Single-Ended to Differential Conversion Circuit With Higher SNR
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Solution Overview
Problem
Conventional conversion circuits for single-ended inputs to differential inputs require additional scaling circuits, degrade signal-to-noise ratio (SNR), and necessitate a lower supply voltage after bucking, resulting in increased component count and reduced operation speed.
Innovation Solution
A conversion circuit with a reduced number of switches and capacitors that directly utilizes the higher supply voltage without bucking, achieving a higher SNR by redistributing charge across capacitors during operation periods, thereby simplifying control and enhancing speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional conversion circuits use additional scaling circuits and bucked supply voltage, then the circuit can handle single-ended inputs, but the component count increases and manufacturing cost increases
Solution Approach 1:
The patent merges the scaling circuit functionality directly into the capacitor array structure by using the same capacitors for both DAC operation and signal scaling. The capacitor array performs dual functions: digital-to-analog conversion and automatic single-ended to differential signal conversion, eliminating the need for separate scaling circuits and reducing overall component count
Solution Approach 2:
The capacitor array is designed to perform multiple functions simultaneously: it acts as the DAC element, the signal scaling mechanism, and the differential signal generator. This multi-functional design eliminates the need for dedicated scaling circuits and bucked voltage regulators, reducing both component count and manufacturing complexity
2Adaptability or versatility
If conventional conversion circuits use additional scaling circuits, then the circuit can process single-ended inputs, but the signal-to-noise ratio degrades
Solution Approach 1:
By merging the scaling function into the capacitor array, the patent eliminates additional active components that would introduce noise. The passive capacitor-based scaling maintains signal integrity while converting single-ended inputs to differential signals, preserving the signal-to-noise ratio
Solution Approach 2:
The capacitor array acts as an intermediary that passively scales and converts the single-ended signal to differential form without requiring active amplification or regulation stages. This passive intermediary approach minimizes noise introduction while achieving the required signal conversion
3Reliability
If conventional conversion circuits use bucked supply voltage, then the circuit can operate with reduced voltage stress, but the operation speed decreases
Solution Approach 1:
The patent dynamically manages voltage stress on capacitors through switched configurations during different operation phases (sampling, conversion, reset). By dynamically reconfiguring the capacitor connections, the circuit handles single-ended inputs with high supply voltage without requiring a permanently bucked voltage, thereby maintaining high operation speed
Solution Approach 2:
The circuit employs periodic switching of capacitor configurations during different operation cycles to manage voltage stress. During specific phases, capacitors are connected to handle high voltage stress from single-ended inputs, while in other phases they are reset, allowing the use of full supply voltage without compromising reliability or speed
4Adaptability or versatility
If conventional conversion circuits use more switches and capacitors, then the circuit can handle single-ended inputs, but the circuit area increases
Solution Approach 1:
The patent combines the scaling circuit components with the existing DAC capacitor array, using the same capacitors and switches for both DAC operation and single-ended to differential conversion. This merging eliminates duplicate components and reduces the overall circuit area required
Solution Approach 2:
The capacitor array and its associated switches are designed to serve multiple functions: DAC operation, signal scaling, and differential conversion. This universal design eliminates the need for additional dedicated components for single-ended input handling, minimizing the circuit area
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 solution reduces manufacturing costs, minimizes circuit area, and achieves higher SNR and operation speed with fewer components, while directly using the higher supply voltage without the need for additional scaling circuits.
Implementation Method 1
achieving a higher SNR by redistributing charge across capacitors during operation periods
Data Source
AI summary
An embodiment of the present disclosure provides a conversion circuit for converting a single-ended input to a differential input, which has fewer switches and fewer capacitors. This conversion circuit increases the signal-to-noise ratio (SNR), and the conversion circuit directly uses the higher supply voltage AVDD without being bucked by the regulator, wherein the common mode voltage is AVDD/2N, and N is greater than 1. Overall, not only the circuit area is smaller and the SNR is higher, but also the manufacturing cost is reduced. In addition, compared with the prior art, the conversion circuit of the embodiment of the present disclosure has only three operation periods, so the control is simpler and the operation speed is faster.