ADC Sampling Noise Cancellation With Smaller Sampling Capacitors
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Solution Overview
Problem
Analog-to-digital converters (ADCs) introduce sampling noise during the conversion process, which limits their accuracy and requires increasing the sampling capacitor to reduce noise, leading to higher power consumption and design complexity in the driving circuit.
Innovation Solution
Incorporating a sampling noise cancelling circuit between the sampling circuit and the comparator, which includes an amplifier and additional capacitors to cancel the noise generated during sampling, allowing for a smaller sampling capacitor without compromising signal-to-noise ratio, thereby reducing the burden on the driving circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sampling capacitor is increased to reduce sampling noise, then the signal-to-noise ratio is improved, but the power consumption and area of the driving circuit increase
Solution Approach 1:
The patent segments the sampling noise cancellation function into a separate circuit module (sampling noise cancelling circuit) that operates independently from the main sampling capacitor. This allows the sampling capacitor to be smaller while the dedicated noise cancellation circuit handles the noise reduction, thus reducing the power consumption burden on the driving circuit while maintaining signal-to-noise ratio.
Solution Approach 2:
The patent introduces a sampling noise cancelling circuit as an intermediary between the sampling circuit and the comparator. This intermediary circuit actively cancels the sampling noise through feedback mechanisms, allowing the use of a smaller sampling capacitor without compromising the signal-to-noise ratio, thereby reducing the power consumption requirements of the driving circuit.
2Measurement precision
If the sampling capacitor is increased to reduce sampling noise, then the signal-to-noise ratio is improved, but the area and design complexity of the driving circuit increase
Solution Approach 1:
The patent divides the system into distinct functional modules: a sampling circuit with a smaller capacitor, a dedicated sampling noise cancelling circuit, and a comparator. This segmentation allows each module to be optimized independently, reducing the overall design complexity compared to a single large capacitor approach while maintaining high signal-to-noise ratio.
Solution Approach 2:
The sampling noise cancelling circuit serves as an intermediary that simplifies the overall design by handling noise cancellation in a dedicated module. This approach reduces the design complexity of the driving circuit since it no longer needs to provide high driving capacity for a large capacitor, while the noise cancellation function is implemented in a separate, optimized circuit.
3Object-affected harmful factors
If the sampling capacitor is increased to reduce sampling noise, then the sampling noise is reduced, but the driving capacity requirement increases
Solution Approach 1:
The patent introduces a sampling noise cancelling circuit as an intermediary that actively reduces sampling noise through feedback mechanisms. This allows the sampling capacitor to be smaller, thereby reducing the driving capacity requirements of the driving circuit while still achieving effective noise reduction.
Solution Approach 2:
The sampling noise cancelling circuit employs feedback mechanisms to detect and cancel sampling noise. This feedback-based approach enables effective noise reduction with a smaller sampling capacitor, reducing the power and driving capacity requirements compared to relying solely on a large capacitor.
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 approach enables the use of a smaller sampling capacitor, reducing power consumption, area, and design complexity in the driving circuit while maintaining signal accuracy by effectively cancelling sampling noise through the noise cancelling circuit.
Implementation Method 1
the sampling switch has thermal noise, the input signal Vin and the thermal noise vns1 of the switch are sampled together onto the capacitor C1
Data Source
AI summary
The present application discloses an analog-to-digital converter capable of cancelling sampling noise, which comprises: a sampling circuit configured to acquire an analog input signal; a sampling noise cancelling circuit has an input end connected with an output end of the sampling circuit, and is configured to cancel noise generated by the sampling circuit; a comparator has an input end connected with an output end of the sampling noise cancelling circuit, and an output end connected with an input end of a logic circuit, and is configured to compare magnitudes of output signals of the sampling noise cancelling circuit and output a comparison result to the logic circuit; and the logic circuit has an output end connected with the sampling circuit, and is configured to output a digital output signal, and process the comparison result to obtain a control signal by which an output voltage of the sampling circuit is controlled.