TWI426675B - Fan systems, fan control circuits and fan control methods - Google Patents

Description

Fan system, fan control circuit, and fan control method

The present invention relates to a fan system, and more particularly to a fan control circuit having automatic dust removal and suppression of surge current.

Generally, the positive and negative reversal of the fan is applied to the inhalation and exhaust to achieve the effect of automatic dust removal, such as exhaust fans, power supply fans, and the like. However, although the three-phase driving chip can drive the fan to rotate forward or reverse, it cannot switch between forward and reverse during operation. Conventional techniques use a software program to write integrated circuits, such as a microcontroller unit (MCU, also known as a microprocessor), to control the forward and reverse rotation of the fan, but at a higher cost.

Figure 1 is a diagram showing the relationship between fan current versus time for fan forward and reverse using conventional techniques. As shown in the figure, when the blade is switched forward and backward, the surge current Ip is generated due to the inertia of the full rotation of the blade. The surge current Ip is about 1.5 times the normal starting current, so the control circuit and system may be burnt. The power supply, and the surge current Ip also consumes system power, resulting in wasted energy. Therefore, a fan system and a fan control method are needed to achieve the effect of automatic dust removal, and also to suppress the surge current.

In view of this, the present invention provides a fan control circuit including a forward and reverse control circuit that outputs a forward and reverse output signal such that a fan rotates in a first direction for a first time and then after a power source is turned on. Rotating in a second direction after the second time, wherein the second time is immediately after the first time And a surge current suppression circuit generates a control signal according to the forward and reverse output signals, so that a driving chip stops driving the fan at a second time, and after a second time, drives the fan to rotate at a full speed in the second direction. To suppress the surge current.

The invention also provides another fan system, comprising a fan; a driving chip, receiving a forward and reverse output signal and a control signal to drive the fan; a forward and reverse control circuit, outputting a forward and reverse output signal, so that the fan is at the power source After starting, first rotating in a first direction for a first time and then after a second time in a second direction, wherein the second time is immediately after the first time; and a surge current suppression circuit, according to the positive The output signal is inverted to generate a control signal such that the drive wafer stops driving the fan at a second time, and after a second time, the fan is driven to rotate at full speed in the second direction to suppress the surge current.

The invention also provides a fan control method, comprising: outputting a forward and reverse output signal to a driving chip and a surge current suppressing circuit, so that a fan rotates in a first direction for a first time after the power is turned on. Rotating in a second direction after a second time, wherein the second time is immediately after the first time; and generating a control signal according to the forward and reverse output signals, so that the driving chip stops driving the fan at the second time, and After the second time, the fan is driven to rotate at full speed in the second direction to suppress the surge current.

The above and other objects, features, and advantages of the present invention will become more apparent and understood.

The present invention provides a fan system having a surge current suppression. In the embodiment of the present invention, a simple circuit can be used to achieve full-speed reversal after a self-starting of the fan system through a reversal time, so that the automatic inhalation and automatic exhausting can achieve the effect of dust removal, and the software program does not need to be written. In the integrated circuit. In addition, the embodiment of the present invention stops driving the fan when the fan has not been fully reversed, and drives the fan at full speed after a period of time to achieve the purpose of suppressing the surge current.

Figure 2 is an embodiment of a fan system of the present invention. As shown, the fan system 21 includes a fan 22, a drive die 23, and a fan control circuit 24. The drive wafer 23 receives a forward and reverse output signal FR and a control signal CS for driving the fan 22. The fan control circuit 24 includes a forward and reverse control circuit 25 for outputting the forward and reverse output signals FR, and a surge current suppressing circuit 26 for generating the control signal CS according to the forward and reverse output signals FR.

For example, when the driving chip 23 receives the positive and negative output signal FR having a first level and a control signal CS of a first level, the driving fan 22 is rotated at a full speed in a first direction. When the driving chip 23 receives a second level of the positive and negative output signal FR and a second level of the control signal CS, or receives the second level of the positive and negative output signal FR and the first level of the control signal CS The drive wafer 23 stops driving the fan 22. In some embodiments, the first level may be a high voltage level, and the second level may be a low voltage level, but is not limited thereto. When the driving chip 23 receives the second level positive and negative output signal FR and the first level control signal CS, the fan 22 rotates at a full speed in a second direction. In some embodiments, the first direction can be the second The opposite direction of the direction, for example, the first direction may be forward/clockwise rotation, and the second direction may be reverse/counterclock rotation, but is not limited thereto.

