Programmable Impedance Control Circuit with Range Shifting
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Solution Overview
Problem
Semiconductor devices face challenges in maintaining impedance matching due to environmental changes such as power source voltage, temperature, and manufacturing process variations, leading to impedance detection failures and reduced resolution, especially when using existing programmable impedance control circuits that require extensive transistor arrays and waste control codes.
Innovation Solution
The implementation of a programmable impedance control circuit with additional range shifting circuits and transistor arrays that automatically adjust impedance ranges in response to PVT changes, allowing for high impedance detection resolution without expanding the transistor array or wasting control codes, by using P-type and N-type MOS transistors for impedance matching and range shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the impedance detection range is extended to accommodate PVT changes, then the circuit can maintain impedance matching under various conditions, but the transistor array size increases and control codes are wasted
Solution Approach 1:
The impedance detection range is divided into multiple sub-ranges, each handled by a smaller transistor array. The range shifting circuit selectively activates appropriate sub-ranges based on PVT conditions, avoiding the need for a single large transistor array while maintaining full detection capability.
Solution Approach 2:
The transistor array configuration is made dynamic through the range shifting circuit, which adjusts the active impedance detection range in real-time based on PVT conditions. This allows the same hardware to adapt to different conditions without requiring a permanently oversized array.
2Reliability
If the transistor array is designed larger to provide design margin for PVT changes, then impedance matching can be maintained, but chip occupation area increases
Solution Approach 1:
The chip area is efficiently utilized by segmenting the impedance detection function into multiple smaller operational modes. The range shifting circuit enables a compact transistor array to provide the equivalent functionality of a much larger array by dynamically adjusting the detection range.
Solution Approach 2:
The circuit changes operational parameters (detection range) based on PVT conditions rather than relying on a fixed oversized transistor array. This allows the same physical hardware to adapt to different conditions, reducing the required chip area while maintaining reliability.
3Measurement precision
If more control codes are used to control a larger transistor array, then impedance detection resolution improves, but control code waste increases when operating at lower impedance values
Solution Approach 1:
The control code utilization is made dynamic through range shifting. When operating at lower impedance values, the range shifting circuit adjusts the detection range to match the actual operating conditions, ensuring that control codes are used efficiently without waste while maintaining high detection resolution.
Solution Approach 2:
The detection range parameter is dynamically changed based on operating conditions. This allows the control codes to be optimally utilized for the current impedance range, preventing code waste while maintaining high measurement precision across different operating points.
Data Source
AI summary
A programmable impedance control circuit for use in a semiconductor device having an impedance range shifting function prevents or substantially reduces an impedance detection failure based on an environment change. An impedance detector includes a first array driver, a second array driver, and an impedance matching transistor array and a range shifting transistor array independently controlled by the first and second array drivers. A comparator each compares first and second output voltage levels of the impedance detector with an array reference voltage, and outputs an up/down signal as the comparison result. A counter performs an up/down counting in response to the up/down signal, and outputs control code data. A range shifting circuit monitors a counting output of the counter and so generates range shifting data. Whereby, even if there is an environment change on a manufacturing process, power source voltage or operating temperature, etc., an impedance matching and correction operation can be performed without a waste of impedance matching transistor array and control code.