TWI417716B - Fan operation detecting apparatus - Google Patents

Description

Fan operation monitoring device

The present invention relates to a fan operation monitoring device.

In order to monitor whether the cooling fan in the computer is running normally, the usual method is to determine whether the fan is rotating by detecting whether the fan has airflow. At present, the detection device has a gas flow detector and an air flow switch. The general electronic airflow detector has a hot wire airflow detector and a fan airflow detector, although the sensitivity is high, the production cost is high, and the price is relatively expensive. The price of the air flow switch is relatively cheap, but the sensitivity is not high. Usually, the wind speed is required to start the air flow switch.

In view of the above, it is necessary to provide a fan operation monitoring device which is simple in method and low in cost, and can judge whether the cooling fan is running or not.

A fan operation monitoring device includes a first current module disposed outside the fan casing, a second current module disposed inside the fan casing, and a warning module, the first current module including the first The second and third transistors, the second current module includes fourth, fifth, and sixth transistors, the warning module includes a voltage source, a seventh transistor, and a warning component, the first electrical a collector of the crystal is respectively connected to the base thereof and the voltage source, the emitter is respectively connected to the collector and the base of the second transistor, and the base is connected to the emitter of the second transistor and the emitter of the third transistor And grounded, the base of the second transistor is connected to the base of the third transistor, and the collector of the third transistor is connected to the base of the seventh transistor and the collector of the sixth transistor. The collectors of the four transistors are respectively connected to the base thereof and the voltage source, the emitters are respectively connected to the collectors and the bases of the fifth transistor, and the base thereof is connected to the emitters of the fifth transistor and the sixth transistor. The emitter is grounded, and the base of the fifth transistor is connected to the base of the sixth transistor. A seventh electrically grounded exit the crystal, a collector connected to the voltage source and ground through the alarm device.

Compared with the prior art, the fan operation monitoring device performs the current of the first transistor of the first current module and the fourth transistor of the second current module in a windy or windless condition. Comparing, according to the comparison result, the light emitting diode is controlled to emit light or not to determine whether the cooling fan is running, has high sensitivity, and has simple circuit and low cost.

Referring to FIG. 1 , a preferred embodiment of the fan operation monitoring device of the present invention includes a first current module 10 , a second current module 20 , and a warning module 30 . The warning module 30 is connected between the first current module 10 and the second current module 20 . The first current module 10 is disposed outside the fan casing (not shown), and the second current module 20 is disposed inside the fan casing.

The first current module 10 includes a first resistor R1, a second resistor R2, a first transistor Q1, a second transistor Q2, and a third transistor Q3. The first resistor R1 is connected in series between the base and the collector of the first transistor Q1. The collector of the first transistor Q1 is connected to the warning module 30, and the emitter is connected to the second transistor Q2. a collector and a base, the base of the first transistor Q1 is connected to the emitter of the second transistor Q2 and the emitter of the third transistor Q3 via the second resistor R2 and grounded, the second transistor The base of Q2 is connected to the base of the third transistor Q3, and the collector of the third transistor Q3 is connected to the warning module 30. The first resistor R1 and the second resistor R2 are current limiting resistors. To further save cost, the two resistors may be deleted, that is, the base of the first transistor Q1 is directly connected to the collector, and the first transistor is directly connected to the collector. The base of Q1 is connected to the emitter of the second transistor Q2 and the emitter of the third transistor Q3 and is grounded.

The second current module 20 includes a third resistor R3, a fourth resistor R4, a fourth transistor Q4, a fifth transistor Q5, and a sixth transistor Q6. The third resistor R3 is connected in series between the base and the collector of the fourth transistor Q4. The collector of the fourth transistor Q4 is connected to the warning module 30, and the emitter is connected to the fifth transistor Q5. a collector and a base, the base of the fourth transistor Q4 is connected to the emitter of the fifth transistor Q5 and the emitter of the sixth transistor Q6 via the fourth resistor R4 and grounded, the fifth transistor The base of Q5 is connected to the base of the sixth transistor Q6, and the collector of the sixth transistor Q6 is connected to the warning module 30. The third resistor R3 and the fourth resistor R4 are current limiting resistors. To further save cost, the two resistors may be deleted, that is, the base of the fourth transistor Q4 is directly connected to the collector, and the fourth transistor is directly connected. The base of Q4 is connected to the emitter of the fifth transistor Q5 and the emitter of the sixth transistor Q6 and is grounded.

