CN211556842U - Fan control circuit with overcurrent and short-circuit protection functions - Google Patents
Fan control circuit with overcurrent and short-circuit protection functions Download PDFInfo
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- CN211556842U CN211556842U CN202020146240.3U CN202020146240U CN211556842U CN 211556842 U CN211556842 U CN 211556842U CN 202020146240 U CN202020146240 U CN 202020146240U CN 211556842 U CN211556842 U CN 211556842U
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Abstract
The utility model discloses a fan control circuit with overcurrent and short-circuit protection functions, which comprises a power supply module, a switch module and a fault signal output module, wherein the fault signal output module comprises a current acquisition circuit and a comparison circuit; the current acquisition circuit comprises a sampling resistor R6, and the sampling resistor R6 is connected in series in the switch module; the comparison circuit comprises a resistor R15, a resistor R16, a resistor R17, a comparator U1A and a comparator U1B, wherein the resistor R15, the resistor R17 and the resistor R16 are sequentially connected between a power supply and the ground in series, the comparator U1A and the comparator U1B form a window comparator, upper limit comparison voltage input pins and lower limit comparison voltage input pins of the window comparator are respectively connected to two ends of the resistor R17, the input end of the window comparator is connected with a sampling resistor R6, and the output end of the window comparator can output a fault signal. The circuit can output fault signals in time when the fan works abnormally, so that the fan can be maintained conveniently.
Description
Technical Field
The utility model relates to a lathe radiator fan control technical field, concretely relates to fan control circuit who overflows and short-circuit protection function in area.
Background
With the high-speed development of the current electronic technology, electronic components are continuously developed towards miniaturization and densification, and the power of the electronic components is also continuously improved, so that the heat generated by the electronic products in unit area is continuously increased, and if the heat cannot be timely dissipated, local high temperature can be formed, so that the electronic components are broken down, and the working stability and the service life of the electronic components are influenced. The heat dissipation capability of the product is very important, so that the air cooling design continuously leads the advance and innovation of the whole heat dissipation system market, and meanwhile, the working stability of the product is also influenced. In order to increase the heat dissipation capability of a product, a fan structure is usually added to the product for heat dissipation when the temperature is too high, however, the existing fan control circuit does not have a fault detection function, and when a fan fails, the fan cannot be timely found and processed, which causes damage to the product or the fan.
SUMMERY OF THE UTILITY MODEL
The utility model provides a fan control circuit of overcurrent and short-circuit protection function in area, this control circuit have solved the problem that current fan circuit can't detect fan work and break down.
The utility model discloses a technical means as follows:
a fan control circuit with overcurrent and short-circuit protection functions comprises a power supply module, a switch module and a fault signal output module, wherein the fault signal output module comprises a current acquisition circuit for acquiring the current of a control circuit and a comparison circuit for judging the working state of a fan; the current acquisition circuit comprises a sampling resistor R6, and the sampling resistor R6 is connected in series in the switch module; the comparison circuit comprises a resistor R15, a resistor R16, a resistor R17, a comparator U1A and a comparator U1B, the resistor R15, the resistor R17 and the resistor R16 are sequentially connected in series between a power supply and the ground, the comparator U1A and the comparator U1B form a window comparator, upper limit comparison voltage input pins and lower limit comparison voltage input pins of the window comparator are respectively connected to two ends of the resistor R17, the input end of the window comparator is connected with the sampling resistor R6, and the output end of the window comparator can output a fault signal.
Further, the overcurrent protection circuit comprises a triode U4, the base of the triode U4 is connected with the sampling resistor R6, the emitter is grounded, and the collector is connected with the control end of the switch module.
Further, a low-pass filter circuit is further arranged in the overcurrent protection circuit, the low-pass filter circuit comprises a resistor R5 and a capacitor C5, the resistor R5 is connected in series between the base of the triode U4 and the sampling resistor R6, and the capacitor C5 is connected in parallel between the base of the triode U4 and the ground.
