Industrial transportation electronics is a broad category. It includes after-market additions for automation and entertainment in cars, trucks, trains, planes, and ships. It also includes infrastructure automation for roads, sea-lanes, trains, and air traffic control to move people and goods more efficiently.
Over the last few decades, after-market automotive products drove remarkable innovation, from infotainment and telematics to ADAS. Examples include GPS, audio, seat back video, rear-view cameras, parking sensors, charging ports, keyless entry, and others. Today, we see all these features integrated into the cars and trucks by OEMs. However, there is a continuous rollout of novel after-market technologies being developed by companies worldwide. Recent innovations include fleet management, on-board diagnostics, heads-up display, gesture-controlled navigation, network gateways, driver assistance, keyless/biometrics-based entry/exit/driving, and freight control/monitoring. These technologies have found places not only in cars and trucks but also in trains, ships, avionics, and defense applications.
Transport infrastructure automation to move people and goods more efficiently includes HOV lane control, parking/toll, fare meters, traffic control, and others. Numerous innovations have made faster movement, on-time schedules, and fewer accidents possible.
In this article, we will discuss the key market trends and customer needs which are presenting new challenges for power supply design for after-market technologies and transport infrastructure automation. Then, we’ll explore solutions to address these challenges, with a special emphasis on power architecture.
One of the most dynamic applications in industrial transportation today is fleet management and logistics. With goods being manufactured and shipped from various regions, states, countries or even overseas, tracking the goods is a big business. For example, when perishables are transported, it is important to ensure they are consistently kept under regulated temperature, pressure, or other parameters. Similarly, secure goods require sensors to track location and entry access. Driver safety is also essential, requiring data from cameras monitoring driver alertness and GPS systems tracking vehicle location.
This data is logged using wireless networks and cloud infrastructure, and complex algorithms synthesize the data to make real-time decisions on route and/or driver safety. Several GPS navigation companies have entered the fleet management market, providing hardware and software products and services. North America, Europe, Japan, and Korea each have a long history of advanced fleet management systems. More recently, Latin America, China, and India are adding this capability, presenting a huge growth opportunity. Interestingly, Israel has several players that develop products for consumption in Israel, Africa, Europe, and the rest of the world.
Some might think there is not much innovative technology to add to infotainment, what with so many audio/video, smartphone, and navigation options coming as standard features from OEMs. Yet, trends in this area include integration beyond a simple smartphone interface to add heads-up display (HUD) that projects the phone screen onto the windshield glass with gesture control to navigate between maps and video calls, or other salient features like weather, stock ticker, calendar, etc. Seat back screens to mirror the phone screen for rear passengers is also an active product development area.
Advanced driver assistance systems (ADAS) is a growing market today. After-market ADAS includes parking sensors, rear-/extended-view cameras, lighting, traffic warnings, car-to-car (vehicle-to-vehicle) interface, and others. Several manufacturers are working on solutions that enable drivers to avoid unintended lane departures, collisions, pedestrians, and road hazards, as well as drive within the speed limit.
With the amount of time people spend in cars in highly congested urban cities, many cars and buses are also adding wireless gateways. This enables passengers to continue to work during long commutes between home and office/school.
Typical System Architecture
Here is a typical fleet tracking/management system architecture:
Figure 1: Typical fleet tracking/management system architecture
The fleet tracking/management device is powered by the vehicle battery, typically 12V in cars and 24V in many trucks. As an after-market add-on, it faces a much harsher power management environment than a well-bounded OEM device. Most devices also have a rechargeable backup battery, typically 3.6V, intended to last two or three days when the main battery power is lost. From the main battery source, the front-end electronics are protected against transient and fault conditions. The protected voltage is converted to useable, lower voltages (3.3V, 2.5V, 1.2V, etc.) by step-down DC-DC converters and LDOs to power various digital logic and analog ICs.
Figure 2: Typical fleet tracking/management power architecture
Protecting the Device from Faults
Like many other electronics that draw power from a vehicle battery, the fleet tracking/management device must be protected from voltage surges commonly known such as load dump, regenerative braking, long cable ringing, etc. Load dump is an event where the battery cable is suddenly disconnected while the alternator is spinning, putting high energy back to the vehicle power cable where there is nothing to absorb it, causing high voltages that could destroy unprotected electronics. Regenerative braking occurs in an electric vehicle when the driver applies the brake; the vehicle kinetic energy is captured by the motor and sent back to charge the battery. Due to the high energy, high di/dt nature of regenerative braking, there will be high voltage ringing associated with this event.