Fan temperature control driving circuit

Abstract

The utility model discloses a fan temperature control driving circuit, which comprises a first divider resistor, a thermistor, a voltage stabilizing diode, a second divider resistor, a first voltage stabilizing diode, a second voltage stabilizing diode, a third divider resistor, a fourth divider resistor, a fourth divider resistor, a fifth divider resistor and a sixth divider resistor, wherein one end of the first divider resistor is connected with the positive electrode of a fan driving interface while the other end is connected with one end of the thermistor; the anode of the Zener diode is connected with the cathode of the power supply end; one end of the second divider resistor is connected with the anode of the fan driving interface, the other end is connected with the collector of the first triode, the base of the first triode is connected with the anode of the Zener diode, and the emitter of the first triode is connected with the cathode of the power supply end; the collector of the second triode is connected with the cathode of the fan driving interface, the emitter of the second triode is connected with the cathode of the power supply end, and the base of the second triode is connected with the collector of the first triode. According to the technical scheme, the working time of the fan can be effectively shortened, and the expected service life of the fan is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fan switch control, and particularly relates to a fan temperature control driving circuit. BACKGROUND

[0002] The rotation of the fan blades can increase the flow rate of the airflow, thereby taking away more heat to achieve the cooling of the target. The existing switch power supply cooling and temperature control technology has active cooling, and the active cooling is to install a fan to strengthen the product internal air convection and take away the internal heat.

[0003] However, the active cooling mode needs the fan to keep running during the product operation, which causes the fan to be in a working state for a long time, and thus seriously reduces the expected service life of the fan. CONTENT OF THE INVENTION

[0004] In view of the defects in the prior art, the fan temperature control driving circuit can effectively reduce the working time of the fan and improve the expected service life of the fan.

[0005] The fan temperature control driving circuit provided in the application comprises:

[0006] A power supply end for providing power;

[0007] A fan driving interface, wherein a positive electrode of the fan driving interface is connected to a positive electrode of the power supply end, and a negative electrode of the fan driving interface is connected to a negative electrode of the power supply end;

[0008] A first voltage dividing resistor and a thermistor, wherein one end of the first voltage dividing resistor is connected to the positive electrode of the fan driving interface and the positive electrode of the power supply end, the other end of the first voltage dividing resistor is connected to one end of the thermistor, the other end of the thermistor is connected to the negative electrode of the power supply end, and the thermistor is a negative temperature coefficient thermistor;

[0009] A voltage stabilizing diode, wherein a negative electrode of the voltage stabilizing diode is connected between the first voltage dividing resistor and the thermistor, and a positive electrode of the voltage stabilizing diode is connected to the negative electrode of the power supply end;

[0010] A second voltage dividing resistor and a first triode, wherein one end of the second voltage dividing resistor is connected to the positive electrode of the fan driving interface and the positive electrode of the power supply end, the other end of the second voltage dividing resistor is connected to a collector of the first triode, a base of the first triode is connected to the positive electrode of the voltage stabilizing diode, and an emitter of the first triode is connected to the negative electrode of the power supply end;

[0011] The second transistor has its collector connected to the negative terminal of the fan drive interface, its emitter connected to the negative terminal of the power supply, and its base connected between the collector of the first transistor and the second voltage divider resistor.

[0012] In one aspect, the driving circuit further includes a switching diode, the anode of which is connected between the first voltage divider resistor and the thermistor.

[0013] In one aspect, the driving circuit further includes a third voltage divider resistor, one end of which is connected to the positive terminal of the switching diode, and the other end of which is connected between the first voltage divider resistor and the thermistor.

[0014] In one aspect, the drive switch further includes a first voltage-regulating capacitor, one end of which is connected to the positive terminal of the power supply terminal, and the other end of which is connected to the negative terminal of the power supply terminal.

[0015] In one aspect, the driving circuit further includes a fourth voltage divider resistor, one end of which is connected between the positive terminal of the Zener diode and the base of the first transistor, and the other end of which is grounded.

[0016] In one aspect, the driving circuit further includes a second voltage-regulating capacitor, one end of which is connected between the positive terminal of the Zener diode and the base of the first transistor, and the other end of which is connected to the negative terminal of the power supply.

[0017] In one aspect, both the first transistor and the second transistor are NPN transistors.

[0018] The beneficial effects of this invention are as follows: when the temperature is too high, the resistance of the thermistor decreases, and the voltage obtained by the series connection of the first voltage divider resistor and the thermistor decreases, which is insufficient to break down the Zener diode. As a result, the first transistor will not conduct, and the collector-emitter of the first transistor is in a high resistance state. Under these circumstances, the voltage obtained by the second voltage divider resistor and the collector-emitter of the first transistor can drive the second transistor to conduct, thereby enabling the fan to enter the power-on working state.

