Positive and negative rotation control circuit and fan system

Patent metadata

Field	Value
Publication number	US-9512845-B2
Application number	US-201514656841-A
Country	US
Kind code	B2
Filing date	Mar 13, 2015
Priority date	Dec 26, 2014
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

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.

First claim

What is claimed is:

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.

2. The positive and negative rotation control circuit according to claim 1 , wherein when the switching circuit receives the voltage signal indicating the second logic and determines that the clock signal is not the oscillation signal, the switching circuit generates the control signal indicating negatively rotating the fan motor.

3. The positive and negative rotation control circuit according to claim 1 , wherein the switching circuit comprises:
a counter, receiving the clock signal, and counting an oscillation number of the clock signal, wherein when the oscillation number does not reach a predefined number, the counter generates the control signal indicating negatively rotating the fan motor, and when the oscillation number reaches the predefined number, the counter generates the control signal indicating positively rotating the fan motor;
a detecting circuit, receiving the voltage signal and the clock signal, wherein when the detecting circuit receives the voltage signal indicating the first logic, generates a select signal indicating the first logic, and when the detecting circuit receives the voltage signal indicating the second logic and determines that the clock signal is the oscillation signal, generates the select signal indicating the second logic; and
a selector, electrically connected to the counter and the detecting circuit, wherein when the selector receives the select signal indicating the first logic, receives the voltage signal as the control signal and transmits the control signal to the driving circuit, and when the selector receives the select signal indicating the second logic, transmits the control signal generated from the counter to the driving circuit.

4. The positive and negative rotation control circuit according to claim 3 , wherein when the detecting circuit receives the voltage signal indicating the second logic and determines that the clock signal is not the oscillation signal, the detecting circuit generates the select signal indicating the second logic for a predefined time, and then generates the select signal indicating the first logic after the predefined time, and the predefined time is less than the delay time.

5. The positive and negative rotation control circuit according to claim 1 , wherein the oscillation circuit comprises:
a charge-discharge circuit, having a charging element and a discharging element, the end configured between the charging element and the discharging element, and the charge-discharge circuit charges or discharges the external component through the end, to generate the fan signal at the end; and
a clock generator, electrically connected to the charge-discharge circuit, and configured for receiving the fan signal to accordingly generate the clock signal.

6. The positive and negative rotation control circuit according to claim 1 , wherein the external component is one of a capacitor, a power supply outputting a supply voltage, and a ground outputting a ground voltage.

7. The positive and negative rotation control circuit according to claim 1 , wherein the counter generates a stop signal to the oscillation circuit and the detecting circuit after the reverse time, to fix the voltage level of the clock signal.

8. The positive and negative rotation control circuit according to claim 3 , wherein the counter generates a stop signal to the oscillation circuit and the detecting circuit after the oscillation number reaching the predefined number, to fix the voltage level of the clock signal.

9. The positive and negative rotation control circuit according to claim 1 , wherein the input stage circuit is a Schmitt trigger.

10. A fan system, having a fan motor and the positive and negative rotation control circuit according to claim 1 , the fan motor configured for driving a fan, and the positive and negative rotation control circuit configured for outputting the control signal, to positively or negatively rotate the fan motor after the delay time.

Assignees

• Anpec Electronics Corp

Inventors

• Liu Yi-Cheng
• Chen Kun-Min
• Li Ching-Sheng

Classifications

• F04D15/00 Primary

  Control, e.g. regulation, of pumps, pumping installations or systems · CPC title

• F04D27/004 Primary

  by varying driving speed · CPC title

• H02P23/24

  Controlling the direction, e.g. clockwise or counterclockwise · CPC title

• Y02B30/70

  Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating · CPC title