A/D Converter Sampling Clock Duty Control for Higher Sampling Rates

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Solution Overview

Problem

Conventional A/D converters face challenges in achieving high-speed operation due to fixed 50% duty ratio of the sampling clock, which does not account for varying environments and results in differing acquisition and settling times, leading to inefficiencies in sampling and holding processes.

Innovation Solution

An A/D converter system that includes a sampling clock generator and an A/D output determination circuit to dynamically adjust the duty ratio of the sampling clock based on measured parameters from a training signal or error rates in the digital signal, optimizing the duty ratio for improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the duty ratio of the sampling clock is fixed at 50%, then the sampling period and holding period have equal duration, but the minimum period becomes twice the longer of acquisition time or settling time, limiting the sampling rate

Engineering Contradiction:

Improvesampling rateVSAvoidminimum period of sampling clock

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the duty ratio of the sampling clock adjustable rather than fixed. The sampling clock generator dynamically changes the duty ratio based on the relationship between acquisition time and settling time, allowing the sampling period and holding period to have different durations. This dynamic adjustment enables the minimum period to be optimized as the sum of acquisition time and settling time rather than twice the longer period, thereby increasing the sampling rate.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of duty ratio from a fixed 50% to an adjustable value. By modifying this parameter based on the specific requirements of acquisition and settling times, the system optimizes the timing parameters to reduce the minimum period and increase productivity.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the duty ratio is uniformly changed from 50%, then some improvement in timing may be achieved, but the duty ratio cannot be adjusted based on environmental conditions

Engineering Contradiction:

Improveenvironmental adaptabilityVSAvoidhigh speed operation capability

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent implements feedback by having the sampling clock generator adjust the duty ratio based on measured or known relationships between acquisition time and settling time. This feedback mechanism allows the system to adapt to different environmental conditions and circuit characteristics, optimizing performance for high-speed operation while maintaining adaptability to various operating scenarios.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7605736B2A/D converter and duty control method of sampling clock

Publication Date: 2009.10.20 RENESAS ELECTRONICS CORP

AI summary

An A/D converter comprises a sample and hold circuit receiving a signal and operating based on a sampling clock, an A/D converting circuit converting an output signal of the sample and hold circuit to a digital signal, an A/D output determination circuit outputting a duty control signal based on the digital signal and a sampling clock generator adjusting a duty ratio of a sampling clock and applying the sampling clock to the sample and hold circuit.