The most concentrated area of ​​the automotive chip market: SerDes introduction

SerDes for transmission from the ECU to the display panel inside the cockpit is basically monopolized by Texas Instruments, namely FPD-LINK. FPD-Link is a communication standard based on the LVDS physical layer. Its full English name is Flat Panel Display Link, which was proposed by National Semiconductor in 1996. The FPD-Link I generation chipset serializes the wide parallel RGB bus into 4 or 5 pairs of LVDS signals. The latest one is the fourth generation, namely FPD-LINK IV.

The panel display field is different from the camera field. Cameras are basically MIPI CSI-2. At present, the main image output interfaces are DP/eDP, MIPI DSI, OLDI, and HDMI. DP/eDP is the future development direction and can support 8K display screens. The mainstream of panel interface is still LVDS, and a few high-resolution ones use DP. LVDS is a digital video signal transmission method developed by National Semiconductor to overcome the shortcomings of high power consumption and large electromagnetic interference when transmitting broadband high-bitrate data in TTL level mode. In 2011, Texas Instruments acquired National Semiconductor for US$6.5 billion, which is why Texas Instruments occupies a dominant position in the field of automotive display panel SerDes. ADI is also making efforts in the field of panel display to challenge the dominant position of Texas Instruments. ADI's product line is also wide enough.

People in China like multiple screens, and using deserializers can easily achieve four screens on one machine.

Image source: ADI

Asymmetric splitting can also be done.

Image source: ADI

The block diagram can also be displayed on two screens at the same time.

Image source: ADI

Texas Instruments is the most advanced company in this area with its SuperFrame technology, the DS90Ux941. With up to 5 to 7 screens in a car, it would be very costly to use multiple application processors (APs) to drive multiple displays or to develop APs that can drive multiple displays. The capabilities of the DS90Ux941AS-Q1 enable more economical IVI system designs, with only one AP required to deliver content to two symmetrical or asymmetrical displays. In these systems, the AP receives two video frames and combines them into a superframe, while the DS90Ux941AS-Q1 separates the superframe and forwards the resulting frames to a compatible FPD-Link III deserializer and connected display.

Image source: Texas Instruments

If two screens are not enough, you can also have three screens, namely DS90UH983.

Image source: Texas Instruments

One video stream is in super frame format, and the other is in regular format. After being separated by DS90UH983, three videos can be obtained, and then deserialized to correspond to three screens.

From cockpit SoC to display panel, SerDes has a very stable position. In the camera field, SerDes faces competition from automotive Ethernet, but the physical layer cost of automotive Ethernet is too high, especially Gigabit or 10 Gigabit, and cockpit chips rarely support 10 Gigabit Ethernet. In the high-pixel field, automotive Ethernet has no advantage, and the advantage in the low-resolution field is not obvious. SerDes will still be the dominant force in the next 5-8 years.