CN213981296U - Stepless speed regulating circuit of two-wire DC fan - Google Patents
Stepless speed regulating circuit of two-wire DC fan Download PDFInfo
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- CN213981296U CN213981296U CN202022538854.9U CN202022538854U CN213981296U CN 213981296 U CN213981296 U CN 213981296U CN 202022538854 U CN202022538854 U CN 202022538854U CN 213981296 U CN213981296 U CN 213981296U
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Abstract
The application relates to a stepless speed regulating circuit of a two-wire direct current fan. Wherein, this two line direct current fan's electrodeless speed governing circuit includes: the PWM driving circuit comprises a first filtering unit, a feedback unit, a voltage stabilization control unit and a first switching tube, wherein the first filtering unit is used for filtering a PWM signal into a first driving voltage; the feedback unit is used for acquiring the voltage of the first input end and generating a feedback voltage according to the voltage of the first input end and the first driving voltage; the voltage stabilization control unit is used for comparing the feedback voltage with the reference voltage to obtain a comparison result, and adjusting the voltage of the first control end according to the comparison result so as to adjust the voltage drop between the first input end and the first output end of the first switch tube. By the aid of the method and the device, the problem that stepless speed regulation of the two-wire direct current fan cannot be realized in the related technology is solved, and pole speed regulation of the two-wire direct current fan is realized.
Description
Technical Field
The present application relates to the field of power electronics, and more particularly to a stepless speed regulating circuit for a two-wire dc fan.
Background
The direct current fan is widely applied to heat dissipation scenes of various electronic products at present. In an actual scene, the state of the fan is often required to be controlled according to different temperature conditions. The current common direct current fan is divided into four lines and two common lines, the four-line fan has a speed regulation function, but the cost is higher, and the neutral cost ratio of the fan in consumer products is lower. The two-wire fan is uncontrollable in rotating speed and always runs at full speed after being started, so that on one hand, excessive performance and power consumption are possibly wasted, and on the other hand, the service life of the fan is usually greatly reduced.
In the related art, the periodic switching of the MOS transistor is generally controlled by a PWM signal to periodically switch the adjustment drive circuit of the two-wire fan, and the average current value in the coils of the two-wire fan can be adjusted by adjusting the duty ratio of the PWM signal, thereby adjusting the rotation speed of the two-wire fan. However, in the process of research, the scheme for controlling the two-wire fan has the problems that the speed regulation effect is not obvious, stepless speed regulation cannot be realized, the noise of the fan is large, and the fan is easy to jam.
At present, no effective solution is provided for the problem that the two-wire direct current fan in the related technology cannot realize stepless speed regulation.
SUMMERY OF THE UTILITY MODEL
The embodiment of the application provides a stepless speed regulating circuit of a two-wire direct current fan, which is used for at least solving the problem that the stepless speed regulation of the two-wire direct current fan cannot be realized in the related technology.
In a first aspect, an embodiment of the present application provides a two-wire dc fan stepless speed regulation circuit, where the two-wire dc fan stepless speed regulation circuit includes: the two-wire direct current fan comprises a power supply end and a speed regulating end, the first switch tube comprises a first input end, a first output end and a first control end, the power supply end is electrically connected with a first power supply, the speed regulating end is electrically connected with the first input end and the feedback end of the feedback unit respectively, the first output end is grounded, the first control end is electrically connected with the output end of the voltage stabilizing control unit, the input end of the voltage stabilizing control unit is electrically connected with the output end of the feedback unit, the input end of the feedback unit is electrically connected with the output end of the first filter unit, the input end of the first filter unit is connected with a PWM signal source,
the first filtering unit is used for filtering the PWM signal into a first driving voltage;
the feedback unit is used for acquiring the voltage of the first input end and generating a feedback voltage according to the voltage of the first input end and the first driving voltage;
the voltage stabilization control unit is used for comparing the feedback voltage with the reference voltage to obtain a comparison result, and adjusting the voltage of the first control end according to the comparison result so as to adjust the voltage drop between the first input end and the first output end of the first switch tube.
