KR100198381B1 - Fan motor controller for cooling - Google Patents

Abstract

The present invention relates to a cooling fan motor control apparatus, comprising: a fan motor installed at a predetermined area of a housing around a heat generating unit or a plurality of heat generating units to rotate a predetermined fan so as to convection air; A sensing unit for sensing a temperature of a predetermined region inside the heating unit or the housing; A sensing circuit which outputs a first driving signal proportional to a sensing signal from the sensing unit and suppresses and outputs the first driving signal to a predetermined level during excessive operation of the sensing unit; An initial operation circuit for transmitting the first drive signal from the sensing circuit and outputting a second drive signal to drive the fan motor at a maximum speed within a control speed range for a predetermined period during an initial operation; And a driving circuit for driving the fan motor proportionally based on the first or second driving signal from the sensing circuit or the initial operation circuit and cutting off the back EMF generated from the fan motor at the end of operation. Regardless of the temperature of the environment, the operation can be surely started at the beginning, the speed of the fan motor can be controlled stably in a wide range, and over-operation can be prevented at high temperatures.

Description

CONTROL APPARATUS OF MOTOR WITH COOLING FAN

The present invention relates to a cooling device, and more particularly to a cooling device capable of appropriately cooling a temperature of a heat generating unit or a housing having a plurality of heat generating units by driving a fan motor stably in an environment having a large temperature change as well as a room temperature. It relates to a fan motor control device for.

Inside the electric and electronic device, a device for generating heat due to power consumption according to its operation is mounted. If the device is out of a predetermined temperature range, the operation becomes unstable or burned out, which causes a problem that the device cannot be used. In order to prevent the burnout of the device due to such overheating and to operate the device at an appropriate temperature, a temperature sensing device and a cooling fan are generally installed in the vicinity of the heating unit (for example, the device) or in the housing of the device, and the cooling fan is installed. A cooling device is mounted which can cool the temperature by convection of air by rotating with a predetermined motor (referred to as a fan motor).

As a method of cooling by driving the fan by a motor and convection of air, there is a method of rotating the cooling fan motor at a constant speed and controlling the speed of the motor by detecting a change in temperature and correspondingly.

1 is a circuit diagram illustrating a fan motor control apparatus for controlling a speed of a fan motor according to a temperature change according to a conventional embodiment, in which 1 is a fan motor, TH1 is a thermistor, Q1 is a transistor, and R1 and R2 are Each resistance is shown.

Hereinafter, a conventional embodiment will be described in detail with reference to FIG. 1.

The first describes the case of operating at low temperature below 0 ° C, for example.

Since the thermistor TH1 that senses temperature in such a low temperature environment has a very high resistance value, almost no current ib flows through the base of the transistor Q1, and is amplified by the transistor Q1 to emit an emi. The current ie output to the emitter becomes minute. Therefore, most of the current supplied to the fan motor 1 from the power supply Vdd flows through the resistor R1.

Therefore, the speed of the fan motor 1 at low temperature is determined by the magnitude of the resistance R1 value, and the speed control by sensing the temperature of the thermistor TH1 is made only in a very narrow range. In addition, the conventional fan motor control device has a problem that the initial operation is not normally performed in a low temperature environment due to the operation as described above.

The second describes the case of operating at a high temperature of, for example, 50 ° C. or higher.

Since the thermistor TH1 that senses temperature in such a high temperature environment has a very low resistance value, the current ib flowing to the base of the transistor Q1 is increased and amplified by the transistor Q1 to the emitter. The output current (ie) is greatly increased from.

Therefore, most of the current supplied to the fan motor 1 from the power supply Vdd flows through the transistor Q1.

Therefore, the speed of the fan motor 1 is determined by the magnitude of the resistance value of the thermistor TH1, but the speed control by sensing the temperature at high temperature is made only in a very narrow range. In addition, in the conventional fan motor control apparatus, excessive current flows through the transistor Q1 during initial operation in a high temperature environment due to the operation as described above, thereby causing element burnout. In addition, there is a problem that the circuit is damaged by the back electromotive force generated from the fan motor 1 during the off operation.

That is, the conventional fan motor control apparatus has a problem in that the fan motor is not normally driven during the initial operation in a low temperature state and a narrow variable range that can control the speed, and an overcurrent flows during the operation in the high temperature state. There is a problem that is burned out.

