Fan Detection Chip Voltage Pulse Identification
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Solution Overview
Problem
Conventional fan detection methods are inefficient due to longer detection times and noise issues, particularly when determining the type of fan before it can be correctly controlled, and existing methods require the fan to be powered or take longer to accurately identify fan types.
Innovation Solution
A fan detection method and system that uses a fan detection chip with specific pin connections and voltage pulse outputs to determine if a fan is PWM or DC based on voltage level changes, allowing for immediate and noise-free identification and subsequent correct control of the fan's speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the second method (adjusting duty cycle and detecting fan speed change) is used to determine fan type, then the fan type can be correctly identified, but the determination time becomes longer and noise is generated
Solution Approach 1:
The patent applies preliminary action by detecting the voltage level change on the fourth pin before the fan is powered on. The detection chip outputs a voltage pulse to the fourth pin and detects the voltage level change that occurs when the fan is connected, which allows the fan type to be identified in advance without requiring the fan to be powered or rotated, thus eliminating the time delay and noise issues of conventional methods
Solution Approach 2:
The patent replaces the mechanical/conventional detection method (measuring fan speed change through mechanical rotation detection) with an electrical detection method (measuring voltage level change on the fourth pin). This substitution eliminates the need for the fan to rotate at high speed during detection, thereby reducing determination time and eliminating noise generation while maintaining accurate fan type identification
2Device complexity
If the first method (using pull-up resistor voltage) is used to determine fan type, then the detection process is simple, but the fan must be supplied with power first which causes noise and delays detection
Solution Approach 1:
The patent applies preliminary action by performing the voltage detection before the fan is powered on. The detection chip actively outputs a voltage pulse to the fourth pin and detects the voltage level change that occurs when the fan is connected, which allows the fan type to be identified in advance without requiring the fan to be powered or rotated, thus eliminating the time delay and noise issues of conventional methods
Solution Approach 2:
The patent introduces an intermediary detection mechanism where the detection chip actively outputs a voltage pulse to the fourth pin and detects the voltage level change. This intermediary voltage pulse mechanism allows the system to detect fan type without requiring the fan itself to be powered first, thereby eliminating the noise and time delay problems while maintaining detection simplicity
Data Source
AI summary
A fan detection method, a fan detection chip and a fan detection system using the same are disclosed. The fan detection method is applied to a fan detection chip including a first pin, a second pin, a third pin, a fourth pin, and the fan is electrically coupled to the first pin, the second pin and the third pin at least. The fan detection method includes following steps: controlling a switch to selectively conduct the first pin and the second pin; controlling a pulse width modulation (PWM) signal processing module to output a voltage pulse to the fourth pin; detecting, by the voltage detection module, a voltage level on the fourth pin; and determining the fan to be a PWM fan when the voltage level is changed, and determining the fan to be a DC fan when the voltage level is not changed.