CN101320952A - Driving device for fan motor - Google Patents

Abstract

The invention provides a driving device of fan motor, the driving device is connected between a pulse width modulation signal generator and a controller, it includes: a converter electrically connected to the PWM signal generator for outputting a first reference voltage according to a duty cycle of a PWM signal generated by the PWM signal generator; a reference voltage generator electrically connected to an external power source and generating a second reference voltage according to the external power source; a comparator including a first input end, a second input end and an output end, the first input end is electrically connected with the converter, the second input end is electrically connected with the reference voltage generator, the output end is electrically connected with the controller, when the first reference voltage is higher than the second reference voltage, the output end outputs a modulatable driving signal to the controller to control the rotating speed of the fan motor.

Description

Drives for fan motors

This application is a divisional application of the application titled "Driving Device for Fan Motor" (application number: 200510091640.9; filing date: August 11, 2005).

technical field

The present invention relates to a driving device, in particular to a driving device applied to driving a fan motor.

Background technique

Please refer to FIG. 1, the current known technology utilizes a controller 2 to drive a fan motor 1. As shown in the figure, the controller 2 can be an integrated circuit element (IC), which has different pins for, for example, a Hall element 3, a temperature sensor 4, a converter 5... and other electronic circuits are connected, wherein the Hall element 3 can obtain a phase signal from the fan motor 1 to input to the controller 2, the temperature sensor 4 A thermistor 41 can be used to detect the temperature and convert a voltage signal to be input to the controller 2, and the converter 5 is mainly used to convert an externally input pulse width modulation signal (PULSE WI-DTHMODULATION; PWM) into A voltage signal is input to the controller 2 .

The above-mentioned controller 2 can generate a drive signal to drive the fan motor 1 after receiving the voltage signals from the converter 5 and the temperature sensor 4. Please also refer to FIG. 2 for inputting different pulse width modulation signals at different temperatures. Looking at the rotational speed relationship table corresponding to the controller, it is obvious that the curve shown in the relationship table is a linear relationship, so it can be known that the output speed of the pulse width modulation signal is in the form of a 0%-100% duty cycle at any temperature. Linear, but in practical applications, it is not necessary to increase the speed of the system when the system is turned on or in standby; in fact, for example, when a large computer is just turned on or in standby, its cooling fan will always follow this pulse width The increase of the duty cycle of the modulation signal increases the rotational speed, and the noise generated by it is disturbing, so there is a need for improvement.

Contents of the invention

In view of the aforementioned shortcomings, the present invention proposes a fan motor driving device, which allows the system to first set a reference voltage value, and the reference voltage value corresponds to a duty cycle reference value, when the externally input pulse width If the converted voltage value of the duty cycle of the modulation signal is greater than the reference voltage value, the controller will start to increase the speed of the external input duty cycle. If the converted voltage value is less than the reference voltage value, then The controller maintains a fixed low speed output, so that the system can have a lower speed when the system is turned on or the system is in standby without excessive noise.

According to the above purpose, a driving device for a fan motor of the present invention includes: a converter electrically connected to a pulse width modulation signal generator, and the converter can generate a pulse according to a pulse width modulation signal generator generated by the pulse width modulation signal generator wide modulation signal duty cycle, and output a first reference voltage; a reference voltage generator, electrically connected to an external power supply, and generate a second reference voltage according to the external power supply; a comparator, including a first input terminal , a second input terminal and an output terminal, the first input terminal is electrically connected to the converter, the second input terminal is electrically connected to the reference voltage generator, and the output terminal is electrically connected to a controller, when the first After the reference voltage is higher than the second reference voltage, the output terminal outputs a driving signal to the controller to control the speed of the fan motor.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment will be described in detail below together with the accompanying drawings.

Description of drawings

FIG. 1 is a conventional circuit diagram for driving a fan motor.

FIG. 2 is a characteristic curve diagram when the circuit of FIG. 1 is driven.

Fig. 3 is a block diagram of the driving device of the present invention.

Fig. 4 is a circuit diagram of the driving device of the present invention.

FIG. 5 is a waveform diagram of each reference point in FIG. 4 .

FIG. 6 is a characteristic graph corresponding to FIG. 5 .

Explanation of main component symbols

1 fan motor 2 controller

3 Hall element 4 Temperature sensor

5 Converter 6 Drive device

61 Converter 62 Reference Voltage Generator

63 comparator 631 first input terminal

632 second input terminal 633 output terminal

7 PWM signal generator 8 External power supply

S _pwm pulse width modulation signal V _ref1 first reference voltage

V _ref2 second reference voltage S _dri drive signal

R1 first resistor R2 second resistor

R3 third resistor R4 fourth resistor

R5 fifth resistor C capacitor

Q1 first switching element Q2 second switching element

G Gate D Drain

S source P1 first reference point

P2 second reference point P3 third reference point

Detailed ways

Please refer to Fig. 3, which is a block diagram of a preferred embodiment of the present invention, the driving device 6 of the present invention shown in the figure, it is electrically connected between a pulse width modulation signal generator 7 and a controller 2, its main It is composed of a converter 61 , a reference voltage generator 62 and a comparator 63 .