The short-circuit protection circuit comprises a resistor R2, a capacitor C3, a voltage regulator tube D3, a resistor R11 and a triode U5; one end of the resistor R2 is connected with one end of the fan, the other end of the resistor R2 is connected with the cathode of the voltage-regulator tube D3 and one end of the capacitor C3, the anode of the voltage-regulator tube D3 is connected with one end of the resistor R11 and the base of the triode U5, the other end of the resistor R11 is grounded, the emitter of the triode U5 is grounded, and the collector of the resistor R11 is connected with the control end of the switch module.
Further, the short-circuit protection auxiliary circuit comprises a resistor R3, a resistor R10 and a triode U3, wherein one end of the resistor R3 is connected with a control signal, the other end of the resistor R3 is connected with one end of the resistor R10 and the base of the triode U3, the other end of the resistor R10 is grounded, the emitter of the triode U3 is grounded, and the collector of the triode U3 is connected with the cathode of the voltage regulator tube D3.
Compared with the prior art, area overflows fan control circuit with short-circuit protection function and has following advantage, through setting up current acquisition circuit and window comparison circuit, can gather the operating current of fan through current acquisition circuit to judge whether fan work is normal through comparison circuit, send fault signal by the window comparator when fan work is abnormal conditions simultaneously, and then can in time send alarm information.
Drawings
Fig. 1 is a circuit block diagram of a fan control circuit disclosed in the present invention;
fig. 2 is a structural diagram of a fan control circuit disclosed in the present invention.
In the figure: 1. the device comprises a power supply module 3, a fault signal output module 4, an overcurrent protection circuit 5 and a short-circuit protection circuit.
Detailed Description
As shown in fig. 1 and 2, the utility model discloses a fan control circuit with overcurrent and short-circuit protection function, including power module 1 and switch module, power module includes diode D1 and stabilivolt D2, and the positive pole of diode D1 is connected with +24V power, and the negative pole is connected with the input of fan and is used for supplying power for the fan, and stabilivolt D2 is used for guaranteeing the stability of the voltage of input fan between diode D1's negative pole and ground; the switch module comprises a resistor R8, a resistor R9, a triode U2, a MOS tube Q1, a resistor R1 and a resistor R12, one end of the resistor R8 is connected with a control signal, the other end of the resistor R9 is connected with the base of the triode U2, the other end of the resistor R9 is grounded, the emitter of the triode U2 is grounded, the collector of the triode U2 is connected with the grid of the MOS tube Q1, one end of the resistor R1 is connected with the cathode of the diode D1, the other end of the resistor R12 is connected with the grid of the MOS tube Q1, the other end of the resistor R12 is grounded, the resistor R1 and the resistor R2 form a voltage division circuit used for providing a turn-on voltage for the MOS tube Q1, the drain of the MOS tube Q1 is connected with the fan, and the source of the MOS tube is connected with.
The fault signal output module 3 is further included, the fault signal output module includes a sampling resistor R6, a resistor R15, a resistor R16, a resistor R17, a comparator U1A and a comparator U1B, the sampling resistor R6 is connected between the source of the MOS transistor and the ground, and is used for collecting current flowing through the MOS transistor Q1 to form a sampling voltage, the resistor R15, the resistor R17 and the resistor R16 are connected in series to form a voltage division circuit, and the other end of the resistor R15 is connected to the power supply, in this embodiment, one end of the resistor R15 is connected to the 3.3V power supply, the other end of the resistor R16 is connected to the ground, the comparator U1A and the comparator U1B form a window comparator, the non-inverting input terminal of the comparator U1A is connected to the common terminal of the resistor R15 and the resistor R17 for setting the upper limit comparison voltage of the threshold comparator, in this embodiment, the upper limit comparison voltage is set to be 0.84V, the input terminal of the comparator U1B is connected to the common terminal of the resistor R, in this embodiment, the lower limit comparison voltage is set to 0.08V, the inverting input terminal of the comparator U1A and the non-inverting input terminal of the comparator U1B are connected to the source of the MOS transistor Q1, the sampling resistor R6 collects the current on the MOS transistor Q1 to form a sampling voltage, and compares the sampling voltage on the sampling resistor R6 with the upper and lower limit voltages of the threshold comparator, the output terminal of the threshold comparator is connected to a controller (not shown in the figure), the controller is connected to an alarm module, when the FAN works abnormally and the current is too large or too small, the sampling voltage on the sampling resistor R6 is greater than 0.84V or less than 0.08V, and at this time, the threshold comparator outputs a fault signal (FAN _ BACK signal in the figure) to the controller, and the controller sends a fault alarm after receiving the fault signal. A filter capacitor C6 is also provided between the inverting input terminal of the comparator U1A and ground.
