Universal Fan Driver Identifies 3-Pin and 4-Pin Types
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Solution Overview
Problem
Conventional computer systems cannot identify and properly drive both 3-pin and 4-pin fans, leading to unstable speed control and potential overheating of system components due to differences in control mechanisms, with 3-pin fans experiencing intermittent power supply issues affecting speed detection and control.
Innovation Solution
A universal method and apparatus that identifies whether a 3-pin or 4-pin fan is connected by providing continuous drive voltage and varying the duty cycle of the speed control signal, allowing differentiation based on speed signal output, and adjusts control accordingly to stabilize fan speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If PWM signal is input to the power contact of 3-pin fan to control speed, then fan speed can be controlled, but the power supply becomes intermittent causing unstable operation and incorrect speed detection
Solution Approach 1:
The patent segments the control function by separating the power supply path from the speed control path. It introduces a dedicated speed control contact (fourth contact) that receives PWM signals independently from the power contacts. This allows the power switch to remain continuously ON while still enabling PWM-based speed control through the separate control contact, thus maintaining both speed controllability and stable power supply for accurate speed detection.
2Ease of operation
If 3-pin fan uses power contact for speed control via PWM, then speed control is achieved, but hardware monitor controller cannot obtain correct speed due to intermittent power supply
Solution Approach 1:
The patent introduces a dedicated speed control contact as an intermediary element between the PWM controller and the power switch. This intermediary contact receives the PWM control signals and transmits them to the fan motor without interrupting the power supply through the power contacts. The continuous power supply ensures the fan operates smoothly and generates accurate tachometer signals, while the intermediary control contact enables precise speed control through PWM modulation.
3Adaptability or versatility
If computer system uses universal receptacle for both 3-pin and 4-pin fans, then compatibility is improved, but the system cannot identify and properly drive different fan types
Solution Approach 1:
The patent implements preliminary identification action by detecting whether a connected fan is 3-pin or 4-pin type before initiating speed control. The system uses the presence or absence of the fourth speed control contact as an identification criterion. Based on this preliminary detection, the system automatically configures the control mechanism: for 4-pin fans, it uses the dedicated speed control contact; for 3-pin fans, it controls the power switch directly. This preliminary action ensures compatible operation with both fan types without requiring complex manual configuration.
Data Source
AI summary
A universal driving apparatus of a computer system inputs two control signals of two different duty cycles through a speed control pin of a receptacle for connecting fans with the electricity supplied continuously. The differentiation percentage of the two speeds is compared with a threshold to identify the fan types. Therefore the computer system is capable of driving the identified fan correctly according to the result of the fan-type identification.