The warning module 30 includes a voltage source Vcc, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a seventh transistor Q7, an eighth transistor Q8, a ninth transistor Q9, and A warning component D, in the embodiment, the warning component D is a light emitting diode. The emitter of the ninth transistor Q9 is connected to the collector of the first transistor Q1 and the voltage source Vcc, and the base thereof is connected to the base and the collector of the eighth transistor Q8, and the collectors are respectively connected to the third The collector of the transistor Q3 is connected to the base of the seventh transistor Q7 via the sixth resistor R6, the base of the seventh transistor Q7 is grounded via the seventh resistor R7, and the emitter is grounded, and the collectors are respectively Connecting the anode of the light-emitting diode D and the voltage source Vcc via the fifth resistor R5, the cathode of the light-emitting diode D is grounded, and the collector of the eighth transistor Q8 is connected to the set of the sixth transistor Q6 The emitter is connected to the collector of the fourth transistor Q4 and the voltage source Vcc, respectively. The sixth resistor R6 and the seventh resistor R7 can be replaced by a variable resistor for adjusting the turn-on voltage of the base of the seventh transistor Q7. The fifth resistor R5, the sixth resistor R6 and the seventh resistor R7 are current limiting resistors, and the eighth transistor Q8 and the ninth transistor Q9 form a current mirror circuit to increase the accuracy of the replica current for further Cost-saving, the three resistors R5, R6 and R7, the eighth transistor Q8 and the ninth transistor Q9 can be deleted, that is, the collector of the seventh transistor Q7 is directly connected to the voltage source Vcc, and the base thereof The collector of the third transistor Q3 is connected, and the collector of the third transistor Q3 is connected to the collector of the sixth transistor Q6. The light-emitting diode D can also be replaced by a warning element such as a buzzer.

The current mirror circuit composed of the eighth transistor Q8 and the ninth transistor Q9 functions to copy the current of the sixth transistor Q6 to the ninth transistor Q9, and to make current with the third transistor Q3. In comparison, a voltage Vout is generated, and the voltage Vout is controlled by the voltage division of the sixth resistor R6 and the seventh resistor R7 to control the opening and closing of the seventh transistor Q7, and the seventh transistor Q7 generates a control signal. The light-emitting diode D is informed by the light-emitting or non-light-emitting of the light-emitting diode D that the fan operation monitoring device is in a windy or windless environment, that is, whether the heat-dissipating fan is running.

Since the current through the first transistor Q1 and the fourth transistor Q4 are the same, and the heat generated by the same is also the same, the current of the first transistor Q1 is the second transistor Q2 and the third transistor Q3. a current mirror circuit is formed to be copied to the third transistor Q3, and a current of the fourth transistor Q4 is copied to the sixth transistor Q6 by a current mirror circuit composed of the fifth transistor Q5 and the sixth transistor Q6. The current mirror circuit composed of the eighth transistor Q8 and the ninth transistor Q9 copies the current of the sixth transistor Q6 to the ninth transistor Q9, and the collector of the ninth transistor Q9 is connected to the third The collector of the transistor Q3, so that the current of the first transistor Q1 and the current of the fourth transistor Q4 are superimposed here, if the fan operation monitoring device is in a windless environment, the first transistor Q1 and the The current of the fourth transistor Q4 is equal, that is, the current of the third transistor Q3 and the ninth transistor Q9 are equal, and the current flowing into the sixth resistor R6 is opposite, so that the superimposed current is equal to zero, and the generated voltage is generated. Vout is also zero, and the seventh transistor Q7 cannot be guided. Since the anode of the LED D is connected to the voltage source Vcc and has a fixed voltage value, the LED D emits light, that is, a warning signal is generated to alert the user that the cooling fan is not operating.