Therefore, the present invention has been proposed to solve the above-mentioned problems, and can be surely started at the beginning regardless of the operating environment temperature, and can stably control the speed of the fan motor in a wide range. It is an object of the present invention to provide a fan motor control device for cooling that can prevent overoperation at a high temperature.

1 is a circuit diagram showing a fan motor control apparatus according to a conventional embodiment;

2 is a block diagram showing a cooling fan motor control apparatus according to an embodiment of the present invention;

3 is a circuit diagram showing in detail a fan motor control apparatus for cooling according to an embodiment of the present invention;

4A is a diagram showing a circuit configuration of an initial operation of a cooling fan motor control apparatus according to an embodiment of the present invention;

4B is a diagram showing a circuit configuration after the initial operation of the cooling fan motor control apparatus according to the embodiment of the present invention;

5 is a view showing an example of the rotational speed of the fan motor with respect to the drive signal in the embodiment of the present invention;

Figure 6 is a view showing an example of the rotational speed of the fan motor by the initial control of the cooling fan motor control apparatus according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

10: sensing unit 20: sensing circuit

30: initial operation circuit 40: driving circuit

50: fan motor

According to a feature of the present invention proposed to achieve the above object, the cooling fan motor control device is installed in the periphery of the heat generating portion or a predetermined region of the housing fan motor for rotating the predetermined fan so as to convection air Wow; A sensing unit for sensing a temperature of a predetermined region inside the heating unit or the housing; A sensing circuit which outputs a first driving signal proportional to a sensing signal from the sensing unit and suppresses and outputs the first driving signal to a predetermined level during excessive operation of the sensing unit; An initial operation circuit for transmitting the first drive signal from the sensing circuit and outputting a second drive signal to drive the fan motor at a maximum speed within a control speed range for a predetermined period during an initial operation; And a driving circuit which cuts back electromotive force generated from the fan motor at the end of operation while driving the fan motor proportionally based on the first or second driving signal from the sensing circuit or the initial operation circuit.

In a preferred embodiment of this feature, the sensing unit comprises a thermistor whose resistance is changed in proportion to temperature.

In a preferred embodiment of this aspect, the sensing circuit comprises: a first voltage divider connected at one side to a power supply voltage in parallel with the sensing unit while dividing the power supply voltage to a predetermined first voltage; An over-operation preventing resistor having one side connected to the other side of the first voltage divider to prevent over-operation of the fan motor; A second voltage divider resistor having one side connected to the other side of the over-operation preventing resistor and the other side connected to the ground to divide the power supply voltage into a predetermined second voltage; And a first output terminal configured to output a predetermined first driving signal from the connection point between the over-operation preventing resistor and the second voltage divider resistor.

In a preferred embodiment of this aspect, the initial operation circuit includes: an initial operation capacitor having one side connected to a predetermined power supply voltage and passing a predetermined initial operating current for a predetermined period from the initial operation time; An initial operation current control resistor connected at one side to the other side of the initial operation capacitor to control a current flowing through the initial operation capacitor to a predetermined level during initial operation; A second output terminal connected to the other end of the initial operating current control resistor and outputting a second drive signal; An output direction control diode for blocking a second drive signal from the second output terminal from being transmitted to the first output terminal while allowing a first drive signal from the first output terminal of the sensing circuit to be transmitted to the second output terminal; Include.

In a preferred embodiment of this aspect, the driving circuit includes a fan motor having one side connected to the power supply voltage; The collector is connected to the other side of the fan motor, the emitter is connected to ground, and the base is connected to the second output terminal of the initial operation circuit, in proportion to the first or second drive signal from the second output terminal. A motor driving transistor for controlling the speed of the fan motor; A high voltage diode which cuts back electromotive force generated from the fan motor at the end of operation; And a third voltage divider connected in series between the fan motor and the ground to divide the power supply voltage so as to start operation of the transistor during low temperature operation, thereby applying a predetermined voltage between the collector and the emitter of the transistor. do.

The present invention relates to a cooling fan motor control device, comprising: a fan motor installed at a periphery of a heat generating unit or a predetermined area of a housing to rotate a predetermined fan so as to convection air; A sensing unit for sensing a temperature of a predetermined region inside the heating unit or the housing; A sensing circuit which outputs a first driving signal proportional to a sensing signal from the sensing unit and suppresses and outputs the first driving signal to a predetermined level during excessive operation of the sensing unit; An initial operation circuit for transmitting the first drive signal from the sensing circuit and outputting a second drive signal to drive the fan motor at a maximum speed within a control speed range for a predetermined period during an initial operation; And a driving circuit for driving the fan motor proportionally based on the first or second driving signal from the sensing circuit or the initial operation circuit and cutting off the back EMF generated from the fan motor at the end of the operation. Regardless of the temperature of the environment, the operation can be started reliably at an early stage, the speed of the fan motor can be controlled in a wide range, and over-operation can be prevented at high temperatures.

