CN220487904U - Fan temperature control circuit with negative voltage feedback - Google Patents
Fan temperature control circuit with negative voltage feedback Download PDFInfo
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- CN220487904U CN220487904U CN202321695831.6U CN202321695831U CN220487904U CN 220487904 U CN220487904 U CN 220487904U CN 202321695831 U CN202321695831 U CN 202321695831U CN 220487904 U CN220487904 U CN 220487904U
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- 238000001514 detection method Methods 0.000 claims abstract description 15
- 238000010586 diagram Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Abstract
The embodiment of the utility model discloses a fan temperature control circuit with negative voltage feedback, which comprises: the device comprises a main control unit, a temperature detection unit, a switch assembly, a voltage acquisition unit and a fan; the temperature detection unit is used for detecting the ambient temperature of the device; the voltage acquisition unit is used for acquiring the voltages at two ends of the fan; the main control unit is used for adjusting PWM duty ratio according to the ambient temperature and the voltage at two ends of the fan so as to obtain an output signal; the switch component is used for conducting or cutting off according to the output signal so as to adjust the rotating speed of the fan. By implementing the circuit provided by the embodiment of the utility model, the fan can accurately control the temperature of the device.
Description
Technical Field
The utility model relates to the technical field of fans, in particular to a fan temperature control circuit with negative voltage feedback.
Background
In the conventional project, in order to control the temperature of the circuit device under test within a certain range, a fan is manually used for cooling. The risk cannot be accurately controlled by manpower to be cooled to the target range, and the actual temperature of the device is easy to exceed the target range.
Therefore, it is necessary to design a new circuit to realize precise control of the temperature of the fan to the device.
Disclosure of Invention
The utility model aims to provide a fan temperature control circuit with negative voltage feedback.
In order to solve the technical problems, the aim of the utility model is realized by the following technical scheme: a fan temperature control circuit providing negative voltage feedback includes: the device comprises a main control unit, a temperature detection unit, a switch assembly, a voltage acquisition unit and a fan; the temperature detection unit is used for detecting the ambient temperature of the device; the voltage acquisition unit is used for acquiring the voltages at two ends of the fan; the main control unit is used for adjusting PWM duty ratio according to the ambient temperature and the voltage at two ends of the fan so as to obtain an output signal; the switch component is used for conducting or cutting off according to the output signal so as to adjust the rotating speed of the fan.
The further technical scheme is as follows: the temperature detection unit includes a temperature sensor.
The further technical scheme is as follows: the switch component comprises a switch piece, a primary push-pull control circuit and a secondary push-pull control circuit; the primary push-pull control circuit is connected with the main control unit; the first-stage push-pull control circuit is connected with the second-stage push-pull control circuit; the two-stage push-pull control circuit is connected with the switch piece, and the switch piece is connected with the fan.
The further technical scheme is as follows: the primary push-pull control circuit comprises a triode Q37 and a triode Q41, and the base electrode of the triode Q37 is connected with the main control unit; the collector electrode of the triode Q37 is connected with the base electrode of the triode Q41; and the collector electrode of the triode Q41 is connected with the two-stage push-pull control circuit.
The further technical scheme is as follows: the two-stage push-pull control circuit comprises a triode Q25 and a triode Q29, wherein the collector electrode of the triode Q41 is respectively connected with the base electrode of the triode Q25 and the base electrode of the triode Q29.
The further technical scheme is as follows: the collector electrode of the triode Q41 is grounded through a resistor R27; the collector of the triode Q37 is connected with a power supply through a resistor R31.
The further technical scheme is as follows: the emitter of the triode Q25 is connected with the switch element through a resistor R22, and a resistor R14 is connected between the resistor R22 and the switch element.
The further technical scheme is as follows: the emitter of the triode Q29 is connected with the switch element through a resistor R18; the resistor R14 is connected between the resistor R18 and the switch element.
The further technical scheme is as follows: the switch piece comprises a MOS tube Q33.
The further technical scheme is as follows: one end of the fan, which is connected with a power supply, is connected with a resistor R43, and one end of the resistor R43 is connected with a resistor R52 with one end grounded; the fan with MOS pipe Q33 is connected with resistance R48 in one end, resistance R48 is connected with the resistance R49 of one end ground connection, the both ends of fan are parallelly connected with diode D7, resistance R43 and resistance R48 respectively with the main control unit is connected.
