Pipeline ADC Capacitor Switching for Linearity and Accuracy
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Solution Overview
Problem
Pipeline analog-to-digital converters (ADCs) face challenges such as quantization errors, non-linearity, and aperture errors due to non-uniformity of physical components like capacitors, which affect accuracy and power consumption, especially as integrated circuit sizes decrease.
Innovation Solution
The system and method involve a differential operational amplifier with multiple capacitors and switches that allow for adjustable configurations to optimize capacitor divider relationships, enabling better matching of capacitance and reducing non-linearity, thereby improving ADC accuracy and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional pipeline ADC designs are used, then the ADC can perform high-speed conversion, but quantization errors and non-linearity occur due to non-uniformity of physical components
Solution Approach 1:
The patent implements dynamic capacitor configuration where switches selectively connect capacitors to different nodes (first or second reference voltage sources) based on operational requirements. This dynamic reconfiguration allows the capacitor array to adapt its effective capacitance values during operation, enabling compensation for non-uniformity and improvement of linearity while maintaining high-speed conversion capability
Solution Approach 2:
The patent changes the electrical parameters of the capacitor array by selectively connecting capacitors to different voltage references through switches. This parameter modification allows adjustment of the effective capacitance values to compensate for manufacturing non-uniformity, thereby improving measurement precision without sacrificing conversion speed
2Use of energy by moving object
If capacitor sizes are reduced to save power and area, then power consumption decreases, but non-uniformity of physical components increases affecting accuracy
Solution Approach 1:
The patent compensates for the non-uniformity introduced by smaller capacitor sizes through dynamic parameter adjustment. By selectively connecting capacitors to different reference voltage sources, the system can adjust effective capacitance values to counteract manufacturing variations, maintaining accuracy even with reduced capacitor sizes and lower power consumption
3Productivity
If device geometry is reduced to increase circuit density, then more devices can be fabricated on each wafer, but manufacturing precision and component uniformity become more difficult to achieve
Solution Approach 1:
The patent employs dynamic switching configurations that allow post-manufacturing adjustment of capacitor relationships. This dynamic capability compensates for non-uniformity introduced by scaled-down device geometries, enabling high fabrication throughput while maintaining the precision required for ADC operation through software-controlled or digitally-assisted calibration
4Measurement precision
If multiple capacitors are used to improve accuracy, then conversion accuracy improves, but device complexity and area increase
Solution Approach 1:
The patent makes the capacitor array multi-functional by enabling each capacitor to serve different effective roles through switching to different reference voltage sources. The same physical capacitor can contribute to different capacitance values depending on its connection state, reducing the need for additional dedicated capacitors and thereby managing complexity while maintaining accuracy
Data Source
AI summary
Method and system for analog-to-digital conversion. According to an embodiment, the present invention provides an integrated circuit. The integrated circuit includes a different operational amplifier, which includes a first output, a second output, a first input, and a second input. The operational amplifier is associated with an amplification factor. The integrated circuit also includes a first voltage input. The first voltage input can be characterized by a first voltage. Additionally, the integrated circuit includes a second voltage input. The second voltage input can be characterized by a second voltage. Furthermore, the integrated circuit includes a first voltage source configured to provide a first reference voltage. In addition, the integrated circuit includes a second voltage source configured to provide a second reference voltage. Furthermore, the integrated circuit includes a first capacitor being electrically coupled to the first input and disengageably coupled to the first voltage input.