In some embodiments, the first filtering unit includes an RC filtering circuit, the RC filtering circuit includes a first resistor and a first capacitor, wherein one end of the first resistor is connected to the PWM signal source, the other end of the first resistor is electrically connected to the first capacitor and the input end of the feedback unit, respectively, and the other end of the first capacitor is grounded.
In some embodiments, the feedback unit includes a second resistor, a third resistor, and a fourth resistor, wherein one end of the second resistor is electrically connected to the output terminal of the first filtering unit, the other end of the second resistor is electrically connected to the third resistor, the fourth resistor, and the input terminal of the voltage stabilization control unit, respectively, the other end of the third resistor is electrically connected to the first input terminal, and the other end of the fourth resistor is grounded.
In some of these embodiments, the stepless speed regulating circuit of the two-wire direct current fan further comprises: and one end of the feedforward unit is electrically connected with the first input end, and the other end of the feedforward unit is electrically connected with the output end of the voltage stabilization control unit, wherein the feedforward unit is used for adjusting the feedback voltage output by the feedback unit.
In some of these embodiments, the feed forward unit includes a second capacitor connected in parallel with the third resistor.
In some embodiments, the voltage stabilization control unit includes: the feedback unit comprises a voltage stabilizing control subunit, a second switching tube, a third capacitor, a fifth resistor and a sixth resistor, wherein the second switching tube comprises a second input end, a second output end and a second control end, the input end of the voltage stabilizing control subunit is electrically connected to the output end of the feedback unit, and the output end of the voltage stabilizing control subunit is electrically connected to the second control end; the second input end is electrically connected to the first control end, and the second output end is grounded; the third capacitor is electrically connected between the first input terminal and the second input terminal; the fifth resistor is electrically connected between the first power supply and the second input terminal; the sixth resistor is electrically connected between the first power supply and the output terminal of the voltage stabilization control subunit.
In some embodiments, the voltage regulation control subunit includes: a reference electrode of the TL431 voltage stabilization chip is electrically connected to the output end of the feedback unit, a cathode of the TL431 voltage stabilization chip is electrically connected to the second control end, and an anode of the TL431 voltage stabilization chip is grounded; and/or the second switching tube comprises an N-type MOS switching tube.
In some embodiments, the first switch tube comprises an N-type MOS switch tube.
In some embodiments, the two-wire dc fan electrodeless speed regulation circuit further includes a slow start unit, an input end of the slow start unit is electrically connected to the speed regulation terminal, and an output end of the slow start unit is electrically connected to the first control terminal, where the slow start unit is configured to slow down the start of the two-wire dc fan.
In some embodiments, the stepless speed regulating circuit of the two-wire direct current fan further comprises a fourth capacitor, wherein one end of the fourth capacitor is electrically connected to the first input end, and the other end of the fourth capacitor is grounded.
Compared with the related art, the stepless speed regulating circuit of the two-wire direct current fan provided by the embodiment of the application, the two-wire direct current fan comprises a power supply end and a speed regulation end, the first switch tube comprises a first input end, a first output end and a first control end, the power supply end is electrically connected with a first power supply, the speed regulation end is electrically connected with the first input end and the feedback end of the feedback unit respectively, the first output end is grounded, the first control end is electrically connected with the output end of the voltage stabilization control unit, the input end of the voltage stabilization control unit is electrically connected with the output end of the feedback unit, the input end of the feedback unit is electrically connected with the output end of the first filter unit, the input end of the first filter unit is connected with a PWM signal source, and the first filter unit is used for filtering a PWM signal into a first driving voltage; the feedback unit is used for acquiring the voltage of the first input end and generating a feedback voltage according to the voltage of the first input end and the first driving voltage; the voltage stabilization control unit is used for comparing the feedback voltage with the reference voltage to obtain a comparison result, adjusting the voltage of the first control end according to the comparison result and adjusting the voltage drop between the first input end and the first output end of the first switching tube, so that the problem that the two-wire direct current fan cannot realize stepless speed regulation in the related technology is solved, and the stepless speed regulation of the two-wire direct current fan is realized.