Figure 3 is an embodiment of a fan control circuit of the present invention. As shown, the fan control circuit 24 includes a forward and reverse control circuit 25 and a surge current suppression circuit 26. For example, the forward/reverse control circuit 25 is configured to output the forward/reverse output signal FR, so that the fan 22 rotates in the first direction for the first time after the power is turned on, and then rotates in the second direction after the second time. The second time is immediately after the first time. The surge current suppression circuit 26 is configured to generate a control signal CS according to the forward and reverse output signals FR, so that the driving chip 23 stops driving the fan 22 at the second time, and after the second time, drives the fan 22 to drive at a full speed in the second direction. Rotate to suppress the surge current.

In this embodiment, the forward and reverse control circuit 25 includes a first comparator 31, a first capacitor C1, a first resistor R1, a second resistor R2, and a third resistor R3. For example, the first comparator 31 has a first input terminal for receiving a first storage voltage V2, a second input terminal for receiving a reference voltage V1, and an output terminal for outputting a forward and reverse output signal FR. . The first resistor R1 has a first end coupled to a voltage source Vref and a second end coupled to the second input of the first comparator 31. The first capacitor C1 has a first end coupled to a ground end, and a second end coupled to the second input end of the first comparator 31. The second resistor R2 has a first end coupled to the voltage source Vref and a second end coupled to the first input end of the first comparator 31. The third resistor R3 has a second end coupled to the ground end, and a second end coupled to the first input end of the first comparator 31.

Further, the reference voltage V1 is a voltage source Vref by the second power The resistor R2 and the third resistor R3 are divided by pressure. Similarly, the first storage voltage V2 is generated by the voltage source Vref being divided by the first resistor R1 and the first capacitor C1. When the first storage voltage V2 is less than the reference voltage V1, the first comparator 31 outputs a forward and reverse output signal FR having a first level such that the drive wafer 23 controls the fan 22 to rotate in the first direction. When the first storage voltage V2 is greater than the reference voltage V1, the first comparator 31 outputs a forward and reverse output signal FR having a second level to drive the wafer 23 to rotate the fan 22 in the second direction after a second time.

In this embodiment, the surge current suppression circuit 26 also includes a second comparator 32, a second capacitor C2, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. For example, the second comparator 32 has a first input terminal for receiving a second storage voltage V3, a second input terminal for receiving the reference voltage V1, and an output terminal for outputting the control signal CS. The second capacitor C2 is coupled between the output end of the first comparator 31 and the first input end of the second comparator 32. The fourth resistor R4 has a first end coupled to the voltage source Vref and a second end coupled to the output end of the first comparator. The fifth resistor R5 has a first end coupled to the voltage source Vref, and a second end coupled to the first input of the second comparator 32 for charging the second capacitor C2. The sixth resistor R6 has a first end coupled to the voltage source Vref and a second end coupled to the output end of the second comparator 32.

Further, the second storage voltage V3 is generated by a voltage difference between the voltage source Vref and the forward and reverse output signals FR, and is further divided by the first resistor R1 and the first capacitor C1. For example, when the first comparator 31 outputs the positive and negative output signals FR of the second level, the second capacitor C2 is discharged to be lower than the reference voltage V1, and then charged by the voltage source Vref in the second time. The electricity is higher than the reference voltage V1. Therefore, when the second storage voltage V3 is greater than the reference voltage V1, the second comparator 32 outputs the control signal CS having the first level, so that the driving wafer 23 controls the fan 22 to rotate at full speed, and when the second storage voltage V3 is smaller than the reference voltage At V1, the second comparator 32 outputs a control signal CS having a second level such that the drive wafer 23 stops driving the fan 22 to rotate.

The invention also provides a fan control method, which is used for achieving the effect of automatic dust removal, and can also achieve the purpose of suppressing the surge current. Figure 4 is a flow chart of a fan control method of the present invention. As shown, the fan control method includes the following steps.

In step S41, the forward/reverse control circuit 25 outputs the forward/reverse output signal FR to the driving chip 23 and the surge current suppressing circuit 26, so that the fan 22 rotates in the first direction for the first time and then the second after the power is turned on. After the time, the second direction is rotated, wherein the second time is immediately after the first time. For example, after the power is turned on, since the first storage voltage V2 is smaller than the reference voltage V1, the above-described forward and reverse output signals FR having the first level are output, so that the driving wafer 23 controls the fan 22 to rotate in the first direction. After the first time, since the first storage voltage V2 is greater than the reference voltage V1, the positive and negative output signal FR having the second level is output to rotate the fan 22 in the second direction after the second time is driven by the driving wafer 23. .

