Voltage Selection Circuit Using Static and Dynamic Comparators

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Solution Overview

Problem

Electronic systems with multiple power sources face challenges in efficiently selecting and distributing the maximum source supply voltage while minimizing static power consumption of switching circuitry.

Innovation Solution

The system employs a combination of static and dynamic comparators to selectively couple supply voltages to power consuming circuitry, using a lower precision static comparator for large voltage differences and a higher precision dynamic comparator for small differences, with the dynamic comparator being periodically powered up and down to conserve power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a high-precision comparator is used continuously to select the maximum supply voltage, then the voltage selection accuracy is improved, but the power consumption increases

Engineering Contradiction:

Improvevoltage comparison precisionVSAvoidcomparator power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system dynamically switches between static and dynamic comparators based on operating conditions. The static comparator handles large voltage differences continuously, while the dynamic comparator is activated only when small voltage differences require higher precision, optimizing the balance between accuracy and power consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The dynamic comparator is powered up and down periodically or on-demand rather than operating continuously. This periodic activation reduces average power consumption while maintaining high precision when needed, as the dynamic comparator is only active during specific comparison cycles requiring its enhanced precision.

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If a low-precision comparator is used to reduce power consumption, then the power efficiency is improved, but the voltage selection accuracy deteriorates

Engineering Contradiction:

Improvecomparator power consumptionVSAvoidvoltage comparison precision

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The voltage comparison function is segmented into two distinct comparator types with different precision levels. The static comparator handles the majority of comparisons for large voltage differences, while the dynamic comparator is reserved for specific cases requiring high precision, allowing the system to achieve overall accuracy without continuous high-power operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The static comparator acts as an intermediary that pre-processes voltage comparisons and only triggers the dynamic comparator when its precision is insufficient. This intermediary approach allows the low-precision static comparator to handle most cases, reducing overall power consumption while maintaining accuracy through selective engagement of the high-precision dynamic comparator.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If the dynamic comparator is continuously powered to maintain high precision, then the measurement accuracy is improved, but the static power consumption increases

Engineering Contradiction:

Improvevoltage comparison precisionVSAvoidstatic power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10090674B2Maximum supply voltage selection

Publication Date: 2018.10.02 SILICON LABORATORIES INC

AI summary

A method includes providing supply voltages to a supply voltage switching circuit that controls routing of the supply voltages to power consuming circuitry associated with the supply voltage switching circuit. The method includes comparing the supply voltages, including using at least one relatively lower precision comparator to compare the supply voltages for a relatively large difference between the supply voltages; and using at least one relatively higher precision comparator to compare the supply voltages for a relatively smaller difference between the supply voltages. The method further includes, based on a result of comparing the supply voltages, selectively coupling the supply voltages to at least one of an isolation well and a power supply rail of the supply voltage switching circuit.