Usb circuit provided with electrostatic protection circuit

Abstract

The utility model provides a USB circuit with static protection circuit, it includes USB controller, USB interface: at least one signal line, the first connecting end of signal line is connected with the signal pin of USB controller, its second connecting end is connected with the signal pin of USB interface, at least one static protection circuit, in static protection circuit, coupling capacitor is connected between the first connecting end and the second connecting end of corresponding signal line, the anode of first voltage stabilizing tube is connected with the first connecting end of corresponding signal line, its cathode is connected with node C, one end of capacitor C2 is connected with node C, its other end is grounded, the cathode of second voltage stabilizing tube is connected with the first connecting end of corresponding signal line, its anode is grounded, one end of two-way trigger diode is connected with the second connecting end of corresponding signal line, its other end is grounded. Compared with prior art, the utility model effectively improves the board level static voltage resistance grade, and guarantees signal transmission quality, increases the robustness of product.

Description

[Technical Field]

[0001] This utility model relates to the field of circuit design technology, and in particular to a USB circuit with an electrostatic protection circuit. [Background Technology]

[0002] In the development of the automotive industry, in-cabin entertainment has improved travel comfort to a certain extent. From radios to Bluetooth on mobile phones, and then to the increasing variety of entertainment methods such as AR, VR, and DP, the diversification, sophistication, and intelligence of functions are inseparable from the development of information technology. In high-speed communication, due to the low communication level, low signal pin withstand voltage, and manufacturing process limitations, the electrostatic discharge (ESD) protection level of the chip itself cannot meet the requirements. Therefore, ESD protection for automotive-grade high-speed communication chips has always been a key focus of hardware design, requiring both protection against ESD damage and assurance of signal transmission quality. Especially for output ports, customers face the risk of introducing ESD when plugging and unplugging wiring harnesses, making ESD protection crucial in hardware design.

[0003] Currently, due to limitations in design, manufacturing, and process technology, the withstand voltage threshold of USB 3.0 signal lines is generally low for USB 3.0 chips, which forces a reduction in the board-level electrostatic discharge withstand voltage rating of hardware designs.

[0004] Therefore, it is necessary to propose a new technical solution to overcome the above problems. [Utility Model Content]

[0005] One of the objectives of this invention is to provide a USB circuit with an electrostatic discharge (ESD) protection circuit, which effectively improves the board-level ESD withstand voltage level, ensures signal transmission quality, and increases the robustness of the product.

[0006] According to one aspect of this utility model, a USB circuit with an electrostatic discharge (ESD) protection circuit is provided, comprising a USB controller; a USB interface; at least one signal line, wherein a first connection terminal A of the signal line is connected to a signal pin corresponding to the USB controller, and a second connection terminal B of the signal line is connected to a signal pin corresponding to the USB interface; at least one ESD protection circuit, each ESD protection circuit corresponding to one signal line, the ESD protection circuit comprising a coupling capacitor C1, a bidirectional trigger diode D1, a first Zener diode D2, a second Zener diode D3, and a capacitor C2, wherein the coupling capacitor C1 is connected between the first connection terminal A and the second connection terminal B of the corresponding signal line; the positive terminal of the first Zener diode D2 is connected to the first connection terminal A of the corresponding signal line, and its negative terminal is connected to a node C; one end of the capacitor C2 is connected to the node C, and its other end is grounded; the negative terminal of the second Zener diode D3 is connected to the first connection terminal A of the corresponding signal line, and its positive terminal is grounded; one end of the bidirectional trigger diode D1 is connected to the second connection terminal B of the corresponding signal line, and its other end is grounded.

[0007] Furthermore, the USB controller is a USB 3.0 controller; the USB interface is a Type-C interface; and the signal line is a USB 3.0 high-speed signal line.

[0008] Furthermore, the first connection terminal A of the signal line is connected to the TX signal pin corresponding to the USB controller, and its second connection terminal B is connected to the TX signal pin corresponding to the USB interface; or the first connection terminal A of the signal line is connected to the RX signal pin corresponding to the USB controller, and its second connection terminal B is connected to the RX signal pin corresponding to the USB interface.

[0009] Furthermore, node C is connected to the voltage required for the USB controller to operate normally.

[0010] Furthermore, the USB controller is an automotive-grade ultra-high-speed communication chip.

[0011] Furthermore, the USB controller is a USB7002 HUB chip.

