Multi-fan stalling detection circuit

Abstract

The utility model discloses a multi-fan locked-rotor detection circuit. The multi-fan locked-rotor detection circuit comprises a control chip and at least two locked-rotor detection modules, the locked-rotor detection module comprises an acquisition port, a feedback port, a rectification unit, an electronic switch unit, a first feedback resistor and a second feedback resistor, the acquisition port is connected with the control end of the electronic switch unit through the rectification unit, and the output end of the electronic switch unit is grounded; the input end of the electronic switch unit is connected with the first end of the first feedback resistor and the first end of the second feedback resistor, the first end of the first feedback resistor is connected to a control power supply, and the second end of the second feedback resistor is connected with the feedback port; the feedback port of each locked-rotor detection module is connected with the same IO port of the control chip. According to the utility model, whether a plurality of direct-current fans are stalled or not can be detected through one IO port of the control chip, and the occupation of the IO port of the control chip is effectively reduced.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuits, and in particular to a multi-fan stall detection circuit. Background Technology

[0002] Currently, many devices incorporate DC fans for heat dissipation. Existing DC fan speed feedback uses a square wave signal with a 50% duty cycle. The control chip detects fan stall status by detecting a square wave signal of a certain frequency, indicating normal fan operation, and a persistent low level signal, indicating a stalled fan. This detection method requires the control chip to occupy one I / O port for each stall detection. As the number of DC fans increases, the number of I / O ports used by the control chip also increases, resulting in wasted control chip resources and increased cost.

[0003] In view of the above problems, it is necessary to study a multi-fan stall detection circuit, which can effectively reduce the occupation of the I / O ports of the control chip. Utility Model Content

[0004] The purpose of this invention is to provide a multi-fan stall detection circuit that can effectively reduce the occupation of the I / O ports of the control chip.

[0005] To achieve the above objectives, the solution of this utility model is:

[0006] A multi-fan stall detection circuit includes a control chip and at least two stall detection modules. Each stall detection module includes a data acquisition port, a feedback port, a rectifier unit, an electronic switch unit, a first feedback resistor, and a second feedback resistor. The data acquisition port is used to receive the speed signal output by the DC fan. The input terminal of the rectifier unit is connected to the data acquisition port, and the output terminal of the rectifier unit is connected to the control terminal of the electronic switch unit. The output terminal of the electronic switch unit is grounded. The input terminal of the electronic switch unit is connected to the first terminal of the first feedback resistor and the first terminal of the second feedback resistor. The first terminal of the first feedback resistor is connected to a control power supply, and the second terminal of the second feedback resistor is connected to the feedback port. The feedback ports of each stall detection module are connected to the same I / O port of the control chip. The resistance values ​​of the first feedback resistors and / or the resistance values ​​of the second feedback resistors of each stall detection module are not identical.

[0007] The rectifier unit includes a rectifier diode, a rectifier capacitor, and a rectifier resistor. The positive terminal of the rectifier diode is connected to the input terminal of the rectifier unit, the negative terminal of the rectifier diode, the first terminal of the rectifier capacitor, and the first terminal of the rectifier resistor are connected to the output terminal of the rectifier unit, and the second terminal of the rectifier capacitor and the second terminal of the rectifier resistor are grounded.

[0008] The output terminal of the rectifier unit is connected to the control terminal of the electronic switch unit through a protection resistor.

[0009] The electronic switching unit includes a transistor, the collector, emitter, and base of which are respectively connected to the input, output, and control terminals of the electronic switching unit.

[0010] After adopting the above scheme, the working principle of this utility model is as follows: For each stall detection module, when the DC fan connected to the acquisition port of the stall detection module is normal (i.e., the speed signal output by the DC fan is a square wave signal), the speed signal output by the DC fan is rectified by the rectifier unit of the stall detection module and controls the electronic switch unit to turn on; when the DC fan connected to the acquisition port of the stall detection module is stalled (i.e., the speed signal output by the DC fan is a continuous low-level signal), the speed signal output by the DC fan controls the electronic switch unit to turn off; as mentioned above, the on / off state of the electronic switch unit of each stall detection module depends on whether the DC fan connected to each stall detection module is stalled; and because each stall detection module... The resistance values ​​of the first feedback resistors in the stall detection modules are not all the same, and / or the resistance values ​​of the second feedback resistors in each stall detection module are not all the same. Thus, the switching on and off of the electronic switching units of each stall detection module will cause a corresponding change in the voltage of the I / O port of the control chip, which is connected to the feedback ports of each stall detection module. This means that whether the DC fan connected to each stall detection module is stalled will correspondingly control the voltage change of the I / O port of the control chip. In this way, the control chip can detect whether the DC fan connected to each stall detection module is stalled by detecting the voltage of this I / O port, thereby realizing the detection of whether multiple DC fans are stalled through one I / O port of the control chip, effectively reducing the occupation of the control chip's I / O ports. Attached Figure Description

[0011] Figure 1 This is a circuit diagram of the present invention.

