1 / 2019-10-01 01:33:36

Design and Implement EMI effective noise suppression filters for video circuits applications while preserving data transfers

EMI, suppression filters, display technology, LVDS, integrated EMI filters

Displays in consumer vehicles have long been dominated by head unit screens, providing navigation and display audio for drivers and passengers. Such displays were once the preserve of premium vehicles, but have since penetrated through to high volume vehicle segments, often as standard fitment. The capacities and content of these displays will evolve over time to meet the increasing connectivity of consumer vehicles, and to ensure that these separate displays are more seamlessly integrated.
As automotive display market continue to evolve, the next display generation requires increased functionality with more colorful and high-resolution features. The implementation of high resolution LCDs will pose several challenges for designers. One of the major design considerations for those devices is the electromagnetic interference for these new modules, which are getting more and more severe nowadays.

In video circuit application, PCBs incorporate many signal lines with high-level noise. In most cases, transmission signals to the LCD are LVDSs (Low Voltage Differential Signals). Since the LVDSs are high-speed signals containing high-level noise, the connection cable (flex) between the main PCBA and the LCD also emits high-level noise.
In this paper characteristics, effectiveness and efficiency of the various types of EMI suppression filters for LCD applications are discussed. Design constraints as board saving, high filtering performances at some frequencies and preservation of signal integrity are presented. To suppress these EMI interference and preserving data transfers, several filters solution are put forward and can easily be implemented. This can be accomplished using discrete resistors and capacitors with some layout considerations or integrated EMI filters.

With the rapid development of electronic technology, systems shrink in size and become more interconnected, EMC is of huge concern to overall system performance. EMI is getting more and more serious with each passing day. If there is no EMI problem the situation of electromagnetic compatibility has been achieved. Therefore, the study of the elimination of electromagnetic pollution has wide significant.