Example

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 2 to 6.

Referring to FIG. 2, the novel cooling fan motor control apparatus of the present invention includes a sensing unit 10, a sensing circuit 20, an initial operation circuit 30, a driving circuit 40, and a fan motor 50. It is possible to start the operation reliably at the initial stage regardless of the temperature of the operating environment, to stably control the speed of the fan motor in a wide range, and to prevent over-operation at high temperatures.

The first describes the operation at low temperatures.

In such a low temperature environment, the thermistor TH10 that senses temperature has a very high resistance value. Therefore, the voltage of the driving signal output terminal A of the sensing circuit 20 is relatively low, and a driving current for driving the fan motor 50 at a speed of about 1200 rpm flows toward the driving circuit 40. Therefore, in a low temperature environment, the driving circuit 40 rotates the fan motor 50 at a speed of about 1200 rpm.

The second explains its operation at high temperatures.

In such a high temperature environment, the thermistor TH10 that senses temperature has a very low resistance value. Therefore, the voltage of the driving signal output terminal A of the sensing circuit 20 becomes relatively high, and a driving current for driving the fan motor 50 at a speed of about 2400 rpm flows toward the driving circuit 40. Therefore, in the high temperature environment, the drive circuit 40 rotates the fan motor 50 at a speed of about 2400 rpm.

At this time, when the over-operation preventing resistor R11 is absent, the driving signal close to the voltage of the power supply Vdd is output from the driving signal output terminal A, thereby causing the transistor Q10 of the driving circuit 40 to be burned out. Therefore, the resistor R11 functions to enable stable operation during high temperature operation.

Third, the initial operation by the initial operation circuit 30 independent of temperature will be described with reference to FIG. 4A.

Initially, since the capacitor C10 of the initial operation circuit 30 is discharged, the capacitor C10 becomes as in the short state. Therefore, the current from the predetermined power supply Vdd is applied to the base of the transistor Q10 of the driving circuit 40 through the resistor R13. At this time, the current applied to the base of the transistor Q10 is supplied to be the maximum speed (about 2400rpm) of the range to drive the fan motor 50, by the thermistor (TH10) of the sensing circuit 20 The driving current does not affect the transistor Q10.

The potential of VB becomes higher than that of VA, and the driving signal VA of the sensing circuit is not transmitted to the base of the transistor Q10 due to the reverse bias of the diode D10.

Therefore, the voltage of the power supply Vdd is applied to the base of the transistor Q10 as it is via the resistor R13, and the fan motor is driven at about 2400 rpm during the initial operation even at a low temperature, so that the operation can be reliably started.

6 is a view showing an example of the rotational speed of the fan motor by the initial control of the cooling fan motor control apparatus according to the embodiment.

As shown in the figure, the fan motor 50 is rotated at a speed of about 2400 rpm for a predetermined time Ts from the time t0 at which the operation is started.

The capacitor C10 is charged as the time t1 approaches, and the current flowing through the capacitor C10 and the resistor R13 from the power supply Vdd is greatly reduced.

Therefore, the driving circuit 40 controls the fan motor 50 according to the operation of the sensing unit 20 at the time t1.

For reference, in this embodiment, the time constant RC is set such that the time t1 is 5 to 50 msec.

Fourth, the operation at room temperature will be described with reference to FIG. 4B.

After the operation is started as described above, as shown by the dotted line, the capacitor C10 interrupts the power supply Vdd voltage, whereby the potential of VB becomes lower than the potential of VA.

That is, a forward bias is formed in the diode D10, so that the change in VA affects the base of the transistor Q10. Therefore, the driving circuit by linearly changing the driving signal from the driving signal output terminal A of the sensing circuit 20 in accordance with the change in the resistance value of the thermistor TH10 of the sensing unit 10 according to the temperature change. 40 may be controlled by varying the drive speed of the fan motor 50. That is, when the driving signal input to the base of the transistor Q10 of the driving circuit 40 is variable, the transistor Q10 controls the amount of current flowing to the fan motor 50 in proportion thereto.

