Comparator Trigger Timing Control for Wide-Range Low-Noise Inputs
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Solution Overview
Problem
Existing comparators, such as two-stage and single-stage comparators, suffer from higher offset variation and worse noise performance due to input voltage levels near the supply voltage, making them unsuitable for wide input voltage ranges.
Innovation Solution
A multi-stage or single-stage comparator design with a control circuit that controls the trigger timing of subsequent stages to operate in saturation regions, optionally with gain boosting, to minimize noise and offset across a wide input range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a typical two-stage comparator is used, then the comparator can operate at high input voltage levels near the supply voltage, but the offset and noise performance deteriorate because the second stage does not trigger at the optimal moment
Solution Approach 1:
The control circuit triggers the second stage operation in advance based on a trigger signal generated from the first stage output, ensuring that the second stage is ready to operate at the optimal moment before the input voltage reaches levels that would cause performance deterioration. This preliminary triggering action resolves the contradiction by maintaining precision while accommodating wide input ranges.
2Adaptability or versatility
If a typical single-stage comparator is used, then the comparator can operate at high input voltage levels near the supply voltage, but the offset and noise performance deteriorate because the second sub-stage does not trigger at the optimal moment
Solution Approach 1:
The control circuit generates a trigger signal from the first sub-stage output to advance-trigger the second sub-stage operation. This ensures that the second sub-stage operates at the optimal moment even when input voltages are high, preventing the deterioration of offset and noise performance while maintaining wide input voltage range capability.
3Adaptability or versatility
If the second stage operates at high input voltage levels, then the comparator can handle wide input ranges, but the gain from the first stage vanishes resulting in higher offset and bad noise performance
Solution Approach 1:
By using the first stage output to generate a trigger signal that advances the second stage operation, the system ensures that the second stage operates at the optimal moment when the first stage still provides sufficient gain. This preliminary triggering maintains reliability and noise performance while allowing the comparator to handle wide input voltage ranges.
Data Source
AI summary
A multi-stage comparator includes a first stage circuit, a second stage circuit, and a control circuit. The first stage circuit receives an input signal of the multi-stage comparator, generates a first-stage output signal according to the input signal, and outputs the first-stage output signal at an output port of the first stage circuit. The second stage circuit receives a second-stage input signal at an input port of the second stage circuit, and performs a second-stage operation to generate an output signal of the multi-stage comparator. The control circuit is coupled between the output port of the first stage circuit and the input port of the second stage circuit, and controls a start time of the second-stage operation for triggering the second-stage operation at a moment when the first stage circuit operates in a saturation region.