New IC and topology to break through the bottleneck of automotive data network (1)

Photocoupler

Today's car designers face a major challenge with opportunities: customers need more connectivity and graphics, and are clearly willing to pay for it. Drivers and passengers naturally need basic operational information, but they also need real-time maps, entertainment and information. If they are used to it and actually like to use multiple screens in a home and office environment, how can they not want this in a mobile car environment?

The reality is that for today's young car buyers, this connection and display has changed from "dispensable" to "necessary." Whether you call it an infotainment system, a smart drive interface, a connected car, a car cloud connection, or any other name, this trend will not change, and it is becoming a standard accessory for all cars except low-end cars.

But we also face a technical problem. The manageable problems in a fixed home/office environment are quite different in a car environment. Supporting multiple screens is not only a matter of computing power. It also involves complex wiring, connectors, heat dissipation, and signal integrity issues, all of which are complex and severely constraining the automotive world.

In theory, three issues must be addressed: a high-performance interconnect network between the graphics processing core, multi-display, graphics engine, and display. Consider assembling an instrument panel on the car, a front passenger side display, a center console, and possibly a head-up display [HUD], a rear-view camera, or even a rear-seat surveillance camera. The biggest challenge is how to effectively use a single centralized set of graphics rendering and image processing kernels to support four, five or even more displays and cameras?

The obvious solution is to use large standard PC cables and interfaces like HDMI, but this approach doesn't work for a variety of reasons. First of all, the wiring of these cables is extremely labor intensive. Second, signal integrity is also a major problem in noisy automotive environments, especially at long distances. In addition, the cost and weight of the copper cabling is also a problem, and the connector itself is too large and awkward. Reliability and performance are not guaranteed in harsh automotive environments.

Fortunately, there is a solution that can leverage existing mass consumer market technologies to be economically and efficiently applied to automotive applications and environments. First mentioned, today's video subsystem is capable of supporting 3D streaming video, with images visible to both the left and right eyes.

But with the proprietary technology of leading IC vendors such as Inova Semiconductors and Analog Devices, the stereo video format and HDMI interface are used to solve bandwidth issues and physical connectivity issues.

The interface trunk does not use a 19-wire HDMI cable, but only requires a 4-wire cable to provide differential signals through two pairs, using a "star-stranded four-core" structure with a 100Ω nominal impedance. The 1Gbps APIX link (shown in Figure 1) introduced in 2007 proved to be efficient and reliable.

Of course, users will never be satisfied with speed, so the second-generation AIPX2 achieves 3Gbps speed (as shown in Figure 2), which is backward compatible with the original APIX1 and has been in production since last year.