Fault protection circuit for cooling fan and impedance matching device

Abstract

A fault protection circuit for cooling fans, characterized in that the fault protection circuit comprises an input circuit, a discrimination circuit, and a switch circuit connected in series; wherein the input circuit comprises at least one input diode, a positive electrode of each input diode being electrically connected to an alarm terminal of a cooling fan, and a negative electrode being electrically connected to the discrimination circuit; wherein the discrimination circuit comprises a second switching transistor and a voltage divider circuit; wherein the voltage divider circuit is connected to the input circuit and to the input terminal of the second switching transistor, respectively.wherein the switch circuit comprises a first switching transistor and a relay, wherein the input terminal of the first switching transistor is connected to the output terminal of the second switching transistor, wherein the input terminal of the relay is connected to the output terminal of the first switching transistor;

Description

Technical field

[0001] The utility model belongs to the technical field of fault protection circuits for cooling fans and specifically relates to a fault protection circuit for cooling fans and an impedance matching device. Technical background

[0002] An impedance matching device is a device used to adjust the impedance match between different parts of a circuit or system. It can improve system performance and efficiency by modifying the components or parameters in the circuit to adjust the impedance between the input and output terminals. The impedance matching device generates a lot of heat during operation. To ensure normal operation, a cooling fan is required for active heat dissipation. For example, if the cooling fan fails, a large amount of heat will build up in the corresponding devices, leading to device damage.

[0003] Therefore, the operating status of the cooling fan must be monitored. In the current technology, the cooling fan is equipped with a monitoring sensor. When the heat dissipation is blocked or in an abnormal state, the I / O port of the cooling fan alarm port will switch the level. For example, when the MCU detects a level change, it will take corresponding protective measures to ensure the safety of personnel and equipment. However, the anti-interference ability of the I / O port of the cooling fan alarm port is insufficient, and the hardware and software of the MCU are relatively complex, resulting in instability in monitoring cooling fan abnormalities, which can easily lead to failure or delay of protective measures, thus posing a risk to the safety of personnel and equipment. Content of the utility model

[0004] The technical problem to be solved by the utility model is to remedy the deficiency of the lack of stability of the fault monitoring device for cooling fans in the prior art and thereby to provide a fault protection circuit for cooling fans.

[0005] The present utility model discloses a fault protection circuit for cooling fans, comprising an input circuit, a discrimination circuit, and a switch circuit connected in series; wherein the input circuit includes at least one input diode, a positive electrode of each input diode being electrically connected to an alarm terminal of a cooling fan, and a negative electrode being electrically connected to the discrimination circuit; wherein the discrimination circuit includes a second switching transistor and a voltage divider circuit; wherein the voltage divider circuit is connected to the input circuit and to the input terminal of the second switching transistor, respectively;wherein the switch circuit comprises a first switching transistor and a relay, wherein the input terminal of the first switching transistor is connected to the output terminal of the second switching transistor, wherein the input terminal of the relay is connected to the output terminal of the first switching transistor;

[0006] In a further development, it is provided that the input circuit further comprises an input resistor, wherein the alarm terminal of each cooling fan is connected to one end of an input resistor, wherein the second end of the input resistor is connected to a DC power supply.

[0007] In a further development, it is provided that the voltage divider circuit of the differentiation circuit comprises a fifth resistor, a sixth resistor and a seventh resistor, wherein the second switching transistor is a triode; wherein a first end of the fifth resistor is connected to a DC power supply, wherein a second end is connected to a first end of a sixth resistor; wherein the second end of the sixth resistor is connected to the first end of the seventh resistor; wherein the second end of the seventh resistor is connected to ground; wherein the negative electrode of the input diode is connected to the first end of the seventh resistor; wherein the emitter of the second switching transistor is connected to the DC power supply, wherein the base is connected to the second end of the fifth resistor, wherein the collector serves as the output terminal of the second switching transistor.

[0008] In a further development, it is provided that the switch circuit comprises a first resistor, a fourth resistor and a first diode, wherein the first switching transistor is a triode; wherein a first end of the first resistor is connected to the output terminal of the second switching transistor, wherein a second end is connected to the base of the first switching transistor; wherein a first end of the fourth resistor is connected to the output terminal of the second switching transistor, wherein a second end is connected to the emitter of the first switching transistor; wherein the emitter of the first switching transistor is connected to ground, wherein the collector is connected to the positive electrode of the first diode, wherein the negative electrode of the first diode is connected to a DC power supply; wherein the input terminal of the relay is connected in parallel to the first diode.

[0009] In a further development, two input diodes are provided, each of which is connected to the alarm terminal of the respective one of the two cooling fans.