In step S42, the surge current suppression circuit 26 generates a control signal CS according to the forward and reverse output signals FR, so that the drive wafer 23 stops driving the fan 22 at the second time, and after the second time, drives the fan 22 to the second. The direction is rotated at full speed to suppress the surge current. For example, since the output signal FR is inverted to the second level after the first time, the second storage is caused. When the storage voltage V3 is smaller than the reference voltage V1, the surge current suppression circuit 26 outputs a control signal CS having the second level so that the drive wafer 23 stops driving the fan 22 to rotate. After the second time, since the second storage voltage V3 is greater than the reference voltage V1, the surge current suppression circuit 26 outputs a control signal CS having a first level such that the drive wafer 23 is rotated at full speed in the second direction.

Fig. 5 is another flow chart of the fan control method of the present invention, and Fig. 6 is a timing chart of the fan control method of the present invention. Fig. 6 corresponds to Figs. 4 and 5.

In step S510, at time t0 (ie, when the power is turned on), the first comparator 31 compares whether the first storage voltage V2 is greater than the reference voltage V1. When the first storage voltage V2 is less than the reference voltage V1, step S521 is performed. Conversely, when the first storage voltage V2 is greater than the reference voltage V1, step S522 is performed. According to FIG. 6, at the first time (ie, time t0 to time t1), since the first storage voltage V2 is smaller than the reference voltage V1, the flow proceeds to step S521. In step S521, the first comparator 31 outputs the positive and negative output signals FR of the first level to the drive wafer 23 and the surge current suppression circuit 26. Next, the second comparator 32 compares whether the second storage voltage V3 is greater than the reference voltage V1. Since the second storage voltage V3 is greater than the reference voltage V1 from time t0 to time t1, the process proceeds to step S541. In step S541, the second comparator 32 outputs the first level control signal CS to the drive wafer 23 for driving the fan 22 to rotate at full speed in the first direction (step 551).

As shown in FIG. 6, since the first storage voltage V2 is greater than the reference voltage V1 at the second time (ie, time t1 to time t2), the flow comes to the step. Step S522. In step S522, the first comparator 31 outputs a positive and negative output signal FR of the second level to the drive wafer 23 and the surge current suppression circuit 26. Next, in step S530, the second comparator 32 compares whether the second storage voltage V3 is greater than the reference voltage V1. When the second storage voltage V3 is less than the reference voltage V1, step S542 is performed, and when the second storage voltage V3 is greater than the reference voltage V1, step S543 is performed. Since the second storage voltage V3 is smaller than the reference voltage V1 from time t1 to time t2, the flow proceeds to step S542. In step S542, the second comparator 32 outputs a second level control signal CS to the drive wafer 23 to stop driving the fan 22 (step S552).

After the time t2, since the first storage voltage V2 is greater than the reference voltage V1 and the second storage voltage V3 is greater than the reference voltage V1, the process proceeds to step S543. In step S543, the second comparator 32 outputs a first level control signal CS to the drive wafer 23 to drive the fan 22 to rotate at full speed in the second direction (step S553).

According to the fan current of Fig. 6, it is apparent that no surge current occurs after time t2 (i.e., after the fan is reversed). Therefore, it can be known that the first time is rotated in the first direction, and the driving of the fan 22 is stopped at the end of the first time. After the second time, the fan 22 is driven to rotate at the full speed in the second direction, which has the effect of achieving automatic dust removal. The purpose of suppressing the surge current is achieved.

While the invention has been described above in the preferred embodiments, it is not intended to limit the invention. In addition, those skilled in the art will recognize that the scope of the present invention should be broadly construed to cover all embodiments and variations thereof.

Ifan‧‧‧Fan current

Ip‧‧‧ surge current

21‧‧‧Fan system

22‧‧‧Fan

23‧‧‧Drive chip

24‧‧‧Fan control circuit

25‧‧‧ Forward and reverse control circuit

26‧‧‧ Surge current suppression circuit

31‧‧‧First comparator

32‧‧‧Second comparator

R1‧‧‧first resistance

R2‧‧‧second resistance

R3‧‧‧ third resistor

R4‧‧‧fourth resistor

R5‧‧‧ fifth resistor

R6‧‧‧ sixth resistor

C1‧‧‧first capacitor

C2‧‧‧second capacitor

Vref‧‧‧voltage source

V1‧‧‧ reference voltage

V2‧‧‧First storage voltage

V3‧‧‧Second storage voltage

FR‧‧‧ reverse output signal

CS‧‧‧Control signal

Steps S41, S42, S510, S521, S522, S530, S541, S542, S543, S551, S552, S553‧‧

Figure 1 is a diagram showing the relationship between fan current versus time for fan forward and reverse using conventional techniques.

Figure 2 is an embodiment of a fan system of the present invention.

