Switch Drive Circuit Saves MCU Timers for Fan Processors
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Solution Overview
Problem
Conventional fan motor drive circuits require multiple timers to achieve high precision in pulse width modulation signals, leading to increased cost and size due to limited pin resources in micro control units, which is unbeneficial for lightweight and miniaturized electronic products.
Innovation Solution
A switch drive circuit design that utilizes multiple upper and lower arm switch components with drive control units to manage pulse width modulation signals, allowing for efficient use of timers and reducing the need for additional pins, thereby saving cost and optimizing fan design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple timers are used in the micro control unit to achieve high precision PWM output for driving lower arm switches, then the output precision of PWM signals is improved, but the device complexity and cost increase due to limited pin resources
Solution Approach 1:
A drive control unit is introduced as an intermediary component between the micro control unit and the lower arm switches. This drive control unit receives PWM signals from a single timer in the MCU and generates the required high-frequency PWM signals for driving the lower arm switches, eliminating the need for multiple timers in the MCU while maintaining signal precision.
Solution Approach 2:
The control function is segmented into two parts: the micro control unit handles high-level control decisions, while the drive control unit handles the detailed signal generation and timing for the lower arm switches. This segmentation allows the MCU to use fewer timers while still achieving precise control through the dedicated drive control unit.
2Adaptability or versatility
If more timers are supported in the micro control unit, then the adaptability for specific fan functions is improved, but the cost and package size increase
Solution Approach 1:
The drive control unit is designed as a universal interface that can handle multiple fan control functions through a single timer resource. It can support various fan functions (such as virtual rotational speed control) by processing PWM signals differently, eliminating the need for additional timers for each function while maintaining full adaptability.
3Device complexity
If conventional micro control unit with limited timers is used, then the device complexity is reduced, but the productivity decreases due to insufficient timer resources for additional fan functions
Solution Approach 1:
The drive control unit serves as a mediator that bridges the gap between the simple MCU timer resource and the complex fan control requirements. It enables rapid development of various fan functions by providing a standardized interface that handles the complexity of PWM signal generation, allowing developers to focus on application logic rather than low-level signal timing.
Data Source
AI summary
A switch drive circuit for a fan processor is applied to a fan processor. The switch drive circuit includes multiple upper arm switch components, multiple lower arm switch components correspondingly electrically connected with the upper arm switch components, a first drive switch unit and a second drive switch unit. The upper arm switch components are driven by a first pulse width modulation signal and a second pulse width modulation signal. The first and second drive switch units serve to receive a third pulse width modulation signal and a high-frequency puke width modulation signal. The third pulse width modulation signal is switched between a voltage high-level state and a voltage low-level state to trigger and turn on the lower arm switch components.