The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below to provide a more thorough understanding of the application.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
FIG. 1 is a block diagram of a stepless speed regulation circuit of a two-wire DC fan according to an embodiment of the present application;
fig. 2 is a topological schematic diagram of a stepless speed regulating circuit of a two-wire direct current fan according to a preferred embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments provided in the present application without any inventive step are within the scope of protection of the present application. Moreover, it should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another.
Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of ordinary skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments without conflict.
Unless defined otherwise, technical or scientific terms referred to herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which this application belongs. Reference to "a," "an," "the," and similar words throughout this application are not to be construed as limiting in number, and may refer to the singular or the plural. The present application is directed to the use of the terms "including," "comprising," "having," and any variations thereof, which are intended to cover non-exclusive inclusions; for example, a process, method, system, article, or apparatus that comprises a list of steps or modules (elements) is not limited to the listed steps or elements, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus. Reference to "connected," "coupled," and the like in this application is not intended to be limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Reference herein to "a plurality" means greater than or equal to two. "and/or" describes an association relationship of associated objects, meaning that three relationships may exist, for example, "A and/or B" may mean: a exists alone, A and B exist simultaneously, and B exists alone. Reference herein to the terms "first," "second," "third," and the like, are merely to distinguish similar objects and do not denote a particular ordering for the objects.
Fig. 1 is a block diagram of a two-wire dc fan stepless speed regulation circuit according to an embodiment of the present application, and as shown in fig. 1, the two-wire dc fan stepless speed regulation circuit includes: the two-wire direct current fan 500 comprises a power supply end and a speed regulation end, the first switch tube 400 comprises a first input end, a first output end and a first control end, the power supply end is electrically connected with a first power supply +12V, the speed regulation end is electrically connected with the first input end and the feedback end of the feedback unit 200 respectively, the first output end is grounded GND, the first control end is electrically connected with the output end of the voltage stabilization control unit 300, the input end of the voltage stabilization control unit 300 is electrically connected with the output end of the feedback unit 200, the input end of the feedback unit 200 is electrically connected with the output end of the first filter unit 100, the input end of the first filter unit 100 is connected with a PWM signal source, wherein the first filter unit 100 is used for filtering PWM signals into first driving voltage; the feedback unit 200 is configured to collect a voltage of the first input terminal, and generate a feedback voltage according to the voltage of the first input terminal and the first driving voltage; the voltage stabilization control unit 300 is configured to compare the feedback voltage with the reference voltage to obtain a comparison result, and adjust the voltage of the first control end according to the comparison result to adjust the voltage drop between the first input end and the first output end of the first switching tube.
In this embodiment, the PWM signal is sent by the PWM signal source, filtered by the first filtering unit 100 to be the first driving voltage, and then the feedback unit 200 generates the feedback voltage according to the first driving voltage and the voltage at the first input terminal of the first switching tube 400, and finally the voltage stabilization control unit 300 compares the feedback voltage with the reference voltage, and reduces the voltage at the first control terminal and increases the voltage at the speed regulation terminal under the condition that the feedback voltage is smaller than the reference voltage, or increases the voltage at the first control terminal and decreases the voltage at the speed regulation terminal under the condition that the feedback voltage is greater than the reference voltage, so as to implement the stepless speed regulation of the two-wire dc fan 500, and solve the problem that the two-wire dc fan 500 cannot implement the stepless speed regulation in the related art.
It should be noted that the reference voltage may be configured by a user, and the first power supply +12V may be a dc power supply.
In some embodiments, referring to fig. 2, the first filtering unit 100 may include an RC filtering circuit, the RC filtering circuit includes a first resistor R1 and a first capacitor C1, wherein one end of the first resistor R1 is connected to the PWM signal source, the other end of the first resistor R1 is electrically connected to the first capacitor C1 and the input end of the feedback unit 200, respectively, and the other end of the first capacitor C1 is grounded to GND.
In this embodiment, the filtering of the PWM signal output from the PWM signal source can be realized by providing an RC filter circuit to filter the PWM signal output from the PWM signal source into the dc driving voltage.