The converter 61 is electrically connected to the pulse width modulation signal generator 7, and the converter 61 can generate a duty cycle (0%-100%) of a pulse width modulation signal S _pwm according to the pulse width modulation signal generator 7 , and output a corresponding first reference voltage V _ref1 .

The reference voltage generator 62 is electrically connected to an external power source 8 and can generate a second reference voltage V _ref2 according to the external power source 8 .

The comparator 63 includes a first input terminal 631, a second input terminal 632 and an output terminal 633, the first input terminal 631 is electrically connected to the converter 61, and the second input terminal 632 is electrically connected to the reference voltage generator 62 , and the output terminal 633 is electrically connected to the controller 2 .

When the above-mentioned first reference voltage V _ref1 is lower than the second reference voltage V _ref2 , the output terminal of the comparator 63 has no signal output, and the controller 2 maintains the constant speed of the fan motor 1 according to a low speed setting value. low speed, and when the first reference voltage V _ref1 is higher than the second reference voltage V _ref2 , the output terminal 633 of the comparator 63 outputs a drive signal S _dri to the controller 2, and the controller 2 can be based on the The rotation speed of the fan motor 1 is controlled by the modulation of the drive signal S _dri .

Please refer to FIG. 4 again, which is a circuit diagram of a preferred implementation of the present invention, wherein the controller 2 can be implemented as an integrated circuit element (IC), and it has a plurality of pins for a Hall element 3, a temperature sensor 4. The driving device 6 is connected to electronic circuits, wherein the functions of the Hall element 3 and the temperature sensor 4 have been described in the prior art, so no further description is given.

In this embodiment, the converter 61 of the driving device 6 can be implemented as a charging and discharging circuit, which is mainly composed of a first resistor R1, a second resistor R2, a third resistor R3, a capacitor C, a The first switching element Q1 and a second switching element Q2 are composed, wherein the first switching element Q1 and the second switching element Q2 are a transistor in this embodiment, especially a metal oxide semiconductor (MOSFET). A gate G of the switching element Q1 is electrically connected to the pulse width modulation signal generator 7, and a gate G of the second switching element Q2 is electrically connected to a drain D of the first switching element Q1; A source S of a switching element Q1 and a source S of the second switching element Q2 are electrically connected to a ground terminal; a first end of the first resistor R1 is electrically connected to the pulse width modulation signal generator device 7 and an external power supply 8, and a second end of the first resistor R1 is electrically connected to a drain D of the first switching element Q1; a first end of the second resistor R2 is electrically connected to A drain D of the second switching element Q2, and a second terminal of the second resistor R2 is electrically connected to a second terminal of the third resistor R3, and a first terminal of the third resistor R3 Electrically connected to the first end of the first resistor R1; a first end of the capacitor C is electrically connected to the second end of the third resistor R3, and a second end of the capacitor C is electrically connected to to this ground.

In this embodiment, the reference voltage generator 62 of the driving device 6 can be implemented as a voltage divider, which is composed of a fourth resistor R4 and a fifth resistor R5, wherein a first resistor of the fourth resistor R4 end is electrically connected to the first end of the third resistor R3 to obtain the external power supply 8, and a second end of the fourth resistor R4 is electrically connected to a first end of the fifth resistor R5 , and a second end of the fifth resistor R5 is electrically connected to the ground end.

In this embodiment, the comparator 63 of the driving device 6 includes a positive input terminal (+) (ie the second input terminal 632), a negative input terminal (-) (ie the first input terminal 631) and an output Terminal 633, the positive input terminal (+) is electrically connected to a third reference point P3 between the fourth resistor R4 and the fifth resistor R5, and the negative input terminal (-) is electrically connected to the third A second reference point P2 between the resistor R3 and the capacitor C, and the output terminal 633 of the comparator 63 is defined as a first reference point P1 here, and it is electrically connected to the controller 2 .

Please cooperate as shown in Figure 5 and Figure 6, the driving method of the present invention is as follows:

In a preferred embodiment of the present invention, the pulse width modulation signal generator 7 inputs a pulse width modulation signal S _pwm to the converter 61, and passes through the elements of the first switching element Q1 and the second switching element Q2 The characteristic is to perform a charging operation on the capacitor C, and when the charging value of the capacitor C (that is, the first reference voltage value V _ref1 ) exceeds the second reference voltage value V _ref2 generated by the voltage division of the reference voltage generator 62 (that is, the value of the negative input terminal (-) of the comparator 63 is greater than the value of the positive input terminal (+), the comparator 63 can output a driving signal S _dri to the fan motor from the output terminal 633 1, so that the fan motor 1 is modulated according to the magnitude of the driving signal S _dri .

In FIG. 5, the waveform diagrams of the first reference point P1, the second reference point P2, and the third reference point P3 in _FIG . The duty cycle is between 0% and 20%, and the signals output by the comparator 63 are all high potentials, that is, the controller 2 only outputs a fixed low-speed operation signal set internally to the fan motor 1, And make this fan motor 1 maintain a low-speed operation (also can be referred to as a base speed operation), but when the duty cycle of the pulse width modulation signal S _pwm exceeds 20%, then the output of the comparator 63 is low potential, and at this moment the controller 63 can control the change of the speed of the fan motor 1 according to the duty cycle of the pulse width modulation signal S _pwm .

