I-V Converting Module Feedback Loop Accelerates Sampling Speed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing I-V converting modules have a slow setup speed due to the slow sampling and holding circuit, which decreases the conversion rate and requires a longer time to collect alternating current signals.
Innovation Solution
The introduction of a feedback loop using an N-type field-effect transistor and a loop switch, along with a loop capacitor, separates the sampling and holding circuit from the current output sensor, significantly reducing the time constant and accelerating the setup speed, while maintaining consistent output current and improving signal-to-noise ratio through a bypass circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the sampling and holding circuit is used to counteract the direct current component, then the output dynamic range is enlarged, but the setup speed becomes slow
Solution Approach 1:
The patent divides the sampling and holding circuit into two distinct circuits: a first sampling and holding circuit for collecting the alternating current component, and a second sampling and holding circuit for counteracting the direct current component. This segmentation allows each circuit to be optimized independently - the first circuit can use smaller capacitance for faster setup speed, while the second circuit handles the DC component separately, resolving the contradiction between dynamic range and setup speed.
Solution Approach 2:
The patent introduces a subtractor as an intermediary component that receives the output current from the current output sensor and subtracts the direct current component (after voltage conversion) from it. This intermediary structure enables the AC component to be extracted without being constrained by the slow setup speed of the DC counteracting circuit, as the subtraction operation occurs in the voltage domain rather than directly in the current sampling path.
2Adaptability or versatility
If the field-effect transistor works in sub-threshold region, then the resistance is proportional to direct current component, but the time constant becomes large
Solution Approach 1:
The patent extracts the direct current component handling function into a separate second sampling and holding circuit with its own dedicated sampling switch and holding capacitor. By taking out the DC component processing from the AC signal path, the time constant issue in the original circuit is eliminated, as the first sampling and holding circuit no longer needs to deal with the large capacitance requirements for DC counteracting.
Solution Approach 2:
The patent changes the operational parameters by using two different sampling and holding circuits with different capacitance values optimized for their respective functions. The first circuit uses smaller capacitance for fast AC sampling, while the second circuit uses larger capacitance for stable DC holding, allowing each to operate in its optimal parameter range without compromising the other.
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
This solution greatly accelerates the setup speed of the sampling and holding circuit, increasing the conversion rate of the I-V transforming circuit and enhancing the signal-to-noise ratio by reducing the time constant and stabilizing the feedback loop.
Implementation Method 1
a feedback loop that is formed by the source follower, the I-V transforming circuit and the loop switch, is conducted
Implementation Method 2
a source follower, a loop switch and a bypass circuit... a drain of the source follower connects to an input/output end of the sampling and holding circuit, a source of the source follower connects to an input end of the I-V transforming circuit
Implementation Method 3
a voltage of a plate of a parasitic capacitor C 3 connected to a sampling capacitor C 2 begins to be established, and a time constant of the sampling and holding circuit 2 is therefore τ = (C 3 +C 2 )/gm
Implementation Method 4
Because a field-effect transistor M 2 usually works in a sub-threshold region, the resistance of the field-effect transistor M 2 is in positive proportion to the direct current component I output by the current output sensor 3, that is, gm = α·I
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Embodiments of the present disclosure relate to the field of electrical technologies and disclose an I-V converting module. The I-V converting module includes: a current output sensor, an I-V transforming circuit, a sampling and holding circuit, a source follower, a loop switch, and a bypass circuit. A drain of the source follower is connected to an input/output end of the sampling and holding circuit, a source of the source follower is connected to an input end of the I-V transforming circuit and an output end of the current output sensor, and a gate of the source follower is connected to an output end of the I-V transforming circuit via the loop switch. The gate of the source follower further is connected to the bypass circuit. When the loop switch is closed and the bypass circuit is disabled, a feedback loop formed by the source follower, the I-V transforming circuit and the loop switch is conducted, and the I-V converting module enters into a sampling setup stage. The present disclosure greatly accelerates a setup speed of the sampling and holding circuit, thereby increasing the converting rate of the I-V transforming circuit.