Impedance Calibration Circuit Using Multiple Reference Resistors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor apparatuses face challenges in achieving precise impedance matching due to external noise and impedance mismatching, leading to signal distortion, and existing calibration methods using a single reference resistor are inadequate for accurate impedance setting.
Innovation Solution
A semiconductor apparatus incorporating multiple reference resistors with different resistance values, a calibration circuit, a selection circuit, and a data circuit to generate and select calibration signals for precise impedance control, ensuring accurate impedance matching by generating multiple calibration signals and selecting the appropriate ones based on impedance setting signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single reference resistor is used for calibration, then the device complexity is reduced, but the impedance matching precision deteriorates
Solution Approach 1:
The calibration circuit is segmented into multiple independent calibration signal generation units, each associated with a different reference resistor (RZQ1, RZQ2, ..., RZQn). Each unit can independently generate calibration signals for specific impedance settings, allowing precise impedance matching for different operating conditions without requiring a single complex calibration mechanism.
Solution Approach 2:
The calibration circuit dynamically selects and activates appropriate calibration signals based on the impedance setting signal (ZSS). The selection circuit chooses from multiple calibration signals (CAL1, CAL2, ..., CALn) generated by different reference resistors, enabling the system to adaptively adjust impedance calibration for different operating modes and external device configurations.
2Reliability
If multiple reference resistors are used for calibration, then the impedance matching precision is improved, but the device complexity increases
Solution Approach 1:
Multiple reference resistors (RZQ1, RZQ2, ..., RZQn) are designed with different resistance values to serve universal calibration needs across various impedance settings. The same calibration circuit structure can calibrate different impedance levels by selecting appropriate reference resistors, making the system universally applicable to different external devices and transmission conditions.
Solution Approach 2:
The calibration circuit uses feedback from the impedance setting signal (ZSS) to selectively activate appropriate calibration signals. The selection circuit monitors the impedance setting and feeds back control information to enable only the relevant calibration signals, ensuring reliable impedance matching while managing circuit complexity through intelligent signal selection.
3Adaptability or versatility
If calibration signals are generated for different impedance settings, then the adaptability is improved, but the loss of time in calibration increases
Solution Approach 1:
Multiple calibration signals (CAL1, CAL2, ..., CALn) are pre-generated and prepared in advance, each corresponding to different impedance settings. When a specific impedance setting is required, the pre-prepared calibration signal can be immediately selected and applied without requiring time-consuming real-time calculation or adjustment, significantly reducing calibration time while maintaining adaptability.
Solution Approach 2:
The calibration circuit operates periodically by switching between different calibration signals based on impedance setting changes. Instead of continuous calibration, the system performs discrete calibration actions when impedance settings change, using periodic selection of appropriate calibration signals from the available set, which reduces overall calibration time while maintaining adaptability to different impedance requirements.
Data Source
AI summary
A semiconductor apparatus includes a calibration circuit, a selection circuit, and a data circuit. The calibration circuit generates a plurality of calibration signals by being coupled to a plurality of reference resistors. The selection circuit selects at least one signal among the plurality of calibration signals on the basis of an impedance setting signal. The data circuit sets an impedance based on the selected calibration signal.