[0019] When the temperature is too low, the resistance of the thermistor increases. The voltage across the series connection between the first voltage divider resistor and the thermistor increases significantly, enough to break down the Zener diode. This causes the first transistor to conduct. The collector-emitter junction of the first transistor is in a low-resistance state, and consequently, the voltage across the second voltage divider resistor and the collector-emitter junction of the first transistor is insufficient to turn on the second transistor. The fan then enters a power-off and stops. Therefore, the technical solution of this application can automatically drive the fan to run for cooling when the temperature is high and automatically stop the fan when the temperature is low, thereby effectively reducing the fan's operating time and increasing its expected lifespan. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0021] Figure 1 This is a schematic diagram of the fan temperature control drive circuit of this application.

[0022] Figure description: 10, power supply terminal; XT1, fan drive interface; R1, first voltage divider resistor; R2, second voltage divider resistor; R3, third voltage divider resistor; R4, fourth voltage divider resistor; RT1, thermistor; VZ1, Zener diode; VT1, first transistor; VT2, second transistor; VD1, switching diode; C1, first voltage stabilizing capacitor; C2, second voltage stabilizing capacitor. Detailed Implementation

[0023] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0024] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0025] like Figure 1 As shown, this application provides a fan temperature control drive circuit, which includes: a power supply terminal 10, a fan drive interface XT1, a first voltage divider resistor R1, a thermistor RT1, a Zener diode VZ1, a second voltage divider resistor R2, a first transistor VT1, and a second transistor VT2.

[0026] Power supply terminal 10 is used to provide power.

[0027] The positive terminal 1 of the fan driver interface XT1 is connected to the positive terminal +VIN of the power supply terminal 10, and the negative terminal 3 of the fan driver interface XT1 is connected to the negative terminal -VIN of the power supply terminal 10. The fan driver interface XT1 also has a non-functional pin 2.

[0028] One end of the first voltage divider resistor R1 is connected to the positive terminal 1 of the fan drive interface XT1 and the positive terminal +VIN of the power supply terminal 10. The other end of the first voltage divider resistor R1 is connected to one end of the thermistor RT1. The other end of the thermistor RT1 is connected to the negative terminal -VIN of the power supply terminal 10. The thermistor RT1 is a negative temperature coefficient thermistor. The resistance of a negative temperature coefficient thermistor decreases when the temperature is high and increases when the temperature is low.

[0029] The negative terminal of Zener diode VZ1 is connected between the first voltage divider resistor R1 and the thermistor RT1, and the positive terminal of Zener diode VZ1 is connected to the negative terminal -VIN of power supply terminal 10. One end of the second voltage divider resistor R2 is connected to the positive terminal 1 of fan drive interface XT1 and the positive terminal +VIN of power supply terminal 10, and the other end of the second voltage divider resistor R2 is connected to the collector of the first transistor VT1. The base of the first transistor VT1 is connected to the positive terminal of Zener diode VZ1, and the emitter of the first transistor VT1 is connected to the negative terminal of power supply terminal 10. Zener diode VZ1 is a semiconductor device that maintains high resistance until the critical reverse breakdown voltage. It utilizes the phenomenon that the current can vary over a wide range while the voltage remains essentially constant during the reverse breakdown state of a PN junction to achieve voltage regulation. At this critical breakdown point, the reverse resistance drops to a very small value. In this low-resistance region, the current increases while the voltage remains constant. Zener diodes VZ1 are graded according to their breakdown voltage. Because of this characteristic, Zener diodes are mainly used as voltage regulators or voltage reference elements. Zener diodes VZ1 can be connected in series for use at higher voltages; by connecting them in series, an even higher stable voltage can be obtained.

[0030] The collector of the second transistor VT2 is connected to the negative terminal -VIN of the fan drive interface XT1, the emitter of the second transistor VT2 is connected to the negative terminal -VIN of the power supply terminal 10, and the base of the second transistor VT2 is connected between the collector of the first transistor VT1 and the second voltage divider resistor R2.

[0031] When the temperature is too high, the resistance of the thermistor RT1 decreases, and the voltage across the series connection between the first voltage divider resistor R1 and the thermistor RT1 decreases, becoming insufficient to break down the Zener diode VZ1. As a result, the first transistor VT1 will not conduct, and the collector-emitter junction of the first transistor VT1 will be in a high-resistance state. In this case, the voltage across the collector-emitter junction of the second voltage divider resistor R2 and the first transistor VT1 can drive the second transistor VT2 to conduct, thus putting the fan into a powered-on state. Here, the collector-emitter junction refers to the position between the emitter and the collector, where a voltage difference is formed, and the magnitude of this voltage difference can drive the second transistor VT2 to conduct.

[0032] When the temperature is too low, the resistance of the thermistor RT1 increases. The voltage across the series connection between the first voltage divider resistor R1 and the thermistor RT1 increases, becoming sufficient to break down the Zener diode VZ1. This causes the first transistor VT1 to conduct. Since the collector-emitter relationship of VT1 is low, the voltage across the collector-emitter connection of the second voltage divider resistor R2 is insufficient to turn on the second transistor VT2, causing the fan to shut down. Therefore, the technical solution of this application can automatically drive the fan to operate for cooling when the temperature is high and automatically stop the fan when the temperature is low, effectively reducing the fan's operating time and increasing its expected lifespan.

