ESD Solution for Vehicular Multimedia Unit
Vehicular multimedia systems have been developed for years by an increasing number of technical manufacturers. For the protection against electrostatic discharge (ESD), many of these systems are equipped with ESD protectors to keep the I/O ports from destructive ESD energy. The multimedia system is subject to electrostatic interference when its I/O is exposed to excessive ESD energy. Without appropriate ESD protection, it is likely to see system damage or even I/O port malfunction. It is necessary to have good ESD protectors for vehicular multimedia system units.
It was common to see USB2.0 for I/O ports in vehicular multimedia systems. Some R & D design engineers tend to have a single-channel ESD protector for all signals at all I/O ports of a unit. To realize new applications, such as Apple Car Play / Android Auto, however, the previous USB2.0 Type A is often replaced with USB Type C in recent vehicular multimedia system designs. Some systems are provided with HDMI port in place of video transmission through AV-in port. It is recommended not to have a single ESD protector for all signals for easy material preparation, since the signal voltage varies from one I/O port to another. With one universal protector, chances are the clamping voltage of the protector does not fit for every I/O port in terms of voltage withstanding. The correct way is to select an ESD protector for individual I/O ports based on the application needs. This provides better ESD protection for multimedia system units.
ESD protectors recommended for common I/O ports in vehicular multimedia system units
1. Dual Port USB2.0
A vehicular multimedia system is often provided with USB2.0 ports. With a single-channel ESD protector, 6 such protectors are needed to protect USB2.0 ports. However, only one 4-channel array type protector, such as AZ9115-04S, is needed to have previous 6 protectors in one single package. Figure 1 below provides the wiring schematics for the Dual Port USB2.0 ESD protector.
2. USB Type C
AZ9143-04F is suitable for the ESD protection at TX/RX of a USB Type C port. D+/D- works well with AZ9115-04S ESD. At Vbus, it should be considered whether there is a need to support USB Power Delivery at the Type C port. A 20V ESD protector is needed if high-voltage, quick charging at 20V is supported at Type C Vbus in the vehicular multimedia system. The available selections are listed in Figure 2.
3. HDMI Port
The AZ9143-04F is perfect for ESD protection at TMDS high-speed signal position of an HDMI port. For the low-speed signal position of an HDMI port, AZ9115-04S is suitable for the job. The HDMI ESD protection wiring is presented in Figure 3 below.
Conclusion:
With vehicular multimedia devices becoming more and more multifunctional, the AV signal ports are upgraded to HDMI and Type C featuring faster data transmission. The system stability becomes increasingly demanding and more and more attention is paid to ESD protection. While HDMI and Type C ports are fairly common in consumer electronics, the ISO10605 ESD test specifications are requested the most for their applications in vehicular multimedia system units. In the ESD test level for vehicular products, the maximum test requirement is Air 25kV, which is far different from Air 15kV for consumer electronics. The system may fail the ESD test and certification if a TVS product with inappropriate ESD protection is selected. Amazing’s vehicular TVS series provides outstanding ESD protection recognized by the AEC-Q101 certification. Contact us if you have a need for ESD/EOS protection in your vehicular system.
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