[0010] In a further development, it is provided that the alarm connection of the cooling fan and the positive electrode of the input diode are electrically connected to each other via a jumper cable.

[0011] In a further development, it is intended that the relay is a signal relay.

[0012] In a further development, it is provided that the first switching transistor is an NPN type triode.

[0013] In a further development, it is provided that the second switching transistor is a PNP-type triode.

[0014] In a further development, it is provided that the input diode is a switching diode.

[0015] An impedance matching device includes a cooling fan, the cooling fan being connected to the cooling fan fault protection circuit.

[0016] The positive effect is that the present utility model discloses a fault protection circuit for cooling fans, which comprises an input circuit, a discrimination circuit and a switch circuit connected in series, wherein the input circuit can receive the alarm terminal signal from at least one cooling fan via the input diode.According to the voltage division principle, when at least one cooling fan fails, the second switching transistor in the discrimination circuit is turned off, and the first switching transistor of the switch circuit is controlled to turn off and the relay is driven to turn off, thereby turning off the drive circuit or the action circuit of the impedance matching device, thereby ensuring the safety of personnel and equipment; the cooling fan fault protection circuit of the present application can simultaneously receive the alarm terminal signal from at least one cooling fan and directly drive the relay, the circuit is constructed with basic circuit components and does not include any MCU software and hardware module, which improves the working reliability of the protection circuit. Description of the characters

[0017] In order to more clearly explain the technical solutions of the embodiments of the present application or the prior art, the drawings necessary for the descriptions in the embodiments or the prior art are briefly described below. Obviously, the attached drawings in the following description are only some embodiments of the present application, and other drawings can be obtained from these drawings without creative effort by those of ordinary skill in the art. Fig. 1 is a schematic block diagram of the overall structure of the utility model; Fig. 2 is a schematic structural principle representation of the entire circuit of the utility model.

[0018] Key to reference symbols: K1. Relay; Q1. First switching transistor; Q2. Second switching transistor; D1. First diode; D2. Input diode; P1. First jumper wire; P2. Second jumper wire; R1. First resistor; R2. Second resistor; R3. Third resistor; R4. Fourth resistor; R5. Fifth resistor; R6. Sixth resistor; R7. Seventh resistor; VCC. DC power supply. Detailed description

[0019] To make the above purpose, features, and advantages of the present application more obvious and easier to understand, specific embodiments of the present application are described below in detail in conjunction with the accompanying drawings. In the following description, many specific details are set forth in order to fully understand the present application, but the present application may be implemented in many other ways other than those described herein, and one skilled in the art may make similar improvements without violating the connotation of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0020] In the description of the present application, it should be understood that the terms "first" and "second" are used in this application for descriptive purposes only and should not be understood to indicate or imply a relative importance or to implicitly specify the set of technical features specified. Thus, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present application, "plural" means at least two, such as two, three, or the like, unless specifically defined otherwise.

[0021] In the present application, it should also be noted that, unless otherwise specified and limited, the terms "installation", "attachment", "connection", "fastening" or similar terms should be understood broadly. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical or electrical connection; it may be a direct connection or an indirect connection via an intermediate medium; and it may be an internal communication between two elements or an interrelationship between two elements, unless clearly defined otherwise. One of ordinary skill in the art can understand the specific meanings of the above terms in the present application according to specific situations.

[0022] With reference to Fig. 1 and Fig.2, the present embodiment provides a fault protection circuit for cooling fans, comprising an input circuit 1, a discrimination circuit 2, and a switch circuit 3 connected in series; wherein the input circuit includes at least one input diode D2, a positive electrode of each input diode D2 being electrically connected to an alarm terminal of a cooling fan, and a negative electrode being electrically connected to the discrimination circuit; wherein the discrimination circuit includes a second switching transistor Q2 and a voltage divider circuit; wherein the voltage divider circuit is connected to the input circuit and to the input terminal of the second switching transistor Q2, respectively.wherein the switch circuit comprises a first switching transistor Q1 and a relay K1, wherein the input terminal of the first switching transistor Q1 is connected to the output terminal of the second switching transistor Q2, wherein the input terminal of the relay K1 is connected to the output terminal of the first switching transistor Q1;

[0023] The present embodiment discloses a fault protection circuit for cooling fans comprising an input circuit, a discrimination circuit and a switch circuit connected in series, wherein the input circuit can receive the alarm terminal signal from at least one cooling fan via the input diode D2.According to the voltage division principle, when at least one cooling fan fails, the second switching transistor Q2 in the discrimination circuit is turned off, and the first switching transistor Q1 of the switch circuit is controlled to turn off and the relay K1 is driven to turn off, thereby turning off the driver circuit or the action circuit of the impedance matching device, thereby ensuring the safety of personnel and equipment; the cooling fan fault protection circuit of the present application can simultaneously receive the alarm terminal signal of at least one cooling fan and directly drive the relay K1, and the circuit adopts the basic circuit element design and does not include the MCU software and hardware module, which improves the operation reliability of the protection circuit.