[0012] Label Explanation:

[0013] Control chip U1,

[0014] Stall detection module 1;

[0015] Rectifier unit 11, electronic switch unit 12, acquisition port Vin, feedback port Vout, rectifier diode D1, rectifier capacitor C1, rectifier resistor R1, protection resistor R2, first feedback resistor R3, second feedback resistor R4, transistor Q1.

[0016] Control power supply Vcc. Detailed Implementation

[0017] To further explain the technical solution of this utility model, the following detailed description is provided through specific embodiments.

[0018] like Figure 1 As shown, this utility model discloses a multi-fan stall detection circuit, which includes a control chip U1 and at least two stall detection modules 1. Each stall detection module 1 includes a data acquisition port Vin, a feedback port Vout, a rectifier unit 11, an electronic switch unit 12, a first feedback resistor R3, and a second feedback resistor R4. The data acquisition port Vin is used to receive the speed signal output by the DC fan. The input terminal of the rectifier unit 11 is connected to the data acquisition port Vin, and the output terminal of the rectifier unit 11 is connected to the control terminal of the electronic switch unit 12. The output terminal of the electronic switch unit 12 is grounded, and the input terminal of the electronic switch unit 12 is connected to the first terminal of the first feedback resistor R3 and the first terminal of the second feedback resistor R4. The first terminal of the first feedback resistor R3 is connected to the control power supply Vcc, and the second terminal of the second feedback resistor R4 is connected to the feedback port Vout. The feedback ports Vout of each stall detection module 1 are connected to the same I / O port of the control chip U1. The resistance values ​​of the first feedback resistor R3 and / or the resistance values ​​of the second feedback resistor R4 of each stall detection module 1 are not identical.

[0019] In an embodiment of this utility model, the rectifier unit 11 includes a rectifier diode D1, a rectifier capacitor C1, and a rectifier resistor R1. The positive terminal of the rectifier diode D1 is connected to the input terminal of the rectifier unit 11, and the negative terminal of the rectifier diode D1, the first terminal of the rectifier capacitor C1, and the first terminal of the rectifier resistor R1 are connected to the output terminal of the rectifier unit 11. The second terminal of the rectifier capacitor C1 and the second terminal of the rectifier resistor R1 are grounded.

[0020] In an embodiment of this utility model, the output terminal of the rectifier unit 11 is connected to the control terminal of the electronic switch unit 12 through a protection resistor R2, and the protection resistor R2 can play a current limiting protection role.

[0021] In an embodiment of this utility model, the electronic switch unit 12 includes a transistor Q1, the collector, emitter and base of which are respectively connected to the input terminal, output terminal and control terminal of the electronic switch unit 12.

[0022] The working principle of this utility model is as follows: For each stall detection module 1, when the DC fan connected to the acquisition port Vin of the stall detection module 1 is normal (i.e., the speed signal output by the DC fan is a square wave signal), the speed signal output by the DC fan is rectified by the rectifier unit 11 of the stall detection module 1 and controls the electronic switch unit 12 to be turned on; when the DC fan connected to the acquisition port Vin of the stall detection module 1 is stalled (i.e., the speed signal output by the DC fan is a continuous low-level signal), the speed signal output by the DC fan controls the electronic switch unit 12 to be turned off; as mentioned above, the on / off state of the electronic switch unit 12 of each stall detection module 1 depends on whether the DC fan connected to each stall detection module 1 is stalled; and because each stall detection module 1... The resistance values ​​of the first feedback resistor R3 and / or the second feedback resistor R4 of each stall detection module 1 are not all the same. Thus, the switching on and off of the electronic switch unit 12 of each stall detection module 1 will cause a corresponding change in the voltage of the control chip U1 IO port, which is connected to the feedback port Vout of each stall detection module 1. This means that whether the DC fan connected to each stall detection module 1 is stalled will correspondingly control the voltage of the IO port of the control chip U1 to change. In this way, the control chip U1 can obtain whether the DC fan connected to each stall detection module 1 is stalled by detecting the voltage of the IO port. This realizes the detection of whether multiple DC fans are stalled through one IO port of the control chip U1, effectively reducing the occupation of the IO port of the control chip U1.

