Design circuit for effectively improving USB signal quality

Abstract

The embodiment of the utility model discloses a design circuit capable of effectively improving USB signal quality, the circuit comprises a USB Power module, an EMC circuit module, a host USB driving capability adjusting module and a USB connector module, the USB Power module, the EMC circuit module, the host USB driving capability adjusting module and the USB connector module are electrically connected, the EMC circuit module is used for suppressing high-frequency signals, the EMC circuit module is used for controlling the EMC circuit module, the EMC circuit module is used for controlling the EMC circuit module, and the EMC circuit module is used for controlling the EMC circuit module. According to the utility model, the USB interface circuit is used for improving the design of the USB interface circuit, and the signal quality is improved under the conditions of USB charging and data transmission. The EMC circuit plays a role in suppressing high-frequency signals, and the USB driving capability of the host is actually adjusted according to the product design. In the product design, the EMC circuit is added and the output capability of the USB host is adjusted, so that the effect of suppressing high-frequency interference waveforms under the condition of ensuring the signal quality is achieved. And when the USB interface is connected with the peripheral, the communication of the USB interface is satisfied.

Description

Technical Field

[0001] The utility model belongs to the technical field of vehicle-mounted USB, and in particular relates to a design circuit that effectively improves the quality of USB signals. Background Art

[0002] In automotive USB applications, the USB interface is usually required to support communication while also supporting power supply for peripherals to meet the needs of drivers and passengers for charging their mobile phones and connecting to the vehicle computer. The system design requirements for automotive products are higher in product quality and reliability than other civilian products. Figure 1 This method of circuit design is currently the most common design method. Figure 2 This is a reference circuit for Power Converter IC suppliers. If the circuit is designed in this way, in actual products, due to the long USB cable and external interference, there will be communication quality problems such as USB communication disconnection, EMC test RE exceeding the standard, and poor anti-interference ability. Utility Model Content

[0003] The purpose of the design of this utility model is to solve the data transmission problem caused by signal interference in USB communication, the RE exceeding the standard problem, ensure the quality of USB signals, optimize the performance of high-speed signal data transmission, improve product competitiveness, and avoid abnormal working conditions caused when the host is connected to peripherals. In order to achieve the above purpose, the technical solution of the utility model is as follows: a design circuit that effectively improves the quality of USB signals, the circuit includes a USB Power module, an EMC circuit module, a host USB drive capability adjustment module and a USB Connector module, the USB Power module, the EMC circuit module, the host USB drive capability adjustment module and the USB Connector module are electrically connected, the EMC circuit module is used for high-frequency signal suppression, and the host USB drive capability adjustment module is actually adjusted according to the product design.

[0004] As an improvement of the present invention, the EMC circuit module includes an LC filter module, a Common choke circuit and an ESD protection module. The LC filter module is connected to the Common choke circuit FL1. The USB PHY outputs signals through USB_DP and USB_DM, which are connected to the LC filter module.

[0005] As an improvement of the present invention, the LC filter module includes an inductor L1, a capacitor C1, an inductor L2 and a capacitor C2, and the USB PHY outputs signals through USB_DP and USB_DM, connecting the inductor L1, the capacitor C1, the inductor L2 and the capacitor C2.

[0006] As an improvement of the present invention, one end of the inductor L1 is connected to the second pin of the common choke circuit FL1, and one end of the inductor L2 is connected to the first pin of the common choke circuit FL1.

[0007] Based on the above technical solution, adding LC filtering can ensure that the LC on the transmission line absorbs a certain amount of high-frequency harmonics and reduce harmonic energy. As shown in the simulation data, adding LC networks L1, C1 and L2, C2 at the output end can realize that the harmonic energy is consumed by the inductor, and the capacitor charging suppresses the high-frequency pulse harmonics, slows down the rising and falling edges, reduces Overshoot and Undershoot, and thus realizes the function of harmonic suppression and improves the communication reliability of the product. By adjusting the drive parameters of the USB host, the signal level value, rising edge and pre-emphasis of the USB data line can be adjusted, thereby adjusting the signal quality. From the test eye diagram, it can be seen that the signal indicators have been greatly improved.

