Semiconductor I/O Pad Impedance Control With Best-Code Selection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional impedance controllers for semiconductor devices face issues with precise impedance matching, leading to improper operation and dithering due to undesired bit patterns and the arbitrary selection of codes without considering better impedance matching.
Innovation Solution
An impedance controller with an impedance control transistor array, first and second determination units, and an error detector to identify and select the best code for impedance matching, and an error prevention unit to adjust impedance and prevent undesired bit patterns, ensuring accurate impedance matching between the semiconductor device and external impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional impedance controllers use arbitrary code selection without considering impedance matching quality, then device complexity is reduced, but impedance matching precision deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the comparator continuously monitors the impedance matching status by comparing the actual impedance with the target impedance. The up/down counter adjusts the code based on the comparator output, creating a closed-loop control system that automatically optimizes impedance matching without requiring complex external intervention.
Solution Approach 2:
The impedance controller performs self-adjustment through the integrated comparator and counter mechanism. The system automatically detects impedance mismatches and corrects them by adjusting the code, eliminating the need for external calibration equipment or complex manual tuning procedures.
2Manufacturing precision
If conventional impedance controllers detect alternating bit patterns for impedance matching, then manufacturing precision is improved, but reliability deteriorates due to undesired bit patterns causing improper operation
Solution Approach 1:
The patent converts the harmful effect of alternating bit patterns (which cause improper operation) into a beneficial detection mechanism. The dithering detector specifically identifies these alternating patterns as indicators of successful impedance matching, allowing the system to distinguish between desired and undesired states and operate reliably.
Solution Approach 2:
The system performs preliminary detection of bit patterns before final impedance matching is declared. By monitoring for specific alternating patterns in advance, the controller can prepare appropriate responses and avoid improper operation, ensuring reliable impedance matching.
3Device complexity
If conventional impedance controllers use simple code selection, then device complexity is reduced, but measurement precision deteriorates due to inability to select optimal impedance matching codes
Solution Approach 1:
The patent segments the code selection process into multiple discrete steps using the up/down counter. Instead of arbitrary code selection, the counter incrementally adjusts the code through defined steps, allowing precise control over impedance matching while maintaining a relatively simple controller structure.
Data Source
AI summary
An impedance controller includes multiple determination units for determining which of multiple candidate codes results in a best impedance match for an I/O pad of a semiconductor device. In addition, an error prevention unit of the impedance controller prevents any undesired bit pattern from causing improper operation of the impedance controller. Furthermore, the impedance controller includes a dummy transistor array for improved linearity of impedance variation.