PoC Filter Inductor Layout for Wideband Serial AC Blocking
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Solution Overview
Problem
Existing technologies struggle to effectively block undesired alternating current (AC) signals in serial communication links while maintaining proper operation over a wide frequency range, which is crucial for advanced driver assistance systems (ADAS) in vehicles.
Innovation Solution
The implementation of power over cable (PoC) filters using two inductors per filter to present a sufficiently high impedance across the entire operating frequency range, effectively blocking AC signals and allowing DC power transmission, thereby promoting small size and low cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional filtering technologies are used to block AC signals, then AC signal blocking is achieved, but the filter size and cost increase significantly
Solution Approach 1:
The filtering function is segmented into two separate PoC filters placed at opposite ends of the serial communication link, with each filter containing only two inductors. This segmentation allows each filter to be simple and small, while collectively achieving the required AC signal blocking performance across the wide frequency range.
Solution Approach 2:
The solution moves from a single complex filter design to a distributed filtering approach across the communication link. By placing simple filters at both ends of the link, the system achieves superior AC blocking performance without requiring large, complex individual filters.
2Reliability
If high impedance is presented across the entire operating frequency range (10 MHz to 3 GHz), then AC signal blocking is improved, but filter complexity increases
Solution Approach 1:
The frequency range coverage is achieved by segmenting the filtering function across two geographically separated filters, each handling a portion of the overall filtering requirement. Each filter uses only two inductors with specific inductance values that, when combined with the transmission line characteristics, provide the necessary impedance across the entire 10 MHz to 3 GHz range.
Solution Approach 2:
The solution changes the approach from using complex filter structures to carefully selecting inductor parameters (inductance values). The two inductors in each PoC filter are configured with specific L values that, together with the transmission line impedance, create the required high impedance condition across the wide frequency range through parameter optimization rather than structural complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The PoC filters ensure reliable data and power transmission in ADAS systems by blocking AC signals, achieving high impedance across a wide frequency range, thus enhancing system performance and reducing size and cost.
Implementation Method 1
the first PoC filter includes two inductors that are configured to collectively present a sufficiently high impedance, e.g., an impedance of at least one thousand ohms, to enable proper serial communication link operation
Data Source
AI summary
A serial communication link includes a waveguide having a first end and a second end, a serializer communicatively coupled to the first end of the waveguide, a deserializer communicatively coupled to the second end of the waveguide, a first power over cable (PoC) filter, and a second PoC filter. The first PoC filter is electrically coupled between to first end of the waveguide, and the first PoC filter includes two inductors that are configured to collectively present an impedance of at least one thousand ohms over an entire operating frequency range of the serial communication link. The second PoC filter is electrically coupled to the second end of the waveguide, and the second PoC filter includes two inductors that are configured to collectively present an impedance of at least one thousand ohms over the entire operating frequency range of the serial communication link.