Ratiometric ADC Circuit Using Core-Domain Reference Division

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Solution Overview

Problem

Standard ADCs face challenges in compact design and efficiency due to the need to handle high external reference voltages, leading to increased area consumption and lower speed, as they require devices capable of handling voltages like 5V, which are larger and slower than core logic devices operating at lower voltages.

Innovation Solution

A ratiometric ADC arrangement that reduces the reference voltage to the core voltage domain (e.g., 1.5V or less) by using only core devices and employs a multiplexing and division process to calculate the digital output, allowing the ADC to operate within the core voltage domain and avoiding the use of external reference voltages that exceed the ADC's design range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If external reference voltage (3.3V or 5V) is applied to the ADC core, then the ADC can handle standard reference voltages, but the area consumption increases and speed decreases due to requiring high voltage devices

Engineering Contradiction:

Improvereference voltage compatibilityVSAvoidADC area consumption

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent segments the reference voltage handling into two separate functions: (1) the ADC core operates exclusively at low voltage (1.5V or less) using core devices, and (2) a separate voltage division circuit handles the external reference voltage (3.3V or 5V). This segmentation allows the ADC core to use smaller, faster low-voltage devices while still supporting standard external reference voltages through the division circuit.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a voltage division circuit as an intermediary between the external reference voltage source and the ADC core. This intermediary circuit divides the external reference voltage (3.3V or 5V) into a lower voltage suitable for the ADC core (1.5V or less), allowing the ADC to handle standard reference voltages without requiring high-voltage capable devices in the core.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If external reference voltage (3.3V or 5V) is applied to the ADC core, then the ADC can handle standard reference voltages, but the conversion speed decreases due to high voltage device performance limitations

Engineering Contradiction:

Improvereference voltage compatibilityVSAvoidADC conversion speed

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

3Area of stationary object

If core devices operating at low voltage (1.5V or less) are used, then area consumption is reduced, but the ADC cannot directly handle external reference voltages (3.3V or 5V)

Engineering Contradiction:

ImproveADC area consumptionVSAvoidreference voltage compatibility

Core Design Contradiction:

Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the voltage parameter of the reference signal through a voltage division circuit, transforming the external reference voltage (3.3V or 5V) into a lower voltage (1.5V or less) that matches the ADC core's operating parameters. This parameter transformation enables the low-voltage ADC core to process standard external reference voltages.

Inventive Principle:

Principle #35Parameter changes

4Use of energy by stationary object

If core devices operating at low voltage (1.5V or less) are used, then area consumption and power consumption are reduced, but the ADC cannot directly handle external reference voltages (3.3V or 5V)

Engineering Contradiction:

ImproveADC power consumptionVSAvoidreference voltage compatibility

Core Design Contradiction:

Use of energy by stationary objectVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8604961B1Ratiometric ADC circuit arrangement

Publication Date: 2013.12.10 INFINEON TECH AUSTRIA AG

AI summary

In various embodiments an analog-to-digital converter arrangement is provided, which may include an input terminal configured to receive a signal to be converted; a reference terminal configured to receive a reference signal; a voltage domain specific reference terminal configured to receive a voltage domain specific reference signal; an analog-to-digital converter circuit coupled to the input terminal, the reference terminal, and to the voltage domain specific reference terminal configured to compare the signal to be converted with the voltage domain specific reference signal, thereby generating a first digital comparison signal, and to compare the reference signal with the voltage domain specific reference signal, thereby generating a second digital comparison signal; and a ratiometric circuit configured to determine a digitally converted signal of the signal to be converted using the first digital comparison signal and the second digital comparison signal.