Chopped ADC Circuit With Polarity-Stable Quantizer Input
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Solution Overview
Problem
Existing A/D converters face complexity in timing control due to the need to manage signal polarity changes caused by chopping switches, particularly affecting the feedback path and quantizer operation.
Innovation Solution
Incorporation of input-signal, output-side, and feedback chopping switches operating at identical frequencies, with additional switches to maintain consistent signal polarity before and after chopping, simplifying timing control and reducing susceptibility to kickback noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chopping switches are used to reduce kickback noise, then noise immunity is improved, but timing control complexity increases
Solution Approach 1:
The patent divides the chopping operation into separate segments: input-signal chopping switches (first and second) handle signal input chopping, while output-side chopping switches (third and fourth) handle output chopping. This segmentation allows independent control of chopping timing at different stages, reducing the complexity of coordinating multiple chopping operations while maintaining noise immunity benefits.
Solution Approach 2:
The patent introduces an intermediary mechanism through the quantizer and feedback path that mediates between the chopping operations and the overall timing control. By positioning chopping switches at specific points (input and output of integrator) and using the quantizer as an intermediary element, the system simplifies timing coordination while effectively suppressing kickback noise through targeted chopping actions.
2Stability of the object's composition
If multiple chopping switches are added to maintain signal polarity, then signal consistency is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by placing chopping switches at specific locations where they are most effective: input-signal chopping switches at the integrator input and output-side chopping switches at the integrator output. This localized application maintains signal polarity consistency at critical points without requiring chopping switches throughout the entire signal path, thereby reducing overall device complexity while achieving the desired stability.
Solution Approach 2:
The patent merges the functionality of multiple chopping switches into coordinated pairs: first and second input-signal chopping switches work together, while third and fourth output-side chopping switches work together. This merging approach allows the system to maintain signal polarity consistency through coordinated operation of switch pairs rather than requiring independent control of numerous individual switches, simplifying the overall device structure.
Data Source
AI summary
An analog-to-digital converter includes an input-signal chopping switch, an integrator, an output chopping switch, a quantizer, and a feedback switch. The integrator is located after the input-signal chopping switch. The integrator includes an operational amplifier, an integral capacitor, and an integral-capacitor-chopping input switch being at on an input side of the integral capacitor. The output chopping switch is on an output side of the operational amplifier. The quantizer is located after the output chopping switch. The feedback chopping switch is in a feedback path from an output of the quantizer to an input of the first integrator. The input-signal chopping switch, the integral-capacitor-chopping input switch, the output chopping switch, and the feedback chopping switch execute chopping at an identical frequency. The output chopping switch sets a polarity of an input value of the quantizer to be identical before and after the chopping.