MIPI spec update maximizes device display power efficiency across mobile, automotive, gaming applications

Autonomous vehicle cockpit with headsup display
The automotive industry is just one sector that needs effective standard interfaces between device semiconductors and external displays. (metamorworks/iStock/Getty Images Plus)

The semiconductors that power mobile devices are out of sight and often out of mind for end users. It’s the electronic video displays of those devices that engage them, but that makes it all the more important to get the interface between the semiconductors and the displays right.

That’s an increasing challenge at a time when different kinds of mobile and portable devices--not just smartphones, but automotive dashboard displays and virtual reality and augmented reality headsets--are adding more kinds of displays to the market mix. At the same time, as the semiconductor industry responds to increasing pressure for greater power efficiency without sacrificing performance, device displays can prove to be hungry power consumers as well.

A newly-updated standard from the MIPI Alliance (MIPI stands for mobile industry processor interface) could help manufacturers address these challenges.

The group, an international organization that develops interface specifications for mobile and mobile-influenced industries, today announced the next generation of its already widely implemented MIPI Display Serial Interface 2 (MIPI DSI-2) specification.

MIPI DSI-2 specifies the high-bandwidth link between host processors and device displays. The new MIPI DSI-2 v2.0 spec will significantly boost power savings while also improving bandwidth and end user experience across a wide range of applications in the mobile, automotive and gaming sectors, the MIPI Alliance said. 

Regarding bandwidth, the v2.0 spec can help double bandwidth over the previous version of the standard when used in combination with the most recent versions of the MIPI C- and D-PHY physical interfaces, the alliance said. That translates to support for more than 6 gigapixels per second of uncompressed image content.

“MIPI DSI-2 is deployed in many of the world’s handsets, smartwatches, virtual reality headsets, laptops, tablets and automobiles, and this significant update delivers the next generation of features required to propel innovation in display technologies,” said Joel Huloux, chairman of MIPI Alliance, in a statement. “The new features introduced in MIPI DSI-2 v2.0 work together to enable dramatically enhanced gaming and other rich visual experiences at the lowest power consumption across the gamut of display applications.”

For automotive applications, DSI-2 is a core component of MIPI’s Automotive SerDes Solutions (MASS), a standardized connectivity framework built on the MIPI A-PHY SerDes specification for camera, sensor and display integration. 

MIPI DSI-2 supports the MIPI MASS framework for automotive use cases. (MIPI Alliance)

MIPI DSI-2 is particularly focused on helping systems designers to enable ultra-high-definition (UHD) video experience for end users, while maximizing battery life, and minimizing cost and complexity. Features in the new version enable displays to seamlessly and efficiently operate in a variety of use cases, from high-resolution, high-frame-rate video modes (such as 8K with 120 fps), to responsive, low-latency graphical user interface “command” modes, and static modes—for dramatically improved display performance at the lowest possible power consumption, the MIPI Alliance said. 

Among those key features, a video-to-command mode allows device displays to seamlessly transition from highly immersive video modes of operation to less-intensive command modes for low-frame-rate GUI images. That will help smartphone users, for example, to switch between gaming and other applications with minimal latency and performance impacts, while also keeping the device power consumption in check. 

The v2.0 spec also achieves power savings in other ways. A new adaptive refresh panel feature enables a device display to retain images for variable, extended durations without fixed refreshes from the host processor, saving power without requiring a peripheral frame buffer, the MIPI Alliance said.

In a nod to industry collaboration, the group also is continuing its work the Video Electronic Standards Association a group whose standards often apply to larger device displays like TVs. The v2.0 update includes support for the latest VESA Display Stream Compression (VESA DSC) 1.2b and VESA Display Compression-M (VDC-M) 1.2 codecs. By incorporating both codecs, which provide between three to six times data compression while maintaining visually lossless viewing, DSI-2 offers design options to suit a variety of bandwidth and power requirements, according to the MIPI Alliance.

The DSI-2 v2.0 spec is backward compatible with all previous versions of the specification. 

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