Switching value detection circuit and device

Abstract

The utility model discloses a switching value detection circuit and device, and the circuit comprises a third-order filter circuit, the input end of the third-order filter circuit is used for being connected with the output pin of an external switching value interface, the first grounding end of the third-order filter circuit is connected with the grounding pin of the switching value interface, and the second grounding end of the third-order filter circuit is connected with the grounding pin of the switching value interface. The second grounding end of the third-order filter circuit is grounded; the first-order filter circuit is connected in parallel between the first grounding end of the third-order filter circuit and the second grounding end of the third-order filter circuit and is used for being combined with the third-order filter circuit and performing double third-order filter processing on the switching signal output by the switching value interface; the input end of the signal conversion circuit is connected with the output end of the third-order filter circuit, and the signal conversion circuit is used for outputting a state detection signal of a corresponding level according to the switching signal; the technical scheme of the utility model aims to realize suppression of voltage surge caused by switching pulse and power supply disturbance with low cost during switching value detection.

Description

Technical Field

[0001] The utility model relates to the technical field of household appliances, in particular to a switch quantity detection circuit and a device. Background Art

[0002] At present, since the electronic control products of multi-split units are easy to affect each other, their electromagnetic compatibility is worse than that of unit units. Therefore, when performing switch quantity detection on them, the difficulty of EMC (Electromagnetic Compatibility) rectification of the detection circuit used is much greater than that of unit units. It is necessary to effectively design and adjust the detection circuit to reduce the manpower cost and time consumption of EMC rectification. Utility Model Content

[0003] The main purpose of the utility model is to provide a switch quantity detection circuit and device, aiming to suppress the voltage surge caused by the switch pulse and the power supply disturbance at a low cost during the switch quantity detection.

[0004] To achieve the above-mentioned purpose, the present utility model provides a switch value detection circuit. In some embodiments, the switch value detection circuit includes:

[0005] A third-order filter circuit, wherein the input end of the third-order filter circuit is used to be connected to the output pin of the external switch quantity interface, the first ground end of the third-order filter circuit is connected to the ground pin of the switch quantity interface, and the second ground end of the third-order filter circuit is grounded;

[0006] A first-order filter circuit is connected in parallel between the first ground terminal of the third-order filter circuit and the second ground terminal of the third-order filter circuit, and is used for combining with the third-order filter circuit to perform double third-order filtering processing on the switch signal output by the switch quantity interface;

[0007] A signal conversion circuit, wherein the input end of the signal conversion circuit is connected to the output end of the third-order filtering circuit, and is used to output a state detection signal of a corresponding level according to the switch signal.

[0008] In some embodiments, the third-order filtering circuit includes:

[0009] A π-type filter circuit, wherein the input end of the π-type filter circuit is used to be connected to the output pin of the switch quantity interface, the first ground end of the π-type filter circuit is connected to the ground pin of the switch quantity interface, and the second ground end of the π-type filter circuit is grounded; the π-type filter circuit is used to be combined with the first-order filter circuit to perform double third-order filtering on the switch signal.

[0010] In some embodiments, the π-type filter circuit includes:

[0011] A first inductor, wherein a first end of the first inductor is an input end of the π-type filter circuit, and a second end of the first inductor is an output end of the π-type filter circuit;

[0012] A first capacitor is connected in series between the first end of the first inductor and the ground;

[0013] The second capacitor is connected in series between the second end of the first inductor and the ground.

[0014] In some embodiments, the first-order filtering circuit comprises:

[0015] The second inductor is connected in parallel between the first ground terminal of the third-order filter circuit and the second ground terminal of the third-order filter circuit.

[0016] In some embodiments, the signal conversion circuit includes:

[0017] A switch tube, wherein the input end of the switch tube is used to connect to the first power supply, and the output end of the switch tube is the output end of the signal conversion circuit;

[0018] a first resistor, wherein a first end of the first resistor is used to connect to the first power supply;

[0019] The second resistor is connected in series between the second end of the first resistor and the controlled end of the switch tube.

[0020] In some embodiments, the signal conversion circuit further includes:

[0021] The third capacitor is connected in series between the controlled end of the switch tube and the ground.

[0022] In some embodiments, the switch value detection circuit further includes:

[0023] An isolation circuit, wherein the input end of the isolation circuit is connected to the output end of the signal conversion circuit, and is used for isolating the connected state detection signal and then outputting the signal.