[0008] As an improvement of the present invention, the ESD protection module includes a first diode and a second diode, the cathode of the first diode is connected to the third pin of the common choke circuit FL1, and the cathode of the second diode is connected to the fourth pin of the common choke circuit FL1.

[0009] As an improvement of the present utility model, the USB host in the host USB drive capability adjustment module is a vehicle-grade cockpit domain SOC.

[0010] Compared with the prior art, the beneficial effects of the utility model are as follows: the utility model design relates to an EMC filter network for suppressing high-frequency harmonics and a USB signal quality adjustable circuit. On the basis of the design scheme of adding common-mode inductance to suppress common-mode interference in the circuit design, an LC filter network is added to suppress differential-mode interference and high-frequency harmonics, which can solve the signal quality problem of high-speed signals being interfered with by high-frequency interference; the USB host adjusts the drive capability, signal rising edge and pre-emphasis and other parameters of the USB path to adjust the output signal quality; the utility model is used to improve the USB interface circuit design to meet the conditions of USB charging and data transmission and improve the signal quality. The EMC circuit plays a role in high-frequency signal suppression, and the host USB drive capability adjustment is actually adjusted according to the product design. In the product design, by adding the EMC circuit and adjusting the USB host output capability, the effect of suppressing high-frequency interference waveforms under the condition of ensuring signal quality is achieved. It is ensured that when the USB interface is connected to peripherals, the USB interface communication is met. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Design of a general USB circuit in the prior art;

[0012] Figure 2It is a universal USB interface circuit in the prior art;

[0013] Figure 3 It is the updated USB circuit design in the utility model;

[0014] Figure 4 This is a USB interface circuit with LC filtering in the utility model;

[0015] Figure 5 This is a simulation diagram of a circuit without LC in this embodiment;

[0016] Figure 6 This is a simulation diagram of the LC network in this embodiment;

[0017] Figure 7 The USB signal eye diagram before adjustment in this embodiment;

[0018] Figure 8 This is the improved USB signal eye diagram in this embodiment. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and specific implementations. It should be understood that the following specific implementations are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0020] Example: Figures 3 to 4 As shown, this embodiment is a design circuit for effectively improving USB signal quality, the circuit includes a USB Power module, an EMC circuit module, a host USB drive capability adjustment module and a USB Connector module, the USB Power module, the EMC circuit module, the host USB drive capability adjustment module and the USB Connector module are electrically connected, the EMC circuit module is used for high-frequency signal suppression, and the host USB drive capability adjustment module is actually adjusted according to product design.

[0021] Furthermore, the EMC circuit module includes an LC filter module, a common choke circuit and an ESD protection module. The LC filter module is connected to the common choke circuit FL1. The USB PHY outputs signals through USB_DP and USB_DM, which are connected to the LC filter module.

[0022] Furthermore, the LC filter module includes an inductor L1, a capacitor C1, an inductor L2 and a capacitor C2, and the USB PHY outputs signals through USB_DP and USB_DM, connecting the inductor L1, the capacitor C1, the inductor L2 and the capacitor C2.

[0023] Further, one end of the inductor L1 is connected to the second pin of the common choke circuit FL1, and one end of the inductor L2 is connected to the first pin of the common choke circuit FL1.

[0024] Furthermore, adding LC filtering can ensure that the LC on the transmission line absorbs a certain amount of high-frequency harmonics and reduce harmonic energy. As shown in the simulation data, adding LC networks L1, C1 and L2, C2 at the output end can achieve the consumption of harmonic energy by inductors, and the charging of capacitors can suppress high-frequency pulse harmonics, slowing the rising and falling edges, reducing overshoot and undershoot, and thus achieving the function of harmonic suppression and improving product communication reliability. By adjusting the drive parameters of the USB host, the signal level value, rising edge and pre-emphasis of the USB data line can be adjusted, thereby adjusting the signal quality. From the test eye diagram, it can be seen that the signal indicators have been greatly improved.

