Dual-DAC Power-State Switching for Harmonic Suppression
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Solution Overview
Problem
Existing sigma-delta modulators introduce significant distortion during analog-to-digital conversions due to mismatch in digital-to-analog converters, leading to noise and spurious signals that degrade performance.
Innovation Solution
A signal converter system that includes two resistor ladders and a controller to generate control signals that change the power supply state of at least one converter, suppressing harmonics and distortion in the converted analog signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If data-weighted-averaging algorithms are used to perform noise shaping, then distortion control is improved, but noise is introduced and device complexity increases
Solution Approach 1:
The patent divides the single DAC into two separate DACs (first and second digital-to-analog converters) operating in parallel. Each DAC processes the same digital input signal but with different power supply states, segmenting the distortion sources so they do not correlate, thereby preventing the generation of spurious signals while avoiding the need for complex DWA algorithms.
Solution Approach 2:
The controller periodically alternates the power supply states of the two DACs in a pseudorandom sequence. This periodic switching causes the distortion products from each DAC to appear at different frequencies and times, effectively spreading and reducing the peak distortion while maintaining average performance, without requiring complex real-time algorithms.
2Manufacturing precision
If excessive switches, amplifiers, and circuit components are used, then matching precision is improved, but noise increases, power consumption increases, and device complexity increases
Solution Approach 1:
The patent combines two simple DAC structures with a pseudorandom switching controller to achieve the functionality that would otherwise require complex DWA algorithms and numerous additional components. By merging parallel DAC paths with temporal switching, the system achieves high matching precision without excessive circuit complexity.
Solution Approach 2:
The patent changes the power supply state parameters of the DACs dynamically according to a pseudorandom sequence generated by the controller. By varying the operational state (power supply voltage levels) of each DAC over time, the system achieves effective matching without requiring precise hardware matching of numerous components.
3Manufacturing precision
If DWA algorithms are used for noise shaping, then distortion is controlled, but power consumption increases
Solution Approach 1:
The system uses the inherent distortion characteristics of each DAC combined with pseudorandom switching to achieve distortion control without requiring complex real-time algorithms. The controller generates simple pseudorandom sequences that automatically distribute distortion products, eliminating the need for computationally intensive DWA calculations and reducing power consumption.
Data Source
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AI summary
A signal converter includes a first converter, a second converter, a signal generator, and a controller. The first converter generates a first analog signal from a digital signal, and the second converter generates a second analog signal from the digital signal. The signal generator outputs a converted analog signal based on the first analog signal and the second analog signal. The controller generates one or more control signals to change a power supply state of at least one of the first converter and the second converter. The change in power supply state suppress even order harmonics.