Constant-Slope Ramp Circuit for Precise Sampled-Data Sampling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Sample-data circuits face challenges in maintaining accurate output voltages due to delays and noise, particularly in maintaining the virtual ground node at the instant output voltage is sampled, which affects speed, accuracy, and power consumption.
Innovation Solution
The implementation of zero-crossing detectors and waveform generators with multiple linear segments in sample-data circuits to accurately detect zero crossings and minimize delays, ensuring precise sampling and reducing noise, thereby optimizing performance parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional operational amplifiers are used to process signals in sample-data circuits, then the circuits can perform basic signal processing functions, but the circuits suffer from delays and noise that reduce accuracy and speed
Solution Approach 1:
The patent replaces conventional operational amplifier-based signal processing with a charge-transfer mechanism using switched-capacitor circuits. This substitution eliminates the need for high-gain amplifiers and their associated delays, achieving faster and more accurate signal processing through direct charge transfer between capacitors controlled by non-overlapping clock phases.
Solution Approach 2:
The patent introduces a virtual ground node as an intermediary element that maintains precise voltage levels during sampling. This virtual ground acts as a reference point that enables accurate charge transfer and minimizes noise and delays in the signal processing path.
2Measurement precision
If conventional operational amplifiers with high open-loop gain are used to maintain virtual ground at ground potential, then accuracy is improved, but power consumption increases and settling time is extended
Solution Approach 1:
The patent replaces the power-hungry operational amplifier with a passive switched-capacitor network that maintains the virtual ground through clocked charge transfer. This substitution dramatically reduces power consumption while maintaining accuracy through the periodic resetting and charge transfer mechanism controlled by non-overlapping clock phases.
Solution Approach 2:
The patent uses periodic clock signals with non-overlapping phases to reset and transfer charges between capacitors. This periodic action maintains the virtual ground potential without requiring continuous high-power amplification, achieving low-power operation with high accuracy through timed charge redistribution.
3Speed
If faster operational amplifiers are used to reduce settling time, then speed is improved, but power consumption increases and noise increases
Solution Approach 1:
The patent replaces the noisy, high-speed operational amplifier with a quiet switched-capacitor charge transfer system. The noise-free charge transfer mechanism achieves fast settling through direct capacitor coupling and clocked switching, eliminating the thermal noise and bandwidth-related noise inherent in high-speed amplifiers.
Solution Approach 2:
The virtual ground node serves as a noise-immune intermediary that enables fast charge transfer without introducing amplifier noise. The switched-capacitor network transfers charges through this quiet reference point, achieving high speed without the noise penalty of high-bandwidth operational amplifiers.
Data Source
AI summary
A circuit includes a level-crossing detector to generate a level-crossing detection signal when an input signal crosses a predetermined voltage level. A first stage set of capacitors is operatively coupled to the level-crossing detector. A ramp circuit is operatively coupled to the set of series-connected capacitors. A second stage set of capacitors is operatively coupled to the first stage set of capacitors and the ramp circuit. The ramp circuit includes a feedback capacitor and a preset switch to provide a linear ramp output.