[0025] Further, the ESD protection module includes a first diode and a second diode, the cathode of the first diode is connected to the third pin of the common choke circuit FL1, and the cathode of the second diode is connected to the fourth pin of the common choke circuit FL1.

[0026] Furthermore, the USB host in the host USB driver capability adjustment module is an automotive-grade cockpit domain SOC.

[0027] The following are simulation and test data: Figures 5 to 8 For the simulation with 90Ω simulated load:

[0028] Figure 5 This is a simulation diagram of a circuit with a 90Ω simulated load and no LC.

[0029] Figure 6 With 90Ω simulated load and LC filter (L=10nH, C=6.8pF), including LC network simulation diagram;

[0030] Figure 7 For LC filtering (L=10nH, C=6.8pF), host TXPREEMPAMPTUNE = 0, TXRISETUNE = 0, DC Voltage Adjustment = 0, USB interface measurement with USB harness 80cm, USB signal eye diagram before adjustment;

[0031] Figure 8This is the improved USB signal eye diagram measured at the USB interface with LC filtering (L=10nH, C=6.8pF), host TXPREEMPAMPTUNE = 3, TXRISETUNE = 3, DC Voltage Adjustment = 4, and a USB harness of 80cm.

[0032] like Figure 4 In the USB PHY, the signal is output through USB_DP and USB_DM, and the inductor L1, capacitor C1 and the inductor L2, capacitor C2 are connected to absorb and process high-frequency interference signals, and the common choke circuit FL1 is connected to filter out common-mode interference signals, and ESD protects the data line from static electricity. The LC network inductor L1, capacitor C1 and inductor L2, capacitor C2 realize the function of harmonic suppression after the capacitor is charged, and the harmonic energy is consumed by the inductor to achieve harmonic suppression. The USB host selects the automotive-grade cockpit domain SOC, and the modified SOC supports USB drive capability adjustment.

[0033] like Figure 3 In the USB host, the USB signal TX-Rise, TX pre-emphasis and DC VoltageLevel parameters can be adjusted through software. Adjusting the parameters can adjust the quality of the USB eye diagram, and the signal quality can be characterized by the eye width and eye height of the signal in the eye diagram.

[0034] It should be noted that the above content only illustrates the technical idea of ​​the utility model and cannot be used to limit the protection scope of the utility model. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model. These improvements and modifications all fall within the protection scope of the claims of the utility model.

Claims

1. A circuit design for effectively improving USB signal quality, characterized in that: The circuit includes a USB Power module, an EMC circuit module, a host USB drive capability adjustment module and a USB Connector module. The USB Power module, the EMC circuit module, the host USB drive capability adjustment module and the USB Connector module are electrically connected. The EMC circuit module is used for high-frequency signal suppression, and the host USB drive capability adjustment module is actually adjusted according to product design.

2. A design circuit for effectively improving USB signal quality according to claim 1, characterized in that: The EMC circuit module includes an LC filter module, a common choke circuit and an ESD protection module. The LC filter module is connected to the common choke circuit FL1. The USB PHY outputs signals through USB_DP and USB_DM, which are connected to the LC filter module.

3. A circuit design for effectively improving USB signal quality according to claim 2, characterized in that: The LC filter module includes an inductor L1, a capacitor C1, an inductor L2 and a capacitor C2. The USB PHY outputs signals through USB_DP and USB_DM, and connects the inductor L1, the capacitor C1, the inductor L2 and the capacitor C2.

4. A circuit design for effectively improving USB signal quality according to claim 3, characterized in that: One end of the inductor L1 is connected to the second pin of the common choke circuit FL1, and one end of the inductor L2 is connected to the first pin of the common choke circuit FL1.

5. A circuit design for effectively improving USB signal quality according to claim 2, characterized in that: The ESD protection module includes a first diode and a second diode, wherein a cathode of the first diode is connected to a third pin of the common choke circuit FL1, and a cathode of the second diode is connected to a fourth pin of the common choke circuit FL1.

6. A circuit design for effectively improving USB signal quality according to claim 1, characterized in that: The USB host in the host USB driver capability adjustment module is an automotive-grade cockpit domain SOC.

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