Partial DAC Data Ignore Switching for Lower Glitching
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Solution Overview
Problem
Digital-to-analog converters (DACs) experience significant switching activity, leading to power consumption, glitching, and crosstalk issues, particularly during code transitions, which can result in undesirable performance and signal distortion.
Innovation Solution
Implementing a partial DAC data ignore switching mode, where a control circuit compares first and second digital data and operates analog switches only when the decoded states differ, reducing unnecessary switching and minimizing power consumption and glitching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional DAC switching operation is used, then the DAC can respond to all digital input changes, but switching activity increases leading to power consumption and glitching
Solution Approach 1:
The patent applies partial action by implementing a control circuit that selectively activates analog switches only when necessary. The control circuit compares consecutive digital input codes and generates switch control signals only for bits that actually changed state, rather than activating all switches on every code transition. This partial switching approach reduces power consumption while maintaining accurate DAC response to meaningful input changes.
2Reliability
If DAC switches operate on every code transition, then all digital input changes are reflected in the analog output, but glitching and crosstalk increase
Solution Approach 1:
The control circuit implements partial action by generating switch control signals only for the specific analog switches corresponding to bits that changed state between consecutive digital codes. By comparing the current digital input with the previous input and identifying only the changed bits, the system activates only the necessary switches, thereby reducing glitching and crosstalk while maintaining accurate signal representation.
3Reliability
If all analog switches are activated on every digital input change, then the DAC output accurately follows the digital input, but switching activity and crosstalk increase
Solution Approach 1:
The patent applies segmentation by dividing the DAC switch control into independent, bit-specific control signals. The control circuit generates separate control signals for each analog switch corresponding to individual digital bits. This segmentation allows selective activation of only those switches whose corresponding bits changed state, reducing overall switching activity and crosstalk while maintaining output fidelity.
4Productivity
If conventional switching mode is used, then the DAC processes all digital input signals, but unnecessary switching increases power consumption
Solution Approach 1:
The control circuit implements partial action by comparing consecutive digital input codes and generating switch control signals only for the minimal subset of bits that changed state. This approach maintains signal processing throughput by quickly identifying and responding to actual changes, while eliminating energy waste associated with activating switches for bits that remained unchanged.
Data Source
AI summary
A digital technique to reduce or minimize switching in a DAC by using a partial DAC data ignore switching mode. In the partial DAC data ignore switching mode, a control circuit compares first and second data, such a first and second digital words, and operates corresponding switches only when the first data differ from the second data. The techniques are applicable to many types of DACs, including voltage output DACs, current output DACs, variable resistance DACs, digital rheostats, digital potentiometers, digiPOTs.