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This article discusses various multimedia features of LVDS, including: low power supply voltage, low power consumption, low radiation, high anti-interference ability, and simple cable routing and terminal matching.
Low voltage differential signal transmission (LVDS) has been proven in many applications. LVDS has other advantages while transmitting high data rate signals: compatibility with low power supply voltage, low power consumption, low radiation, high interference resistance, simple wiring and The terminal-matched LVDS is in differential mode (Figure 1). The inherent common-mode rejection capability of this mode provides a high level of interference immunity. Due to the high signal-to-noise ratio, the signal amplitude can be reduced to approximately 100mV (Figure 2). Allows very high transmission rates. The lower signal swing also helps reduce power consumption. Compared with the above advantages, the shortcomings of LVDS (each channel requires two wires to transmit signals) have become insignificant. 
Figure 1. Basic LVDS transmit and receive structure 
Figure 2. LVDS signal strength and amplitude
With the increase of integrated safety and auxiliary electronic equipment in the car, the demand for high-speed interconnection in the automotive field has increased dramatically, mainly focused on driving support (electronic mirrors, navigation systems, parking distance control, over-the-horizon display , Look-up display) video display system, car entertainment system (TV and DVD player), etc. These applications require high-speed data transmission to meet the requirements of image transmission. It is these growth in demand that has driven LVDS products to emerge in these areas (Figure 3). 
Figure 3. Typical LVDS connection for automotive applications
LVDS is very suitable for automotive applications. There are many sources of electromagnetic radiation inside the car, so anti-interference ability is the most basic requirement for automotive electronic design. In addition, considering the low-radiation advantage of the LVDS transmission line itself, there is almost no additional interference to other facilities of the system. LVDS transmission only requires a simple resistance connection, which simplifies the circuit layout, and the line connection is also very simple (using twisted-pair copper cables). LVDS is compatible with various bus topologies: point-to-point topology (one transmitter, one receiver) multi-branch topology (one transmitter, multiple receivers) multi-point topology (multiple transmitters, multiple receivers) automotive design There is a key problem, that is, the ground potential at different positions of the car body is very different, and the potential difference may reach several volts. In the DC-coupled interface configuration, such a potential difference will quickly interrupt data transmission. This problem can be solved by capacitively transmitting signals, provided that the capacitors are not charged in the same direction for a long time during signal transmission.
However, practical applications cannot rule out the possibility of charging in the same direction for a long time, for example, when transmitting a long series of continuous 1 signals. MAX9213 / 9214 (Figure 4) uses the "DC balance" technology to avoid the above problems. This type of device monitors its transmission data. When it shows an excessively long continuous 1 or 0 signal, the chip will flip the data before sending the data. The receiver can easily reconstruct the original signal by flipping the signal. These operations eliminate the long series of continuous 1 or continuous 0 signals, reduce the impact of capacitor charging, and effectively solve the problem of ground potential deviation. 
Figure 4. Two-chip transmission scheme, combining transceiver function and serial-deserialization function
From Figure 3, another potential problem can be seen: the interconnection of many systems means a large number of cable connections, and the cable (harness) connection in the original car design has been very crowded. To solve this problem, different data needs to be distinguished Transmission requirements, not all connections require particularly high speeds, Maxim's MAX9217 / 9218 can provide up to 700Mbps data rate through a pair of twisted pairs (Figure 5). With this capacity, you can easily connect a 480 x 800 resolution monitor. 
Figure 5. Functional block diagram of the AC-coupled serializer and deserializer
In order to further optimize the electromagnetic radiation characteristics, Maxim's chip also synchronizes all switching operations in the parallel data display process to the clock frequency, which can be adjusted in the range of 3MHz to 35MHz (for a given application, use the lowest allowable clock frequency To minimize electromagnetic radiation). In addition, by reducing the amount of switching caused by the data stream itself, including special coding and serial output common mode filtering, it also helps to improve electromagnetic compatibility. Optical fiber interface can also improve EMI, but this solution has other problems and is expensive.
LVDS devices must have high ESD protection, especially input and output pins, which is also a very common requirement in the automotive industry. These pins must be able to withstand ± 15kV air gap discharge and ± 8kV contact discharge specified by IEC 61000-4-2, or ± 10kV air gap discharge and ± 8kV contact protection specified by ISO 10605.
In summary, the LVDS interface is an excellent choice for connecting board-level systems in automotive applications, both now and in the future. In order to achieve this goal, Maxim has developed increasingly perfect chips based on the experience of the first generation LVDS product testing and application. In recent years, these chips will surely become the leading LVDS connection scheme in the design of automotive bus systems product.
Application prospects of LVDS multimedia interface in the field of automotive electronics
Abstract: The increasing demand for data communications has created a variety of new data interfaces that provide corresponding level indicators for different application areas. High data rate, high anti-interference and simple structure have become the key requirements for developing these interfaces.