Track-and-Hold Amplifier Calibration for ADC Resolution Loss
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Solution Overview
Problem
Analog to digital converters face degradation in resolution due to inherent nonlinearity in track and hold amplifiers, which affects the accurate representation of analog input signals as digital signals.
Innovation Solution
The implementation of a track and hold amplifier with a voltage generating unit that provides a common signal and a reference signal independent from the analog signal, coupled with a calibration processor to correct nonlinearity, and a configuration of switching circuits with capacitors to manage signal tracking and holding, ensuring accurate digital conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a track and hold amplifier is used in an A/D converter, then the analog input signal can be tracked and held for accurate conversion, but inherent nonlinearity of the amplifier degrades the resolution of the A/D converter
Solution Approach 1:
The patent applies preliminary action by performing calibration of the track and hold amplifier before the actual A/D conversion process. The calibration procedure characterizes the nonlinearity of the amplifier in advance and stores correction data, which is then used to compensate for nonlinearity effects during normal operation. This preliminary characterization and correction setup enables the system to achieve both accurate signal tracking and high resolution by pre-establishing the correction mechanism.
2Measurement precision
If calibration is performed to correct nonlinearity, then resolution is improved, but device complexity increases due to additional calibration circuits and procedures
Solution Approach 1:
The patent implements self-service by designing a calibration system that automatically characterizes and corrects its own nonlinearity without requiring external intervention or complex manual adjustment procedures. The calibration circuitry is integrated into the A/D converter structure, and the system performs self-diagnosis and self-correction by using its own internal resources. This self-calibrating capability reduces operational complexity while maintaining high resolution performance.
Solution Approach 2:
The patent merges the calibration function with the main A/D conversion structure by integrating calibration circuits within the existing amplifier and converter architecture. Rather than adding completely separate calibration equipment, the calibration functionality is combined with the signal path components, sharing common elements such as the track and hold amplifier and capacitor structures. This integration reduces overall device complexity while achieving the desired calibration effect.
Data Source
AI summary
A track and hold amplifier is provided. The track and hold amplifier includes an input node receiving an analog signal, a buffer coupled between a first node and an output node, a first switch coupled between the input node and the first node, a plurality of switching circuits and a voltage generating unit. Each of the switching circuits includes a capacitor coupled between the first node and a second node. The voltage generating unit selectively provides a common signal and a reference signal to the capacitors of the switching circuits, wherein the reference signal is independent from the analog signal and the common signal.