[0024] Specifically, the input circuit further includes an input resistor, and the alarm terminal of each cooling fan is connected to one end of an input resistor, the second end of the input resistor being connected to a DC power supply VCC. In the present embodiment, two input diodes D2 are provided, each connected to the alarm terminal IN1, IN2 of the respective one of the two cooling fans. The input diode D2 is a switching diode. In the present embodiment, the input resistor includes a second resistor R2 and a third resistor R3.

[0025] As a further improvement of the present embodiment, the alarm terminal of the cooling fan and the positive electrode of the input diode D2 are electrically connected via a jumper wire. Specifically, the jumper wire includes jumper pins at both ends and jumper caps connecting the jumper pins at both ends, allowing the jumper wire to be connected when the alarm terminal of a cooling fan needs to be monitored and flexibly disconnected when monitoring is not required. In the present embodiment, the jumper wire includes a first jumper wire P1 and a second jumper wire P2.

[0026] The voltage divider circuit of the discrimination circuit includes a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7, wherein the second switching transistor Q2 is a triode; a first end of the fifth resistor R5 is connected to the DC power supply VCC, while a second end thereof is connected to a first end of the sixth resistor R6; wherein the second end of the sixth resistor R6 is connected to the first end of the seventh resistor R7; a second end of the seventh resistor R7 is connected to ground; the negative electrode of the input diode D2 is connected to the first end of the seventh resistor R7; wherein the emitter of the second switching transistor Q2 is connected to the DC power supply VCC, the base is connected to the second end of the fifth resistor R5, the collector serving as an output terminal of the second switching transistor Q2.

[0027] Specifically, the second switching transistor Q2 is a PNP triode.

[0028] The switch circuit comprises a first resistor R1, a fourth resistor R4 and a first diode D1, wherein the first switching transistor Q1 is a triode; wherein a first end of the first resistor R1 is connected to the output terminal of the second switching transistor Q2, wherein a second end is connected to the base of the first switching transistor Q1; wherein a first end of the fourth resistor R4 is connected to the output terminal of the second switching transistor Q2, wherein a second end is connected to the emitter of the first switching transistor Q1; wherein the emitter of the first switching transistor Q1 is connected to ground and the collector is connected to the positive electrode of the first diode D1, wherein the negative electrode of the first diode D1 is connected to the DC power supply VCC; the input terminal of the relay K1 is connected in parallel to the first diode D1.

[0029] Specifically, the first switching transistor Q1 is an NPN triode; the relay K1 is a signal relay. Operating principle:

[0030] When the cooling fan is working normally, the alarm terminal of the cooling fan is at a low level, and at this time, no reverse current occurs to the negative electrode of the input diode D2. Therefore, according to the voltage division theorem, the Vbe voltage of the second switching transistor Q2 is lower than -0.7V, and the second switching transistor Q2 is turned on. At this time, the current flows through the second switching transistor Q2, causing Q1 to enter the saturation region, the current flows through the pickup coil of relay K1, and the output terminal of relay K1 is turned on, thereby driving the subsequent driving circuit or action circuit to work.In some embodiments of the utility model, when relay K1 is turned on, the cooling fan operates normally, the OUT1 terminal and the OUT2 terminal are connected and conductive, so that the action circuit connected at both ends functions, where the OUT1 terminal and the OUT2 terminal are used to connect to the client station and to alarm or indicate the working state of the cooling fan; when relay K1 is turned off, the cooling fan does not operate normally, where the OUT1 terminal and the OUT3 terminal are connected together, where the OUT3 terminal is an empty pin and the action circuit no longer functions. When one of the cooling fans is blocked, the level at the alarm terminal is pulled high and a forward current flows through the input diode D2.Due to the superposition theorem, the current at this node increases and the voltage increases, so the Vbe voltage of the second switching transistor Q2 is greater than -0.7 V, the second switching transistor Q2 is off, and at the same time the Vbe voltage of the first switching transistor Q1 is less than 0.7 V, the first switching transistor Q1 is off, and the relay K1 is off. The output terminal of the relay K1 is turned off, which turns off the subsequent driver circuit or action circuit, thus providing a protective function.

