Car electronics circuit board
1. Td-based ESD protection
The best way to deal with the damage of transient impulse is to lead the transient current away from the sensitive device.The method is that TVS diodes are connected in parallel with the protected circuit on the circuit board.In this way, when the instantaneous voltage exceeds the normal working voltage of the circuit, the TVS diode will have an avalanche to provide an ultra-low resistance path to the instantaneous current. As a result, the instantaneous current is diverted through the diode to avoid the protected device, and the protected loop will be kept at the cut-off voltage until the voltage returns to normal.When the transient pulse is finished, the TVS diode will automatically restore the high resistance state, and the whole circuit will enter the normal voltage state.
2. Protection of video line
Video data line has high data transmission rate (its data transmission rate is up to 48OMbit/s, and some video data transmission rate is above IG), so low capacitance TVS should be selected.
3. USB protection
Universal serial bus (USB) technology is a new method to connect the main controller to different external devices.It can realize data exchange between the downstream port and the upstream port of peripheral.Current USB technology has two data rates: low speed (1.5mbit /a) and full speed (12MbiVs) 0 12MbiV.The USB data stream is 10 times faster than the parallel port and 100 times faster than the standard serial port.The increase of frequency must be correspondingly equipped with devices that can adapt to ESD sensitivity, TVS application circuit with quick response can meet the ESD protection of USB line terminal, and have a good low-pass filtering function.
4. Audio/speaker data line protection
In terms of audio data line protection, the protection circuit is relatively simple due to the low signal rate in the same way of audio and the requirement on capacitor parts is not too high (about 100pF is acceptable).It is a convenient, effective and reliable way to protect information equipment by TVS in automobile electronic system. Compared with other components, TVS has its unique advantages.However, components should be selected according to different protection objects in the specific application, and corresponding parameters and different designs of various manufacturers should be paid attention to. At the same time, optimal PCB design is also indispensable.