Control circuit, circuit board of magnetic latching relay and air conditioner

Abstract

The application discloses a control circuit of a magnetic latching relay, a circuit board and an air conditioner. The control circuit of the magnetic latching relay comprises a DC power supply end, a first capacitor, a voltage sampling module and a power-off reset control module. The positive pole of the first capacitor is connected with the DC power supply end and the magnetic latching relay, and the negative pole is grounded. The voltage sampling module is connected with the DC power supply end. The input end of the power-off reset control module is connected with the output end of the voltage sampling module, and the output end is connected with the magnetic latching relay. In response to the detection of the voltage sampling module that the DC power supply end is powered off, the power-off reset control module controls the magnetic latching relay to reset. According to the technical scheme of the embodiment of the application, the automatic reset of the magnetic latching relay can be realized when the circuit is powered off, and the working reliability of the circuit is improved.

Description

Technical Field

[0001] This invention relates to the field of air conditioning circuit technology, and in particular to a control circuit, circuit board and air conditioner of a magnetic latching relay. Background Technology

[0002] A magnetic latching relay allows the relay to maintain its controlled state even after power is cut off. However, if a power outage occurs and the relay retains its original state, unintended consequences may occur upon power restoration. For example, if an air conditioner's indoor unit uses a magnetic latching relay to control the power supply to the outdoor unit, a sudden power outage and subsequent power restoration will cause the outdoor unit's electrical control to be directly energized, resulting in a surge current more than 10 times the normal current, thus reducing circuit reliability. Summary of the Invention

[0003] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a control circuit, circuit board and air conditioner for a magnetic latching relay, which can realize the automatic reset of the magnetic latching relay when the circuit is de-energized, thereby improving the reliability of the circuit.

[0004] In a first aspect, embodiments of the present invention provide a control circuit for a magnetic latching relay, comprising a DC power supply terminal, a first capacitor, a voltage sampling module, and a power-off reset control module, wherein:

[0005] The positive terminal of the first capacitor is connected to the DC power supply terminal and the magnetic latching relay, while the negative terminal is grounded.

[0006] The voltage sampling module is connected to the DC power supply terminal;

[0007] The input terminal of the power failure reset control module is connected to the output terminal of the voltage sampling module, and the output terminal is connected to the magnetic latching relay; in response to the voltage sampling module detecting that the DC power supply terminal is de-energized, the power failure reset control module controls the magnetic latching relay to reset.

[0008] The control circuit for the magnetic latching relay provided in the embodiments of the present invention has at least the following beneficial effects: When the circuit is normally powered on, the DC power supply terminal provides DC power, and the first capacitor can store electrical energy. After the circuit is powered off, the voltage sampling module detects the voltage drop at the DC power supply terminal and outputs a voltage signal to the power-off reset control module. Under the control of the power-off reset control module, the voltage at the positive terminal of the first capacitor can be applied to the magnetic latching relay, thereby resetting the magnetic latching relay. This control circuit can realize the automatic reset of the magnetic latching relay when the circuit is powered off, avoiding a large surge current to the load when the circuit is powered on again after being powered off, and improving the working reliability of the circuit.

[0009] In the control circuit of the magnetic latching relay described above, the power-off reset control module includes a voltage reference element, a first switching transistor, and a second switching transistor; the output terminal of the voltage sampling module is connected to the reference terminal of the voltage reference element, and the voltage reference element is connected to the control pin of the first switching transistor; one switching pin of the first switching transistor is connected to the positive terminal of the first capacitor, and the other switching pin is connected to the control pin of the second switching transistor; one switching pin of the second switching transistor is grounded, and the other switching pin is connected to the magnetic latching relay, so as to reset the magnetic latching relay when the second switching transistor is turned on.

[0010] In this embodiment, when the circuit is powered off, the voltage sampling module detects a drop in the DC power supply voltage. The voltage output by the voltage sampling module to the reference terminal of the voltage reference element is lower than the reference voltage of the voltage reference element, causing the on / off state of the voltage reference element to change. This causes the first switch to turn on, and the voltage at the positive terminal of the first capacitor is applied to the second switch through the first switch, thereby turning on the second switch. This enables the magnetic latching relay to automatically reset when the power is off, which helps to improve the reliability of the circuit.

[0011] The control circuit of the magnetic latching relay described above also includes a third switching transistor, a set control terminal, and a reset control terminal. The reset control terminal is connected to the control pin of the second switching transistor. One switch pin of the third switching transistor is grounded, and the other switch pin is connected to the magnetic latching relay to set the magnetic latching relay when the third switching transistor is turned on. The set control terminal is connected to the control pin of the third switching transistor.

