Fan Control Circuit Using PWM Voltage Conversion
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Solution Overview
Problem
Conventional fan controlling circuits for server systems are complex and costly due to the use of expensive micro-controllers and require additional voltage sources, increasing design complexity and cost.
Innovation Solution
A fan controlling circuit that transforms PWM signals into voltages using integral circuits and operational amplifiers to compare and output the PWM signal with a higher operation frequency, eliminating the need for micro-controllers and allowing the same voltage source as the fans, thereby simplifying design and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a micro-controller is used to integrate and compare PWM signals, then fan speed control functionality is achieved, but design cost and complexity increase
Solution Approach 1:
The patent divides the fan control function into separate modular components: PWM signal generation units, integral circuit units for frequency-to-voltage conversion, operational amplifier units for comparison, and control signal output units. Each module performs a specific function, allowing independent design, testing, and replacement without affecting the entire system.
Solution Approach 2:
The patent replaces expensive micro-controllers with cheaper discrete electronic components including integral circuits, operational amplifiers, and logic gates. These simpler components achieve the same fan control functionality at lower cost, aligning with the principle of using cost-effective components when full micro-controller capabilities are not required.
2Ease of operation
If a micro-controller is used to integrate PWM signals, then fan control is achieved, but additional voltage sources are required
Solution Approach 1:
The patent designs the integral circuit units and operational amplifiers to operate from the same voltage source that powers the fan motors. This multi-functional voltage source serves both the fan operation and the control circuitry, eliminating the need for separate micro-controller power supply and reducing the total number of voltage sources required in the system.
3Ease of manufacture
If discrete elements are used instead of micro-controllers, then design cost is reduced, but signal processing capability may be limited
Solution Approach 1:
The patent introduces integral circuit units as intermediary components that convert PWM frequency signals into proportional voltage signals. These voltage signals are then processed by operational amplifiers for comparison and logic circuits for control decisions. This intermediary conversion approach enables complex signal processing functionality using simpler, more cost-effective discrete components.
Solution Approach 2:
The patent replaces the electronic signal processing functions of a micro-controller with an analog circuit-based approach using integral circuits and operational amplifiers. Instead of digital sampling and processing, the system uses analog frequency-to-voltage conversion and continuous voltage comparison, achieving similar control objectives through different physical principles.
Data Source
AI summary
A fan controlling circuit is provided. The fan controlling circuit includes an integral unit, an operational amplifier, and an output unit. The integral unit transforms pulse width modulation signals to voltages, and then the output unit outputs one of the pulse width modulation signals having a higher operation frequency according to the comparison result between the voltages. As the fan controlling circuit may be constituted with discrete elements and use a same voltage source as fans, the design cost and complexity are reduced.