| 摘要 |
The present disclosure provides a positive and negative rotation control circuit and fan system, which can positively or negatively rotate a fan motor according to an end connecting to different external components or being floating. When the end generates an oscillatory fan signal, the positive and negative rotation control circuit negatively rotates the fan motor for a period of time after the positive and negative rotation control circuit is started for a delay time, to execute the operation of exhausting the accumulated dust, so that a fan connecting to the fan motor may exhaust the accumulated dust from an electronic device. Then the control circuit positively rotates the fan motor to execute the operation of dissipating heat, so that the fan may dissipate heat in the situation of having less dust within the electronic device. Accordingly, the heat dissipation effect of the fan may be enhanced. |
| 主权项 |
1. A positive and negative rotation control circuit, which is started based on a start signal, and then configured for controlling a fan motor after being started for a delay time, and the positive and negative rotation control circuit comprising:
an oscillation circuit, having an end connecting an external component or being floating, and configured for generating a fan signal at the end to transform the fan signal to a clock signal; an input stage circuit, electrically connected to the end of the oscillation circuit, and configured for generating a voltage signal based on the voltage level of the fan signal; a switching circuit, electrically connected to the oscillation circuit and the input stage circuit, and configured for outputting a control signal according to the voltage signal and the clock signal, wherein when the switching circuit receives the voltage signal indicating a first logic, outputs the control signal indicating positively rotating the fan motor, and when the switching circuit receives the voltage signal indicating a second logic, determines whether the clock signal is an oscillation signal, wherein when the clock signal is the oscillation signal, the switching circuit generates the control signal indicating negatively rotating the fan motor for a reverse time, and then generating the control signal indicating positively rotating the fan motor after the reverse time; and a driving circuit, electrically connected to the switching circuit, and configured for positively or negatively rotating the fan motor after the delay time according to the control signal. |
