Fan Control Chip Using Pulse Width Encoding for Pin Reduction
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Solution Overview
Problem
Existing fan control systems face challenges in efficiently controlling fan operations due to limited pin compatibility with communication interfaces and space constraints in miniaturized electronic devices, limiting the ability to configure additional control parameters beyond rotational speed.
Innovation Solution
A fan control system and method that utilizes a fan chip with specific pulse patterns (first and second forms of code) to determine control commands from received pulse signals, allowing for the setup of operation parameters and fan operations, including the use of a command table and firmware or hardware comparison circuits to decode pulse patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fan chip increases the number of pins to achieve additional control functions, then the control versatility is improved, but the compatibility with existing communication interfaces is worsened and the device space requirement increases
Solution Approach 1:
The fan chip is designed to perform multiple functions through a single pin interface. The same input pin can receive different pulse patterns that are decoded to execute various control operations including rotation speed adjustment, startup control, and parameter configuration, eliminating the need for separate pins for each function
Solution Approach 2:
The control method changes the parameter of pulse width ratio in pulse signals to encode different control commands. By varying the pulse width ratio between 0-100%, the system can represent multiple control parameters and commands through a single communication channel, achieving versatile control without additional pins
2Adaptability or versatility
If the fan chip uses more pins for additional control parameters, then the control functionality is improved, but the ease of manufacture is worsened due to interface compatibility issues
Solution Approach 1:
The fan chip accepts a universal pulse signal interface that can convey multiple types of control information. The single input pin serves as a multi-functional interface compatible with existing communication protocols, simplifying the manufacturing integration process
Solution Approach 2:
The patent replaces the mechanical/expansion approach of adding physical pins with a signal-processing approach. Instead of expanding the physical interface, the system encodes additional control functionality in the temporal characteristics of existing pulse signals, making the chip easier to manufacture and integrate
3Device complexity
If the fan chip uses pulse width ratio to represent control parameters, then the device complexity is reduced, but the measurement precision of parameter encoding is worsened
Solution Approach 1:
The system uses pulse width ratio ranging from 0-100% to represent control parameters. This excessive range allows for fine-grained control and precise parameter encoding, as small changes in pulse width can represent discrete control levels with high precision
Solution Approach 2:
The fan chip includes a decoding mechanism that accurately interprets the pulse width ratio signals. The comparison circuit and control logic provide feedback processing to ensure precise decoding of the encoded parameters, maintaining measurement precision despite the simplified single-pin interface
Data Source
AI summary
The invention provides a fan control system, which comprises a fan, a control unit, and a fan chip. The fan chip comprises a command table. A first specific pulse pattern represented as a first form of code, and a second specific pulse pattern represented as a second form of code are defined in the fan chip. The command table records at least one control command. Each control command is corresponding to a code string, respectively. When the fan chip receives a series of pulse signals from the control unit, it will determine that the code string is represented by the pulse signals, and inquire the corresponding control command from the command table according to the determinated code string so as to set up at least one operation parameter of the fan chip or control the fan to perform a corresponding operation according to the inquired control command.