It is also worth noting that the controller 2 in this embodiment maintains the output of the low-speed operation signal when it is at a high potential, and outputs operation signals with different speeds according to the change of the duty cycle when it is at a low potential. It is also possible to replace another controller, so that the above-mentioned control method is implemented in reverse.

It is also worth noting that the converter 62 of the present invention can also be implemented as an analog/digital conversion circuit, which can also convert the pulse width modulation signal S _pwm into a digital first reference voltage V _ref1 , and the first reference voltage V ref1 The second reference voltage V _ref2 can also be generated from an internal oscillation circuit of the controller 2 .

Through the setting of the drive device 6 of the present invention, the system end can first set a voltage value (corresponding to a preset duty cycle) through the reference voltage generator 62, so that the system end can be set at the set Keep a fixed low-speed operation before the work cycle, so that the speed of the system side can be kept at a low speed when it is turned on or in standby, which can effectively reduce noise generation and even reduce energy waste, so it can be described as an excellent design By.

The foregoing descriptions are illustrative only, not restrictive. Any equivalent modifications or changes made without departing from the spirit and scope of the present invention shall be included in the scope of the proposed claims.

Claims (14)

1. A speed control circuit for a fan motor, comprising: a pulse width modulation signal generator; a controller; and A driving device, electrically connected between the pulse width modulation signal generator and the controller, wherein the driving device includes: a converter electrically connected to the pulse width modulation signal generator, the converter outputs a first reference voltage according to a pulse width modulation signal generated by the pulse width modulation signal generator; a reference voltage generator, electrically connected to an external power source, and generates a second reference voltage according to the external power source; and a comparator, electrically connected to the converter and the reference voltage generator, wherein when the first reference voltage is greater than the second reference voltage, the comparator outputs a modulable driving signal to the controller to control the The speed of the fan motor changes. 2. A speed control circuit for a fan motor, comprising: a pulse width modulation signal generator; A driving device electrically connected to the pulse width modulation signal generator, wherein the driving device includes: a converter electrically connected to the pulse width modulation signal generator, the converter outputs a first reference voltage according to a pulse width modulation signal generated by the pulse width modulation signal generator; and a comparator electrically connected to the converter; and a controller electrically connected to the driving device and generating a second reference voltage, wherein when the first reference voltage is greater than the second reference voltage, the comparator outputs a modulable driving signal to the controller to control The rotational speed of the fan motor varies. 3. The speed control circuit according to claim 1 or 2, wherein the controller is an integrated circuit. 4. The rotation speed control circuit according to claim 1 or 2, wherein the controller is further electrically connected to a Hall element, and obtains a phase wave signal from the fan motor for input to the controller. 5. The rotational speed control circuit according to claim 1 or 2, wherein the controller is also electrically connected to a temperature sensor, and converts and outputs a voltage signal to the controller after detecting the temperature. 6. The rotation speed control circuit according to claim 1 or 2, wherein when the first reference voltage is not higher than the second reference voltage, the controller drives the fan motor to rotate at a low speed according to a low speed setting value. 7. The rotational speed control circuit as claimed in claim 1 or 2, wherein the converter is a charging and discharging circuit. 8. The rotational speed control circuit as claimed in claim 7, wherein the charging and discharging circuit is composed of a first resistor, a second resistor, a third resistor, a capacitor, a first switch assembly and a second switch composed of components. 9. The speed control circuit as claimed in claim 8, wherein the first switch element and the second switch element are a transistor. 10. The rotational speed control circuit according to claim 8, wherein a gate of the first switch element is electrically connected to the pulse width modulation signal generator, and a gate of the second switch element is electrically connected to the first A drain of the switch component; a source of the first switch component and a source of the second switch component are electrically connected to a ground terminal. 11. The speed control circuit according to claim 8, wherein one end of the first resistor is electrically connected to the pulse width modulation signal generator, and the other end of the first resistor is electrically connected to the first switch component. A drain; one end of the second resistor is electrically connected to a drain of the second switch component, and the other end is electrically connected to one end of the third resistor; the other end of the third resistor is electrically connected to the a first resistor; one end of the capacitor is electrically connected to the third resistor, and the other end is electrically connected to a ground terminal. 12. The speed control circuit as claimed in claim 1, wherein the reference voltage generator is a voltage divider composed of a fourth resistor and a fifth resistor, wherein one end of the fourth resistor is electrically connected to The third resistor is used to obtain the external power supply, and the other end thereof is electrically connected to the fifth resistor, and one end of the fifth resistor is electrically connected to a grounding end. 13. The rotational speed control circuit according to claim 1 or 2, wherein the comparator comprises a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal is electrically connected to the fourth resistor and the first Between the five resistors, the negative input terminal is electrically connected between the third resistor and the capacitor. 14. The rotation speed control circuit according to claim 1 or 2, wherein the converter is an analog/digital conversion circuit for converting the PWM signal into a digital first reference voltage.

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