Fan Noise Suppression Circuit for Power Rail Contamination
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Solution Overview
Problem
Power rail contamination caused by rotating fan loads in electronic systems, particularly due to high current transients from powerful fans, is not effectively mitigated by existing technologies, leading to significant voltage noise and inefficiencies in cooling systems.
Innovation Solution
A fan noise suppression circuit is introduced, featuring a filter circuit, an adjustable current source, and a feedback loop with a PID controller, which presents a constant current load to the power source, reducing voltage noise and maintaining a stable power input to the fan, using a combination of LC filtering and adjustable inductance to manage current transients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If powerful fans are used to increase cooling capacity, then cooling performance is improved, but voltage noise and power rail contamination increase
Solution Approach 1:
The patent introduces an intermediate circuit between the power source and the fan that acts as a mediator. This circuit includes current sensing, energy storage elements (inductors and capacitors), and control logic that decouples the fan's transient current demands from the power source, thereby eliminating voltage noise while maintaining high cooling performance
Solution Approach 2:
The patent implements a feedback control system that continuously monitors the current drawn by the fan and adjusts the power delivery accordingly. The controller uses feedback from current sensors to regulate the energy storage elements, ensuring constant current draw and preventing voltage fluctuations that cause noise
2Object-affected harmful factors
If existing filtering technologies are used, then some voltage noise is reduced, but high current transients from powerful fans are not effectively mitigated
Solution Approach 1:
The patent fundamentally changes the operating parameters of the fan power system by enforcing constant current draw rather than allowing variable current. This parameter change transforms the fan's electrical characteristics, eliminating the high current transients that traditional filters cannot handle, while maintaining effective noise suppression
3Object-affected harmful factors
If constant current load is presented to power source, then voltage noise is reduced, but additional circuit complexity is introduced
Solution Approach 1:
The patent segments the power delivery function into distinct modular components: current sensing circuitry, energy storage elements (inductors and capacitors), control logic, and power switching elements. This segmentation makes the complex constant current regulation system more manageable, maintainable, and integrable into existing fan systems
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 suppresses voltage noise and maintains a constant power draw, reducing the impact of fan-induced power contamination on the power rail, allowing for improved cooling performance without the need for large, impractical filter components.
Implementation Method 1
The fan noise suppression may include a filter circuit (e.g., an LC filter) configured to reduce voltage noise seen by the fan noise suppression circuit
Implementation Method 2
The one or more delay elements and/or energy storage elements (e.g., a capacitor) coupled to the output of the adjustable current source
Data Source
AI summary
A fan noise suppression circuit may be coupled between a power source and a power input to at least one fan. The fan noise suppression circuit may include an adjustable current source coupled to the power source. The adjustable current source may provide a voltage output and a current output based on a power output of the power source. The fan noise suppression circuit may include a feedback controller coupled to an output of the adjustable current source. The feedback controller may be configured to compare the voltage output to a reference voltage and provide an error value to the adjustable current source, wherein the adjustable current source may adjust the current output based on the error value.