[0024] In some embodiments, the isolation circuit comprises:

[0025] An optical coupler, wherein a first end of the light-emitting side of the optical coupler is connected to an output end of the signal conversion circuit, and a second end of the light-emitting side of the optical coupler and a second end of the receiving side of the optical coupler are grounded respectively;

[0026] A third resistor, wherein a first end of the third resistor is used to be connected to a second power supply, and a second end of the third resistor is connected to a first end of a receiving side of the optical coupler.

[0027] In some embodiments, the isolation circuit further comprises:

[0028] A first current limiting circuit is connected in series between the input end of the isolation circuit and the output end of the signal conversion circuit, and is used to limit the current of the level signal output by the signal conversion circuit;

[0029] A second current limiting circuit, wherein the input end of the second current limiting circuit is connected to the output end of the isolation circuit, and the output end of the second current limiting circuit is used to be connected to an external control chip for current limiting the isolated level signal.

[0030] The utility model also proposes a switch quantity detection device, comprising a control chip and the above-mentioned switch quantity detection circuit, wherein the control chip is connected to the output end of the switch quantity detection circuit to output corresponding detection result information according to the connected state detection signal.

[0031] The technical solution of the utility model connects a first-order filtering circuit in parallel between the two ground terminals of a third-order filtering circuit, so that the first-order filtering circuit and the third-order filtering circuit form an interactive filtering network, and realizes double the third-order filtering function through a small number of device connections. At the same time, the application also provides a signal conversion circuit to convert the switching signal output by the electrical device into a certain high and low level for representation, so as to avoid the switching signal being in an uncertain state that cannot be detected due to interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0033] Figure 1 This is a structural schematic diagram of an embodiment of a switch quantity detection circuit of the utility model;

[0034] Figure 2 It is a structural schematic diagram of another embodiment of the switch quantity detection circuit of the utility model;

[0035] Figure 3 This is a structural schematic diagram of another embodiment of the switch quantity detection circuit of the utility model;

[0036] Figure 4 This is a structural schematic diagram of an embodiment of a switch quantity detection device of the utility model;

[0037] Figure 5 This is a circuit connection diagram of an embodiment of a switch quantity detection circuit of the utility model.

[0038] Description of Figure Numbers:

[0039]

[0040]

[0041] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0043] In addition, in the present utility model, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0044] The utility model provides a switch quantity detection circuit.

[0045] Reference Figure 1 In one embodiment, the switch value detection circuit includes:

[0046] A third-order filter circuit 110, wherein the input end of the third-order filter circuit 110 is used to be connected to the output pin of the external switch interface, the first ground end of the third-order filter circuit 110 is connected to the ground pin of the switch interface, and the second ground end of the third-order filter circuit 110 is grounded;

[0047] The first-order filter circuit 120 is connected in parallel between the first ground terminal of the third-order filter circuit 110 and the second ground terminal of the third-order filter circuit 110, and is used for combining with the third-order filter circuit 110 to perform double third-order filtering processing on the switch signal output by the switch quantity interface;

[0048] The signal conversion circuit 130 has an input end connected to the output end of the third-order filter circuit 110 and is used to output a state detection signal of a corresponding level according to the switch signal.

[0049] It should be noted that multi-split devices such as central air-conditioning systems have worse electromagnetic compatibility than single air conditioners because devices affect each other. When performing switch quantity tests on multi-split electrical products, the testing process is more likely to be disturbed by surges.

[0050] Therefore, in this embodiment, a third-order filter circuit 110 and a first-order filter circuit 120 are provided on the input side of the switch detection circuit. By connecting the first-order filter circuit 120 in parallel between the two ground terminals of the third-order filter circuit 110, the first-order filter circuit 120 and the third-order filter circuit 110 form an interactive filter network. By connecting a small number of devices, double the third-order filtering function is achieved.

[0051] Specifically, when performing switch quantity detection on electrical equipment such as central air conditioners, the electrical equipment is connected to the switch quantity detection circuit, and the output pin and the ground pin of the switch quantity output interface are respectively connected to the filtering network composed of the first-order filtering circuit 120 and the third-order filtering circuit 110. After the connection is completed, the user controls the switch state in the electrical equipment so that the switch quantity output interface outputs the corresponding switch signal. If the switch signal carries electromagnetic interference, the surge impacts the detection circuit. At this time, the third-order filtering circuit 110 will perform a third-order filtering on the surge. At the same time, the first-order filtering circuit 120 will combine the two ground terminals of the filtering circuit to form another circuit with a third-order filtering function, and perform another third-order filtering on the surge, so as to output a stable switch signal to the signal conversion circuit 130, and control the signal conversion circuit 130 to output the corresponding stable level as a state detection signal.

