Power Supply On-Off Detection Circuit Using Current Transformer

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Solution Overview

Problem

Existing flash break switch on-off detection methods in smart appliances are prone to inaccurate detection and long detection periods, leading to misjudgments.

Innovation Solution

A power supply on-off detection circuit comprising a signal acquisition circuit, a signal conversion circuit, and a signal processing circuit, which collects and converts alternating current signals into level signals to determine the on-off state of the power supply, using a current transformer, rectifier bridge, load resistor, and voltage comparator to provide reliable and fast detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional flash break switch on-off detection methods are used, then the detection function is provided, but the detection accuracy is low and detection period is long

Engineering Contradiction:
Improvedetection accuracyVSAvoiddetection period
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces traditional mechanical or simple electronic detection methods with a current transformer-based detection system. The current transformer converts the current signal from the power supply into a measurable voltage signal, enabling accurate and rapid detection of the flash break switch state without mechanical contact or complex circuitry.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a current transformer as an intermediary device between the power supply circuit and the detection circuit. This intermediary component isolates the detection circuit from the high-voltage power supply while accurately transferring the current state information, enabling safe and precise detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If simple detection circuits are used, then the device complexity is reduced, but detection accuracy and reliability deteriorate

Engineering Contradiction:
Improvecircuit complexityVSAvoiddetection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent uses electromagnetic induction through a current transformer to achieve detection, replacing complex electronic signal processing circuits with a simple yet reliable electromagnetic coupling mechanism. This substitution maintains low circuit complexity while significantly improving detection reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The current transformer automatically adapts to different current levels and switch states without requiring external calibration or adjustment. The detection circuit self-regulates by measuring the induced voltage, which naturally corresponds to the power supply current state, eliminating the need for complex reference voltage generation or threshold adjustment circuits.

Inventive Principle:
Principle #25Self-service

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 solution enables accurate and rapid detection of the power supply state, reducing resource consumption and power usage while minimizing misjudgments, and can be applied to various types of switches and power supplies.

Implementation Method 1

A primary side of the current transformer is configured to collect the alternating current signal output by the power supply, and to couple the alternating current signal collected by the primary side to a secondary side of the current transformer according to a preset ratio

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the transient voltage suppression diode is coupled in parallel with the current transformer to discharge a surge current of the current transformer

Methodology Applied
Scientific EffectTransient voltage suppression: Diode

Implementation Method 3

The rectifier bridge is coupled in parallel with the signal acquisition circuit to convert the alternating current signal output by the signal acquisition circuit into a direct current signal

Methodology Applied
Scientific EffectRectification: Diode

Implementation Method 4

The load resistance is coupled in parallel with the rectifier bridge, and is configured to convert the direct current signal into the voltage signal

Methodology Applied
Scientific EffectOhm's law: Ohm's Law

Implementation Method 5

A first input end of the voltage comparator is coupled to an output end of the signal conversion circuit to receive the voltage signal, and a second input end of the voltage comparator is coupled to voltage divider resistors to generate a reference voltage

Methodology Applied
Scientific EffectVoltage comparison:

Data Source

PatentEP3910354B1Power supply on-off detection circuit, method, apparatus and storage medium
Publication Date: 2024.04.10 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP3910354B1 patent drawingFigure 1~4
  • EP3910354B1 patent drawingFigure 5~6
  • EP3910354B1 patent drawingFigure 7~8

AI summary

The present disclosure provide a power supply on-off detection circuit, a method, an apparatus and a storage medium. The power supply on-off detection circuit includes: a signal acquisition circuit, a signal conversion circuit, and a signal processing circuit. The signal acquisition circuit is configured to collect an alternating current signal output by the power supply, and to output the alternating current signal to the signal conversion circuit. The signal conversion circuit is configured to convert the alternating current signal into a voltage signal, and to output the voltage signal to the signal processing circuit. The signal processing circuit is configured to convert the voltage signal into a level signal. The level signal is used to determine whether the power supply is on or off by determining whether the switch is switched on or off. Thus the resources of a control circuit is saved and power consumption is reduced.