Figure 3 is an embodiment of a fan control circuit of the present invention.

Figure 4 is a flow chart showing one of the fan control methods of the present invention.

Fig. 5 is another flow chart of the fan control method of the present invention.

Fig. 6 is a timing chart of the fan control method of the present invention.

25‧‧‧ Forward and reverse control circuit

26‧‧‧ Surge current suppression circuit

31‧‧‧First comparator

32‧‧‧Second comparator

R1‧‧‧first resistance

R2‧‧‧second resistance

R3‧‧‧ third resistor

R4‧‧‧fourth resistor

R5‧‧‧ fifth resistor

R6‧‧‧ sixth resistor

C1‧‧‧first capacitor

C2‧‧‧second capacitor

Vref‧‧‧voltage source

V1‧‧‧ reference voltage

V2‧‧‧First storage voltage

V3‧‧‧Second storage voltage

FR‧‧‧ reverse output signal

CS‧‧‧Control signal

24‧‧‧Fan control circuit

Claims (21)

A fan control circuit includes: a forward/reverse control circuit that outputs a forward and reverse output signal to a driving chip, so that after a power source is started, a fan rotates in a first direction for a first time and then a second After the time, the second direction is rotated, wherein the second time is immediately after the first time; and a surge current suppression circuit receives the forward and reverse output signals for outputting a control signal to the driving chip. The driving chip is caused to stop driving the fan at the second time, and after the second time, the fan is further driven to rotate at a full speed in the second direction to suppress a surge current. The fan control circuit of claim 1, wherein the forward and reverse control circuit includes a first comparator having a first input terminal, receiving a reference voltage, and a second input terminal, receiving a first Storing a voltage, and an output terminal, outputting the forward and reverse output signals; wherein when the first storage voltage is less than the reference voltage, the first comparator outputs the forward and reverse output signals having a first level, so that The driving chip controls the fan to rotate in the first direction, and when the first storage voltage is greater than the reference voltage, the first comparator outputs the positive and negative output signals having a second level for driving The wafer rotates the fan in the second direction after the second time. The fan control circuit of claim 2, wherein the forward and reverse control circuit further includes: a first resistor having a first end coupled to a voltage source, and a second end coupled to the The second input end of the first comparator; a first capacitor having a first end coupled to a ground end, and a second end coupled to the second input end of the first comparator; a second resistor having a first end coupled to The voltage source, and a second end coupled to the first input end of the first comparator; and a third resistor having a second end coupled to the ground end, and a second end coupled to the second end The first input end of the first comparator. The fan control circuit of claim 2, wherein the surge current suppression circuit comprises: a second comparator having a first input terminal, receiving a second storage voltage, and a second input terminal, receiving The reference voltage, and an output terminal, outputting the control signal; wherein when the second storage voltage is greater than the reference voltage, the second comparator outputs the control signal having a first level, so that the driving chip controls the above The fan rotates at full speed, and when the second storage voltage is less than the reference voltage, the second comparator outputs the control signal having a second level, so that the driving chip stops driving the fan to rotate. The fan control circuit of claim 4, wherein the surge current suppression circuit further comprises: a second capacitor coupled to the output end of the first comparator and the second comparator Between an input terminal, wherein when the first comparator outputs the forward and reverse output signals of the second level, the second capacitor is discharged to be lower than the reference voltage, and then is A voltage source is charged above the reference voltage. A fan control circuit as described in claim 5, wherein the upper The spur current suppressing circuit further includes: a fourth resistor having a first end coupled to the voltage source, and a second end coupled to the output end of the first comparator; and a fifth resistor, The first terminal is coupled to the voltage source, and the second terminal is coupled to the first input terminal of the second comparator to charge the second capacitor. The fan control circuit of claim 1, wherein the driving chip is a three-phase driving chip. A fan system includes: a fan; a driving chip, receiving a forward and reverse output signal and a control signal to drive the fan; a forward and reverse control circuit, outputting the forward and reverse output signals to a driving chip, so that After the power is turned on, the fan rotates in a first direction for a first time and then after a second time in a second direction, wherein the second time is immediately after the first time; and a surge current The suppression circuit receives the forward/reverse output signal to generate the control signal, so that the driving chip stops driving the fan at the second time, and after the second time, drives the fan to rotate at full speed in the second direction. To suppress the surge current. The fan system of claim 8, wherein the driving chip receives the positive and negative output signals having a first level and the first level of the control signals when the power is turned on, so that the fan is Rotating at a full speed in the first direction, and after the first time, the driving chip receives the second inversion output signal and a second level The control signal causes the driving chip to stop driving the fan, and after the second time, the driving chip receives the positive and negative output signals of the second level and the control signal of the first level, so that The fan rotates at full speed in the second direction. The fan system of claim 8, wherein the forward and reverse control circuit includes a first comparator having a first input terminal for receiving a reference