It should be noted that the voltage across the first capacitor C1 is proportional to the duty ratio of the input PWM signal and the amplitude of the wave of the PWM signal.
In some embodiments, referring to fig. 2, the feedback unit 200 may include a second resistor R2, a third resistor R3, and a fourth resistor R4, wherein one end of the second resistor R2 is electrically connected to the output terminal of the first filtering unit 100, the other end of the second resistor R2 is electrically connected to the third resistor R3, the fourth resistor R4, and the input terminal of the voltage regulation control unit 300, the other end of the third resistor R3 is electrically connected to the first input terminal, and the other end of the fourth resistor R4 is connected to the ground GND.
In the present embodiment, the voltage division is realized by providing the third resistor R3 and the fourth resistor R4, and the first driving voltage output by the first filtering unit 100 is buffered by providing the second resistor R2, and in the case of receiving the first driving voltage, the voltage across the fourth resistor R4 is taken as the output voltage of the feedback unit 200 to change the output voltage of the feedback unit 200, so as to facilitate the regulation of the wind speed of the two-wire dc fan 500 by the voltage regulation control unit 300.
In some of these embodiments, the stepless speed regulating circuit of the two-wire direct current fan further comprises: and one end of the feedforward unit is electrically connected to the first input end, and the other end of the feedforward unit is electrically connected to the output end of the voltage stabilization control unit 300, wherein the feedforward unit is used for adjusting the feedback voltage output by the feedback unit 200.
In this embodiment, by providing the feedforward unit, it is possible to adjust parameters of a loop of the stepless speed regulating circuit of the two-wire dc fan, and to increase stability of the control voltage of the two-wire dc fan 500.
In some of the embodiments, referring to fig. 2, the feed forward unit may include a second capacitor C2, the second capacitor C2 being connected in parallel with the third resistor R3. In this embodiment, by providing the second capacitor C2, the adjustment of the parameters of the loop of the stepless speed regulating circuit of the two-wire dc fan is realized, and the stability of the control voltage of the two-wire dc fan 500 is increased.
In some embodiments, referring to fig. 2, the voltage regulation control unit 300 may include: the voltage stabilizing control subunit, a second switching tube Q2, a third capacitor C3, a fifth resistor R5 and a sixth resistor R6, the second switching tube Q2 includes a second input end, a second output end and a second control end, the input end of the voltage stabilizing control subunit is electrically connected to the output end of the feedback unit 200, and the output end of the voltage stabilizing control subunit is electrically connected to the second control end; the second input end is electrically connected to the first control end, and the second output end is grounded GND; the third capacitor is electrically connected between the first input end and the second input end; the fifth resistor R5 is electrically connected between the first power supply +12V and the second input terminal; the sixth resistor R5 is electrically connected between the first power supply +12V and the output terminal of the regulation control subunit.
In this embodiment, the voltage regulation control subunit obtains the feedback voltage output by the feedback unit 200, compares the feedback voltage with the reference voltage, and gradually increases the voltage at the output end of the voltage regulation control subunit when the reference voltage is less than the feedback voltage, so as to increase the voltage at the second control end of the second switching tube Q2, gradually turn on the second switching tube Q2, and further decrease the voltage at the first control end of the first switching tube 400, so as to increase the voltage at the speed regulation end, or gradually decreases the voltage at the output end of the voltage regulation control subunit when the reference voltage is greater than the feedback voltage, so as to decrease the voltage at the second control end of the second switching tube Q2, so as to gradually turn off the second switching tube Q2, and further increase the voltage at the first control end of the first switching tube 400, so as to decrease the voltage at the speed regulation end. By the mode, the voltage of the speed regulation ends of the two direct current fans is adjusted, and stepless speed regulation of the two direct current fans is achieved.
In some embodiments, referring to fig. 2, the voltage regulation control subunit includes: the reference electrode of the TL431 voltage stabilization chip is electrically connected to the output end of the feedback unit 200, the cathode of the TL431 voltage stabilization chip is electrically connected to the second control end, and the anode of the TL431 voltage stabilization chip is grounded to GND; and/or the second switch tube Q2 comprises an N-type MOS switch tube.