Compared with the prior art, the utility model has the beneficial effects that: according to the utility model, the main control unit, the temperature detection unit, the switch assembly, the voltage acquisition unit and the fan are arranged, the voltage acquisition unit is used for acquiring the voltages at two ends of the fan, the PWM duty ratio is adjusted by the main control unit in combination with the ambient temperature of the device acquired by the temperature detection unit, and then the rotating speed of the fan is adjusted, so that the fan can accurately control the temperature of the device.
The utility model is further described below with reference to the drawings and specific embodiments.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic block diagram of a fan temperature control circuit with negative voltage feedback according to an embodiment of the present utility model;
FIG. 2 is a schematic diagram of a fan temperature control circuit with negative voltage feedback according to an embodiment of the present utility model;
the figure identifies the description:
10. a main control unit; 20. a temperature detection unit; 30. a switch assembly; 40. a voltage acquisition unit; 50. a fan.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the utility model herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
Referring to fig. 1, fig. 1 is a schematic block diagram of a fan temperature control circuit with negative voltage feedback according to an embodiment of the present utility model, which can be applied to a product requiring temperature control of a fan 50 to realize accurate control of the fan 50 on the device temperature.
Referring to fig. 1, the fan temperature control circuit with negative voltage feedback includes: the main control unit 10, the temperature detection unit 20, the switch assembly 30, the voltage acquisition unit 40 and the fan 50; a temperature detection unit 20 for detecting an ambient temperature of the device; a voltage acquisition unit 40 for acquiring voltages at both ends of the fan 50; the main control unit 10 is used for adjusting the PWM duty ratio according to the ambient temperature and the voltage at two ends of the fan 50 to obtain an output signal; the switch assembly 30 is used for conducting or cutting off according to the output signal so as to adjust the rotating speed of the fan 50.
In this embodiment, the rotation speed of the fan 50 is adjusted in real time according to the ambient temperature of the device, and the fan 50 stops working, so as to realize precise control of the temperature of the device. The device is a part that dissipates heat by the fan 50.
In one embodiment, referring to fig. 2, the temperature detecting unit 20 includes a temperature sensor.
In one embodiment, referring to fig. 2, the switch assembly 30 includes a switch element, a first push-pull control circuit and a second push-pull control circuit; the primary push-pull control circuit is connected with the main control unit 10; the first-stage push-pull control circuit is connected with the second-stage push-pull control circuit; the secondary push-pull control circuit is connected to a switch, which is connected to a fan 50.
In an embodiment, referring to fig. 2, the first-stage push-pull control circuit includes a transistor Q37 and a transistor Q41, wherein a base of the transistor Q37 is connected to the main control unit 10; the collector of the triode Q37 is connected with the base of the triode Q41; the collector of the triode Q41 is connected with a two-stage push-pull control circuit.
In an embodiment, referring to fig. 2, the two-stage push-pull control circuit includes a transistor Q25 and a transistor Q29, wherein a collector of the transistor Q41 is connected to a base of the transistor Q25 and a base of the transistor Q29, respectively.
In an embodiment, referring to fig. 2, the collector of the transistor Q41 is grounded through a resistor R27; the collector of transistor Q37 is connected to a power supply via resistor R31.
In an embodiment, referring to fig. 2, an emitter of the transistor Q25 is connected to the switch through a resistor R22, and a resistor R14 is connected between the resistor R22 and the switch.
In an embodiment, referring to fig. 2, the emitter of the transistor Q29 is connected to the switch through a resistor R18; a resistor R14 is connected between the resistor R18 and the switch element.
In an embodiment, referring to fig. 2, the switch device includes a MOS transistor Q33.
In this embodiment, the main control unit 10 includes a main control chip. The model of the main control chip is but not limited to HC32F4A0.
In this embodiment, when drive_Contro is set to high level through MCU, i.e. the main control chip, the Vbe voltage of NPN triode Q37 is larger than the on voltage, triode Q37 is in a conducting state, power forms a loop through resistor R31 and triode Q37 to GND, the Vbe voltage of PNP triode Q41 is larger than the on voltage, and Power forms a loop through triode Q41 and resistor R27 to GND. The Vbe of NPN transistor Q25 of the two-stage push-pull control circuit is greater than the on voltage, transistor Q25 is in an on state, the Vbe voltage of PNP transistor Q29 is less than the on voltage, and transistor Q29 is in an off state. The Vgs voltage of the Power NMOS tube Q33 is larger than the starting voltage, the MOS tube Q33 is in a conducting state, a Power supply loops through the fan 50 and the MOS tube Q33 to GND, the fan 50 starts to work, and the voltage at two ends of the fan 50 is Power.
