Wearable Device Control Circuit Automatic Power Switching

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Solution Overview

Problem

Wearable devices require manual operation of a power switch, which is inconvenient and can lead to accidental start-ups due to internal impedance loops.

Innovation Solution

A control circuit comprising a power supply circuit, DC blocking circuit, and voltage comparison circuit that automatically switches the wearable device on and off by comparing voltages and controlling the communication module's state, preventing accidental start-ups by blocking DC signals and allowing AC signals to reach sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a manual power switch is provided in wearable devices, then users can control power on and off, but it causes inconvenience and can lead to accidental start-ups

Engineering Contradiction:

Improvepower switching convenienceVSAvoidaccidental start-up prevention

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The wearable device automatically detects whether it is being worn through voltage comparison between first and second signal input ends, and automatically switches between working state and sleep state without manual intervention. The device serves itself by using the human body's electrical characteristics as the trigger for power state changes, eliminating the need for manual power switch operation and preventing accidental start-ups.

Inventive Principle:

Principle #25Self-service

2Reliability

If DC signals are allowed to flow to sensors, then sensors can operate normally, but internal impedance loops cause accidental start-ups

Engineering Contradiction:

Improvesensor operation stabilityVSAvoidinternal impedance loop effects

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The signal path is segmented into DC signal path and AC signal path using coupling capacitors. The DC blocking circuit separates DC components from AC components, allowing AC sensor signals to pass while blocking DC signals that would create harmful current loops through internal impedance. This segmentation resolves the conflict between sensor operation and prevention of accidental start-ups.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Coupling capacitors are introduced as intermediary components between the power supply circuit and sensors. These capacitors block DC signals while allowing AC signals to pass through, acting as a mediator that prevents harmful DC current loops while maintaining normal sensor AC signal operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If automatic power switching is implemented, then user convenience is improved, but circuit complexity increases

Engineering Contradiction:

Improveautomatic power switchingVSAvoidcontrol circuit structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The voltage comparison circuit serves multiple functions: it detects whether the device is being worn by comparing voltages, determines power state transitions, and triggers appropriate state changes. By making this single circuit component multi-functional, the design achieves automatic power switching without adding excessive circuit complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The detection function and power control function are merged into a single integrated control approach. The voltage comparison circuit simultaneously performs wear detection and power state determination, combining multiple functions into one unified mechanism rather than separate independent systems.

Inventive Principle:

Principle #5Merging (Combining)

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

Enables convenient automatic switching and prevents accidental start-ups by ensuring sensors operate normally while avoiding internal impedance loops, optimizing power management and reducing user inconvenience.

Implementation Method 1

the DC blocking circuit is connected to the first node, the second node, and a sensor in the wearable device, and configured to block DC signals on the first node and the second node from flowing to the sensor, and cause AC signals on the first node and the second node to flow to the sensor

Methodology Applied

Scientific EffectDC blocking: Capacitance

Implementation Method 2

the voltage comparison circuit is connected to the first node, a reference voltage end and an output end, and configured to compare voltages of the first node and the reference voltage end

Methodology Applied

Scientific EffectVoltage comparison: Ohm's Law

Data Source

PatentUS11539209B2Control circuit for wearable device, wearable device

Publication Date: 2022.12.27 BEIJING BOE TECH DEV CO LTD

AI summary

A control circuit for a wearable device includes: a power supply circuit, a DC blocking circuit, and a voltage comparison circuit. The power supply circuit is connected to a high voltage end, a low voltage end, a first signal input end, a second signal input end; the DC blocking circuit is connected to the first node, the second node, and a sensor in the wearable device; the voltage comparison circuit is connected to the first node, a reference voltage end and an output end, and configured to compare voltages of the first node and the reference voltage end; and output a first control signal through the output end when the voltage of the first node is smaller than the voltage of the reference voltage end, and output a second control signal through the output end when the voltage of the first node is larger than the voltage of the reference voltage end.