Passive PCB Manufacturing Data Identification via TDR
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is no cost-effective method for systems management devices to track or read manufacturing information on passive printed circuit boards without active components, as they typically rely on expensive personality cards with additional connectors and development costs.
Innovation Solution
Using time-domain reflectometry to measure signal reflection delay in conductive traces on passive printed circuit boards, which is then used as an index to retrieve manufacturing information from a predetermined table, and drilling holes at specific positions along the traces to indicate manufacturing data without the need for active components or separate personality cards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a personality card with EEPROM is used to store manufacturing information, then manufacturing information can be tracked and read, but the system cost increases due to additional connectors and development/production costs
Solution Approach 1:
The invention extracts the manufacturing information storage function from separate active components (EEPROM, personality cards) and embeds it directly into the passive PCB structure through conductive trace variations. The PCB itself becomes the storage medium by utilizing differences in trace length, geometry, or configuration that create distinct electrical characteristics measurable by TDR, eliminating the need for additional information storage components.
Solution Approach 2:
The conductive traces on the PCB serve multiple functions: they provide electrical connectivity for signal transmission and simultaneously encode manufacturing information through their physical characteristics. The same trace structure that performs its primary electrical function also serves as the information storage medium, eliminating the need for separate dedicated information storage components.
2Reliability
If no active components are used on the passive PCB, then reliability is improved by avoiding components that may compromise failure rates, but the ability to track manufacturing information is lost
Solution Approach 1:
The invention replaces electronic active components (EEPROM, microcontrollers) with a passive mechanical/physical structure (conductive traces with specific geometries, lengths, or configurations). The manufacturing information is encoded in the physical dimensions and arrangement of copper traces rather than in active electronic memory cells, achieving reliable passive information storage.
Solution Approach 2:
The invention encodes manufacturing information by varying physical parameters of the conductive traces such as trace length, trace width, trace geometry, or trace configuration. These parameter variations create distinct electrical characteristics (impedance, propagation delay, reflection coefficients) that can be measured and used to identify manufacturing information without requiring active components.
3Ease of manufacture
If TDR is used to measure signal reflection delay for identifying manufacturing information, then cost-effective identification is achieved, but measurement precision requirements increase
Solution Approach 1:
The invention creates distinct local characteristics in specific portions of the PCB by varying conductive trace parameters only in targeted areas. Instead of requiring precise measurement of the entire trace, the information encoding is localized to specific trace segments with unique geometries or configurations, allowing manufacturing information to be identified through measurements of these localized features rather than requiring high-precision measurement of the complete trace length.
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
This method allows for cost-effective identification of manufacturing information on high-reliability passive printed circuit boards without active components or separate personality cards, improving system management efficiency and reducing costs.
Implementation Method 1
using time-domain reflectometry to measure a signal reflection delay in a conductive trace
Data Source
AI summary
A method uses time-domain reflectometry to measure a signal reflection delay in a conductive trace formed on a specific passive printed circuit board, and uses the measured signal reflection delay as an index into a table storing a predetermined association between signal reflection delay and passive printed circuit board manufacturing information, wherein the table includes a plurality of predetermined signal reflection delay values, and wherein each of the predetermined signal reflection delay values is associated with unique passive printed circuit board manufacturing information. During manufacturing of the passive printed circuit board, a hole is drilled through the passive printed circuit board so that the hole intersects with the conductive trace and divides the conductive trace into a proximal segment extending from the connector to the hole and a distal segment that is electrically isolated from the proximal segment by the hole.