[0012] Compared with the prior art, this invention effectively improves the board-level electrostatic withstand voltage rating, ensures signal transmission quality, and increases the robustness of the product. [Attached Image Description]

[0013] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Among them:

[0014] Figure 1 This is a design block diagram of a USB circuit with electrostatic protection circuit in one embodiment of the present invention.

[0015] Figure 2 As shown in one embodiment of the present invention Figure 1 The diagram shown is a schematic of a USB circuit with electrostatic discharge protection for a USB 3.0 interface.

[0016] Figure 3 As shown in one embodiment of the present invention Figure 2 The diagram shows the +4KV electrostatic discharge path of a USB circuit with electrostatic protection for a USB 3.0 interface.

[0017] Figure 4 As shown in one embodiment of the present invention Figure 2 The diagram shows a -4KV electrostatic discharge path for a USB circuit with electrostatic protection for a USB 3.0 interface. 【Detailed Implementation Methods】

[0018] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments. Unless otherwise specified, the terms coupling, connection, linking, and interconnection used herein to indicate electrical connection mean direct or indirect connection. For example, A being connected to B includes both a direct electrical connection between A and B and a connection between A and B via electrical components or circuits.

[0020] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "back", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0021] Please refer to Figure 1 As shown, it is a design block diagram of a USB circuit with electrostatic protection circuit in one embodiment of the present invention. Figure 1 The USB circuit shown includes a USB controller 110, a USB interface 120, at least one signal line 130, and at least one electrostatic discharge (ESD) protection circuit 140, wherein each ESD protection circuit 140 corresponds to one signal line 130. For ease of description, Figure 1 Only one electrostatic discharge (ESD) protection circuit 140 and a corresponding signal line 130 are shown. Figure 1 In the illustrated embodiment, the first connection terminal A of signal line 130 is connected to the corresponding signal pin of USB controller 110, and its second connection terminal B is connected to the corresponding signal pin of USB interface 120. The electrostatic discharge protection circuit 140 includes a coupling capacitor C1, a bidirectional trigger diode D1, a first Zener diode D2, a second Zener diode D3, and a capacitor C2. The coupling capacitor C1 is connected between the first connection terminal A and the second connection terminal B of the corresponding signal line 130 (or the coupling capacitor C1 is disposed on the corresponding signal line 130). The positive terminal of the first Zener diode D2 is connected to the first connection terminal A of the corresponding signal line 130, and its negative terminal is connected to node C. One end of the capacitor C2 is connected to node C, and its other end is grounded. The negative terminal of the second Zener diode D3 is connected to the first connection terminal A of the corresponding signal line 130, and its positive terminal is grounded. One end of the bidirectional trigger diode D1 is connected to the second connection terminal B of the corresponding signal line 130, and its other end is grounded.

[0022] exist Figure 1In the illustrated embodiment, the USB controller 110 is a USB 3.0 controller; the USB interface 120 is a Type-C interface; and the signal line 130 is a USB 3.0 high-speed signal line. For example, the first connection terminal A of the signal line 130 is connected to the TX signal pin (i.e., the ultra-high-speed data transmitter) corresponding to the USB controller 110, and its second connection terminal B is connected to the TX signal pin (i.e., the ultra-high-speed data transmitter) corresponding to the USB interface 120; or the first connection terminal A of the signal line 130 is connected to the RX signal pin (i.e., the ultra-high-speed data receiver) corresponding to the USB controller 110, and its second connection terminal B is connected to the RX signal pin (i.e., the ultra-high-speed data receiver) corresponding to the USB interface 120.

