Multi-Rate Weight Level Generation for Low-Noise DACs

Solution Overview

Problem

Conventional digital-to-analog converters face limitations in reducing out-of-band noise and distortion performance due to the need for increasing the number of weight generators or operating speed, which are constrained by IC chip area and distortion considerations.

Innovation Solution

The method involves using weight generators at multiple time rates to increase the number of weight levels without increasing the number of generators, thereby reducing quantization noise while maintaining distortion performance by employing time-domain interpolation encoding and dynamic element matching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the number of weight generators is increased to increase the number of quantization levels, then the out-of-band noise is reduced, but the IC chip area occupied by analog segments increases

Engineering Contradiction:

Improveout-of-band noiseVSAvoidIC chip area

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent applies dynamic operation by varying the time rates at which weight generators are activated. Instead of using all weight generators continuously, the system dynamically selects and operates subsets of weight generators at different time rates, enabling effective multiplication of weight levels without proportionally increasing the physical number of weight generators or chip area

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs periodic activation patterns where weight generators are operated in cycles at different time rates. By periodically activating different subsets of weight generators at accelerated time rates, the system achieves the equivalent effect of having more weight generators while using fewer physical components, thus reducing IC chip area while maintaining noise performance

Inventive Principle:

Principle #19Periodic action

2Object-affected harmful factors

If the operating speed of the ΔΣ modulator is increased to reduce quantization noise, then the out-of-band noise is reduced, but the distortion performance deteriorates

Engineering Contradiction:

Improvequantization noiseVSAvoiddistortion performance

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies dynamic operation by varying the time rates at which weight generators are activated. Instead of using all weight generators continuously, the system dynamically selects and operates subsets of weight generators at different time rates, enabling effective multiplication of weight levels without proportionally increasing the physical number of weight generators or chip area

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs periodic activation patterns where weight generators are operated in cycles at different time rates. By periodically activating different subsets of weight generators at accelerated time rates, the system achieves the equivalent effect of having more weight generators while using fewer physical components, thus reducing IC chip area while maintaining noise performance

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS7623055B2Weight level generating method and device utilizing plural weights at different time rates

Publication Date: 2009.11.24 TEXAS INSTRUMENTS INC

AI summary

A weight level generator is provided. Weight level generator W has plural weight generators 5-1-5-j. At least one of said plural weight generators is used at at least two different time rates. Also, a digital-to-analog converter (DAC) using said weight generators is equipped with a digital signal source, a weight controller, and a weight generator.