PVT-Calibrated Impedance Matching Circuit for Post Driver Accuracy
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Solution Overview
Problem
Impedance mismatching in semiconductor devices due to process, voltage, and temperature variations (PVT) leads to signal distortion and hinder high-speed data transmission.
Innovation Solution
An impedance matching circuit embedded in semiconductor devices, utilizing a PVT calibration circuit with a replica post driver and comparator to adjust resistance values of post drivers to match external resistors, reducing power consumption and increasing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If impedance matching is not performed, then device complexity is reduced, but signal distortion increases and data transmission speed decreases
Solution Approach 1:
The post driver automatically adjusts its output impedance to match the external resistor impedance through self-calibration. The calibration circuit measures the actual impedance and generates correction codes that are fed back to the post driver, enabling it to self-correct for PVT variations without external intervention.
Solution Approach 2:
The invention dynamically changes the output impedance parameter of the post driver based on measured PVT conditions. By adjusting the impedance parameter in response to process, voltage, and temperature variations, the system maintains optimal signal transmission across different operating conditions.
2Measurement precision
If PVT calibration circuit is added, then impedance matching accuracy is improved, but device complexity and power consumption increase
Solution Approach 1:
The calibration circuit is integrated within the existing post driver structure, sharing common components such as the output node and control logic. This merging approach allows impedance calibration functionality to be added without proportionally increasing overall device complexity.
Solution Approach 2:
The invention uses a replica post driver that copies the main post driver's structure and characteristics. This replica is used for calibration measurements, allowing the system to determine impedance corrections without directly interfering with the main signal path, thereby maintaining accuracy while managing complexity.
3Measurement precision
If PVT calibration circuit is added, then impedance matching accuracy is improved, but power consumption increases
Solution Approach 1:
The impedance calibration is performed periodically or at specific events (such as power-up or mode changes) rather than continuously. This periodic calibration approach maintains impedance matching accuracy while significantly reducing average power consumption compared to continuous monitoring and adjustment.
4Use of energy by moving object
If impedance matching is not performed, then power consumption is reduced, but signal distortion increases
Solution Approach 1:
The post driver automatically adjusts its output impedance to match the external resistor impedance through self-calibration. The calibration circuit measures the actual impedance and generates correction codes that are fed back to the post driver, enabling it to self-correct for PVT variations without external intervention.
Data Source
AI summary
An impedance matching circuit is provided. The impedance matching circuit includes a reference voltage generator configured to generate a reference voltage. A code generator is configured to generate a first calibration code by comparing the reference voltage with a first voltage associated with a first node and a second calibration code by comparing the reference voltage with a second voltage associated with a second node. A first resistance unit is configured to supply the first voltage to the first node in response to the first calibration code to calibrate its resistance to be equal to a reference resistance. A second resistance unit is configured to supply the second voltage to the second node in response to the second calibration code to thereby calibrate its resistance to the reference resistance.