Shared-Resistor Calibration Circuit for Faster Impedance Matching
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Solution Overview
Problem
Impedance mismatch between internal and external terminals of electronic devices leads to operational reliability issues due to noise, power supply variations, and manufacturing variations, necessitating efficient impedance matching techniques.
Innovation Solution
A calibration circuit and apparatus that share a resistor for impedance matching, where one die initiates an impedance matching operation and generates a completion signal, allowing subsequent dies to start their matching operations sequentially, reducing total impedance matching time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If multiple dies perform impedance matching operations simultaneously using separate resistors, then each die can complete its matching independently, but the total time consumption increases and device complexity increases
Solution Approach 1:
Multiple calibration circuits share a single common resistor for impedance matching instead of each circuit having its own dedicated resistor. The resistor is coupled to multiple calibration circuits through separate coupling capacitors, allowing one resistor to serve multiple functions and reducing overall component count and complexity.
Solution Approach 2:
The impedance matching process is divided into sequential segments where each calibration circuit operates in turn rather than simultaneously. Each die completes its impedance matching operation sequentially, with completion signals triggering the next die to begin its operation, thereby reducing total time while sharing the common resistor.
2Device complexity
If multiple calibration circuits share a common resistor, then device complexity is reduced, but signal interference and matching accuracy may deteriorate
Solution Approach 1:
Coupling capacitors are introduced as intermediary components between each calibration circuit and the common resistor. These capacitors electrically isolate the circuits during charging/discharging phases while still allowing the resistor to function as the impedance matching element, preventing direct signal interference between circuits.
Solution Approach 2:
Each calibration circuit operates in periodic cycles with distinct phases: a charging phase where the capacitor charges through the resistor, and a discharging phase where the capacitor discharges. This periodic operation ensures that only one circuit actively uses the resistor at any given moment, maintaining matching accuracy while sharing the component.
3Loss of time
If impedance matching is performed sequentially on multiple dies, then total matching time is reduced, but the coordination complexity and signal routing increase
Solution Approach 1:
Completion signals are generated by each calibration circuit when its impedance matching operation finishes, and these signals are fed back to trigger the next calibration circuit in the sequence. This feedback mechanism automates the sequential coordination, reducing the need for external control logic and simplifying the overall system management.
Data Source
AI summary
A system may include: a first memory device; a second memory device; a third memory device; and a fourth memory device, wherein the first memory device to the fourth memory device are configured to share a resistor for impedance matching, wherein the first memory device to the fourth memory device are coupled to have a chain shape, wherein the forth memory device generates a completion signal when performance is completed and the first memory device receives the completion signal provided from the fourth memory device.