When drive_Contro is set to a low level by MCU, the Vbe voltage of NPN triode Q37 is smaller than the starting voltage, triode Q37 is in an off state, power cannot form a loop to GND through resistor R31 and triode Q37, the Vbe voltage of PNP triode Q41 is smaller than the starting voltage, and Power cannot form a loop to GND through triode Q41 and resistor R27. The Vbe of NPN transistor Q25 of the two-stage push-pull control circuit is smaller than the on voltage, transistor Q25 is in the off state, the Vbe voltage of PNP transistor Q29 is greater than the on voltage, and transistor Q29 is in the on state. The Vgs voltage of the Power NMOS tube Q33 is smaller than the starting voltage, the MOS tube Q33 is in an off state, the Power supply cannot form a loop to GND through the fan 50 and the MOS tube Q33, the fan 50 stops working, and the voltage at the two ends of the fan 50 is 0V.
In an embodiment, referring to fig. 2, a resistor R43 is connected to one end of the fan 50 connected to the power source, and a resistor R52 with one end grounded is connected to the resistor R43; one end of the fan 50 connected with the MOS tube Q33 is connected with a resistor R48, one end of the resistor R48 is connected with a resistor R49 grounded, two ends of the fan 50 are connected with a diode D7 in parallel, and the resistor R43 and the resistor R48 are respectively connected with the main control unit 10.
In this embodiment, when the MCU collects that the temperature of the device is too high through the I2C bus, the MCU will adjust the PWM output duty ratio (the ratio of the high level duration to the total period time in one period) set by the drive_control pin to be high, and the on time of the NPN transistor Q37 and the PNP transistor Q41 in one period occupies a longer total period time. The push-pull circuit takes up longer total period time in Q25 conduction time in one period, the Power NMOS tube Q33 takes up longer total period time in one period, the time that the voltage at the two ends of the fan 50 is Power takes up longer total period time, the equivalent weighted average voltage value at the two ends of the fan 50 is larger, the rotation speed of the fan 50 is higher, and the temperature of the device is reduced.
When the temperature of the device collected by the MCU through the I2C bus is too low, the MCU can regulate down the PWM output duty ratio (the ratio of the high level duration time to the total period time in one period) set by the drive_control pin, and the conduction time of the NPN triode Q37 and the PNP triode Q41 in one period is shorter than the total period time. The push-pull circuit has the advantages that the conduction time of the triode Q25 in one period is shorter than the total period time, the conduction time of the PowerNMOS tube Q33 in one period is shorter than the total period time, the time of the voltage at the two ends of the fan 50 at 0V is longer than the total period time, the equivalent weighted average voltage value at the two ends of the fan 50 is smaller, the rotating speed of the fan 50 is lower, and the temperature of a device is increased.
When the MCU acquires that the voltage at two ends of the fan 50 is higher than the theoretical fan 50 voltage output by the current PWM control through the ADC+/ADC-; the MCU will adjust the PWM duty cycle (the ratio of the duration of the high level to the total period time in one period) set by the current software down by controlling drive_control, and the on time of NPN transistor Q37 and PNP transistor Q41 in one period is shorter than the total period time. The push-pull circuit has the advantages that the conduction time of the Q25 in one period is shorter than the total period, the conduction time of the Power NMOS tube Q33 in one period is shorter than the total period, the time of the voltage at the two ends of the fan 50 being 0V is longer than the total period, the equivalent weighted average voltage value at the two ends of the fan 50 is smaller, and the PWM output duty ratio controlled by the MCU is consistent with the equivalent duty ratio at the output end of the fan 50.
When the MCU acquires that the voltage at two ends of the fan 50 is lower than the theoretical fan 50 voltage output by the current PWM control through ADC+/ADC-; the MCU will adjust the PWM duty cycle (the ratio of the duration of the high level to the total period time in one period) set by the current software to be high by controlling the drive_control, and the on time of NPN transistor Q37 and PNP transistor Q41 in one period is longer than the total period time. The push-pull circuit has the advantages that the conduction time of the Q25 in one period is longer than the total period, the conduction time of the Power NMOS tube Q33 in one period is longer than the total period, the time of the voltage at the two ends of the fan 50, which is Power, is longer than the total period, the equivalent weighted average voltage value at the two ends of the fan 50 is larger, and the PWM output duty ratio controlled by the MCU is consistent with the equivalent duty ratio at the output end of the fan 50.