It should be noted that TL431 is a controllable precision voltage regulator, and its output voltage can be set to any value from Vref (2.5V) to 36V by using two resistors, and the typical dynamic impedance of the TL431 voltage regulator chip is 0.2 Ω. And it has the advantages of good performance and low price.
In other embodiments, the voltage regulation control subunit may select other controllable precise voltage regulation sources besides the TL43 voltage regulation chip in the above embodiment.
In this embodiment, the cost of the stepless speed regulation circuit of the two-wire dc fan 500 can be reduced by using the TL431 voltage stabilization chip.
In some embodiments, referring to fig. 2, the first switch tube 400 includes an N-type MOS switch tube. In this embodiment, the first switch tube 400 is set as an N-type MOS switch tube, so that the voltage division at the first input end of the first switch tube 400 can be reduced to be very small or even negligible, and full-scale driving of the two-wire dc fan 500 is further achieved.
In some embodiments, the electrodeless speed regulation circuit of the two-wire dc fan further includes a slow start unit, an input end of the slow start unit is electrically connected to the speed regulation terminal, and an output end of the slow start unit is electrically connected to the first control terminal, where the slow start unit is configured to slow down the start of the two-wire dc fan 500. In this embodiment, by providing the slow start unit, the start of the two-wire dc fan 500 is slowed down, and the overshoot of the inductive voltage generated at the instant when the two-wire dc fan 500 is powered on can be prevented.
It should be noted that the slow start unit may be a capacitor, so as to enable the first switching tube to operate in a miller state, thereby increasing the amplification gain of the first switching tube.
In some of these embodiments, the stepless speed regulating circuit of the two-wire direct current fan comprises a fourth capacitor C4, wherein one end of the fourth capacitor C4 is electrically connected to the first input end, and the other end of the fourth capacitor is grounded to GND.
The embodiments of the present application are described and illustrated below by means of preferred embodiments.
Fig. 2 is a topological schematic diagram of a stepless speed regulating circuit of a two-wire direct current fan according to a preferred embodiment of the present application. As shown in figure 2 of the drawings, in which,
the first resistor R1 and the first capacitor C1 form an RC filter circuit. When the external control PWM signal is started, the DC driving voltage is filtered by an RC filter circuit consisting of R1 and C1. The voltage at C1 is proportional to the duty cycle u of the input PWM signal and the amplitude Vi of the PWM wave.
The voltage stabilization control subunit D1, the second switch Q2, the second resistor R2, the fifth resistor R5, the sixth resistor R6, and the like constitute a voltage stabilization control unit 300, the first switch 400 is denoted by Q1 and is a variable resistance MOS, and the main function of this portion is to realize stable control of the drive voltage of the two-wire dc fan. When no PWM signal is input, the third resistor R3 and the fourth resistor R4 may form a feedback unit for feeding back the voltage of Q1 (i.e., U1 in fig. 2) to the voltage regulation control unit, and in some embodiments, the feedback unit may further include a second resistor R2. The first switch tube Q1 and the second switch tube Q2 may both adopt N tubes, and the voltage regulation control subunit D1 may adopt a voltage regulation chip (for example, TL 431).
When the voltage regulation control subunit D1 compares that the voltage across the fourth resistor R4 is less than the FB (feedback) voltage of the voltage regulation control subunit D1, the voltage of the cathode of the voltage regulation control subunit D1D1 increases, so that the gate voltage of the second switching transistor Q2 increases, and the second switching transistor Q2 increasesThe Q2 transistor tends to be conducted, the voltage of the drain electrode of the Q2 transistor is reduced, the grid voltage of the Q1 transistor is synchronously reduced, the Q1 transistor tends to be closed, the Q1 voltage drop U1 of the first transistor is increased, and the voltage division U of the two-wire direct current fan is reducedfan(the feedback voltage of D1) is decreased and the wind speed is decreased to achieve the effect of adjusting the wind speed of the two-wire dc fan.
