Maxim Integrated: Adding Power to the Smart Cockpit

The intelligence of cars is also driving the smart cockpit market. According to Visteon's research data, the global market size of major smart cockpit products was about US$32.9 billion in 2018, and is expected to reach US$46.1 billion by 2022, with a compound annual growth rate of about 8.8%. The reason is that no matter how "smart" a car is, it still serves the users sitting in the car, and the smart cockpit is the "interface" that connects the car and the cockpit users. The better the user experience, the happier consumers will be when they pay for the car.

Therefore, in recent years, among the functions related to smart cockpits, people have paid the most attention to the human-machine interface (HMI) technology of automobiles. In the most popular understanding, automobile HMI is to build an effective communication bridge between users and vehicles, so that the two can "talk" without obstacles. Its role can be summarized in two aspects: on the one hand, the instructions issued by users must be "heard" and "understood" by the vehicle; on the other hand, the vehicle must be able to convey the vehicle status and environmental information to the user in a timely and accurate manner through HMI, so that the user can make correct decisions quickly.

The Evolution of Automotive HMI

The evolution of automotive HMI has gone through a long process along with the development of the automotive industry. Initially, the HMI method was purely "mechanical": the driver input control "instructions" through the accelerator, brake, steering wheel, etc., which were directly transmitted to the vehicle through mechanical means; and the car's speed, fuel consumption, mileage and other information were also displayed to the driver through mechanical instruments.

This rather dull way of "conversation" between people and cars has gradually changed with the development of automobile electronics. At this time, users can control more and more body functions through buttons and knobs in the cockpit. Later, the wire control system developed from this took over the control of the core power system. In other words, the way people "give orders" to the car has changed. At the same time, the addition of in-vehicle information and communication systems has also introduced LCD screens into the cockpit, and the way cars transmit information to people has become more intuitive and cool.

Later, with the use of touch screens, a screen can be used to receive vehicle information and issue control commands, which has taken automotive HMI to a new level. The most representative example in this regard is Tesla's Model 3, in which a 15-inch touch screen replaces the dashboard and central control in the traditional cockpit, and almost all physical buttons are eliminated. After that, the large screen has almost become a symbol of whether the cockpit is "smart", and other competitors are also following suit and quickly following suit.

But in fact, as the extension of the definition of automotive intelligence continues to expand and its connotation continues to enrich, the development of automotive HMI will certainly not stop at "a large screen". Therefore, finding subsequent technology and market focus has become an important topic in the current automotive electronics field.

In summary, there are mainly the following competitive tracks in future automotive HMI.

1. Multi-screen display

If all information interactions are concentrated on a large screen, it is likely to cause difficulty in switching between different functions, and the screen is too large to be easily placed in the limited space of the cabin, so "multiple screens in one car, multi-screen linkage" has become a design trend. Different screens such as the central control display, digital instrument panel, co-pilot or rear entertainment screen, smart rearview mirror, etc. can be configured on demand according to different user scenarios. According to Strategy Analytics' forecast, in the future, the number of display screens in some high-end cars will exceed 10.

2. HUD Head-up Display

This information interaction method originated from fighter jet HMI. Through AR technology, key vehicle driving information can be projected onto the windshield in an image format and integrated with the actual road and environment, so that the driver can see the vehicle status at a glance without shifting his or her sight, and can control the vehicle based on information such as vehicle condition, geography, and safety. Although this technology is not yet mature, its market penetration has been accelerating in recent years.

3. Voice Recognition

This may be the most "natural" way for people to "talk" to the vehicle. You don't need to use your hands, just speak, and the vehicle can listen to your commands, which avoids occupying the driver's precious visual "channel", keeps their attention from being distracted, and makes driving safer. As voice recognition is polished and matured in consumer applications, it should be just around the corner for it to become a standard feature in more and more car models.