[0033] In one aspect, the drive circuit also includes a switching diode VD1, the anode of which is connected between the first voltage divider resistor R1 and the thermistor RT1. Further, the drive circuit also includes a third voltage divider resistor R3, one end of which is connected to the anode of the switching diode VD1, and the other end of which is connected between the first voltage divider resistor R1 and the thermistor RT1. The third voltage divider resistor R3 and the switching diode VD1 are used to further reduce the voltage across the first voltage divider resistor R1 and the thermistor RT1 when the fan starts operating, preventing unstable fan drive caused by power fluctuations in the control circuit.

[0034] In one aspect, the drive switch also includes a first voltage-regulating capacitor C1. One end of the first voltage-regulating capacitor C1 is connected to the positive terminal of the power supply terminal 10, and the other end of the first voltage-regulating capacitor C1 is connected to the negative terminal of the power supply terminal 10. The first voltage-regulating capacitor C1 is used to stabilize the voltage between the positive and negative terminals of the power supply terminal 10, which can also be understood as stabilizing the positive and negative terminals of the fan.

[0035] In one aspect, the drive circuit also includes a fourth voltage divider resistor R4. One end of the fourth voltage divider resistor R4 is connected between the positive terminal of the Zener diode VZ1 and the base of the first transistor VT1, and the other end of the fourth voltage divider resistor R4 is grounded. The fourth voltage divider resistor R4 is used to protect the first transistor VT1.

[0036] In one aspect, the driving circuit also includes a second voltage-regulating capacitor C2. One end of the second voltage-regulating capacitor C2 is connected between the anode of the Zener diode VZ1 and the base of the first transistor VT1, and the other end of the second voltage-regulating capacitor C2 is connected to the cathode of the power supply terminal 10. The second voltage-regulating capacitor C2 is used to stabilize the voltage between the anode of the Zener diode VZ1 and the base of the first transistor VT1, and to filter out noise.

[0037] In one aspect, both transistors VT1 and VT2 are NPN transistors. Transistors VT1 and VT2 are of the same type; an NPN transistor can only conduct when its base voltage is higher than its emitter voltage.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A fan temperature control drive circuit, characterized in that, The driving circuit includes: Power supply terminal, which is used to provide power; A fan drive interface, wherein the positive terminal of the fan drive interface is connected to the positive terminal of the power supply terminal, and the negative terminal of the fan drive interface is connected to the negative terminal of the power supply terminal; A first voltage divider resistor and a thermistor, one end of the first voltage divider resistor is connected to the positive terminal of the fan drive interface and the positive terminal of the power supply terminal, the other end of the first voltage divider resistor is connected to one end of the thermistor, and the other end of the thermistor is connected to the negative terminal of the power supply terminal. The thermistor is a negative temperature coefficient thermistor. A Zener diode, wherein the negative terminal of the Zener diode is connected between the first voltage divider resistor and the thermistor, and the positive terminal of the Zener diode is connected to the negative terminal of the power supply terminal; The second voltage divider resistor and the first transistor are connected as follows: one end of the second voltage divider resistor is connected to the positive terminal of the fan drive interface and the positive terminal of the power supply terminal; the other end of the second voltage divider resistor is connected to the collector of the first transistor; the base of the first transistor is connected to the positive terminal of the Zener diode; and the emitter of the first transistor is connected to the negative terminal of the power supply terminal. The second transistor has its collector connected to the negative terminal of the fan drive interface, its emitter connected to the negative terminal of the power supply, and its base connected between the collector of the first transistor and the second voltage divider resistor.

2. The fan temperature control drive circuit according to claim 1, characterized in that, The driving circuit further includes a switching diode, the anode of which is connected between the first voltage divider resistor and the thermistor.

3. The fan temperature control drive circuit according to claim 2, characterized in that, The driving circuit further includes a third voltage divider resistor, one end of which is connected to the positive terminal of the switching diode, and the other end of which is connected between the first voltage divider resistor and the thermistor.

4. The fan temperature control drive circuit according to claim 1, characterized in that, The drive switch further includes a first voltage-stabilizing capacitor, one end of which is connected to the positive terminal of the power supply terminal, and the other end of which is connected to the negative terminal of the power supply terminal.

5. The fan temperature control drive circuit according to claim 1, characterized in that, The driving circuit further includes a fourth voltage divider resistor, one end of which is connected between the positive terminal of the Zener diode and the base of the first transistor, and the other end of which is grounded.

6. The fan temperature control drive circuit according to claim 5, characterized in that, The driving circuit further includes a second voltage-stabilizing capacitor, one end of which is connected between the positive terminal of the Zener diode and the base of the first transistor, and the other end of which is connected to the negative terminal of the power supply.

7. The fan temperature control drive circuit according to any one of claims 1 to 5, characterized in that, Both the first transistor and the second transistor are NPN transistors.

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