Further, the overcurrent protection circuit 4 is further included, the overcurrent protection circuit 4 includes a transistor U4, a base of the transistor U4 is connected with a source of the MOS transistor Q1, an emitter is grounded, a collector is connected with a gate of the MOS transistor Q1, a sampling voltage of the sampling resistor R6 is used as a working voltage of the transistor U4, when the fan normally works, a voltage on the sampling resistor R6 is lower than a conducting voltage of the transistor U4, the transistor U4 is disconnected, the MOS transistor Q1 controls switching of the fan, when the circuit overflows, a voltage on the sampling resistor R6 is higher than a conducting voltage of the transistor U4, the transistor U4 is opened, a gate of the transistor Q1 is pulled down, the transistor Q1 is closed, and further the fan is controlled to stop working to avoid damage of the fan due to long-time overcurrent working, a low-pass filter circuit is further provided in the overcurrent protection circuit, the low-pass filter circuit includes a resistor R5 and a capacitor C5, the resistor R5 is connected in series between the base of the triode U4 and the source of the MOS tube, the capacitor C5 is connected in parallel between the base of the triode U4 and the ground, current fluctuation may occur in the circuit during the working process of the fan, and the low-pass filter circuit is used for preventing the malfunction of the triode U4.
Further, the short-circuit protection circuit 5 is further included, and the short-circuit protection circuit 5 includes a resistor R2, a capacitor C3, a voltage regulator tube D3, a resistor R11, and a triode U5; one end of the resistor R2 is connected with one end of the fan, the other end of the resistor R2 is connected with the cathode of the voltage-regulator tube D3 and one end of the capacitor C3, the anode of the voltage-regulator tube D3 is connected with one end of the resistor R11 and the base of the triode U5, the other end of the resistor R11 is grounded, the emitter of the triode U5 is grounded, and the collector of the resistor R11 is connected with the control end of the switch module. When the fan is in short circuit, the voltage of the cathode of the voltage regulator tube D3 is close to the power supply voltage (24V), at the moment, the resistor R2, the voltage regulator tube D3 and the resistor R11 form a voltage division circuit, so that the voltage of the anode end of the voltage regulator tube D3 is higher than the conduction voltage of the triode U5, the triode U5 is conducted, the grid voltage of the MOS tube Q1 is pulled down, the MOS tube is turned off, and the fan stops working. Meanwhile, the resistor R2 and the capacitor C3 are arranged, the resistor R2 and the capacitor C3 form a charging circuit, the rising rate of the voltage of the cathode end of the D3 is delayed, the base opening speed of the U5 is further reduced, and the normal starting of the fan is guaranteed. Because the fan needs time to start, the RC charging circuit formed by the C3 and the R2 needs to match the fan starting timing, if the RC time is less than the fan starting time, the U5 may be abnormally turned on and the Q1 may be turned off during the fan starting process, which may cause abnormal starting.
Further, the short-circuit protection auxiliary circuit comprises a resistor R3, a resistor R10 and a triode U3, one end of the resistor R3 is connected with a control signal, the other end of the resistor R3 is connected with one end of the resistor R10 and the base of the triode U3, the other end of the resistor R10 is grounded, the emitter of the triode U3 is grounded, the collector of the triode U3 is connected with the cathode of the voltage regulator tube D3, when the control signal is input to a high level, the triode U3 is conducted, electric charge on the capacitor C3 can be released through the triode U3, when the fan is turned off, the electric charge on the capacitor C3 can be released, and misoperation of the circuit is prevented.
