Multi-Channel Sample-and-Hold Circuit With Shared Op-Amp

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Solution Overview

Problem

In wireless portable SoC products, the area and power consumption of sample-and-hold amplifiers (SHAs) are significant design challenges due to the need for multiple SHAs to process multiple channel input signals, with operational amplifiers being the largest consumers of power and area.

Innovation Solution

A sample-and-hold circuit design that uses a single operational amplifier with multiple sampling capacitor blocks and controllers to sequentially process and hold signals from multiple channels, reducing the number of operational amplifiers required and minimizing power consumption and chip area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple operational amplifiers are used to process multiple channel input signals, then signal processing capability is improved, but power consumption and chip area increase

Engineering Contradiction:

Improvesignal processing capabilityVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

Multiple sampling capacitor blocks that were previously dedicated to different channels are merged and shared by a single operational amplifier. The controllers manage the timing and sequencing so that the single amplifier can sequentially service multiple channels, thereby combining multiple amplifier functions into one device and reducing overall power consumption.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single operational amplifier is designed to perform multiple functions by sequentially processing signals from different channels. Through the coordination of controllers and sampling capacitor blocks, the amplifier becomes a universal component that can handle multiple channel inputs over time, replacing what would traditionally require multiple dedicated amplifiers.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If multiple operational amplifiers are used to process multiple channel input signals, then signal processing capability is improved, but chip area increases

Engineering Contradiction:

Improvesignal processing capabilityVSAvoidchip area

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

The circuit architecture merges multiple amplifier instances into a single shared operational amplifier. By combining the sampling capacitor blocks and using controllers to manage access timing, the design consolidates what would be separate amplifier circuits into one compact unit, significantly reducing the chip area required for the amplifier section.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The design transitions from a spatial arrangement where each channel has its own dedicated amplifier (2D plane occupation) to a temporal arrangement where a single amplifier services multiple channels sequentially (adding the time dimension). This dimensional shift allows multiple functions to be packed into a single amplifier unit, reducing area while maintaining processing capability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Use of energy by moving object

If a single operational amplifier is shared across multiple channels, then power consumption and chip area are reduced, but signal processing speed may be affected

Engineering Contradiction:

Improvepower consumptionVSAvoidsignal processing speed

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The system employs periodic sampling and holding operations where the single operational amplifier sequentially processes each channel in a repeating cycle. The controllers coordinate the sampling capacitor blocks to capture signals at appropriate intervals, allowing the amplifier to service multiple channels in rapid succession through periodic action, thereby maintaining effective processing speed despite sharing the amplifier.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS8947277B2Multi-channel sample-and-hold circuit and analog-to-digital converter using the same

Publication Date: 2015.02.03 SAMSUNG ELECTRONICS CO LTD

AI summary

A sample-and-hold circuit including an operational amplifier configured to output a result signal to the ADC; a feedback capacitor connected between an input terminal and an output terminal of the operational amplifier to form a feedback path; a plurality of sampling capacitor blocks each connected to one of a plurality of channels and configured to sample and hold an analog signal input to each of the channels; a plurality of controllers each connected between one of the sampling capacitor blocks and the operational amplifier; and a reset unit connected between a reference voltage source and the input terminal of the operational amplifier to reset the operational amplifier when the operational amplifier does not perform a holding operation. The plurality of controllers configured to switch the sampled signal so that held signals for the respective channels are sequentially input to the operational amplifier.