POC port electrostatic protection circuit

Abstract

The utility model relates to a POC port electrostatic protection circuit. The POC port electrostatic protection circuit comprises a power supply chip, a serial deserializer, a coaxial cable, a first protection filter circuit and a second protection filter circuit connected with the first protection filter circuit. The first protection filter circuit comprises a first ESD device with flyback, the first end of the first ESD device is connected with the power supply chip, the second end of the first ESD device is connected with the serial deserializer, and the third end of the first ESD device is grounded; the second protection filter circuit comprises a second ESD device with flyback, the first end of the second ESD device is connected with the coaxial cable, and the second end of the second ESD device is grounded; the serial deserializer provided by the utility model has good electrostatic discharge capability, can effectively protect electrostatic interference of a power supply end to ensure normal power supply, and can effectively protect electrostatic interference of a POC port to ensure the quality of signals output by the serial deserializer, thereby meeting the electrostatic protection requirements of ultra-high-definition image quality and ultra-high rate under a long wire harness.

Description

Technical Field

[0001] This utility model relates to the field of POC circuit technology, and more specifically, to a POC port electrostatic discharge protection circuit. Background Technology

[0002] In existing technologies, POC ports are susceptible to electrostatic interference due to the spatial induction of long cables, leading to decreased product reliability and difficulty in passing EMC tests. Traditional ESC protection circuits are limited by factors such as junction capacitance, making it difficult to balance signal integrity and ESC protection performance at high transmission rates. For example, conventional ESC tubes have high clamping voltage and slow response speed, resulting in significant signal attenuation and EMI noise transmission problems. Furthermore, as automotive cameras place increasingly stringent requirements on the cable length, image quality, and transmission rate of POC ports, existing technologies struggle to meet the ESC protection needs of ultra-high-definition image quality and ultra-high speed under long cable harnesses. Therefore, there is an urgent need to design a new circuit solution that can integrate ESC protection, EMC testing, and signal quality. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a POC port electrostatic protection circuit to address the above-mentioned deficiencies of the prior art.

[0004] The technical solution adopted by this utility model to solve its technical problem is: a POC port electrostatic discharge protection circuit, including a power chip, a serial deserializer, a coaxial cable, a first protection filter circuit, and a second protection filter circuit connected to the first protection filter circuit; the first protection filter circuit includes a first ESD device with retrace, the first end of the first ESD device is connected to the power chip, the second end of the first ESD device is connected to the serial deserializer, and the third end of the first ESD device is grounded; the second protection filter circuit includes a second ESD device with retrace, the first end of the second ESD device is connected to the coaxial cable, and the second end of the second ESD device is grounded.

[0005] In some embodiments, the first protection filter circuit further includes a first BDL filter and a second BDL filter; the A terminal of the first BDL filter is connected to the first terminal of the first ESD device and the power chip, respectively, and the A terminal of the second BDL filter is connected to the second terminal of the first ESD device and the serializer.

[0006] In some embodiments, the first protection filter circuit further includes an inductor, the first end of which is connected to the base (B) of the first BDL filter, and the second end of which is connected to the base (B) of the second BDL filter.

[0007] In some embodiments, the first terminal of the first ESD device is connected to the positive terminal of the power supply line of the power chip; the second terminal of the first ESD device is connected to the Dout terminal of the signal line of the serializer / deserializer.

[0008] In some embodiments, the second protection filter circuit further includes a third BDL filter, wherein the A terminal of the third BDL filter is connected to the B terminal of the second BDL filter, and the B terminal of the third BDL filter is connected to a coaxial cable.

[0009] The beneficial effects of this utility model are as follows: Unlike existing technologies, the electrostatic discharge (ESD) protection circuit of this utility model for the POC port combines a power chip, a serial deserializer, and a coaxial cable with a first ESD device with retrace in the first protection filter circuit and a second ESD device with retrace in the second protection filter circuit. Utilizing the retrace-equipped ESD device for ESD protection, it possesses good ESD discharge capability, effectively protecting against ESD interference at the power supply end to ensure normal power supply, and effectively protecting against ESD interference at the POC port to ensure the signal quality output by the serial deserializer. Applied to automotive POC circuit design, it meets the ESD protection requirements for ultra-high-definition image quality and ultra-high speed under long wiring harnesses. This not only helps solve the EMC testing and certification problems of corresponding automotive POC circuits but also facilitates market application and expansion. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the electrostatic discharge protection circuit for the POC port in an embodiment of this utility model;

[0011] The labels and numbers in the diagram are as follows: Power chip - 1; Serializer - 2; Coaxial cable - 3; First protection filter circuit - 4; Second protection filter circuit - 5. Detailed Implementation

[0012] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this utility model are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0013] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the present invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0014] "Multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0015] Furthermore, the terms indicating orientation, such as "up," "down," "front," "back," "left," "right," "upper end," and "lower end," are all based on the posture and position of the device or equipment described in this solution during normal use.

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of this utility model. Obviously, the described embodiments are some, but not all, embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0017] This utility model embodiment provides a POC port electrostatic discharge protection circuit, such as Figure 1 As shown, the POC port electrostatic discharge (ESD) protection circuit includes a power chip 1, a serializer / deserializer 2, a coaxial cable 3, a first protection filter circuit 4, and a second protection filter circuit 5 connected to the first protection filter circuit 4. The first protection filter circuit 4 includes a first ESD device ESD1 with a retrace function. The first terminal of the first ESD device ESD1 is connected to the power chip 1, the second terminal of the first ESD device ESD1 is connected to the serializer / deserializer 2, and the third terminal of the first ESD device ESD1 is grounded. The second protection filter circuit 5 includes a second ESD device ESD2 with a retrace function. The first terminal of the second ESD device ESD2 is connected to the coaxial cable 3, and the second terminal of the second ESD device ESD2 is grounded.

