The MIPI interface plays an increasingly important role in mobile displays. This article explains what MIPI is, its development history, and the various standards it encompasses.
Whether at work, in shopping malls, parks, or while traveling, the likelihood of people using mobile devices is as great as the likelihood of face-to-face conversations. The degree of dependence on smartphones, tablets, laptops, and other products is also continuously increasing. Therefore, ensuring the accuracy of signal processing within and between mobile devices and peripherals is a significant concern for electronic designers and developers.
Since its establishment in 2003, the Mobile Industry Processor Interface Alliance (MIPI Alliance) has been a leader in establishing interoperability specifications for mobile devices. These technical specifications for both software and hardware have evolved into the primary design and development standards for mobile electronic system interfaces. Today, for your PCBA or device to be widely accepted and implemented, it is almost mandatory to comply with MIPI standards.
What is the MIPI Standard?
Alliance members develop MIPI specifications to maximize the performance of mobile interconnected devices by supporting and improving operations in the following areas.
Goals of MIPI Standards
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Minimize electromagnetic interference or EMI
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Reduce power consumption, for instance, for low-power IoT cellular applications
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Improve operation for high-bandwidth applications similar to UWB technology
These specifications address issues related to multimedia, chip-to-chip or inter-processor communication (IPC), software integration, debugging, data management, device control, and physical layer interfaces. The physical layer or MIPI PHY standards are essential foundations for designing and developing mobile devices and systems.
MIPI specifications have evolved into the main standards guiding the design and development of mobile electronic products, ensuring compatibility and universality within the industry.
Why are MIPI PHY Standards Important?
MIPI PHY standards fall under one of the categories listed below.
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MIPI Physical Layer Specifications |
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Physical Parameters |
Features |
Applications |
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A-PHY |
32 Gbps data transfer rate Point-to-point or daisy-chain topology Automotive EMC affecting immunity. |
ADS, ADAS, HMI, IVI, IoT, and industrial. |
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A-PHY PALS |
Long-distance A-PHY SerDes A packet transmission and reception. |
ADS, ADAS, and IVI. |
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C-PHY |
Low electromagnetic interference. Low power consumption. High performance. |
Displays and cameras for smartphones, tablets, surveillance cameras, automotive sensors, IVI, IoT, robotics, and drones. |
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D-PHY |
Low electromagnetic interference. Low power consumption. High performance. |
Smartphone cameras and displays, automotive cameras, dashboard displays, radar sensors, large tablets, robotics, and drones. |
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M-PHY |
Low electromagnetic interference. Low power consumption. High bandwidth. |
Radio frequency interfaces. UFS memory Communication between processors |
Each of the above categories of specifications supports MIPI goals and defines features and parameters for some aspect or type of operation of mobile interconnected devices.
A-PHY
A-PHY is a SerDes specification for advanced automotive technology and other applications. A-PHY features downlink speeds of 2-16 Gbps, uplink speeds of 100 Mbp and 200 Mbp, extremely high automotive environmental electromagnetic compatibility (EMC) immunity, daisy-chain or point-to-point topology, and a transmission capability of 15 m.
A-PHY PALS (Protocol Adaptation Layer)
A-PHY PALS supports and facilitates the use of MIPI A-PHY in advanced automotive applications. The design of A-PHY PALS is intended to ease the integration of in-vehicle innovative technologies.
C-PHY
The C-PHY specification applies to cameras and displays used in mobile interconnected systems such as smartphones, tablets, IoT, and surveillance cameras. C-PHY supports the previous MIPI CSI-2 (Camera and Imaging) and MIPI DSI-2 (Display) standards.
D-PHY
Similar to C-PHY, D-PHY targets displays and cameras, maximizing performance while minimizing noise interference and power consumption. The differential signaling protocol specification applies to interconnect distances of 4 meters or less.
M-PHY
M-PHY includes multimedia and IPC communication interface specifications that promote the efficient design of mobile systems for high bandwidth, low power consumption, and minimal EMI operation.
Electronic circuit boards and systems that comply with these MIPI standards help ensure that products from global manufacturers achieve agnostic integration. You must adhere to these standards to ensure the marketability of mobile products.
How to Ensure Your Device Complies with MIPI Standards?
Achieving MIPI compliance is a complex process. However, the MIPI standard specifications provide clear guidance and standards for testing and verifying whether your PCBA or mobile connected electronic devices meet the necessary requirements. As shown below, recognizing and understanding the MIPI standards relevant to your design is the first step in following best practices for achieving compliance.
While appropriate MIPI-defined testing procedures can allow your products to be labeled as compliant and sold, failing to pass testing can have significant negative impacts. This includes repeating most of the PCB design process, rebuilding, and retesting, which requires additional time and costs. The best way to avoid these unexpected situations and damage to project timelines and budgets is to use MIPI compliance testing software tools during the design process.
