Radon Gas Sensor Charge Pump Voltage Regulation
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Solution Overview
Problem
Existing radon gas sensors face challenges in maintaining a consistent electric field within the diffusion chamber, which affects the accuracy of radon concentration measurements, especially in battery-powered devices where voltage variability impacts the instrument's performance and longevity.
Innovation Solution
A radon gas sensor instrument utilizing a microcontroller-provided regulated voltage source to drive a charge pump, creating a stable electric field between the sensor and conductive diffusion chamber walls, while also powering an LCD display, thereby minimizing component count and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a charge pump is used to generate high voltage for the electric field, then the electric field strength is improved, but power consumption increases and battery life decreases
Solution Approach 1:
The charge pump is operated in periodic pulses rather than continuously. The microcontroller activates the charge pump only when voltage supplementation is needed, allowing the capacitor to discharge and maintain the electric field during intervals between charging cycles. This periodic operation dramatically reduces average power consumption while maintaining sufficient electric field strength for detecting radon daughter products.
2Device complexity
If the charge pump output voltage varies with battery voltage, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The microcontroller monitors the charge pump output voltage and dynamically adjusts the charging parameters (pulse width, frequency, or duty cycle) to maintain a substantially constant electric field strength despite variations in battery voltage. This feedback control ensures measurement precision is maintained without requiring complex voltage regulation circuitry, as the system adapts to changing battery conditions in real-time.
3Stability of the object's composition
If continuous charge pump operation is used, then electric field consistency is improved, but battery life decreases
Solution Approach 1:
The charge pump operates periodically rather than continuously, charging the capacitor in pulses and allowing it to discharge between cycles. This periodic operation maintains adequate electric field consistency for detection purposes while dramatically extending battery life compared to continuous operation. The microcontroller optimizes the pulse timing to balance field consistency with power conservation.
Solution Approach 2:
The system transitions from a static continuous charging approach to a dynamic pulsed charging approach. The charge pump voltage and timing are dynamically adjusted based on battery voltage levels and detection requirements, allowing the system to maintain performance while adapting power consumption to actual needs, thereby extending operational duration.
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
This configuration enhances the detection rate of radon daughter products, improves measurement accuracy, and extends battery life by maintaining a consistent electric field and reducing power consumption.
Implementation Method 1
a charge pump arranged to take its input from the regulated voltage source and to provide a charge pump output potential of greater magnitude than the potential of said input; wherein the charge pump output is arranged to provide an electric field between the sensor and the conductive walls of the diffusion chamber
Implementation Method 2
The photodiode detects alpha particles within the sampling chamber and sends a detection signal to the processing circuitry on the main PCB
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
A gas sensor instrument in which a diffusion chamber has conductive walls and a sensor is disposed inside the diffusion chamber. A regulated voltage source provides the input to a charge pump and the charge pump thus generates an output voltage of greater magnitude than its input voltage. The use of a regulated voltage source as the input leads to a more regulated output voltage from the charge pump. The output of the charge pump is arranged to provide a stable electric field between the sensor and the conductive walls of the diffusion chamber. Preferably the regulated voltage source is taken from the LCD supply pin of a microcontroller.