When the voltage regulation control sub-unit D1 compares that the voltage across the fourth resistor R4 is greater than the FB voltage of the voltage regulation control sub-unit D1, the driving voltage division of the two-wire dc fan is increased by negative feedback and the wind speed is increased, contrary to the result that the voltage across the fourth resistor R4 is less than the FB (feedback) voltage of the voltage regulation control sub-unit D1 in the above-described embodiment.
In the above embodiment, the effect of controlling the driving voltage of the two-wire dc fan and achieving stepless speed regulation is achieved by influencing the voltage of the fourth resistor R4.
In addition, as the N-tube is adopted as the first switch tube Q1 for voltage division with the two-wire DC fan, the voltage division U1 on the first switch tube Q1 can be very low, and the two-wire DC fan can basically realize full-amplitude driving of 12V.
When a PWM signal is input, the third resistor R3, the fourth resistor R4, the second resistor R2, the first capacitor C1, and the first resistor R1 form a complete feedback unit. In some embodiments, the first capacitor and the first resistor may form an RC filtering unit, and assuming that an FB (feedback) voltage of the voltage stabilizing control subunit D1 is 2.5V, a duty ratio of the PWM signal is U, and an amplitude is Vi, a voltage drop U1 of the first switching tube Q1 can be calculated according to kirchhoff current:
the drive voltage U of the two-wire DC fanfanIt can be calculated by the following formula:
from the above formula, in this embodiment, UfanThe driving voltage of the two-wire direct current fan can be linearly controlled in a forward direction by regulating the input PWM, so that the stepless speed regulation of the direct current fan is realized.
The third capacitor C3 is equivalent to the slow start unit in the above embodiment, and can make the first switch tube operate in a miller state to perform a slow start function, so as to prevent the overshoot generated by the inductive voltage at the instant when the fan is powered on.
The third capacitor may be a miller capacitor (miller capacitor is a capacitor between the switching tube and GND).
The second capacitor C2 is a feedforward capacitor, which is equivalent to the feedforward unit in the above-mentioned embodiment, and adjusts the parameters of the loop of the system to increase the stability of the fan control voltage.
Through the scheme, the embodiment of the application has the following advantages:
the two-wire direct current fan can realize stepless continuous speed regulation by using PWM signals, and the driving voltage is in linear direct proportion to the duty ratio of the PWM signals.
Under the condition of system voltage power supply, because the Q1 adopts an N-type switch tube, the driving voltage of the two-wire direct current fan can be basically close to the system voltage (equivalent to 12V in the embodiment), and full-amplitude driving can be realized.
The stepless speed regulating circuit of the two-wire direct current fan in the embodiment of the application basically comprises a resistor, a capacitor and a plurality of transistors (such as the first switch tube 400, the second switch tube and the like), and has the advantages of low cost and small occupied single-plate area.
It should be understood by those skilled in the art that various features of the above-described embodiments can be combined in any combination, and for the sake of brevity, all possible combinations of features in the above-described embodiments are not described in detail, but rather, all combinations of features which are not inconsistent with each other should be construed as being within the scope of the present disclosure.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the embodiments of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A two-wire dc fan stepless speed control circuit, comprising: the two-wire direct current fan comprises a power supply end and a speed regulating end, the first switch tube comprises a first input end, a first output end and a first control end, the power supply end is electrically connected with a first power supply, the speed regulating end is electrically connected with the first input end and the feedback end of the feedback unit respectively, the first output end is grounded, the first control end is electrically connected with the output end of the voltage stabilizing control unit, the input end of the voltage stabilizing control unit is electrically connected with the output end of the feedback unit, the input end of the feedback unit is electrically connected with the output end of the first filter unit, the input end of the first filter unit is connected with a PWM signal source,
the first filtering unit is used for filtering the PWM signal into a first driving voltage;
the feedback unit is used for acquiring the voltage of the first input end and generating a feedback voltage according to the voltage of the first input end and the first driving voltage;
the voltage stabilization control unit is used for comparing the feedback voltage with the reference voltage to obtain a comparison result, and adjusting the voltage of the first control end according to the comparison result so as to adjust the voltage drop between the first input end and the first output end of the first switch tube.
