Audio host (master controller of automotive infotainment system) has two HDMI inputs, an audio output, and a display video output. The HDMI receiver (Rx) decodes the video from two HDMI inputs and extracts the audio. The audio is converted to an analog signal and connected to the speaker. The first HDMI input is connected to the installed Blu ray player, which may be located in the trunk of the car. Second HDMI inputs provide connectivity to portable media devices equipped with HDMI, including smartphones, tablets, laptops, digital cameras and camcorders.
Automotive applications may include open systems or closed systems. Open systems allow connecting consumer devices, such as smart phones or tablet computers. The closed system permits the interconnection of dedicated modules within the vehicle entertainment system.
The closed system can be AC coupled to provide battery short circuit (STB) and ground to short circuit (STG) protection. While this is not illustrated in the current HDMI specification, it provides a clever solution to common automotive application problems. The HDMI receiver and transmitter IC shall not be damaged if there is a fault in the HDMI cable, the battery is short circuited or the ground is short circuited. The signal levels used in the HDMI interface are 3.3V and 5V, so the short circuit (12V) of the car battery usually damages the HDMI receiver and transmitter.
I. application background
1, HDMI needs to support hot plug
2, HDMI transmission rate is higher
3, HDMI chip is fragile, easy to static damage
Two, the protection scheme and tage device

The protection scheme and tage device
Transient suppressor diode
TVS1/TVS2/TVS3 [ULC0524P] Vrwm:5.0V; Vb:6.0V; antistatic capability (contact / air): 8KV/15KV; junction capacitor (f=1MHz): 0.8pF; package DSON-10
Three, Scheme Application
1, laptops, PAD, home desktop computers, industrial computers
2, equipment.
3, set-top boxes
4, mobile handheld devices
5, television
6, car
7, DVD burner
8 other HDMI port devices
Four, program description and matters needing attention
1, respectively, in the HDMI data lines, clock frequency transmission line with TVS ground protection, clamping electrostatic voltage.
2. The TVS has a junction capacitance of less than 0.8pF and can transmit the full signal at the highest transmission rate of HDMI.
3, the TVS package for DSON-10, small size, save PCB space, easy for engineers to design.
Protection scheme of HDMI1.4 interface circuit