If the fan operation monitoring device is in a windy environment, since the first current module 10 is located outside the heat dissipation fan casing, the second current module 20 is located inside the heat dissipation fan casing, so in the case of windy The heat generated by a transistor Q1 is dissipated. Using the temperature characteristic curve of the transistor, when the voltage Vbe of the base and emitter of the transistor is a fixed value, the collector current changes according to the temperature. Therefore, the current of the first transistor Q1 is smaller than the current of the fourth transistor Q4, that is, the current of the third transistor Q3 is smaller than the current of the ninth transistor Q9, so the superimposed current is not zero, and the generated voltage is generated. Vout is also not zero, and the seventh transistor Q7 can be turned on. At this time, the light-emitting diode D does not emit light, that is, no warning signal is output to the user.

The fan operation monitoring device can determine whether the heat dissipation fan is operated according to whether the light-emitting diode D inside the device emits light or does not emit light. The fan operation monitoring device has a simple method and a low cost.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. However, the above-mentioned embodiments are only the specific embodiments of the present invention, and equivalent modifications or variations made by those skilled in the art will be included in the following claims.

The first current module. . . 10

Second current module. . . 20

Warning module. . . 30

resistance. . . R1~R7

Crystal. . . Q1~Q9

Warning component. . . D

power source. . . Vcc

1 is a circuit diagram of a preferred embodiment of a fan operation monitoring device of the present invention.

The first current module. . . 10

Second current module. . . 20

Warning module. . . 30

resistance. . . R1~R7

Crystal. . . Q1~Q9

Warning component. . . D

power source. . . Vcc

Claims (7)

A fan operation monitoring device includes a first current module disposed outside the fan casing, a second current module disposed inside the fan casing, and a warning module, the first current module including the first The second and third transistors, the second current module includes fourth, fifth, and sixth transistors, the warning module includes a voltage source, a seventh transistor, and a warning component, the first electrical a collector of the crystal is respectively connected to the base thereof and the voltage source, the emitter is respectively connected to the collector and the base of the second transistor, and the base is connected to the emitter of the second transistor and the emitter of the third transistor And grounded, the base of the second transistor is connected to the base of the third transistor, and the collector of the third transistor is connected to the base of the seventh transistor and the collector of the sixth transistor. The collectors of the four transistors are respectively connected to the base thereof and the voltage source, the emitters are respectively connected to the collectors and the bases of the fifth transistor, and the base thereof is connected to the emitters of the fifth transistor and the sixth transistor. The emitter is grounded, and the base of the fifth transistor is connected to the base of the sixth transistor. A seventh electrically grounded exit the crystal, a collector connected to the voltage source and ground through the alarm device. The fan operation monitoring device of claim 1, wherein the warning component is a light emitting diode. The fan operation monitoring device of claim 1, wherein an eighth transistor and a ninth transistor are connected in series between the collector of the sixth transistor and the base of the seventh transistor. a collector of the ninth transistor is connected to a base of the seventh transistor, an emitter is connected to the voltage source, and a base is respectively connected to a base and a collector of the eighth transistor, and an emitter of the eighth transistor is connected The voltage source is connected to the collector of the sixth transistor. The fan operation monitoring device of claim 3, wherein the voltage source is connected to the collector of the seventh transistor via a fifth resistor, and the collector of the ninth transistor is coupled to the sixth resistor The base of the seventh transistor is connected, and the base of the seventh transistor is grounded via a seventh resistor. The fan operation monitoring device of claim 4, wherein the sixth resistor and the seventh resistor are both variable resistors. The fan operation monitoring device of claim 1, wherein the base of the first transistor is connected to the collector via a first resistor and to the emitter of the second transistor via a second resistor. . The fan operation monitoring device of claim 1, wherein the base of the fourth transistor is connected to the collector via a third resistor and to the emitter of the fifth transistor via a fourth resistor. .