Switched-Capacitor Sampling Circuit for Adjustable Common-Mode Linearity
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Solution Overview
Problem
Traditional sampling devices suffer from low linearity due to second-order nonlinearity generated during capacitance sampling, which affects the accuracy and power consumption of A/D converters.
Innovation Solution
A sampling device with a switch capacitor circuit design that includes multiple switch capacitor groups, where the connection nodes are connected to different power sources, allowing for adjustable output common-mode voltage and eliminating second-order nonlinearity by making charge collection and storage relevant only to first-order terms of the input voltage and output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional capacitance sampling is used, then the sampling device is simple, but second-order nonlinearity is generated causing low linearity
Solution Approach 1:
The sampling device is divided into multiple switch capacitor circuits, each handling a portion of the sampling task. This segmentation allows the system to eliminate second-order nonlinearity through coordinated operation of multiple simpler units, improving linearity without requiring a single complex circuit
Solution Approach 2:
Multiple switch capacitor circuits are combined to work together in parallel, merging their individual sampling capabilities. This combination achieves high linearity performance that would be difficult to obtain in a single circuit, while maintaining the simplicity of individual circuit blocks
2Measurement precision
If A/D converter quantization accuracy is improved, then measurement precision increases, but power consumption increases
Solution Approach 1:
The invention changes the operating parameters of the sampling device by using multiple switch capacitor circuits with specific switching patterns. This parameter optimization enables high-precision sampling at lower power consumption compared to traditional single-circuit approaches that would require higher power to achieve the same accuracy
3Adaptability or versatility
If output common-mode voltage is made adjustable, then adaptability improves, but additional voltage generation circuits are required
Solution Approach 1:
The switch capacitor circuits are designed to perform multiple functions: they simultaneously perform signal sampling and generate adjustable output common-mode voltage. This multi-functionality eliminates the need for separate voltage generation circuits, achieving adaptability without increasing device complexity
Solution Approach 2:
The sampling circuits themselves generate the required output common-mode voltage through their inherent switching operation. The circuits serve themselves by producing the voltage needed for their operation, eliminating the need for external voltage generation components and maintaining simplicity while providing adjustability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution improves the linearity of the sampling device by eliminating second-order nonlinearity, reduces power consumption, and allows for adjustable output common-mode voltage without the need for additional voltage generation circuits, enhancing the device's universality and efficiency.
Implementation Method 1
a second end of the first switch is connected to an upper plate of the first capacitor, a second end of the second switch is connected to a lower plate of the second capacitor, a connection node connecting a lower plate of the first capacitor to an upper plate of the second capacitor
Data Source
AI summary
A sampling device includes a switch capacitor circuit. First ends of two switches are respectively connected to an input signal. Second end of the first switch is connected to an upper plate of a first capacitor. Second end of the second switch is connected to a lower plate of a second capacitor. A connection node connecting a lower plate of the first capacitor to an upper plate of the second capacitor is connected to a power source. The first ends of a third switch and a fourth switch are respectively connected to an input common-mode voltage. A second end of the third switch is connected to the upper plate of the first capacitor. A second end of the fourth switch is connected to the lower plate of the second capacitor. The connection node is connected to the power source. Thus, an output common-mode voltage of the sampling device is adjustable.