[0052] For example, when the switch of the electrical device is closed, the switch signal is at a first level to indicate that the switch is closed. Then, after receiving the first level, the signal conversion circuit 130 outputs a corresponding high-level state detection signal. When the switch of the electrical device is disconnected, the switch signal has no level output to indicate that the switch is disconnected. Then, when the signal conversion circuit 130 does not receive the first level, it outputs a corresponding low-level state detection signal to indicate that the switch signal output by the electrical device is in a determined high and low level, so as to avoid the switch signal being in an uncertain state that cannot be detected due to interference.

[0053] The technical solution of the utility model connects the first-order filter circuit 120 in parallel between the two ground terminals of the third-order filter circuit 110, so that the first-order filter circuit 120 and the third-order filter circuit 110 form an interactive filter network, and realizes double third-order filtering function through a small number of device connections to suppress voltage surges caused by switching pulses and power supply disturbances. At the same time, the application also provides a signal conversion circuit 130 to convert the switching signal output by the electrical device into a certain high and low level for representation, so as to avoid the switching signal being in an undetectable uncertain state due to interference.

[0054] Reference Figure 1 and Figure 5 In one embodiment, the third-order filter circuit 110 includes:

[0055] A π-type filter circuit 111, wherein the input end of the π-type filter circuit 111 is used to be connected to the output pin of the switch quantity interface, the first ground end of the π-type filter circuit 111 is connected to the ground pin of the switch quantity interface, and the second ground end of the π-type filter circuit 111 is grounded; the π-type filter circuit 111 is used to be combined with the first-order filter circuit 120 to perform double third-order filtering on the switch signal.

[0056] In this embodiment, the π-type filter circuit 111 is usually composed of two filter branches connected in series between the two ends of a type-one filter circuit and the ground. Thus, when the π-type filter circuit 111 is connected to the first-order filter circuit 120, the first-order filter circuit 120 can share the above two filter branches with the π-type filter circuit 111 to form a filter network with a double third-order filtering function.

[0057] Specifically, the π-type filter circuit 111 includes:

[0058] A first inductor L1, wherein a first end of the first inductor L1 is an input end of the π-type filter circuit 111, and a second end of the first inductor L1 is an output end of the π-type filter circuit 111;

[0059] A first capacitor C1, connected in series between a first end of the first inductor L1 and ground;

[0060] The second capacitor C2 is connected in series between the second end of the first inductor L1 and the ground.

[0061] The first-order filtering circuit 120 includes:

[0062] The second inductor L2 is connected in parallel between the first ground terminal of the third-order filter circuit 110 and the second ground terminal of the third-order filter circuit 110 .

[0063] In this embodiment, the first inductor L1, the first capacitor C1 and the second capacitor C2 implement the third-order filtering of the first part of the filtering network, and the second inductor L2, the first capacitor C1 and the second capacitor C2 implement the third-order filtering of the second part of the filtering network. By sharing the first capacitor C1 and the second capacitor C2, efficient suppression of input surges is achieved with a lower cost and a simpler circuit.

[0064] Reference Figure 1 and Figure 5 In one embodiment, the signal conversion circuit 130 includes:

[0065] A switch tube Q1, wherein the input end of the switch tube Q1 is used to connect to the first power supply, and the output end of the switch tube Q1 is the output end of the signal conversion circuit 130;

[0066] A first resistor R1, wherein a first end of the first resistor R1 is used to connect to the first power supply;

[0067] The second resistor R2 is connected in series between the second end of the first resistor R1 and the controlled end of the switch tube Q1.

[0068] In this embodiment, the switch tube Q1 is turned on at a low level, and the first level is a low level. For example, the first resistor R1 is a pull-up resistor of the controlled end of the switch tube Q1. When the switch signal is at the first level, the controlled end of the switch tube Q1 is in a clear high level state. The second resistor R2 is a current-limiting resistor of the controlled end of the switch tube Q1. When the switch signal is at the first level, the loop current of the controlled end of the switch tube Q1 is not too large.

[0069] When the switch of the electrical device is closed and the switch signal is at a low level, the switch tube Q1 is turned on because the controlled end is pulled low, and the connected first power supply is output as a high level. When the switch of the electrical device is turned off and the switch signal is not at a low level, the first resistor R1 pulls up the controlled end of the switch tube Q1 to a clear high level state, and the switch tube Q1 is turned off to stop outputting the first power supply. At this time, the output end of the switch tube Q1 is at a low level, so that the switch signal output by the electrical device is represented by a determined high and low level.

