Fan Control Circuit Using Single Pin for Speed and Direction
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Solution Overview
Problem
Existing control circuits for fan speed and rotational direction require two independent circuits and pins on the microprocessor, leading to increased cost and reduced layout space on the PCB.
Innovation Solution
A control circuit design that integrates a signal conversion unit, a processing unit, and a drive unit, where the processing unit generates control signals for fan speed and direction using a single pin, allowing the drive unit to control the fan through switch modules based on DC level signals and preset voltages, thereby reducing the need for multiple pins and increasing layout space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two independent circuits are used to control fan speed and rotational direction, then the control functionality is achieved, but the layout space on PCB is reduced and cost is increased
Solution Approach 1:
The patent combines the control of fan speed and rotational direction into a single circuit that uses one pin of the microprocessor. The signal conversion unit converts a single input signal into a DC level signal that is processed by the microprocessor to generate control signals for both speed and direction, eliminating the need for separate circuits and pins for each function.
Solution Approach 2:
The single control circuit is designed to perform multiple functions: it controls both the speed and rotational direction of the fan using one pin. The processing unit determines both speed and direction control signals based on the same DC level signal from the signal conversion unit, making the circuit universal for both control tasks.
2Ease of operation
If two independent circuits are used to control fan speed and rotational direction, then the control functionality is achieved, but the cost is increased
Solution Approach 1:
The patent merges two independent control circuits into one integrated circuit that controls both fan speed and rotational direction. This reduction in the number of circuits and components directly lowers manufacturing cost while maintaining full control functionality through the unified signal processing approach.
Solution Approach 2:
The control circuit is designed as a universal solution that handles both speed and direction control functions within a single circuit architecture, reducing the total component count and associated manufacturing costs while providing complete fan control capability.
3Ease of operation
If two pins of the microprocessor are used for two independent circuits, then the control functionality is achieved, but one pin of the microprocessor is not available for another circuit
Solution Approach 1:
The patent merges the functionality of two separate control pins into a single pin operation. The signal conversion unit and processing unit work together to extract both speed and direction information from a single DC level signal, freeing up the second pin for other circuit functions and increasing overall system adaptability.
Data Source
AI summary
The present invention provides a control circuit for speed and rotational direction of a fan, including a signal conversion unit, a processing unit, and a drive unit. The signal conversion unit converts the received input signal into a DC level signal. The processing unit determines to generate a plurality of control signals for the fan based on the received DC level signal and at least one preset voltage therein to drive the drive unit, further controlling the rotational speed or clockwise/counter-clockwise rotation of the fan, whereby to reduce the cost and increase the layout space.