[0018] In the POC port electrostatic discharge (ESD) protection circuit of this embodiment, the first ESD device ESD1 is the first ESD transistor, and the second ESD device ESD2 is the second ESD transistor. The first ESD transistor with a flyback function can protect against ESD interference from the power chip 1, ensuring normal power supply. The second ESD transistor with a flyback function can protect against ESD interference from the POC port, ensuring high-quality signal output. Compared with conventional ESD transistors, both the first and second ESD transistors with a flyback function have advantages such as high-efficiency ESD discharge capability, faster response time, lower clamping voltage, and low capacitance and low leakage current. Their low junction capacitance also meets the requirements of signal integrity and S-parameters (the S-parameters of low junction capacitance refer to parameters used to describe the reflection and transmission characteristics of low junction capacitance devices in microwave transmission, used to evaluate the performance of device reflected and transmitted signals), which is more conducive to ensuring the quality of the output signal at the signal line output terminal, and usually also meets the requirements of smaller packaging and board space.

[0019] Specifically, in this embodiment, the first terminal of the first ESD device ESD1 is connected to the positive terminal of the power supply line of the power chip 1; the second terminal of the first ESD device ESD1 is connected to the Dout terminal of the signal line of the serializer 2. Further, the first protection filter circuit 4 also includes a first BDL filter BDL1 and a second BDL filter BDL2; the A terminal of the first BDL filter BDL1 is connected to the first terminal of the first ESD device ESD1 and the power chip 1, respectively, and the A terminal of the second BDL filter BDL2 is connected to the second terminal of the first ESD device ESD1 and the serializer 2, respectively. The BDL filter itself has an extremely low ESL (parasitic inductance) and contains two internal balancing capacitors, giving it a wider frequency band, lower impedance, and smaller junction capacitance than MLCC capacitors, thus reducing signal attenuation at the signal output terminal (Dout terminal).

[0020] Specifically, in this embodiment, the first protection filter circuit 4 further includes an inductor L2. The first end of the inductor L2 is connected to the base of the first BDL filter BDL1, and the second end of the inductor L2 is connected to the base of the second BDL filter BDL2. This forms a π-shaped filter circuit on the positive terminal of the power supply line of the power chip 1, which greatly suppresses EMI noise on the power supply VDD and prevents power supply EMI noise from being conducted and radiated from the coaxial cable 3.

[0021] Specifically, in this embodiment, the second protection filter circuit 5 further includes a third BDL filter BDL3. The A terminal of the third BDL filter BDL3 is connected to the B terminal of the second BDL filter BDL2, and the B terminal of the third BDL filter BDL3 is connected to the coaxial cable 3. Applied to various types of POC ports, while providing primary protection, the second ESD device ESD2 with a flyback capability offers ultra-fast response speed for primary protection. Compared to conventional electrostatic discharge tubes, it has a lower clamping voltage. Combined with the third BDL filter BDL3, it can discharge static electricity more quickly, protecting the downstream circuitry.

[0022] The electrostatic discharge (ESD) protection circuit of the POC port in this embodiment of the present invention not only helps prevent power EMI noise crosstalk to the signal line, but also helps prevent power EMI noise from being conducted and radiated from the coaxial cable 3. It meets the ESD protection requirements for ultra-high-definition image quality and ultra-high speed under long cable harnesses, and simultaneously meets the requirements for power filtering, prevention of power noise EMI crosstalk, and ESD protection in the power and signal sections. Thus, it effectively solves the problems of filtering, crosstalk, and ESD protection in automotive POC applications, and helps POC circuits using this circuit to pass the corresponding EMC tests and certifications, effectively expanding the market and the application of various POC automotive cameras.

[0023] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A POC port electrostatic discharge protection circuit, characterized in that: The system includes a power supply chip, a serializer / deserializer, a coaxial cable, a first protection filter circuit, and a second protection filter circuit connected to the first protection filter circuit. The first protection filter circuit includes a first ESD device with a retrace function, the first terminal of which is connected to the power supply chip, the second terminal of which is connected to the serializer / deserializer, and the third terminal of which is grounded. The second protection filter circuit includes a second ESD device with a retrace function, the first terminal of which is connected to the coaxial cable, and the second terminal of which is grounded.

2. The POC port electrostatic discharge protection circuit according to claim 1, characterized in that: The first protection filter circuit further includes a first BDL filter and a second BDL filter; the A terminal of the first BDL filter is connected to the first terminal of the first ESD device and the power chip, respectively, and the A terminal of the second BDL filter is connected to the second terminal of the first ESD device and the serial deserializer, respectively.

3. The POC port electrostatic discharge protection circuit according to claim 2, characterized in that: The first protection filter circuit further includes an inductor, the first end of which is connected to the base (B) of the first BDL filter, and the second end of which is connected to the base (B) of the second BDL filter.

4. The POC port electrostatic discharge protection circuit according to any one of claims 1-3, characterized in that: The first terminal of the first ESD device is connected to the positive terminal of the power supply line of the power chip; the second terminal of the first ESD device is connected to the Dout terminal of the signal line of the serializer / deserializer.

5. The POC port electrostatic discharge protection circuit according to claim 3, characterized in that: The second protection filter circuit also includes a third BDL filter, wherein the A terminal of the third BDL filter is connected to the B terminal of the second BDL filter, and the B terminal of the third BDL filter is connected to a coaxial cable.

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