Window Comparator Power Detection Circuit With Low Current Sampling

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Solution Overview

Problem

Existing power detection systems in wireless communication systems consume significant current due to the use of continuous logarithmic amplifiers, which is not suitable for battery-powered devices that require minimized current usage.

Innovation Solution

A power detection system utilizing a detector circuit with three transistors of different widths, coupled to a current source and differential input voltage, and a comparator circuit that provides output representative of voltage thresholds, achieving power detection without continuous current consumption by using a voltage divider and current mirror circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If continuous logarithmic amplifiers are used for power detection, then measurement precision is improved, but use of energy worsens due to significant current consumption

Engineering Contradiction:

Improvepower detection precisionVSAvoidcurrent consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic sampling of the power signal instead of continuous monitoring. The detector circuit activates intermittently to sample power levels at predetermined intervals, allowing the system to maintain adequate measurement precision while dramatically reducing average current consumption compared to continuous logarithmic amplifier operation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent employs simplified detector circuits with transistors and resistors that can be rapidly switched on and off, replacing the need for expensive, continuously operating logarithmic amplifiers. These simpler components consume minimal energy during brief activation periods and can be repeatedly used without degradation.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If power detection is performed continuously, then reliability is improved, but use of energy worsens due to battery power requirements

Engineering Contradiction:

Improvepower monitoring reliabilityVSAvoidbattery current

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements a dynamic power detection system that adapts its monitoring frequency and depth based on operational conditions. During normal operation, sampling occurs at lower frequency to conserve battery power, while during critical transitions or anomaly detection events, the system increases sampling rate to maintain reliability without excessive energy consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system performs partial power detection by monitoring only critical power threshold levels rather than continuously measuring the full power spectrum. This selective monitoring approach maintains sufficient reliability for battery-powered applications by detecting only the most significant power variations that affect system operation.

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If logarithmic amplifiers are employed in power detection circuits, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvedetection rangeVSAvoidcircuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the power detection function into multiple discrete transistor-based detection stages, each handling a specific portion of the power range. This segmentation allows the system to achieve wide detection range and good precision through cascaded simple stages rather than a single complex logarithmic amplifier, reducing overall circuit complexity while maintaining measurement capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses multiple identical or near-identical transistor-based detector circuits that can be replicated and cascaded to extend the detection range. This copying approach allows the system to achieve logarithmic-like detection characteristics through parallel simple circuits rather than a single complex logarithmic amplifier, simplifying the overall device architecture.

Inventive Principle:

Principle #26Copying

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system outputs current proportional to the square of the input voltage, reducing power consumption and enabling efficient power monitoring without the need for logarithmic amplifiers, thus extending battery life and preventing network jamming.

Implementation Method 1

a detector circuit (10) that outputs a current that is proportional to the square of an input voltage

Methodology Applied

Scientific EffectTransistor nonlinear characteristics:

Data Source

PatentUS8022734B1Low current power detection circuit providing window comparator functionality

Publication Date: 2011.09.20 PSEMI CORP

AI summary

A power detection system is disclosed that includes a detector circuit and a comparator circuit. The detector circuit includes a first transistor, a second transistor that is not identical to the first transistor, and a third transistor that is substantially identical to the first transistor. Each of the transistors is commonly coupled to a current source and is coupled to a differential input voltage. The comparator circuit is for providing an output that is representative of whether the input voltage is above or below a threshold voltage responsive to a difference between the first transistor and the second transistor.