Comparator Offset Averaging for Compact ADC Range Detection

Solution Overview

Problem

Conventional analog-to-digital converters require multiple comparators to achieve multiple signal ranges, leading to increased size and power consumption, as each comparator needs distinct threshold voltages, which complicates the digitization process.

Innovation Solution

A comparison circuit utilizing two comparators with different offset voltages and time-to-digital comparators to determine if an input signal's voltage is above or below a middle voltage, effectively reducing the number of required comparators and minimizing area by using built-in offset voltages for threshold determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple comparators are used to achieve multiple signal ranges for analog-to-digital conversion, then the signal digitization capability is improved, but the size and power consumption of the converter increase

Engineering Contradiction:

Improvesignal range determination capabilityVSAvoidconverter size

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent combines multiple comparator functions into a single comparator by merging the threshold voltage selection mechanism with the comparison operation. The comparator circuit integrates threshold selection, signal comparison, and range determination in one unified structure, eliminating the need for separate comparators for different signal ranges.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The comparator circuit is designed to perform multiple functions: it can compare input signals against multiple threshold voltages, determine multiple signal ranges, and provide digitized output all through a single circuit implementation. The same comparator structure handles different comparison operations by selectively applying different threshold voltages.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple comparators are used to achieve multiple signal ranges, then the digitization accuracy is improved, but the power consumption increases

Engineering Contradiction:

Improvesignal digitization accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

The patent combines multiple comparator functions into a single comparator by merging the threshold voltage selection mechanism with the comparison operation. The comparator circuit integrates threshold selection, signal comparison, and range determination in one unified structure, eliminating the need for separate comparators for different signal ranges.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The circuit employs periodic switching between different threshold voltage levels to enable the single comparator to sequentially perform multiple comparison operations. By alternating between different threshold references in a periodic manner, the circuit achieves multi-range detection capability while keeping the comparator active only when needed.

Inventive Principle:

Principle #19Periodic action

3Adaptability or versatility

If distinct threshold voltages are assigned to each comparator, then the signal range determination capability is improved, but the device complexity increases

Engineering Contradiction:

Improvesignal range determination capabilityVSAvoidcomparator circuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple comparator functions into a single comparator by merging the threshold voltage selection mechanism with the comparison operation. The comparator circuit integrates threshold selection, signal comparison, and range determination in one unified structure, eliminating the need for separate comparators for different signal ranges.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediate threshold voltage selection mechanism that mediates between the input signal and the comparator. This intermediary structure selectively connects different threshold voltages to the comparator input, enabling multiple comparison operations without requiring multiple comparators. The intermediary adds control logic but eliminates the need for parallel comparator structures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8988265B2Comparison circuits

Publication Date: 2015.03.24 MEDIATEK INC

AI summary

A comparison circuit is provided and includes first and second comparators and a first time-to-digital comparator. The first comparator with a first offset voltage receives an input signal and generates a first comparison signal and a first inverse comparison signal. The second comparator receives the input signal and generates a second comparison signal and a second inverse comparison signal. The first offset voltage is larger than the second offset voltage. The first time-to-digital comparator receives the first comparison signal and the second inverse comparison signal and generates first and second determination signals according to the first comparison signal and the second inverse comparison signal. The first and second determination signals indicate whether a voltage of the input signal is larger than a first middle voltage. The first middle voltage is equal to a half of the sum of the first offset voltage and the second offset voltage.