Comparator Pre-Amplifier Positive Feedback Noise Reduction
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Solution Overview
Problem
Conventional comparator structures in analog-to-digital converters face challenges in achieving high speed, low power consumption, and low noise, especially at high precision levels, due to large noise and offset issues, which are exacerbated by the need for cascaded pre-amplifier stages that increase power consumption and reduce reset speed.
Innovation Solution
A comparator based on a pre-amplifier stage structure that includes a first and second pre-amplifier stage with a positive feedback unit between the input and output terminals of the second pre-amplifier stage, increasing the voltage gain and reducing equivalent input noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pre-amplifier stages are cascaded to reduce noise, then measurement precision is improved, but power consumption increases and reset speed decreases
Solution Approach 1:
The patent introduces a positive feedback mechanism where the output of the second pre-amplifier stage is fed back to its input through a feedback network. This positive feedback increases the voltage gain of the second stage, allowing for reduced noise performance with fewer cascaded stages, thereby reducing power consumption while maintaining precision requirements
2Measurement precision
If multiple pre-amplifier stages are cascaded to reduce noise, then measurement precision is improved, but reset speed decreases
Solution Approach 1:
The positive feedback path provides an additional signal pathway that accelerates the reset process. During reset, the feedback mechanism helps quickly discharge the capacitor at the output terminal of the pre-amplifier stage, significantly improving reset speed while maintaining the noise reduction benefits of the cascaded structure
3Measurement precision
If voltage gain is increased to reduce equivalent input noise, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Instead of simply adding more cascaded pre-amplifier stages to increase voltage gain, the patent employs a positive feedback mechanism within the second pre-amplifier stage. This feedback approach achieves the required voltage gain enhancement without proportionally increasing device complexity, as it utilizes existing circuit nodes and components rather than requiring additional independent stages
Data Source
AI summary
A comparator based on a pre-amplifier stage structure and an analog-to-digital converter are provided. The comparator includes: a first pre-amplifier stage, where an input terminal of the first pre-amplifier stage is connected to a differential input signal, to amplify and output the differential input signal so as to output a first differential output signal; a second pre-amplifier stage, where an input terminal of the second pre-amplifier stage is connected to the first differential output signal, to amplify and output the first differential output signal so as to output a second differential output signal, and a positive feedback unit is disposed between an output terminal of the second pre-amplifier stage and the input terminal of the second pre-amplifier stage, to increase a voltage gain of the second pre-amplifier stage by using the positive feedback unit; and a latch, an input terminal thereof connected to the second differential output signal.