4. Gesture Recognition

This is considered to be the focus technology of the next generation of natural HMI together with voice recognition. With the trend of diversified application scenarios of smart cockpits, it will also have its own place. Based on this technology, users can directly control specific functions in the vehicle through gestures such as sliding and rotating. It can be used as a supplement to voice control solutions in many scenarios, and it also has obvious advantages in feasibility, response speed and cost-effectiveness.

It can be seen that automotive HMI is developing in a more intuitive, natural and diversified direction. The application of these emerging automotive HMI technologies will inevitably give rise to new electronic components and assemblies, which is an opportunity for components and products including sensors, data processing, touch and display, as well as power and analog.

Of course, it is not easy for these new components to be installed in cars. Not only must they meet the functional requirements of the new generation of automotive HMI in terms of performance and functionality, but they must also meet strict automotive regulations in terms of quality and reliability. They must also be competitive in terms of miniaturization and cost... To meet the above requirements, considerable technical background and strength are required.

Today we recommend two devices developed by Maxim Integrated for the next generation of automotive HMI. I believe that after reading their introduction, you will have more "materials" in your BOM when doing your next Design-In.

Highly integrated and reliable screen backlight driver solution

As mentioned above, large-screen and multi-screen display units are an important trend in automotive HMI. In order to meet the increasingly complex system requirements, high-precision, high-reliability, high-flexibility and miniaturized power solutions are essential. The MAX20444B is a device designed according to such standards. It is a 4-channel backlight driver for automotive displays with a boost controller that supports up to 130mA LED current sink per channel. The internal current mode switch DC-DC controller supports boost or SEPIC topology and operates in the 400kHz to 2.2MHz frequency range.

Figure 1: MAX20444B four-channel backlight driver IC
(Source: Maxim Integrated)

Its outstanding performance advantages include:

Highly integrated: Complete 4-channel solution with integrated boost controller, I2C control to minimize component count.

Highly reliable, low EMI: Operating in the 400kHz to 2.2MHz frequency range, integrated spread-spectrum oscillator helps reduce EMI, and a fail-safe operating mode with FSEN pin.

Supports multiple dimming modes: PWM dimming and hybrid dimming controlled by I2C, the minimum PWM pulse width is 500ns, and light string phase shift dimming can be used to reduce EMI.

Wide voltage operating range: 4.5V to 36V wide input voltage, operating supply voltage as low as 4V after startup, and supporting load dump up to 52V.

Comprehensive diagnostic functions: including LED open/short detection and protection, boost output undervoltage and overvoltage, boost measurement, LED current measurement, thermal shutdown.

Low power consumption: Adaptive output voltage control method can minimize the power consumption of LED current drive path.

Small form factor: Compact (4mm x 4mm), 24-pin TQFN or SWTQFN package.

Low-cost, miniaturized automotive gesture recognition solution

In terms of supporting automotive gesture recognition, Maxim Integrated has launched an automotive-grade gesture sensor MAX25205. The sensor uses an integrated 6x10 pixel light sensor array to detect the reflected light of the controlled IR-LED light source to achieve proximity detection and gesture recognition, even in bright ambient light conditions. By using it with a low-power, low-cost MCU, gestures such as sliding, rotating and approaching can be detected to replace traditional electronic knobs and touch screen controls to control systems such as in-vehicle infotainment, telephones, side mirrors, air conditioning, sunroofs and interior lighting.

Compared with gesture recognition solutions based on time-of-flight (ToF) cameras, infrared sensing solutions based on the MAX25205 are lower cost and smaller in size—the cost is 10 times lower than other products on the market, and the volume is 75% smaller. This is undoubtedly very competitive.

Figure 2: Automotive gesture recognition solution based on MAX25205
(Source: Maxim Integrated)

The performance advantages of the MAX25205 are summarized as follows:

Fully functional: It can realize 9 gestures, including sliding (up, down, left, right), finger and palm rotation (clockwise and counterclockwise), approach, etc., and has lower latency than the three-chip solution with complex microprocessors.

Low cost: The cost is significantly lower than ToF camera solutions, and no complicated software development and maintenance process is required.