Resistance Calibration Circuit Using One Resistor for Transceiver Impedance
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Solution Overview
Problem
High-speed transceivers face impedance mismatch issues due to variations in resistances caused by process, voltage, and temperature changes, leading to signal reflections and the need for numerous calibration pins and external resistors, increasing chip and assembly costs.
Innovation Solution
A calibration circuit that uses a single external resistor and calibration pin to calibrate all transceivers by selecting and adjusting multiple identical resistance components through a feedback system to match target impedances, allowing for efficient impedance matching without requiring multiple external resistors or pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple external resistors and calibration pins are used for each transceiver section, then impedance matching precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent implements a universal calibration architecture where a single external resistor and calibration pin serve multiple transceiver sections simultaneously. The calibration signal generated from this shared reference is distributed to all sections, enabling impedance matching across multiple sections without requiring dedicated calibration components for each section, thus reducing device complexity while maintaining calibration capability.
Solution Approach 2:
The patent merges the calibration functions of multiple transceiver sections into a unified calibration system. By combining the calibration signals and using a shared external resistor, the system reduces the total number of calibration pins and external resistors required, directly addressing the contradiction between precision and complexity.
2Manufacturing precision
If multiple external resistors and calibration pins are used for each transceiver section, then impedance matching precision is improved, but production cost increases
Solution Approach 1:
The universal calibration architecture allows a single external resistor and calibration pin to serve multiple transceiver sections, directly reducing the bill of materials and assembly costs. This multi-functional approach maintains impedance matching precision while significantly lowering production costs by eliminating redundant calibration components.
3Manufacturing precision
If multiple external resistors and calibration pins are used for each transceiver section, then impedance matching precision is improved, but silicon area increases
Solution Approach 1:
The patent merges calibration functions across multiple transceiver sections into a shared calibration network. By combining calibration signals and using common reference components, the silicon area required for calibration circuits is significantly reduced compared to having separate calibration circuits for each section, while still achieving precise impedance matching.
Data Source
AI summary
A calibration circuit including a plurality of first resistance components, a plurality of second resistance components, and a first feedback system is provided. The first feedback system selects M1 first resistance components and N1 second resistance components so that a first combination of the M1 first resistance components and the N1 second resistance components substantially matches the impedance of a first resistor. The first feedback system selects M2 first resistance components and N2 second resistance components so that a second combination of the M2 first resistance components and the N2 second resistance components substantially matches the impedance of the first resistor. Based on the values of M1, N1, M2, N2, and a target impedance, the first feedback system generates a first set of calibration signals for a plurality of third resistance components and generates a second set of calibration signals for a plurality of fourth resistance components.