Power Supply Water Ingress Protection via Humidity Sensing
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Solution Overview
Problem
Conventional power supply devices lack effective protection against water ingress, which can lead to safety issues due to gaps between ultrasonic welding bars in the housing, resulting in potential electrical failures.
Innovation Solution
A power supply device incorporating a housing with humidity-sensitive capacitors and a feedback circuit that reduces the output voltage by adjusting the gain value and compensation bandwidth in response to increased humidity at joints, providing a water ingress protection function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ultrasonic bars are separately arranged to avoid appearance defects, then welding quality is improved, but gaps between ultrasonic bars occur leading to water ingress vulnerability
Solution Approach 1:
A waterproofing layer is introduced as an intermediary substance filling the gaps between separately arranged ultrasonic bars. This layer mediates between the welding quality requirement (separate bars) and the water ingress protection requirement (continuous seal), resolving the contradiction by adding a protective intermediate layer rather than changing the fundamental arrangement of ultrasonic bars.
2Reliability
If humidity sensitive capacitors are added to detect water ingress, then protection function is improved, but device complexity increases
Solution Approach 1:
The humidity sensitive capacitors automatically detect water ingress conditions and trigger protection functions without requiring external intervention or complex control systems. The capacitors self-monitor the humidity environment and autonomously activate the appropriate protective measures, reducing the need for additional complex control circuitry while maintaining reliable protection.
3Object-affected harmful factors
If gain value and compensation bandwidth are reduced in response to humidity, then output voltage safety is improved, but power delivery capability deteriorates
Solution Approach 1:
The gain value and compensation bandwidth are made dynamic rather than fixed, automatically adjusting based on real-time humidity detection. Under normal conditions, the system operates at full power delivery capability. When water ingress is detected through humidity sensing, the gain and bandwidth dynamically reduce to safe levels, preventing electrical hazards while maintaining optimal performance during safe operating conditions.
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 effectively reduces the output voltage when water ingress occurs, thereby offering protection against electrical failures and ensuring safety, while also potentially displaying warning signals through a warning light to indicate humidity states.
Implementation Method 1
The multiple humidity sensitive capacitors are respectively configured in the housing and adjacent to a corresponding joint of the joints. The multiple humidity sensitive capacitors jointly provide a sensing capacitance value.
Implementation Method 2
When humidity of at least one of the multiple joints increases, the sensing capacitance value is reduced
Data Source
AI summary
A power supply device is provided. The power supply device includes a housing, a power converter, a controller, multiple humidity sensitive capacitors, and a feedback circuit. The housing has multiple joints. The controller controls the power converter to provide an output voltage. The humidity sensitive capacitors are respectively configured in the housing and adjacent to a corresponding joint of the joints. The humidity sensitive capacitors jointly provide a sensing capacitance value. The feedback circuit changes a gain value and a compensation bandwidth of the output voltage in response to the change of the sensing capacitance value. When the humidity of at least one of the joints increases, the sensing capacitance value is reduced, so that the gain value and the compensation bandwidth are reduced.