[0023] exist Figure 1 In the specific implementation shown, the USB controller 110 is an automotive-grade ultra-high-speed communication chip. Preferably, the USB controller 110 is a Microchip USB7002 HUB chip. The USB7002 integrates one USB 3.0 uplink port and four USB downlink ports, including two USB 3.0 ports (compatible with USB 2.0) and two USB 2.0 ports. The coupling capacitor C1 is a coupling capacitor required by the USB 3.0 protocol, and a 100nF capacitor is recommended. The bidirectional trigger diode D1 is a primary electrostatic discharge (ESD) stage. If the bidirectional trigger diode D1 is removed, ±4KV (i.e., positive or negative voltage) ESD contact discharge will damage the coupling capacitor C1, leading to ESD failure. The first Zener diodes D2 and D3 are designed for ESD voltage clamping. Because the USB7002 TX / RX withstand voltage is only 1.32V, the design needs to ensure that the residual ESD voltage is less than 1.32V. This clamping design has been tested and verified to effectively protect the chip. For -4KV (negative voltage), the electrostatic discharge path is the second Zener diode D3, coupling capacitor C1 to the Type-C interface 120. For +4KV (positive voltage), the discharge path is the Type-C interface 120, coupling capacitor C1, the first Zener diode D2, capacitor C2 to ground GND. Capacitor C2 absorbs a large amount of charge during the instant of electrostatic discharge, ensuring proper conduction. To minimize the impact on high-level signal transmission, the USB7002 core voltage of 1.2V (the voltage required for normal USB7002 operation) is connected between the first Zener diode D2 and diode C2 (node ​​C).

[0024] Please refer to Figure 2 As shown, this is one embodiment of the present invention. Figure 1The diagram shows a USB circuit with electrostatic discharge protection for a USB 3.0 interface. The eight high-speed signal pins of the Microchip USB7002 HUB chip (i.e., USB controller 110) – USB3DN–TXDP2A, USB3DN–TXDM2A, USB3DN–RXDP2A, USB3DN–RXDM2A, USB3DN–RXDM2B, USB3DN–RXDP2B, USB3DN–TXDP2B, and USB3DN–TXDM2B – are connected to the eight high-speed signal pins of the Type-C interface (i.e., USB interface 120) – TX1+, TX1-, RX1+, RX1-, RX2-, RX2+, TX2+, and TX2- – respectively – via USB 3.0 high-speed signal lines.

[0025] The first electrostatic discharge (ESD) protection circuit consists of coupling capacitor C209, bidirectional trigger diode D212, first Zener diode D200, second Zener diode D220, and capacitor C200, providing ESD protection for the USB 3.0 high-speed signal lines connecting the high-speed signal pins USB3DN–TXDP2A and TX1+. The second ESD protection circuit consists of coupling capacitor C210, bidirectional trigger diode D213, first Zener diode D201, second Zener diode D221, and capacitor C201, providing ESD protection for the USB 3.0 high-speed signal lines connecting the high-speed signal pins USB3DN–TXDM2A and TX1-. The third ESD protection circuit consists of coupling capacitor C211, bidirectional trigger diode D214, first Zener diode D202, second Zener diode D222, and capacitor C202, providing ESD protection for the USB 3.0 high-speed signal lines connecting the high-speed signal pins USB3DN–RXDP2A and RX1+. Coupling capacitor C212, bidirectional trigger diode D215, first Zener diode D203, second Zener diode D223, and capacitor C203 constitute the fourth electrostatic discharge (ESD) protection circuit to protect the USB 3.0 high-speed signal lines connecting the high-speed signal pins USB3DN–RXDM2A and RX1- from ESD. Coupling capacitor C213, bidirectional trigger diode D216, first Zener diode D204, second Zener diode D224, and capacitor C204 constitute the fifth ESD protection circuit to protect the USB 3.0 high-speed signal lines connecting the high-speed signal pins USB3DN–RXDM2B and RX2- from ESD. Coupling capacitor C214, bidirectional trigger diode D217, first Zener diode D205, second Zener diode D225, and capacitor C205 constitute the sixth ESD protection circuit to protect the USB 3.0 high-speed signal lines connecting the high-speed signal pins USB3DN–RXDP2B and RX2+ from ESD. Coupling capacitor C215, bidirectional trigger diode D218, first Zener diode D206, second Zener diode D226, and capacitor C206 constitute the seventh electrostatic discharge (ESD) protection circuit to provide ESD protection for the USB 3.0 high-speed signal lines connecting the high-speed signal pins USB3DN–TXDP2B and TX2+. Coupling capacitor C216, bidirectional trigger diode D219, first Zener diode D207, second Zener diode D227, and capacitor C207 constitute the eighth ESD protection circuit to provide ESD protection for the USB 3.0 high-speed signal lines connecting the high-speed signal pins USB3DN–TXDM2B and TX2-.

