Direct-current fan driving circuit

Abstract

The invention provides a direct-current fan driving circuit, and relates to the technical field of direct-current fan control, the circuit comprises a power supply module, a control module and a driving module, the power supply module is used for providing current for the control module and the driving module, and the control module comprises a rotor position acquisition circuit and a dead zone control circuit. The control module obtains a control signal by monitoring a fan and sends the control signal to the driving module; and the driving module receives the control signal and controls the operation of the fan through the H-bridge circuit. The technical problems of MOS tube short circuit, difficult pure hardware control and no dead zone control function in the prior art are solved, and the MOS tube short circuit can be effectively prevented through the pure hardware driving circuit with dead zone control, so that the reliability of the direct current fan is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current fan control, and in particular to a direct current fan drive circuit. Background Art

[0002] During the operation of the DC fan, the MOS tube of the drive circuit cannot be turned off instantly, which easily causes the drive module to short-circuit. In the prior art, due to the particularity of the environmental performance of some DC fans, microprocessors cannot be used for programming control, so pure hardware control of DC fans is difficult. At present, traditional drive circuits have no dead zone control function, and there is a risk of damage when the performance of components varies greatly. Summary of the invention

[0003] In view of this, the present invention provides a DC fan drive circuit to solve the technical problems of MOS tube short circuit, pure hardware control difficulty and no dead zone control function in the prior art. The DC fan drive circuit includes:

[0004] A power module, comprising a power supply end common mode filter capacitor, a power supply end differential mode filter capacitor, a drive end differential mode filter capacitor and a control end differential mode filter capacitor, the power module is used to provide current for the control module and the drive module;

[0005] A control module, including a rotor position acquisition circuit and a dead zone control circuit, wherein the control module acquires a control signal by monitoring the fan and sends the control signal to the drive module;

[0006] The driving module includes an H-bridge circuit. The driving module receives the control signal and controls the operation of the fan through the H-bridge circuit.

[0007] Furthermore, the capacitance of the common-mode filter capacitor at the power supply end is in the nF level, the capacitance of the differential-mode filter capacitor at the power supply end is in the uF level, the capacitance of the differential-mode filter capacitor at the drive end is in the uF level, and the capacitance of the differential-mode filter capacitor at the control end is in the nF level.

[0008] Furthermore, the rotor position acquisition circuit includes a digital Hall sensor, and uses a pull-up circuit to provide a high level for the control circuit; the dead zone control circuit includes a unidirectional delay circuit, and the unidirectional delay circuit includes a high-speed diode, a resistor and a capacitor, which are used to prevent the MOS tubes on the same side of the drive module from being turned on at the same time.

[0009] Furthermore, the H-bridge circuit includes an upper bridge arm and a lower bridge arm, and the upper bridge arm is indirectly controlled by the lower bridge arm; the drive circuit is provided with a uF-level filter capacitor between the winding, the positive pole of the power supply and the negative pole of the power supply.

[0010] Furthermore, the fan is a single-winding brushless DC fan.

[0011] Compared with the prior art, at least one of the above-mentioned technical solutions adopted in the embodiments of this specification can achieve at least the following beneficial effects: by providing a DC fan drive circuit, a pure hardware drive circuit with dead zone control can effectively prevent MOS tube short circuit, thereby improving the reliability of the DC fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 is a schematic diagram of a power module provided by an embodiment of the present invention;

[0014] Figure 2 is a schematic diagram of a control module provided by an embodiment of the present invention;

[0015] Figure 3 is a schematic diagram of a driving module provided by an embodiment of the present invention;

[0016] Attached symbols in the figure: 1. Common-mode filter capacitor at the power supply end; 2. Differential-mode filter capacitor at the power supply end; 3. Differential-mode filter capacitor at the drive end; 4. Differential-mode filter capacitor at the control end; 5. Rotor position acquisition circuit; 6. Dead zone control circuit. DETAILED DESCRIPTION

[0017] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0018] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0019] This embodiment provides a DC fan driving circuit, which can effectively prevent MOS tube short circuit through a pure hardware driving circuit with dead zone control, thereby improving the reliability of the DC fan.

[0020] The DC fan drive circuit provided in the embodiment of the present invention specifically includes a power module, a control module, and a drive module. Among them, the power module is the energy supply center of the entire circuit, providing the required power for the control module and the drive module. The control module is responsible for monitoring the fan status and issuing control instructions, while the drive module drives the operation of the DC fan according to these instructions. The three work closely together through electrical connection and signal transmission to ensure the stable and effective operation of the DC fan.

[0021] like Figure 1 As shown, the power module includes a common-mode filter capacitor 1 at the power supply end, a differential-mode filter capacitor 2 at the power supply end, a differential-mode filter capacitor 3 at the drive end, and a differential-mode filter capacitor 4 at the control end. Among them, the common-mode filter capacitor 1 at the power supply end is connected across the positive and negative input ends of the power line, and the common end of the common-mode filter capacitor 1 at the power supply end is connected to the housing of the DC fan; the differential-mode filter capacitor 2 at the power supply end is connected across the positive and negative inputs of the power line; the differential-mode filter capacitor 3 at the drive end is connected across the positive and negative poles of the fan winding after the anti-reverse diode, and its main function is to filter out the current clutter generated when the fan is commutated; the differential-mode filter capacitor 4 at the control end is connected across the positive and negative poles of the low-voltage control short circuit.