2. The stepless speed regulating circuit of the two-wire direct current fan is characterized in that the first filtering unit comprises an RC filtering circuit, the RC filtering circuit comprises a first resistor and a first capacitor, wherein one end of the first resistor is connected with the PWM signal source, the other end of the first resistor is electrically connected with the first capacitor and the input end of the feedback unit, and the other end of the first capacitor is grounded.
3. The stepless speed regulating circuit of the two-wire direct current fan according to claim 1, wherein the feedback unit comprises a second resistor, a third resistor and a fourth resistor, wherein one end of the second resistor is electrically connected with the output end of the first filtering unit, the other end of the second resistor is electrically connected with the third resistor, the fourth resistor and the input end of the voltage stabilizing control unit, respectively, the other end of the third resistor is electrically connected with the first input end, and the other end of the fourth resistor is grounded.
4. The two wire dc fan stepless speed regulation circuit according to claim 3, characterized in that the two wire dc fan stepless speed regulation circuit further comprises: and one end of the feedforward unit is electrically connected with the first input end, and the other end of the feedforward unit is electrically connected with the output end of the voltage stabilization control unit, wherein the feedforward unit is used for adjusting the feedback voltage output by the feedback unit.
5. The two wire dc fan stepless speed regulation circuit of claim 4, wherein the feedforward unit comprises a second capacitor, and the second capacitor is connected in parallel with the third resistor.
6. The stepless speed regulation circuit of the two-wire direct current fan according to claim 1, characterized in that the voltage stabilization control unit comprises: the feedback unit comprises a voltage stabilizing control subunit, a second switching tube, a third capacitor, a fifth resistor and a sixth resistor, wherein the second switching tube comprises a second input end, a second output end and a second control end, the input end of the voltage stabilizing control subunit is electrically connected to the output end of the feedback unit, and the output end of the voltage stabilizing control subunit is electrically connected to the second control end; the second input end is electrically connected to the first control end, and the second output end is grounded; the third capacitor is electrically connected between the first input terminal and the second input terminal; the fifth resistor is electrically connected between the first power supply and the second input terminal; the sixth resistor is electrically connected between the first power supply and the output terminal of the voltage stabilization control subunit.
7. The stepless speed regulation circuit of a two-wire direct current fan according to claim 6, wherein the voltage-stabilizing control subunit comprises: a reference electrode of the TL431 voltage stabilization chip is electrically connected to the output end of the feedback unit, a cathode of the TL431 voltage stabilization chip is electrically connected to the second control end, and an anode of the TL431 voltage stabilization chip is grounded; and/or the second switching tube comprises an N-type MOS switching tube.
8. The stepless speed regulation circuit of a two-wire direct current fan according to claim 1, characterized in that the first switch tube comprises an N-type MOS switch tube.
9. The two-wire direct current fan stepless speed regulation circuit according to claim 1, characterized in that the two-wire direct current fan stepless speed regulation circuit further comprises a slow start unit, an input end of the slow start unit is electrically connected with the speed regulation terminal, an output end of the slow start unit is electrically connected with the first control terminal, wherein the slow start unit is used for slowing down the start of the two-wire direct current fan.
10. The stepless speed regulation circuit of the two-wire direct current fan according to claim 1, characterized in that the stepless speed regulation circuit of the two-wire direct current fan further comprises a fourth capacitor, wherein one end of the fourth capacitor is electrically connected to the first input end, and the other end of the fourth capacitor is grounded.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117674644A (en) * | 2024-02-02 | 2024-03-08 | 深圳斯诺凡科技有限公司 | Two-wire speed-regulating DC brushless motor and control circuit and control method thereof |
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2020
- 2020-11-05 CN CN202022538854.9U patent/CN213981296U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117674644A (en) * | 2024-02-02 | 2024-03-08 | 深圳斯诺凡科技有限公司 | Two-wire speed-regulating DC brushless motor and control circuit and control method thereof |
| CN117674644B (en) * | 2024-02-02 | 2024-04-19 | 深圳斯诺凡科技有限公司 | Two-wire speed-regulating DC brushless motor and control circuit and control method thereof |
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