media such as RAM (e.g. synchronous dynamic RAM (SDRAM), double data rate (DDR, DDR2, DDR3, etc.) SDRAM, low-power DDR (LPDDR2, etc.) SDRAM, Rambus DRAM (RDRAM), static RAM (SRAM), etc.), ROM, Flash memory, non-volatile memory (e.g. Flash memory) accessible via a peripheral interface such as the Universal Serial Bus (USB) interface, etc. Storage media includes microelectromechanical systems (MEMS), as well as storage media accessible via a communication medium such as a network and/or a wireless link.

Additionally, in various implementations, program instructions include behavioral-level descriptions or register-transfer level (RTL) descriptions of the hardware functionality in a high level programming language such as C, or a design language (HDL) such as Verilog, VHDL, or database format such as GDS II stream format (GDSII). In some cases the description is read by a synthesis tool, which synthesizes the description to produce a netlist including a list of gates from a synthesis library. The netlist includes a set of gates, which also represent the functionality of the hardware including the system. The netlist is then placed and routed to produce a data set describing geometric shapes to be applied to masks. The masks are then used in various semiconductor fabrication steps to produce a semiconductor circuit or circuits corresponding to the system. Alternatively, the instructions on the computer accessible storage medium are the netlist (with or without the synthesis library) or the data set, as desired. Additionally, the instructions are utilized for purposes of emulation by a hardware based type emulator from such vendors as Cadence®, EVE®, and Mentor Graphics®.