Optical Gas Sensor Power Control via Dynamic Voltage Regulation
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Solution Overview
Problem
Optical gas sensors face challenges with peak inrush currents when using radiation sources with positive temperature coefficient behavior, leading to increased energy buffer requirements and reduced battery life in battery-powered systems, and existing solutions either consume excess energy or limit maximum current and pulse duration.
Innovation Solution
An electronic arrangement with a regulated voltage converter that maintains a quasi-constant power to the radiation source during a pulse duration, using a time-dependent control voltage to manage the power profile and reduce peak inrush currents without the need for current or voltage sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a series resistor is used to reduce inrush current, then the switch-on peak current is reduced, but energy consumption increases due to permanent power loss in the resistor
Solution Approach 1:
The patent applies dynamics by transitioning from a static series resistor to a dynamic switching circuit that adjusts resistance over time. The circuit starts with high resistance to limit inrush current, then switches to low resistance for normal operation, making the resistance value time-dependent rather than fixed.
Solution Approach 2:
The patent uses periodic action through a two-stage switching process: first stage with series resistor for current limiting during switch-on, second stage after switching where the resistor is bypassed. This periodic switching between two operational states eliminates continuous energy loss while providing initial current protection.
2Object-affected harmful factors
If constant current operation is used, then peak currents are avoided, but voltage saturation limits maximum current and pulse duration
Solution Approach 1:
The patent applies parameter changes by controlling the voltage parameter dynamically rather than maintaining constant current. The switching circuit allows voltage to increase during pulse duration without current saturation, enabling extended pulse durations and higher maximum currents while avoiding the voltage saturation problem of constant current operation.
3Object-affected harmful factors
If constant current operation is used, then peak currents are avoided, but aging effects are amplified due to lack of self-regulation
Solution Approach 1:
The patent applies feedback through the inherent voltage measurement capability that monitors the actual voltage across the radiation source. This feedback mechanism allows the system to detect resistance changes due to aging and automatically adjust operating parameters, providing self-regulation that compensates for aging effects while avoiding peak currents.
4Object-affected harmful factors
If larger series resistor is selected, then inrush current is reduced, but energy available to radiation source decreases
Solution Approach 1:
The patent resolves this contradiction by making the series resistor dynamic through switching. During the brief switch-on phase, a larger resistance limits inrush current. After switching, the resistance becomes minimal, maximizing power delivery to the radiation source. This time-dependent resistance adjustment satisfies both requirements without compromise.
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 solution effectively reduces peak inrush currents, maintains efficient power delivery, and extends battery life in battery-powered systems while minimizing energy consumption and circuit complexity.
Implementation Method 1
The voltage converter is designed to regulate a lamp voltage in such a way that a reference voltage is kept essentially constant at a feedback connection of the voltage converter
Implementation Method 2
The gas absorbs part of the radiation at certain wavelengths
Implementation Method 3
A detector, for example a photodiode, then detects at least part of the thermal radiation that has passed through the measuring cell and supplies a corresponding signal (e.g. a photocurrent in the case of a photodiode)
Implementation Method 4
Radiation sources with PTC behavior, i. H. to radiation sources that have a positive temperature coefficient. This means that an electrical resistance of the radiation source is lower at low temperatures than at higher temperatures
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An electronic arrangement (1) comprises a radiation source (62) and a regulated voltage converter (3) configured to provide a lamp voltage (vLP) to the radiation source (62) in order to operate the radiation source (62) in a switched-on state for a pulse duration (tP). The voltage converter (3) is configured to regulate the lamp voltage (vLP) such that a reference voltage (vFB) is kept substantially constant at a feedback terminal (FB) of the voltage converter (3).The electronic arrangement (1) further comprises a voltage source (DAC) connected to the feedback terminal (FB), wherein the voltage source (DAC) is configured to provide a time-dependent control voltage (vDAC) with a predefined temporal profile and thereby influence the control of the voltage converter (3) via the feedback terminal (FB) such that the voltage converter (3) specifies a temporal profile of the lamp voltage (vLP) depending on the predefined temporal profile of the control voltage (vDAC) in such a way that the power of the radiation source (62) deviates from a constant power value (PLP) by no more than 25% for at least 90% of the pulse duration (tp).