voltage and a second input terminal coupled to the first The two nodes receive a first storage voltage, and an output terminal, and output the forward and reverse output signals; wherein when the first storage voltage is less than the reference voltage, the first comparator outputs the first positive level Inverting the output signal such that the driving chip controls the fan to rotate in the first direction, and when the first storage voltage is greater than the reference voltage, the first comparator outputs the positive and negative output having a second level And a signal for rotating the fan at a full speed in the second direction after the second time after the driving of the driving chip. The fan system of claim 10, wherein the forward and reverse control circuit further includes: a first resistor having a first end coupled to a voltage source and a second end coupled to the first a second input end of the comparator; a first capacitor having a first end coupled to a ground end, a second end coupled to the second input end of the first comparator; a second resistor, A first end is coupled to the voltage source, a second end is coupled to the first input end of the first comparator, and a third resistor is coupled to the ground end, First The two ends are coupled to the first input end of the first comparator. The fan system of claim 10, wherein the surge current suppression circuit comprises: a second comparator having a first input terminal, receiving a second storage voltage, and a second input terminal, receiving the above a reference voltage, and an output terminal, outputting the control signal; wherein when the second storage voltage is greater than the reference voltage, the second comparator outputs the control signal having a first level, so that the driving chip controls the fan Rotating at full speed; and when the second storage voltage is less than the reference voltage, the second comparator outputs the control signal having a second level such that the driving wafer stops driving the fan to rotate. The fan system of claim 12, wherein the surge current suppression circuit further comprises: a second capacitor coupled to the output end of the first comparator and the first of the second comparator Between the input terminals, wherein when the first comparator outputs the forward and reverse output signals of the second level, the second capacitor is discharged to be lower than the reference voltage, and then is used in the second time The voltage source is charged above the above reference voltage. The fan system of claim 13, wherein the surge current suppression circuit further includes: a fourth resistor having a first end coupled to the voltage source, and a second end coupled to the first The output terminal of the comparator; and a fifth resistor having a first end coupled to the voltage source, and a second end coupled to the first input end of the second comparator, The second capacitor is charged. The fan system of claim 8, wherein the drive wafer is a three-phase drive wafer. A fan control method includes: outputting a forward and reverse output signal to a driving chip and a surge current suppressing circuit, so that a fan rotates in a first direction for a first time and then a second after the power is turned on. After the time is rotated in a second direction, wherein the second time is immediately after the first time; and the surge current suppressing circuit generates a control signal according to the received forward and reverse output signals, so that the driving chip is The second time stops driving the fan, and after the second time, the fan is further driven to rotate at a full speed in the second direction to suppress the surge current. The fan control method of claim 16, wherein when the forward/reverse output signal and the control signal are both at a first level, the fan is driven to rotate at a full speed in the first direction; When the output signal and the control signal are at a second level, the driving of the fan is stopped; and when the forward and reverse output signals and the control signal are respectively the second level and the first level, the fan is caused Rotate at full speed in the second direction described above. The fan control method of claim 16, wherein the step of outputting the forward and reverse output signals to the driving chip comprises: outputting the forward and reverse output signals having a first level when the power is turned on, Enabling the driving wafer to rotationally drive the fan in the first direction; and After the first time, the positive and negative output signals having a second level are outputted, so that the driving wafer drives the fan in the second direction after the second predetermined time. The fan control method of claim 18, wherein the generating the control signal comprises: outputting the control signal having the first level when the forward and reverse output signals are at the first level; The driving chip drives the fan to rotate at a full speed; and when the forward and reverse output signals are at the second level, outputting a control signal of a second level, so that the driving chip stops driving the fan to rotate, and After the second time, the control signal of the first level is outputted, so that the driving chip drives the fan to rotate at full speed. The fan control method of claim 18, wherein when the first storage voltage is less than a reference voltage, the positive and negative output signals having the first level are output, so that the driving chip controls the fan to Rotating in a first direction, and outputting the forward and reverse output signals having the second level when the first storage voltage is greater than the reference voltage, so that the fan is caused by the second time after the driving of the driving wafer by the second time Rotate in two directions. The fan control method of claim 20, wherein when a second storage voltage is greater than the reference voltage, outputting the control signal having a first level, so that the driving chip controls the fan to rotate at full speed, and When the second storage voltage is less than the reference voltage, the control signal having a second level is output, so that the driving wafer stops driving the fan to rotate.