DAC Clock Tracking with Selective Latch Gating

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Solution Overview

Problem

Digital-to-analog converters (DACs) face inefficiencies due to power consumption issues when providing clock signals to inactive unit cells, leading to decreased performance and increased power usage.

Innovation Solution

Implementing a fractal DAC with a branching data path and clock tracking circuitry that dynamically activates only necessary latches based on the digital signal, using static, dynamic, or differential clock tracking techniques to minimize power consumption and maintain synchronicity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If clock signals are provided to all unit cells in a DAC, then synchronous operation is maintained, but power consumption increases due to activation of inactive unit cells

Engineering Contradiction:
Improvesynchronous operationVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the clock signal distribution by introducing a clock gating mechanism that divides the clock signal path into active and inactive branches. The clock signal is selectively gated to only those latches corresponding to active unit cells, thereby maintaining synchronous operation for active cells while preventing unnecessary power consumption in inactive cells. This is achieved through clock gating logic that monitors the digital signal and enables clock signals only to relevant latch groups.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic clock signal activation by using the digital signal itself to control clock gating. The system dynamically adjusts which latches receive clock signals based on the current digital input, allowing the clock distribution network to adapt its activation pattern in real-time. This dynamic approach ensures that only the minimum necessary latches are activated at any given moment, optimizing power efficiency while maintaining operational integrity.

Inventive Principle:
Principle #15Dynamics

2Reliability

If all latches are continuously activated in a DAC, then data synchronization is maintained, but operational speed decreases due to unnecessary switching activity

Engineering Contradiction:
Improvedata synchronizationVSAvoidoperational frequency
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent extracts and removes unnecessary latch activation by implementing clock gating that selectively disables clock signals to latches corresponding to inactive unit cells. By taking out the redundant switching activity from the system, the patent reduces overall power consumption and eliminates unnecessary capacitive charging/discharging cycles, thereby improving operational speed while maintaining synchronization for the active portion of the DAC.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If a traditional DAC structure is used, then simplicity is maintained, but power efficiency decreases due to inability to selectively activate components

Engineering Contradiction:
Improvestructure simplicityVSAvoidpower efficiency
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent introduces clock gating logic as an intermediary component between the clock signal source and the latches. This intermediary layer monitors the digital signal and intelligently controls clock distribution, enabling selective activation of latches based on which unit cells are currently active. This addition of a control layer significantly improves power efficiency by preventing unnecessary clock signal propagation to inactive latches, while the overall structural complexity remains manageable due to the systematic implementation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4293912A1Digital-to-analog converter clock tracking systems and methods
Publication Date: 2023.12.20 APPLE INC
  • EP4293912A1 patent drawingFigure 1~2
  • EP4293912A1 patent drawingFigure 3
  • EP4293912A1 patent drawingFigure 4~5

AI summary

A number of unit cells of a digital-to-analog converter (DAC) may be simultaneously activated to generate an analog signal according to a decoded digital signal. Latches may be used at one or more levels of decoding and may be activated according to a clock signal to recapture the at least partially decoded data signals to maintain/improve the synchronicity of activation of the unit cells. However, the latches may consume additional power during operation. As such, clock tracking techniques such as static clock tracking, dynamic clock tracking, or differential clock tracking may be utilized to generate a clock path activation signal that gates the clock signal and determines which latches to ignore (e.g., leave inactive). In this manner, instead of activating each latch for every digital signal, clock tracking may be implemented to deactivate latches that do not provide useful updates to the decoded digital signal received at the unit cells.