DC Fan Speed Regulation Circuit Using Multi-Step Voltage Control
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Solution Overview
Problem
Existing DC fans lack fine speed regulation and result in high noise and unnecessary power consumption, while PWM fans are costly and complex.
Innovation Solution
A circuit system for digitally regulating DC fan speed, incorporating a parallel data generator, trapezoidal resistor network, current amplifier, and linear voltage-controlled resistor circuits to achieve multiple-stage speed control with reduced noise and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If PWM fans are used to achieve fine speed regulation, then speed regulation precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the speed regulation function into multiple discrete stages using resistor networks and switching circuits. Instead of continuous PWM control, the system divides the voltage range into multiple steps, each controlled by a simple switching element, thereby achieving fine speed regulation without complex control circuits.
Solution Approach 2:
The patent replaces the electronic PWM control system with a passive resistor network-based voltage division system. By using resistors and switching elements to create multiple voltage taps, the system achieves speed regulation through passive electrical components rather than active PWM generation circuits.
2Device complexity
If DC fans with linear step-down regulation are used to reduce cost, then device complexity is reduced, but manufacturing precision and noise control deteriorate
Solution Approach 1:
The patent introduces multiple resistance elements arranged in a network configuration that creates multiple discrete voltage levels. Each resistance element can be switched independently to provide different voltage steps to the fan, transforming a simple DC fan into a multi-speed controllable device without requiring complex control logic.
3Reliability
If DC fans operate at full speed to ensure heat dissipation, then reliability is improved, but energy consumption and noise increase
Solution Approach 1:
The patent implements dynamic speed adjustment capability by providing multiple voltage levels that can be selected based on actual heat dissipation requirements. The system can adaptively change fan speed from full speed to lower speeds, optimizing the balance between heat dissipation effectiveness and power consumption according to system needs.
Solution Approach 2:
The patent changes the voltage parameter supplied to the fan motor by introducing a resistor network that creates multiple voltage taps. By switching between different voltage levels, the system can adjust fan speed to match actual thermal conditions, reducing power consumption when full speed is not required while maintaining adequate heat dissipation.
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 system provides low-cost, multiple-stage speed regulation for DC fans, enhancing noise reduction and power efficiency, addressing the limitations of both DC and PWM fans.
Implementation Method 1
The trapezoidal resistor network circuit is electrically connected to the parallel data generator circuit and can receive the digital parallel data and transfer the digital parallel data into a corresponding analog current signal
Implementation Method 2
The current amplifier circuit is electrically connected to the trapezoidal resistor network circuit and can receive the analog current signal and convert the analog current signal into a voltage signal
Implementation Method 3
The linear voltage-controlled resistor circuit is electrically connected to the current amplifier circuit and can receive the voltage signal and generate a corresponding resistance signal according to the voltage signal
Data Source
AI summary
A circuit system for digitally regulating direct-current fan rotation speed includes a parallel data generator circuit, a trapezoidal resistor network circuit, a current amplifier circuit, a linear voltage-controlled resistor circuit, and a fan power converter circuit. The parallel data generator circuit can receive control data and generate corresponding digital parallel data. The trapezoidal resistor network circuit can receive the parallel data and transfer it into a corresponding analog current signal. The current amplifier circuit can receive the current signal and convert it into a corresponding voltage signal. The linear voltage-controlled resistor circuit can receive the voltage signal and generate a corresponding resistance signal according thereto. The fan power converter circuit can adjust an output voltage according to the resistance signal, generate a corresponding drive voltage value, and transmit it to a fun motor of a direct-current fan so that the fan motor operates according to the drive voltage value.