New Industry Products

High-Frequency Inductors for Automotive ECUs Offer High Reliability

June 10, 2019 by Scott McMahan

TDK says that the automotive industry is transitioning from an era where people drive cars to an era where people provide mobility services and employ autonomous driving capabilities. As a result, the number of electronic components used in cars is steadily increasing. (See comparison above). So, if even a single component fails, a specific function may be impaired. Therefore, designs of vehicles with more electronic components require improved reliability.

For this reason, TDK offers high-frequency power inductors for automotive applications that it designed for excellent reliability to reduce the risk of failure.

The company notes that automobiles are expected to be both safer and reduce environmental impact. Safety is produced via a combination of functionality and automatization.

Electronic control unit (ECU) redundancy and function allocation are an effective means for achieving high performance. The increase of xEV type cars (hybrids and electrical vehicles) is quickly reducing the environmental burden. At the same time, the number of ECUs is increasing, leading to stronger demand for electronic components, that require increased reliability, smaller size, and improved performance.

Trends in car electronics (Click on image to enlarge)

Changing environmental demands for automotive parts

TDK asserts that as xEVs become more commonplace and autonomous driving is progressing, the demands placed on the reliability of components have also changed.

The transition from internal combustion engines to vehicles with battery-powered electric motors results in the gradual elimination of heat sources inside the car, thereby decreasing environmental temperature requirements.

Autonomous driving on the other hand, is expected to prolong the usage times of the vehicle.

TDK says that environmental temperature requirements will depend on the respective functionality of the components, and ECU reliability requirements are expected to be around 3,000 hours.

ECUs use dc-dc converters to eliminate the influence of battery voltage fluctuations. As an EMI countermeasure, switching frequencies have been increased above the AM band to between 1.8MHz and 2.2MHz.

Changing Environmental Demands (Click on image to enlarge)

Three New Series of Inductors used in ADAS and EVs

TDK has launched three new series of inductors used in ECUs to meet the reliability demand of ADAS and EVs. The HPL series is suitable for the high current/low inductance requirements of high power ECUs including ADAS (Advanced Driver Assistance Systems) image processing. The TFM series covers the medium range suitable for secondary circuitry of ADAS and other ECUs. The BCL series supports the high inductance values of low-power ECUs for body and sensor applications, and others.

(Click on the comparison chart image to enlarge)

TDK says its range of high-frequency power inductor solutions optimized for automotive ECU applications meets the high-reliability demands of the sector.

The HPL, TFM, and BCL series of high reliability, high-frequency power inductors further reduce failure risks over the company's previous ECUs with an emphasis towards the realization of level 5 autonomous driving.

Compared to the metal-based power inductors for ICT applications, withstanding voltage and reliability characteristics have been further enhanced.

The HPL series offer high current / low inductance ratings, while TDK designed the BCL series for high inductance and low currents. The TFM series covers intermediate requirements, completing the lineup.

(Click on chart to enlarge)

The HPL and BCL series are designed to minimize open-mode failure risks while the TFM series minimizes the risks of short-mode failures.

HPL products are characterized by low Rdc with small leakage flux. They are 3-terminal types with high vibration resistance and excellent thermal dissipation Featuring improved insulation of the metal material, the inductors of the TFM series are guaranteed to withstand voltages up to 40 V and can be used also in the battery line. They realize low leakage flux and allow high-density mounting.

A new press method for the BCL series inductors minimizes the risk of wire damage. A low-loss magnetic material provides high efficiency for boost circuits with high magnetic flux. High inductance values are supported, making the inductors ideal also for circuits with a large potential difference between the input and the output.