[0023] To facilitate understanding of the working principle of this utility model, in conjunction with Figure 1 As shown, the following explanation uses three stall detection modules 1 as an example; wherein, the resistance values ​​of the first feedback resistor R3 and the second feedback resistor R4 of the first stall detection module 1 are R31 and R41 respectively, the resistance values ​​of the first feedback resistor R3 and the second feedback resistor R4 of the second stall detection module 1 are R32 and R42 respectively, and the resistance values ​​of the first feedback resistor R3 and the second feedback resistor R4 of the third stall detection module 1 are R33 and R43 respectively, and the voltage of the control power supply Vcc is VCC. The working principle of this utility model is as follows:

[0024] When the DC fans connected to the three stall detection modules 1 are working normally, the electronic switching units 12 of the three stall detection modules 1 are all saturated and conducting. Therefore, the voltage drop between the input and output terminals of the electronic switching units 12 of the three stall detection modules 1 is the same (both are Vce, where Vce is actually the collector voltage of transistor Q1 when it is conducting). At this time, the voltage Vo of the I / O port of the control chip U1 connected to the three stall detection modules 1 is:

[0025] ...Equation (1)

[0026] When the DC fan connected to the first stall detection module 1 is stalled, and the DC fans connected to the second and third stall detection modules 1 are operating normally, the electronic switch unit 12 of the first stall detection module 1 is turned off, while the electronic switch units 12 of the second and third stall detection modules 1 are saturated and turned on. At this time, the voltage Vo of the IO port of the control chip U1 connected to the three stall detection modules 1 is:

[0027] ...Equation (2)

[0028] Similarly, for the two cases of "the DC fan connected to the second stall detection module 1 is stalled, the DC fan connected to the first stall detection module 1 and the DC fan connected to the third stall detection module 1 are working normally" and "the DC fan connected to the third stall detection module 1 is stalled, the DC fan connected to the first stall detection module 1 and the DC fan connected to the second stall detection module 1 are working normally", the parameters of equation (2) can be transformed accordingly, which will not be elaborated here.

[0029] When the DC fan connected to the first stall detection module 1 and the DC fan connected to the second stall detection module 1 are stalled, and the DC fan connected to the third stall detection module 1 is operating normally, the electronic switch unit 12 of the first stall detection module 1 and the second stall detection module 1 is turned off, and the electronic switch unit 12 of the third stall detection module 1 is saturated and turned on. At this time, the voltage Vo of the IO port of the control chip U1 connected to the three stall detection modules 1 is:

[0030] ...Equation (3)

[0031] Similarly, for the two cases of "the DC fan connected to the first stall detection module 1 and the DC fan connected to the third stall detection module 1 are stalled, and the DC fan connected to the second stall detection module 1 is working normally", and "the DC fan connected to the second stall detection module 1 and the DC fan connected to the third stall detection module 1 are stalled, and the DC fan connected to the first stall detection module 1 is working normally", the parameters of equation (2) can be transformed accordingly, which will not be elaborated here.

[0032] When all the DC fans connected to the three stall detection modules 1 are stalled, the electronic switch units 12 of the three stall detection modules 1 are all turned off. At this time, the voltage Vo of the IO port of the control chip U1 connected to the three stall detection modules 1 is:

[0033] ...Equation (4)

[0034] Based on the above, by setting the resistance values ​​of the first feedback resistor R3 and the second feedback resistor R4 of each stall detection module, the voltage Vo of the IO port of the control chip U1 can be different when different DC fans are stalled. By setting different judgment logic for the control chip U1, the stall status of different DC fans can be accurately detected.

[0035] The above embodiments and figures are not intended to limit the product form and style of this utility model. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of this utility model.

Claims

1. A multi-fan stall detection circuit, characterized in that: Includes a control chip and at least two stall detection modules; The stall detection module includes a data acquisition port, a feedback port, a rectifier unit, an electronic switch unit, a first feedback resistor, and a second feedback resistor. The data acquisition port is used to receive the speed signal output by the DC fan. The input terminal of the rectifier unit is connected to the data acquisition port, the output terminal of the rectifier unit is connected to the control terminal of the electronic switch unit, the output terminal of the electronic switch unit is grounded, the input terminal of the electronic switch unit is connected to the first terminal of the first feedback resistor and the first terminal of the second feedback resistor, the first terminal of the first feedback resistor is connected to the control power supply, and the second terminal of the second feedback resistor is connected to the feedback port. The feedback ports of each stall detection module are connected to the same I / O port of the control chip. The resistance values ​​of the first feedback resistors of each stall detection module are not the same and / or the resistance values ​​of the second feedback resistors of each stall detection module are not the same.

2. The multi-fan stall detection circuit as described in claim 1, characterized in that: The rectifier unit includes a rectifier diode, a rectifier capacitor, and a rectifier resistor. The positive terminal of the rectifier diode is connected to the input terminal of the rectifier unit, the negative terminal of the rectifier diode, the first terminal of the rectifier capacitor, and the first terminal of the rectifier resistor are connected to the output terminal of the rectifier unit, and the second terminal of the rectifier capacitor and the second terminal of the rectifier resistor are grounded.

3. The multi-fan stall detection circuit as described in claim 1 or 2, characterized in that: The output terminal of the rectifier unit is connected to the control terminal of the electronic switch unit through a protection resistor.

4. The multi-fan stall detection circuit as described in claim 1, characterized in that: The electronic switching unit includes a transistor, the collector, emitter, and base of which are respectively connected to the input, output, and control terminals of the electronic switching unit.

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