DAC Toggle Compensation for Data-Dependent Supply Noise

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Solution Overview

Problem

Existing digital-to-analog converters (DACs) face challenges in reducing data-dependent supply noise, particularly at higher operating frequencies, which leads to harmonic distortion and harmonic spurs in the analog output signal, and conventional methods to address this issue are power-intensive, making them unsuitable for battery-operated devices.

Innovation Solution

The implementation of adaptive toggle number compensation techniques, which involve setting a target toggle number for DAC units and using methods like transparent ISB dither, MSB shuffle, and dummy toggle generation to reduce the number of DAC units that switch, thereby minimizing power consumption and data-dependent supply noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional methods are used to reduce data-dependent supply noise, then noise reduction is achieved, but power consumption increases significantly

Engineering Contradiction:

Improvedata-dependent supply noiseVSAvoidpower consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by selectively toggling only a subset of DAC units rather than all units. The toggle number compensation mechanism determines the minimum necessary number of toggles to maintain signal fidelity while reducing the total number of active switches, thereby lowering power consumption while still achieving noise reduction

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the parameter of toggle number dynamically based on input signal characteristics. By adjusting the number of toggling DAC units according to the specific data pattern and signal requirements, the system optimizes the balance between noise reduction effectiveness and power consumption, avoiding excessive power usage while maintaining performance

Inventive Principle:

Principle #35Parameter changes

2Speed

If operating frequency is increased, then data processing capability is improved, but harmonic distortion and harmonic spurs increase

Engineering Contradiction:

Improveoperating frequencyVSAvoidanalog output signal quality

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent implements feedback through toggle number compensation mechanisms that monitor and adjust the number of toggling DAC units based on the input data pattern. This feedback control ensures that sufficient toggling occurs to maintain signal integrity at higher frequencies while preventing excessive toggling that would generate harmonic distortion and spurs

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the toggle number based on real-time signal characteristics and operating conditions. This dynamic adaptation allows the DAC to maintain optimal performance across varying frequencies by optimizing the number of active toggling units for each specific operating point, thereby reducing harmonic distortion while maintaining high-speed operation

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If more DAC units are toggled, then signal fidelity is maintained, but power consumption increases

Engineering Contradiction:

Improvesignal fidelityVSAvoidpower consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by determining the minimum necessary number of DAC units to toggle for maintaining signal fidelity. The toggle number compensation mechanism calculates and implements only the essential toggles required for accurate signal representation, avoiding unnecessary toggling of additional units that would increase power consumption without providing proportional fidelity benefits

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS10693483B1Adaptive toggle number compensation for reducing data dependent supply noise in digital-to-analog converters

Publication Date: 2020.06.23 ANALOG DEVICES INT UNLTD CO

AI summary

Adaptive toggle number compensation techniques for reducing data dependent supply noise in DACs are disclosed. Various embodiments are based on setting a certain target toggle number for a plurality of DAC units used to convert at least a portion of a digital data sample and then applying various adaptive techniques to try to achieve the target toggle number in converting the data sample from digital to analog domain. Adaptive toggle number compensation techniques described herein try to reduce data dependent supply noise by deliberately limiting, to a certain target number, the number of DAC units that undergo a switch from the digital input of 1 to 0 or from 0 to 1 in converting a digital data sample. Compared to the conventional dummy signal generation approach, such adaptive toggle number compensation techniques may provide significant savings in terms of power consumption of a DAC.