ADC Resolution Boost Using Dithering and Moving Average
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Solution Overview
Problem
Portable electronic devices face inaccuracies in estimating power source remaining due to significant voltage fluctuations and noise, leading to inaccurate digital output values from analog to digital converters.
Innovation Solution
The system employs dithering and averaging techniques to enhance the resolution and accuracy of analog to digital converters by summing and smoothing digital output values, compensating for DC offset and gain errors, and scaling to achieve higher resolution and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional analog to digital converter is used to measure power source voltage, then the device can estimate power remaining, but the measurement precision is degraded due to voltage fluctuations and noise
Solution Approach 1:
The patent applies periodic sampling of the analog voltage signal at multiple time points, converting each sample to a digital value. By taking multiple measurements over time and combining them (through dithering and averaging), the system achieves higher effective resolution and reduces the impact of transient noise and voltage fluctuations on the final power estimation.
Solution Approach 2:
The patent intentionally introduces dithering noise into the analog signal before conversion. This controlled noise addition actually improves measurement precision by preventing quantization errors from creating dead zones and by making the measurement process more robust against other noise sources. The harmful noise is transformed into a beneficial dithering signal that enhances overall measurement accuracy.
2Adaptability or versatility
If voltage divider is used to scale down power source output voltage, then the voltage can be provided to ADC input, but the divided voltage becomes susceptible to fluctuations and noise
Solution Approach 1:
The patent performs preliminary sampling and digital conversion of the divided voltage at multiple time points before final processing. By capturing multiple samples and applying dithering and averaging algorithms, the system compensates for voltage fluctuations that occur during the measurement process, maintaining reliable power estimation despite instability in the divided voltage signal.
3Measurement precision
If multiple digital output values are summed and averaged, then the resolution is increased by a factor of four, but the processing complexity increases
Solution Approach 1:
The patent segments the measurement process into distinct stages: initial analog sampling, digital conversion of multiple samples, dithering application, averaging computation, and final power estimation. This segmentation allows each stage to be optimized independently and enables efficient implementation using standard digital signal processing techniques, reducing the practical complexity despite the increased resolution requirements.
Data Source
AI summary
According to one embodiment, a method for increasing resolution and accuracy of an analog to digital converter receiving an input voltage includes dithering a number of digital output values from the analog to digital converter to generate a number of dithered values. The analog to digital converter can be an 8-bit analog to digital converter, for example. The dithered values are then averaged to generate an average dithered value. For example, the dithered values can be averaged using a moving average technique. The average dithered value is then scaled down to generate a scaled value. Thereafter, the scaled value is mapped to a, for example, 10-bit digital output having higher resolution and higher accuracy than the raw 8-bit output of the analog to digital converter. In this example, the resolution of the analog to digital converter is increased by a factor of four.