[0022] Preferably, the common-mode filter capacitor 1 at the power supply end is a ceramic capacitor with a relatively small capacitance, preferably nF in this embodiment; the capacitance of the differential-mode filter capacitor 2 at the power supply end is uF; the capacitance of the differential-mode filter capacitor 3 at the drive end is uF; the differential-mode filter capacitor 4 at the control end can be a ceramic capacitor, and the preferred capacitance in this embodiment is nF.

[0023] like Figure 2 The control module realizes commutation control of the fan winding by collecting the rotor position, including a rotor position acquisition circuit 5 and a dead zone control circuit 6. Preferably, the rotor position acquisition circuit 5 adopts a digital Hall sensor with open collector output, and uses a KΩ level pull-up circuit to provide the required high level for the control part. The dead zone control circuit 6 uses a unidirectional delay circuit composed of a high-speed diode, a resistor, and a capacitor to realize the rapid shutdown and delayed opening of the MOS tube, which is used to prevent the MOS tubes on the same side of the driving module from being turned on at the same time.

[0024] like Figure 3 As shown, the driving module is composed of a typical H-bridge circuit, which includes an upper bridge arm and a lower bridge arm, and the upper bridge arm is indirectly controlled by the lower bridge arm. At the same time, a uF filter capacitor is set between the winding and VCC (positive power supply) and GND (negative power supply) to absorb the peak current generated during phase switching.

[0025] Furthermore, the power module provides a stable power supply to the control module. The rotor position acquisition circuit 5 and the dead zone control circuit 6 in the control module both require the current provided by the power module to work properly. The power module provides the required current to the drive module. Since the drive module requires a large current to drive the DC fan, the power module ensures that the current provided to the drive module is pure and stable through a filter capacitor.

[0026] The control module monitors the rotor position of the DC fan through the rotor position acquisition circuit 5, and converts this position signal into a control signal for the commutation control of the drive module. At the same time, the dead zone control circuit 6 in the control module ensures that the MOS tubes of the drive module will not be turned on at the same time, thereby avoiding short circuit and damage. The drive module receives the control signals from the control module and controls the start, stop and direction of the DC fan through the H-bridge circuit according to these signals.

[0027] Preferably, in this embodiment, the fan selected is a low-power single-winding brushless DC fan.

[0028] The embodiments of the present invention achieve the following technical effects:

[0029] 1. The present invention can effectively prevent the MOS tube from short-circuiting through a pure hardware driving circuit with dead zone control, thereby improving the reliability of the DC fan. The use of the dead zone control circuit ensures that the MOS tubes of the driving module will not be turned on at the same time, avoiding the problem of product burning caused by the short circuit of the driving module, and improving the stability of the DC fan;

[0030] 2. The present invention provides a solution that does not require microprocessor programming control, simplifies the control method of the DC fan, makes it more suitable for applications in special environments, and can be arbitrarily combined according to the actual situation of the DC fan, providing high flexibility and adaptability to meet the needs of different application scenarios;

[0031] 3. The circuit design of the present invention takes electromagnetic compatibility into consideration, reduces power supply noise through filtering capacitors, and enhances the anti-interference performance of the entire system.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A DC fan drive circuit, characterized in that: include: A power module, comprising a power supply end common mode filter capacitor (1), a power supply end differential mode filter capacitor (2), a drive end differential mode filter capacitor (3) and a control end differential mode filter capacitor (4), wherein the power module is used to provide current for the control module and the drive module; A control module, comprising a rotor position acquisition circuit (5) and a dead zone control circuit (6), wherein the control module acquires a control signal by monitoring the fan and sends the control signal to the drive module; The driving module includes an H-bridge circuit. The driving module receives the control signal and controls the operation of the fan through the H-bridge circuit.

2. A DC fan drive circuit according to claim 1, characterized in that: The capacitance of the common-mode filter capacitor (1) at the power supply end is in the nF level, the capacitance of the differential-mode filter capacitor (2) at the power supply end is in the uF level, the capacitance of the differential-mode filter capacitor (3) at the drive end is in the uF level, and the capacitance of the differential-mode filter capacitor (4) at the control end is in the nF level.

3. A DC fan drive circuit according to claim 1, characterized in that: The rotor position acquisition circuit (5) includes a digital Hall sensor and uses a pull-up circuit to provide a high level for the control circuit; the dead zone control circuit (6) includes a unidirectional delay circuit, which includes a high-speed diode, a resistor and a capacitor, and is used to prevent the MOS tubes on the same side of the drive module from being turned on at the same time.

4. A DC fan drive circuit according to claim 1, characterized in that: The H-bridge circuit comprises an upper bridge arm and a lower bridge arm, wherein the upper bridge arm is indirectly controlled by the lower bridge arm; and the driving circuit is provided with a uF-level filter capacitor between the winding, the positive electrode of the power supply and the negative electrode of the power supply.

5. A DC fan driving circuit according to claim 1, characterized in that: The fan is a single-winding brushless DC fan.

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