The circuit of the embodiment realizes the consistency of the input and output duty ratio and the accurate control of the rotating speed of the fan 50 on the temperature of the device through voltage feedback and temperature sensor acquisition control.
According to the fan temperature control circuit with negative voltage feedback, through the arrangement of the main control unit 10, the temperature detection unit 20, the switch assembly 30, the voltage acquisition unit 40 and the fan 50, the voltage acquisition unit 40 is used for acquiring the voltages at two ends of the fan 50, the main control unit 10 is used for adjusting the duty ratio of PWM (pulse width modulation) in combination with the ambient temperature of a device acquired by the temperature detection unit 20, the rotating speed of the fan 50 is further adjusted, and the like, so that the fan 50 can accurately control the temperature of the device.
While the utility model has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the utility model. Therefore, the protection scope of the utility model is subject to the protection scope of the claims.
Claims (10)
1. A voltage negative feedback fan temperature control circuit, comprising: the device comprises a main control unit, a temperature detection unit, a switch assembly, a voltage acquisition unit and a fan; the temperature detection unit is used for detecting the ambient temperature of the device; the voltage acquisition unit is used for acquiring the voltages at two ends of the fan; the main control unit is used for adjusting PWM duty ratio according to the ambient temperature and the voltage at two ends of the fan so as to obtain an output signal; the switch component is used for conducting or cutting off according to the output signal so as to adjust the rotating speed of the fan.
2. The voltage negative feedback fan temperature control circuit of claim 1, wherein the temperature detection unit comprises a temperature sensor.
3. The voltage negative feedback fan temperature control circuit of claim 1, wherein the switch assembly comprises a switch element, a primary push-pull control circuit and a secondary push-pull control circuit; the primary push-pull control circuit is connected with the main control unit; the first-stage push-pull control circuit is connected with the second-stage push-pull control circuit; the two-stage push-pull control circuit is connected with the switch piece, and the switch piece is connected with the fan.
4. A voltage negative feedback fan temperature control circuit according to claim 3, wherein the primary push-pull control circuit comprises a triode Q37 and a triode Q41, and a base electrode of the triode Q37 is connected with the main control unit; the collector electrode of the triode Q37 is connected with the base electrode of the triode Q41; and the collector electrode of the triode Q41 is connected with the two-stage push-pull control circuit.
5. The negative voltage feedback fan temperature control circuit according to claim 4, wherein the two-stage push-pull control circuit comprises a triode Q25 and a triode Q29, and the collector of the triode Q41 is connected with the base of the triode Q25 and the base of the triode Q29 respectively.
6. The negative voltage feedback fan temperature control circuit according to claim 5, wherein the collector of the triode Q41 is grounded through a resistor R27; the collector of the triode Q37 is connected with a power supply through a resistor R31.
7. The negative voltage feedback fan temperature control circuit according to claim 6, wherein the emitter of the triode Q25 is connected to the switch through a resistor R22, and a resistor R14 is connected between the resistor R22 and the switch.
8. The negative voltage feedback fan temperature control circuit according to claim 7, wherein the emitter of the triode Q29 is connected with the switch element through a resistor R18; the resistor R14 is connected between the resistor R18 and the switch element.
9. The negative voltage feedback fan temperature control circuit of claim 1, wherein the switch comprises a MOS transistor Q33.
10. The negative voltage feedback fan temperature control circuit according to claim 9, wherein a resistor R43 is connected to one end of the fan connected with a power supply, and a resistor R52 with one end grounded is connected to the resistor R43; the fan with MOS pipe Q33 is connected with resistance R48 in one end, resistance R48 is connected with the resistance R49 of one end ground connection, the both ends of fan are parallelly connected with diode D7, resistance R43 and resistance R48 respectively with the main control unit is connected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321695831.6U CN220487904U (en) | 2023-06-29 | 2023-06-29 | Fan temperature control circuit with negative voltage feedback |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321695831.6U CN220487904U (en) | 2023-06-29 | 2023-06-29 | Fan temperature control circuit with negative voltage feedback |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220487904U true CN220487904U (en) | 2024-02-13 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202321695831.6U Active CN220487904U (en) | 2023-06-29 | 2023-06-29 | Fan temperature control circuit with negative voltage feedback |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220487904U (en) |
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2023
- 2023-06-29 CN CN202321695831.6U patent/CN220487904U/en active Active
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