5 is a view showing an example of the rotational speed with respect to the input voltage of the fan motor in the embodiment of the present invention.

As shown in the drawing, when the voltage of the sensing signal output terminal A of the sensing circuit 20 is changed from v1 to v2, the driving circuit 40 controls the fan motor 50 to rotate at a speed of about 1200 rpm to 2400 rpm. Done.

On the other hand, when the operation of the fan motor 50 is momentarily stopped by cutting off the power supply Vdd, counter electromotive force is generated between both ends of the fan motor 50. The counter electromotive force generated as described above causes the diode D11 to form a current path so as not to destroy the transistor Q10.

The present invention is a conventional fan motor control device has a problem that the fan motor is not initially operated at low temperature operation and a variable range that can control the speed is narrow, the circuit is burned out by the flow of overcurrent during high temperature operation By solving the problem, it is possible to start the operation reliably at the initial stage regardless of the temperature of the operating environment, to stably control the speed of the fan motor in a wide range, and to prevent over-operation at high temperatures.

Claims (5)

A cooling device for convection of air generated in or around a heat generating portion to reduce heat generated from a single heat generating portion or heat inside a housing having a plurality of heat generating portions: A fan motor 50 installed around the heat generating unit or in a predetermined region of the housing to rotate a predetermined fan so as to convection air; A sensing unit 10 for sensing a temperature of a predetermined region inside the heating unit or the housing; The sensing circuit 20 outputs the first driving signal proportional to the sensing signal from the sensing unit 10 while suppressing the first driving signal to a predetermined level during excessive operation of the sensing unit 10. Wow; Initially outputting a second drive signal to drive the fan motor 50 at a maximum speed within a control speed range for a predetermined period during initial operation while transmitting the first drive signal from the sensing circuit 20. An operation circuit 30; Reverse electromotive force generated from the fan motor 50 at the end of operation while driving the fan motor 50 proportionally based on the first or second drive signal from the sensing circuit 20 or the initial operation circuit 30. Cooling fan motor control device, characterized in that it comprises a drive circuit for blocking the. The method of claim 1, The sensing unit 10 is a cooling fan motor control device, characterized in that it comprises a thermistor whose resistance value changes in proportion to temperature. The method of claim 1, The sensing circuit 20 includes a first voltage divider R10 connected at one side to a power supply voltage Vdd and connected in parallel with the sensing unit 10 while dividing the power supply voltage to a predetermined first voltage; An over-operation preventing resistor (R11) connected at one side to the other side of the first voltage dividing resistor (R10) to prevent over-operation of the fan motor 50; A second voltage divider R12, one side of which is connected to the other side of the overoperation preventing resistor R11 and the other side of which is connected to ground to divide the power supply voltage Vdd into a predetermined second voltage; And a first output terminal (A) for outputting a predetermined first driving signal from a connection point of the over-operation resistance resistor (R11) and the second voltage divider resistor (R12). The method of claim 1, The initial operation circuit (30) includes an initial operation capacitor (C10) connected at one side to a predetermined power supply voltage (Vdd) to pass a predetermined initial operating current for a predetermined period from the initial operation time point; An initial operation current control resistor (R13) connected at one side to the other side of the initial operation capacitor (C10) to control a current flowing through the initial operation capacitor (C10) to a predetermined level during initial operation; A second output terminal (B) connected to the other end of the initial operating current control resistor (R13) to output a second drive signal; The second driving signal from the second output terminal (B) is the first driving signal from the first output terminal (A) of the sensing circuit 20 is transmitted to the second output terminal (B) side Cooling fan motor control device characterized in that it comprises an output direction control diode (D10) for blocking the transmission to the output terminal (A) side. The method of claim 1, The driving circuit 40 includes a fan motor 50 having one side connected to the power supply voltage Vdd; The collector is connected to the other side of the fan motor 50, the emitter is connected to ground, and the base is connected to the second output terminal B of the initial operation circuit 30, to the second output terminal B. A motor drive transistor (Q10) for controlling the speed of the fan motor (50) in proportion to the first or second drive signal from the second motor; A high voltage diode (D11) for blocking back electromotive force generated from the fan motor 50 at the end of operation; In order to start the operation of the transistor Q10 during low temperature operation, it is connected in series between the fan motor 50 and the ground to divide the power supply voltage Vdd so that the collector and emitter of the transistor Q10 are separated. A fan motor control device for cooling, comprising a third voltage dividing resistor (R14) for applying a predetermined voltage.