Modular Sample-and-Hold Circuit With Staggered Sampling Phases
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Solution Overview
Problem
Conventional sample-and-hold circuits experience high power consumption due to spiky current drawn during sampling, especially in high-resolution systems, leading to increased settling error and circuit area requirements.
Innovation Solution
A sample-and-hold circuit design utilizing multiple parallel modules with staggered clock phases and reduced capacitor sizes, reducing peak current and power consumption by dividing capacitance into smaller steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single large sampling capacitor is used in a conventional sample-and-hold circuit, then high-resolution sampling is achieved, but spiky current increases and power consumption rises
Solution Approach 1:
The single large sampling capacitor is divided into multiple smaller capacitors (first sampling capacitor and second sampling capacitor) that operate in parallel. Each capacitor is controlled by its own switch and clock phase, allowing the total capacitance to be achieved while distributing the current draw over multiple smaller units, thereby reducing spiky current and power consumption.
2Measurement precision
If a single large sampling capacitor is used, then high-resolution sampling is achieved, but settling error increases due to high peak current
Solution Approach 1:
By segmenting the sampling capacitor into multiple smaller capacitors operated in parallel with staggered clock phases, the peak current demand on the driving amplifier is reduced. This allows the amplifier to settle more accurately to the input signal voltage, thereby reducing settling error while maintaining the total capacitance needed for high-resolution sampling.
Solution Approach 2:
The multiple capacitors are controlled by clock signals with different phases, creating a periodic staggering effect where capacitors are charged at different times. This periodic distribution of charging events smooths out the current waveform and reduces peak current, allowing the driving amplifier to maintain better settling accuracy.
3Productivity
If conventional sample-and-hold circuit is used, then sampling function is achieved, but circuit area increases due to high power requirements
Solution Approach 1:
The sampling capacitor is segmented into multiple smaller capacitors that can be arranged in a more compact configuration. The parallel structure with shared control logic and staggered clock phases allows for better spatial utilization, reducing the overall circuit area while maintaining the required sampling function and resolution.
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 design achieves lower power consumption and improved linearity in analog-to-digital converters by minimizing spiky current and reducing circuit area, while maintaining effective sampling and holding capabilities.
Implementation Method 1
a first capacitor connected to the first switch for receiving the input signal when the first switch is activated
Data Source
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Figure 5
AI summary
A sample-and-hold circuit is broken down into multiple parallel modules, and an output switch, where each module includes a switch and a capacitor. Each of the switches in the modules and the output switch are controlled by different phases of a clock signal. The sample-and-hold circuit receives an input signal and operates in sample and hold modes to generate a sampled output signal.