Electronic Cigarette Pressure Sensor Control Circuit

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Solution Overview

Problem

Existing electronic cigarettes lack accurate pressure sensing techniques to detect user inhalation, often requiring multiple sensors and consuming excessive power, while current microphone-type sensors only detect discrete pressure changes.

Innovation Solution

A single pressure sensor measures pressure in the main vapor flow channel, calculating a moving average to differentiate between background and current pressure, allowing the control circuitry to switch between sleep and active states based on pressure differences, and optionally using an accelerometer to adjust sampling frequency, thereby reducing power consumption and enhancing detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple pressure sensors are used to detect spatial pressure differences, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvepressure detection accuracyVSAvoidnumber of sensors

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple sensing functions (pressure detection, acceleration detection, and usage pattern recognition) into a single integrated control circuit that processes data from one pressure sensor and one accelerometer. This merging approach achieves accurate usage detection without requiring multiple pressure sensors, thereby reducing device complexity while maintaining measurement precision.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control circuit acts as an intermediary that processes raw pressure measurements and accelerometer data to detect usage patterns. By implementing sophisticated signal processing algorithms in the control circuit, the system achieves accurate detection of intentional usage versus environmental changes without requiring additional physical sensors.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If pressure sampling frequency is increased to accurately detect user inhalation, then measurement precision is improved, but power consumption increases

Engineering Contradiction:

Improveinhalation detection accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the pressure sampling frequency based on detected usage patterns. During normal operation, sampling occurs at a lower frequency to conserve power, while the accelerometer continuously monitors for motion that indicates potential usage. When usage is detected, the sampling frequency increases to accurately capture inhalation patterns, then returns to lower frequency afterward.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control circuit implements periodic sampling at variable intervals rather than continuous high-frequency sampling. By using the accelerometer to trigger periodic high-frequency sampling only when motion is detected, the system achieves accurate inhalation detection during usage while minimizing power consumption during non-usage periods.

Inventive Principle:

Principle #19Periodic action

3Device complexity

If a single pressure sensor is used to reduce device complexity, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:

Improvenumber of sensorsVSAvoidusage detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system changes the parameters of the single pressure sensor by dynamically adjusting the sampling frequency and processing methodology. Instead of relying on multiple sensors providing spatial resolution, the single sensor achieves accurate usage detection through temporal analysis of pressure changes combined with acceleration data, effectively compensating for the reduced sensor count through enhanced signal processing.

Inventive Principle:

Principle #35Parameter changes

4Measurement precision

If continuous high-frequency pressure sampling is implemented, then measurement precision is improved, but loss of energy increases

Engineering Contradiction:

Improvepressure measurement accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The sampling frequency is made dynamic rather than static, adjusting based on operational context. The system transitions between low-power periodic sampling and high-precision continuous sampling based on accelerometer-triggered usage detection, optimizing the balance between measurement precision and energy loss throughout the device lifecycle.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20240122265A1Electronic Cigarette and Method for Controlling an Electronic Cigarette

Publication Date: 2024.04.18 JT INTERNATIONAL SA

AI summary

An electronic cigarette includes a vaporizing unit configured to generate a vapor from a substrate; an air flow inlet; a vapor outlet configured for a user to inhale the vapor; a main vapor flow channel extending past the vaporizing unit from the air flow inlet to the vapor outlet; a pressure sensor arranged to measure a pressure at the main vapor flow channel; and control circuitry configured to monitor user inhalation by: obtaining pressure measurements from the pressure sensor at a sampling frequency; calculating a background pressure as a moving average of the pressure measurements obtained within a moving sampling period; and calculating a current pressure difference as a difference between a current pressure measurement and the background pressure. The control circuitry is configured to select an operation state depending upon the current pressure difference. The operation state is one of: at least a sleep state; and an active state.