Post-Sampling Selectable Gain in S/H ADCs for Accurate Multiplexing

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Solution Overview

Problem

Conventional S/H ADCs face limitations in measurement accuracy due to the use of dedicated amplifiers per channel, which consume silicon area, require timely enablement, limit bandwidth, and introduce gain errors, especially in multiplexed operations, while capacitive attenuation leads to increased silicon area, longer sample times, and dielectric relaxation issues.

Innovation Solution

A post-sampling selectable gain (PSSG) circuit that uses shared reference generators to adjust gain post-sampling, reducing area and power consumption, and allowing flexible gain settings without latency, thereby improving measurement accuracy and speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If dedicated amplifiers are used per channel in conventional S/H ADCs, then measurement accuracy is improved, but silicon area consumption increases

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidsilicon area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent merges the amplifier function into the shared reference generator circuit, eliminating the need for separate dedicated amplifiers per channel. The reference generator serves dual purposes: providing reference voltages and performing signal amplification, thereby reducing silicon area while maintaining measurement accuracy through the shared amplification resource.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The reference generator is designed to perform multiple functions: it generates reference voltages for the ADC and simultaneously acts as a programmable gain amplifier for the input signal. This multi-functionality eliminates the need for separate amplifier circuits, reducing overall circuit complexity and silicon area while preserving measurement capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If dedicated amplifiers are used per channel, then measurement accuracy is improved, but power consumption increases

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

By combining the amplifier function with the reference generator, the patent reduces the total number of active circuits. The shared reference generator serves all channels, eliminating redundant amplifier power consumption while maintaining the ability to provide accurate measurements through its programmable gain capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The reference generator's multi-functionality allows it to serve as both reference voltage source and amplification stage. This eliminates the need for separate dedicated amplifiers that would consume additional power, while the programmable gain feature ensures measurement accuracy is preserved across multiple channels.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If dedicated amplifiers are used per channel, then measurement accuracy is improved, but gain errors increase due to amplifier limitations

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidgain errors

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent implements a dynamic, programmable gain structure within the reference generator that can be adjusted in post-sampling stages. This allows the gain to be optimized for each specific measurement scenario, reducing gain errors that occur with fixed-gain dedicated amplifiers. The dynamic adjustment capability ensures accurate measurements while minimizing the introduction of gain-related errors.

Inventive Principle:

Principle #15Dynamics

4Area of stationary object

If capacitive attenuation is used to reduce amplifier requirements, then silicon area is reduced, but sample time increases

Engineering Contradiction:

Improvesilicon areaVSAvoidsample time

Core Design Contradiction:

Area of stationary objectVSLoss of time

Solution Approach 1:

The patent employs periodic switching of capacitors in the reference generator to achieve programmable gain attenuation. By selectively connecting or disconnecting capacitors in a periodic switching manner during the sampling cycle, the circuit achieves variable gain without requiring long sample times for capacitor charging/discharging, thus reducing both silicon area and sample time compared to traditional capacitive attenuation methods.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS12592715B2Post-sampling selectable gain in sample and hold analog-to-digital converters

Publication Date: 2026.03.31 INFINEON TECHNOLOGIES AMERICAS CORP

AI summary

A system and method for a post-sampling selectable gain circuit in sample and hold (S/H) analog-to-digital converters (ADCs). The method includes scaling down or scaling up a reference voltage to generate a plurality of candidate voltages associated with a plurality of measurement accuracies of a sampler circuit, each candidate voltage of the plurality of candidate voltages is respectively associated with a respective measurement accuracy of the plurality of measurement accuracies. The method includes selecting, by a processing device and based on an input voltage for the sampler circuit, a particular candidate voltage from the plurality of candidate voltages that is associated with an optimal measurement accuracy of the plurality of measurement accuracies. The method includes generating a sampler voltage associated with the optimal measurement accuracy by operating the sampler circuit based on the particular candidate voltage or an additional voltage associated with the particular candidate voltage.