[0031] When both cooling fans are blocked, the levels at the alarm terminal of the cooling fans are pulled up and the total current flowing through the input diode D2 is larger, so the second switching transistor Q2 is turned off, making the circuit characteristics the same as if only one cooling fan were blocked.

[0032] In some other embodiments of the present utility model, it is provided that the input circuit comprises only one input diode D2 and is connected to an alarm terminal of a cooling fan.

[0033] In some other embodiments of the present invention, the input circuit includes more than two input diodes D2 and is connected to more than two cooling fan alarm terminals, at which time the parameters of the circuit components are adaptively adjusted. When a high level is input to at least one cooling fan alarm terminal, relay K1 is driven to turn off.

[0034] The present embodiment also discloses an impedance matching device including a cooling fan, wherein the cooling fan is connected to the cooling fan fault protection circuit, thereby effectively improving the reliability of heat dissipation of the impedance matching device during operation.

[0035] The technical features of the above-mentioned embodiments can be combined in any way. However, for the sake of simplicity, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope of this specification.

[0036] The above embodiments represent only some embodiments of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present application. It should be noted that several modifications and improvements can be made by those skilled in the art without departing from the concept of the present application, and all of these fall within the scope of the present application. Therefore, the scope of the present application should be determined by the appended claims.

Claims

[1] Fault protection circuit for cooling fan, characterized bythat the fault protection circuit comprises an input circuit, a discrimination circuit and a switch circuit connected in series; wherein the input circuit comprises at least one input diode, wherein a positive electrode of each input diode is electrically connected to an alarm terminal of a cooling fan and a negative electrode is electrically connected to the discrimination circuit; wherein the discrimination circuit comprises a second switching transistor and a voltage divider circuit; wherein the voltage divider circuit is connected respectively to the input circuit and to the input terminal of the second switching transistor; wherein the switch circuit comprises a first switching transistor and a relay, wherein the input terminal of the first switching transistor is connected to the output terminal of the second switching transistor, wherein the input terminal of the relay is connected to the output terminal of the first switching transistor. [2] Fault protection circuit for cooling fans according to claim 1, characterized by that the input circuit further comprises an input resistor, wherein the alarm terminal of each cooling fan is connected to one end of an input resistor, wherein the second end of the input resistor is connected to a DC power supply. [3] Fault protection circuit for cooling fans according to claim 1, characterized bythat the voltage divider circuit of the discrimination circuit comprises a fifth resistor, a sixth resistor and a seventh resistor, wherein the second switching transistor is a triode; wherein a first end of the fifth resistor is connected to a DC power supply, wherein a second end is connected to a first end of a sixth resistor; wherein the second end of the sixth resistor is connected to the first end of the seventh resistor; wherein the second end of the seventh resistor is connected to ground; wherein the negative electrode of the input diode is connected to the first end of the seventh resistor; wherein the emitter of the second switching transistor is connected to the DC power supply, wherein the base is connected to the second end of the fifth resistor, wherein the collector serves as an output terminal of the second switching transistor. [4] Fault protection circuit for cooling fans according to claim 1, characterized by that the switch circuit comprises a first resistor, a fourth resistor and a first diode, wherein the first switching transistor is a triode; wherein a first end of the first resistor is connected to the output terminal of the second switching transistor, wherein a second end is connected to the base of the first switching transistor; wherein a first end of the fourth resistor is connected to the output terminal of the second switching transistor, wherein a second end is connected to the emitter of the first switching transistor; wherein the emitter of the first switching transistor is connected to ground, wherein the collector is connected to the positive electrode of the first diode, wherein the negative electrode of the first diode is connected to a DC power supply; wherein the input terminal of the relay is connected in parallel with the first diode. [5] Fault protection circuit for cooling fans according to claim 1, characterized bythat two input diodes are provided, each connected to the alarm terminal of the respective one of the two cooling fans. [6] Fault protection circuit for cooling fans according to protection claim 1, characterized by that the alarm terminal of the cooling fan and the positive electrode of the input diode are electrically connected to each other via a jumper cable. [7] Fault protection circuit for cooling fans according to claim 1, characterized by that the relay is a signal relay. [8] Fault protection circuit for cooling fans according to claim 1, characterized by that the first switching transistor is an NPN triode. [9] Fault protection circuit for cooling fans according to claim 1, characterized by that the second switching transistor is a PNP triode. [10] Fault protection circuit for cooling fans according to claim 1, characterized by that the input diode is a switching diode. [11] Impedance matching device, characterized bythat the impedance matching device comprises a cooling fan, wherein the cooling fan is connected to the fault protection circuit for cooling fans according to one of claims 1 to 10.

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