[0070] Furthermore, the signal conversion circuit 130 further includes:

[0071] The third capacitor C3 is connected in series between the controlled end of the switch tube Q1 and the ground, and is used for stabilizing the voltage of the controlled end of the switch tube Q1 to avoid instability of the signal connected to the controlled end.

[0072] Reference Figure 2 In one embodiment, the switch value detection circuit further includes:

[0073] The isolation circuit 140 has an input end connected to the output end of the signal conversion circuit 130 and is used for isolating the state detection signal received and then outputting the signal.

[0074] In this embodiment, after the switch quantity detection circuit is connected to the electrical device to be tested, it is necessary to output the output status detection signal to the control chip at the back end for result detection. Since the electrical device is usually a strong current device powered by a three-phase power supply, it is easy to cause electrical interference to the weak current devices at the back end of the switch quantity detection circuit. Therefore, in order to realize that the detection front end of the switch quantity detection circuit and the output back end do not share a common power supply or ground, and once again prevent the voltage surge caused by such switching pulses and power supply disturbances from damaging the electronic products, the utility model provides an isolation circuit 140 at the output end of the signal conversion circuit 130 to electrically isolate the detection front end of the switch quantity detection circuit from the output back end.

[0075] Reference Figure 2 and Figure 5 In one embodiment, the isolation circuit 140 includes:

[0076] An optical coupler U1, wherein a first end of the light-emitting side of the optical coupler U1 is connected to an output end of the signal conversion circuit 130, and a second end of the light-emitting side of the optical coupler U1 and a second end of the receiving side of the optical coupler U1 are grounded respectively;

[0077] A third resistor R3, wherein a first end of the third resistor R3 is used to be connected to a second power supply, and a second end of the third resistor R3 is connected to a first end of a receiving side of the optical coupler U1.

[0078] In this embodiment, the optical coupler U1 is used for photoelectric isolation, and the third resistor R3 is a pull-up resistor, which pulls up the pin level of the back-end control chip to a high level when the optical coupler U1 is not conducting.

[0079] When the user closes the switch inside the electrical device to be tested, so that the switch tube Q1 of the signal conversion circuit 130 is connected to the first level, the controlled end of the switch tube Q1 is connected to the first level and turned on, and current flows through the light-emitting side of the optocoupler U1, so that the receiving side is turned on after being exposed to light, and the pin of the control chip at the back end is grounded. At this time, the state detection signal corresponding to the low level represents the closed state of the switch quantity. When the user disconnects the switch inside the electrical device to be tested; when the user turns off the switch inside the electrical device to be tested, so that the switch tube Q1 of the signal conversion circuit 130 is pulled up to a high level, the switch tube Q1 is turned off, so that no current passes through the light-emitting side of the optocoupler U1, so that the receiving side does not receive light and is turned off, and the third resistor R3 pulls up the pin of the control chip at the back end to a high level. At this time, the state detection signal corresponding to the high level represents the disconnected state of the switch quantity.

[0080] Reference Figure 3 and Figure 5 In one embodiment, the isolation circuit 140 further includes:

[0081] A first current limiting circuit 150 is connected in series between the input end of the isolation circuit 140 and the output end of the signal conversion circuit 130, and is used to limit the current of the level signal output by the signal conversion circuit 130;

[0082] The second current limiting circuit 160 has an input end connected to the output end of the isolation circuit 140 , and an output end of the second current limiting circuit 160 is used to connect to an external control chip for current limiting the isolated level signal.

[0083] In this embodiment, the first current limiting circuit 150 includes a fourth resistor R4, and the second current limiting circuit 160 includes a fifth resistor R5. The fourth resistor R4 is a current limiting resistor. The corresponding specifications of this resistor are selected according to actual requirements, and are used to protect the LED lamp inside the optocoupler U1 from being damaged by current shock. The fifth resistor R5 is used to perform current limiting protection on the chip pins of the control chip connected to the back end.

[0084] Reference Figure 4 In one embodiment, the utility model further proposes a switch quantity detection device, including a control chip 200 and the above-mentioned switch quantity detection circuit 100, wherein the control chip 200 is connected to the output end of the switch quantity detection circuit 100 to output corresponding detection result information according to the connected state detection signal.

