Introduction to MIPI C-PHY: Revolutionizing Mobile Communication

Introduction to MIPI C-PHY: Revolutionizing Mobile Communication

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Introduction to MIPI C-PHY: Revolutionizing Mobile Communication

“ With the increasing number of smartphones and smart devices, communication between the CPU and most modules inside the phone occurs via the MIPI protocol, such as between the display and the camera. However, as the resolution of screens and cameras continues to rise, traditional communication protocols may not suffice, making MIPI C-PHY increasingly important.“

The author has been involved with MIPI C-PHY since early 2018 and participated in the verification of MIPI C-PHY compliance algorithms from late 2018 to 2019. The author has a good understanding of MIPI C-PHY’s specifications and compliance test specifications (CTS). Previously, the author wished to write a document introducing this emerging technology but lacked sufficient time. This year, due to the COVID-19 pandemic, time has become slightly more available, and as C-PHY has become more widespread, it is now used in many high-end smartphones. Therefore, this article is published on the public account, providing a detailed introduction to C-PHY and its HS mode compliance testing, along with video explanations.

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The Evolution of Displays and Cameras

Ten years ago, during the era dominated by Nokia, the mainstream smartphone resolution was 320×240, and the iPhone 4, which first introduced the Retina display concept, had a resolution of only 950×540. MIPI D-PHY 1.0 supports up to 4 lanes, with a maximum rate of 1 Gbit/s (referred to as G below), making D-PHY’s maximum rate capable of supporting up to 4G. After upgrading to version 1.1, D-PHY can support rates of up to 6G, sufficient for common 1080P scenarios.
Currently, photography has become the main feature of smart smartphones, and at the launch events of flagship and high-end phones from various brands, significant effort is spent introducing the photography and video capabilities, including low noise, optical zoom, snapshot, and high-definition photography. High-definition photography requires sufficient bandwidth between the camera and processor.
Introduction to MIPI C-PHY: Revolutionizing Mobile Communication
For example, referring to HDMI, if one needs to achieve 4K 30fps video recording, approximately 9G of bandwidth is required. If one needs to achieve 4K 60fps video recording, approximately 18G of bandwidth is required. The latest specification of D-PHY is version 2.0, with each lane supporting up to 4.5G, but this rate poses significant challenges for both design and testing.
MIPI C-PHY was developed to meet this need, with a baud rate of 2.5G, achieving a bandwidth of 5.7G per lane, and with three lanes, it can reach a maximum of 17.1G, thus supporting standard 4K at 60fps.

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MIPI C-PHY’s

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