AUTONOMOUS & CONNECTED VEHICLES
Advanced circuit protection for connected autonomous vehicles New protocols for high connectivity need robust protection for reliability and safety.
Human ESD models 330 Ω
JAMES COLBY | LITTELFUSE, INC. At the turn of the century, automobiles hosted many electronic systems that were basically independent. Since then, the growth of connectivity and rise of artificial intelligence
330 pF Occupants inside passenger compartment
and machine learning have changed automotive electronics dramatically. Vehicles of all types are becoming complex interconnected communication centers, and autonomous vehicle functions are only increasing that level of sophistication. New protocols are being deployed to boost connectivity while facilitating broadband-like automobile communications. V2X technology is designed to help vehicles to communicate with the road and each other to prevent collisions and optimize traffic flow. Automotive versions of Ethernet and HDBaseT are being implemented to boost the speed and efficiency of highspeed data transmission between key subsystems such as high-definition cameras, Lidar and radar sensors, and wireless connectivity features.
ISO 10695 basic test circuit 100M Ω
330 Ω / 2,000 Ω
150 pF/330 pF
26
DESIGN WORLD — EE NETWORK
Littelfuse — A&CV HB 08-19_v2.indd 26
DUT
8 • 2019
2,000 Ω
150 pF
Outside person reaching into passenger compartment
ISO 10605 testing uses two different resistors, 2 kΩ and 330 Ω, to simulate different types of ESD events. The 2 kΩ resistor represents a human body discharging directly through the skin, while the 330 Ω resistor simulates a human body discharging through a metallic object. The test also takes place at two different capacitances: 150 pF and 330 pF. These values represent a human body inside and outside the vehicle respectively. The 330 pF and 330 Ω test is the highest energy/current of any of the ISO 10605 test parameters, and thus is the most widely used test standard. A typical ISO 10695 test starts with the test circuit switch open and charges the 150 pF/330 pF capacitor. Closing the switch causes the capacitor to discharge across the DUT. The 100 M resistor in the diagram represents the resistance of the ESD gun typically used for such tests. The parallel L-C represents parasitics.
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8/8/19 8:19 AM