[0085] In this embodiment, the control chip 200 can be connected to the controlled end of the internal switch of the electrical device under test, so that after outputting the corresponding state control signal, it detects whether the corresponding state detection signal can be received through the switch quantity detection circuit 100. At this time, the detection result information is whether the switch quantity of the electrical device under test is qualified. It can also be the subsequent connection of the corresponding interactive components, such as display screens, LEDs, etc. After the user controls the internal switch action of the electrical device, according to the received state detection signal, the subsequent interactive components are controlled to output the corresponding detection result information. At this time, the detection result information is the switch state of the electrical device detected by the switch quantity detection circuit 100, so that the user can intuitively understand the current state detection result.

[0086] The above description is only an optional embodiment of the utility model, and does not limit the patent scope of the utility model. All equivalent structural changes made by using the contents of the utility model specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the utility model.

Claims

1. A switch quantity detection circuit, characterized in that: include: A third-order filter circuit, wherein the input end of the third-order filter circuit is used to be connected to the output pin of the external switch quantity interface, the first ground end of the third-order filter circuit is connected to the ground pin of the switch quantity interface, and the second ground end of the third-order filter circuit is grounded; A first-order filter circuit is connected in parallel between the first ground terminal of the third-order filter circuit and the second ground terminal of the third-order filter circuit, and is used for combining with the third-order filter circuit to perform double third-order filtering processing on the switch signal output by the switch quantity interface; A signal conversion circuit, wherein the input end of the signal conversion circuit is connected to the output end of the third-order filtering circuit, and is used to output a state detection signal of a corresponding level according to the switch signal.

2. The switch quantity detection circuit according to claim 1, characterized in that: The third-order filtering circuit comprises: A π-type filter circuit, wherein the input end of the π-type filter circuit is used to be connected to the output pin of the switch quantity interface, the first ground end of the π-type filter circuit is connected to the ground pin of the switch quantity interface, and the second ground end of the π-type filter circuit is grounded; the π-type filter circuit is used to be combined with the first-order filter circuit to perform double third-order filtering on the switch signal.

3. The switch quantity detection circuit according to claim 2, characterized in that: The π-type filter circuit comprises: A first inductor, wherein a first end of the first inductor is an input end of the π-type filter circuit, and a second end of the first inductor is an output end of the π-type filter circuit; A first capacitor is connected in series between the first end of the first inductor and the ground; The second capacitor is connected in series between the second end of the first inductor and the ground.

4. The switch quantity detection circuit according to claim 1, characterized in that: The first-order filtering circuit comprises: The second inductor is connected in parallel between the first ground terminal of the third-order filter circuit and the second ground terminal of the third-order filter circuit.

5. The switch quantity detection circuit according to claim 1, characterized in that: The signal conversion circuit comprises: A switch tube, wherein the input end of the switch tube is used to connect to the first power supply, and the output end of the switch tube is the output end of the signal conversion circuit; a first resistor, wherein a first end of the first resistor is used to connect to the first power supply; The second resistor is connected in series between the second end of the first resistor and the controlled end of the switch tube.

6. The switch quantity detection circuit according to claim 5, characterized in that: The signal conversion circuit also includes: The third capacitor is connected in series between the controlled end of the switch tube and the ground.

7. The switch quantity detection circuit according to claim 1, characterized in that: The switch quantity detection circuit also includes: An isolation circuit, wherein the input end of the isolation circuit is connected to the output end of the signal conversion circuit, and is used for isolating the connected state detection signal and then outputting the signal.

8. The switch quantity detection circuit according to claim 7, characterized in that: The isolation circuit comprises: An optical coupler, wherein a first end of the light-emitting side of the optical coupler is connected to an output end of the signal conversion circuit, and a second end of the light-emitting side of the optical coupler and a second end of the receiving side of the optical coupler are grounded respectively; A third resistor, wherein a first end of the third resistor is used to be connected to a second power supply, and a second end of the third resistor is connected to a first end of a receiving side of the optical coupler.

9. The switch quantity detection circuit according to claim 7, characterized in that: The isolation circuit further comprises: A first current limiting circuit is connected in series between the input end of the isolation circuit and the output end of the signal conversion circuit, and is used to limit the current of the level signal output by the signal conversion circuit; A second current limiting circuit, wherein the input end of the second current limiting circuit is connected to the output end of the isolation circuit, and the output end of the second current limiting circuit is used to be connected to an external control chip for current limiting the isolated level signal.

10. A switch quantity detection device, characterized in that: It comprises a control chip and a switch quantity detection circuit as described in any one of claims 1 to 9, wherein the control chip is connected to the output end of the switch quantity detection circuit to output corresponding detection result information according to the connected state detection signal.

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