The above, only be the concrete implementation of the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art is in the technical scope of the present invention, according to the technical solution of the present invention and the utility model, the concept of which is equivalent to replace or change, should be covered within the protection scope of the present invention.
Claims (5)
1. The utility model provides a take fan control circuit who overflows and short-circuit protection function, includes power module and switch module, its characterized in that: the fan control circuit also comprises a fault signal output module, wherein the fault signal output module comprises a current acquisition circuit for acquiring the current of the control circuit and a comparison circuit for judging the working state of the fan;
the current acquisition circuit comprises a sampling resistor R6, and the sampling resistor R6 is connected in series in the switch module;
the comparison circuit comprises a resistor R15, a resistor R16, a resistor R17, a comparator U1A and a comparator U1B, the resistor R15, the resistor R17 and the resistor R16 are sequentially connected in series between a power supply and the ground, the comparator U1A and the comparator U1B form a window comparator, upper limit comparison voltage input pins and lower limit comparison voltage input pins of the window comparator are respectively connected to two ends of the resistor R17, the input end of the window comparator is connected with the sampling resistor R6, and the output end of the window comparator can output a fault signal.
2. The fan control circuit with overcurrent and short-circuit protection of claim 1, wherein: the overcurrent protection circuit comprises a triode U4, the base of the triode U4 is connected with a sampling resistor R6, the emitter is grounded, and the collector is connected with the control end of the switch module.
3. The fan control circuit with overcurrent and short-circuit protection of claim 2, wherein: the overcurrent protection circuit is also internally provided with a low-pass filter circuit, the low-pass filter circuit comprises a resistor R5 and a capacitor C5, the resistor R5 is connected between the base of the triode U4 and the sampling resistor R6 in series, and the capacitor C5 is connected between the base of the triode U4 and the ground in parallel.
4. The fan control circuit with overcurrent and short-circuit protection of claim 1, wherein: the circuit further comprises a short-circuit protection circuit, wherein the short-circuit protection circuit comprises a resistor R2, a capacitor C3, a voltage regulator tube D3, a resistor R11 and a triode U5; one end of the resistor R2 is connected with one end of the fan, the other end of the resistor R2 is connected with the cathode of the voltage-regulator tube D3 and one end of the capacitor C3, the anode of the voltage-regulator tube D3 is connected with one end of the resistor R11 and the base of the triode U5, the other end of the resistor R11 is grounded, the emitter of the triode U5 is grounded, and the collector of the resistor R11 is connected with the control end of the switch module.
5. The fan control circuit with over-current and short-circuit protection function according to claim 4, characterized in that: the short-circuit protection circuit further comprises a short-circuit protection auxiliary circuit, the short-circuit protection auxiliary circuit comprises a resistor R3, a resistor R10 and a triode U3, one end of the resistor R3 is connected with a control signal, the other end of the resistor R3 is connected with one end of the resistor R10 and the base of the triode U3, the other end of the resistor R10 is grounded, the emitting electrode of the triode U3 is grounded, and the collector is connected with the cathode of the voltage regulator tube D3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020146240.3U CN211556842U (en) | 2020-01-22 | 2020-01-22 | Fan control circuit with overcurrent and short-circuit protection functions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020146240.3U CN211556842U (en) | 2020-01-22 | 2020-01-22 | Fan control circuit with overcurrent and short-circuit protection functions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211556842U true CN211556842U (en) | 2020-09-22 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020146240.3U Active CN211556842U (en) | 2020-01-22 | 2020-01-22 | Fan control circuit with overcurrent and short-circuit protection functions |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211556842U (en) |
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- 2020-01-22 CN CN202020146240.3U patent/CN211556842U/en active Active
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