Automotive Transformers for Ultrasonic Sensors
Tech Notes
Products & Technologies
TDK Corporation (TSE:6762) presents the new B78302A* series of compact EPCOS transformers with innovative E5 cores for ultrasonic applications. It comprises three types with transformation ratios between 1:1:10.8 and 1:1:15.3. Depending on the type, the new transformers in SMD design offer inductance values between 2 mH and 4 mH and are suitable for frequencies from 50 kHz to 300 kHz. The AEC-Q200 qualified components have very compact dimensions of only 8.1 x 7.0 x 7.0 mm and are shielded by a counter-winding for better interference suppression. The permissible temperature range is between -40 °C and +125 °C.
TDK Corporation (TSE:6762) presents the new B78416A* series of compact EPCOS transformers with EP 6 cores for ultrasonic applications. The series comprises five types with transformation ratios between 1:1:8.42 and 1:1:15. Depending on the type, the new SMD-version transformers offer inductance values between 3 mH and 5 mH and are suitable for frequencies between 52 kHz and 300 kHz. The components are compliant with AEC-Q200, feature highly compact dimensions of just 9.0 x 7.6 x 7.1 mm and are magnetically shielded for better interference suppression. The permissible temperature range lies between -40 °C and +125 °C.
The evolution of sensing technology and communication network contribute to the realization of an Autonomous driving society and its growth. Ultrasonic parking assistant is a key sensor for automated driving and parking functions. Ultrasonic parking sensors were in use in Europe long before debate on automated driving became active. TDK has for many years supplied Piezo Disks and ultrasonic driver transformers for use with ultrasonic parking sensors. TDK also developed a multilayer ceramic chip capacitor that exhibits attenuating capacitance (ZL characteristics) under high-temperature environments that is suitable for resonant circuits with Piezo Disk. This article presents Piezo Disk, ultrasonic driver transformers, and MLCC with ZL characteristics.
TDK Product Features
Ultrasonic sensors are used for measuring distances in many applications. Probably the best known of these are the parking assistant sensors. As many as four sensors may be mounted in each car bumper. By transmitting an ultrasonic signal and evaluating the signal reflected from an obstacle in the electronic control unit (ECU), these sensors then help determine the distance from an obstacle. The use of a transformer is recommended in order to ensure optimum adaptation of the sensor piezoceramic to the logic. The EP6 transformer, which is suitable for this application, features close inductance tolerance, minimal drift across the temperature range and very low sensitivity to external electromagnetic fields. The component is designed as an SMD and is qualified to AEC-Q200 for automotive use.
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