[0026] Please refer to Figure 3 As shown, this is one embodiment of the present invention. Figure 2 The diagram shows the +4KV electrostatic discharge path of a USB circuit with electrostatic protection for a USB 3.0 interface. Figure 3The protection principle is as follows: when a +4KV (positive voltage) electrostatic discharge is applied, the static electricity is mainly released through the bidirectional trigger diode D1. After being released by the bidirectional trigger diode D1, the residual voltage still far exceeds the chip's withstand voltage threshold. If the residual voltage is released from the USB7002 chip pins, the chip will be damaged, causing abnormal USB 3.0 functionality. Therefore, a clamping design is added after the coupling capacitor C1. The positive residual voltage is absorbed by capacitor C2 through the first Zener diode D2, ensuring that the static electricity is completely released and protecting the USB7002 from electrostatic damage.

[0027] Please refer to Figure 4 As shown, this is one embodiment of the present invention. Figure 2 The diagram shows a -4KV electrostatic discharge path for a USB circuit with electrostatic protection for a USB 3.0 interface. Figure 4 The protection principle is as follows: when a -4KV (negative voltage) electrostatic discharge is applied, the static electricity is mainly released through the bidirectional trigger diode D1. After being released by the bidirectional trigger diode D1, the residual voltage still far exceeds the chip's withstand voltage threshold. If the residual voltage is released from the USB7002 chip pins, the chip will be damaged, leading to abnormal USB 3.0 functionality. Therefore, a clamping design is added after the coupling capacitor C1. The negative residual voltage is absorbed by the coupling capacitor C1 through the second Zener diode D3, ensuring that the static electricity is completely released and protecting the USB7002 from electrostatic damage.

[0028] In summary, this utility model, based on the Microchip USB7002 HUB chip, incorporates electrostatic discharge (ESD) protection for USB 3.0 high-speed signal lines. This design enables transmission rates up to 5Gbps and effectively resists ±4KV of electrostatic discharge interference, ensuring the normal operation of the USB7002 HUB chip. It also effectively improves the board-level ESD withstand voltage, guarantees signal transmission quality, and enhances product robustness.

[0029] It should be noted that any modifications made by those skilled in the art to the specific embodiments of this utility model do not depart from the scope of the claims of this utility model. Accordingly, the scope of the claims of this utility model is not limited to the foregoing specific embodiments.

Claims

1. A USB circuit equipped with an electrostatic discharge (ESD) protection circuit, characterized in that, It includes USB controller; USB interface: At least one signal line, wherein the first connection end A of the signal line is connected to the signal pin corresponding to the USB controller, and its second connection end B is connected to the signal pin corresponding to the USB interface; At least one electrostatic discharge (ESD) protection circuit is provided, each ESD protection circuit corresponding to one signal line. The ESD protection circuit includes a coupling capacitor C1, a bidirectional trigger diode D1, a first Zener diode D2, a second Zener diode D3, and a capacitor C2. The coupling capacitor C1 is connected between the first connection terminal A and the second connection terminal B of the corresponding signal line. The positive terminal of the first Zener diode D2 is connected to the first connection terminal A of the corresponding signal line, and its negative terminal is connected to node C. One end of the capacitor C2 is connected to node C, and its other end is grounded. The negative terminal of the second Zener diode D3 is connected to the first connection terminal A of the corresponding signal line, and its positive terminal is grounded. One end of the bidirectional trigger diode D1 is connected to the second connection terminal B of the corresponding signal line, and its other end is grounded.

2. The USB circuit with electrostatic discharge protection circuit according to claim 1, characterized in that, The USB controller is a USB 3.0 controller; The USB interface is a Type-C interface; The signal cable is a USB 3.0 high-speed signal cable.

3. The USB circuit with electrostatic discharge protection circuit according to claim 2, characterized in that, The first connection terminal A of the signal line is connected to the TX signal pin corresponding to the USB controller, and its second connection terminal B is connected to the TX signal pin corresponding to the USB interface; or The first connection terminal A of the signal line is connected to the RX signal pin corresponding to the USB controller, and its second connection terminal B is connected to the RX signal pin corresponding to the USB interface.

4. The USB circuit with electrostatic discharge protection circuit according to claim 1, characterized in that, The node C is connected to the voltage required for the USB controller to operate normally.

5. The USB circuit with electrostatic discharge protection circuit according to any one of claims 1-4, characterized in that, The USB controller is an automotive-grade ultra-high-speed communication chip.

6. The USB circuit with electrostatic discharge protection circuit according to claim 5, characterized in that, The USB controller is a USB7002 HUB chip.

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