[0012] In this embodiment, by connecting the third switch to the magnetic latching relay, the third switch can be turned on, thus setting the magnetic latching relay. When the circuit is normally powered on, i.e., when the DC power supply is energized, if it is necessary to control the magnetic latching relay to close, the set control terminal receives a set signal and can then control the third switch to turn on, thereby achieving the closing of the magnetic latching relay. When the DC power supply is energized and it is necessary to control the magnetic latching relay to reset, the reset control terminal receives a reset signal and can then control the second switch to turn on, thereby achieving the reset of the magnetic latching relay. By setting the set control terminal and the reset control terminal, the magnetic latching relay can be set and reset according to actual needs when the circuit is normally powered on, achieving efficient control of the control circuit.

[0013] In the control circuit of the magnetic latching relay described above, the magnetic latching relay is a dual-coil magnetic latching relay. The common pin of the dual-coil magnetic latching relay is connected to the positive terminal of the first capacitor. The other switch pin of the second switch is connected to the reset pin of the dual-coil magnetic latching relay. The other switch pin of the third switch is connected to the set pin of the dual-coil magnetic latching relay.

[0014] In this embodiment, by connecting the second switching transistor to the reset pin of the dual-coil magnetic latching relay, the dual-coil magnetic latching relay can be reset when the second switching transistor is turned on. By connecting the third switching transistor to the set pin of the dual-coil magnetic latching relay, the dual-coil magnetic latching relay can be set when the third switching transistor is turned on. When the circuit is de-energized, the first and second switching transistors are turned on, and the voltage at the positive terminal of the first capacitor can be applied to the reset coil of the dual-coil magnetic latching relay, causing the reset coil to be energized and thus realizing the function of resetting the magnetic latching relay when de-energized.

[0015] In the control circuit of the aforementioned magnetic latching relay, the magnetic latching relay is a single-coil magnetic latching relay. The control circuit further includes a fourth, a fifth, a sixth, and a seventh switching transistor. One switching pin of the fourth switching transistor and one switching pin of the sixth switching transistor are both connected to the positive terminal of the first capacitor. The other switching pin of the fourth switching transistor and one switching pin of the fifth switching transistor are both connected to one end of the coil of the single-coil magnetic latching relay. The other switching pin of the sixth switching transistor and one switching pin of the seventh switching transistor are both connected to the other end of the coil of the single-coil magnetic latching relay. The other switching pin of the fifth switching transistor and the other switching pin of the seventh switching transistor are grounded. The other switching pin of the second switching transistor is connected to the control pin of the fourth switching transistor and the control pin of the seventh switching transistor. The other switching pin of the third switching transistor is connected to the control pin of the fifth switching transistor and the control pin of the sixth switching transistor.

[0016] In this embodiment, after the circuit is powered off, when the second switch is turned on, the fourth and seventh switches are also turned on, thereby causing the voltage at the positive terminal of the first capacitor to be applied in reverse to the single-coil magnetic latching relay, thus realizing the power-off reset function; when the third switch is turned on, the sixth and fifth switches are also turned on, thereby causing the voltage at the positive terminal of the first capacitor to be applied in the forward direction to the single-coil magnetic latching relay, thus realizing the closing control of the magnetic latching relay.

[0017] The control circuit of the magnetic latching relay described above also includes a first diode, with the DC power supply terminal connected to the positive terminal of the first diode and the negative terminal of the first diode connected to the positive terminal of the first capacitor.

[0018] In this embodiment, the DC power supply terminal is connected to the positive terminal of the first capacitor through the first diode. By utilizing the unidirectional conductivity of the first diode, it can be ensured that the electrical energy stored in the first capacitor is only used by the components in the control circuit, and that the voltage at the positive terminal of the first capacitor can be normally applied to the magnetic latching relay to realize the automatic reset of the magnetic latching relay.

[0019] The control circuit of the magnetic latching relay also includes a second diode. The reset control terminal is connected to the positive terminal of the second diode, and the negative terminal of the second diode is connected to the control pin of the second switching transistor.

[0020] In this embodiment, the reset control terminal is connected to the control pin of the second switching transistor via a second diode. By utilizing the unidirectional conductivity of the second diode, it can be ensured that the reset signal received by the reset control terminal can be transmitted normally to the control pin of the second switching transistor, thereby realizing the reset control of the magnetic latching relay.

[0021] The control circuit of the magnetic latching relay mentioned above also includes a third diode and a fourth diode. The reset pin is connected to the positive terminal of the third diode, the set pin is connected to the positive terminal of the fourth diode, and the negative terminals of the third diode and the fourth diode are both connected to the positive terminal of the first capacitor.

[0022] In this embodiment, by setting a third diode and connecting its positive terminal to the reset pin of the magnetic latching relay, a freewheeling circuit can be provided for the reset coil of the magnetic latching relay. This prevents the current in the reset coil from impacting the second switching transistor after the second switching transistor is suddenly turned off, thus protecting the second switching transistor. By setting a fourth diode and connecting its positive terminal to the set pin of the magnetic latching relay, a freewheeling circuit can be provided for the closed coil of the magnetic latching relay. This prevents the current in the closed coil from impacting the third switching transistor after the third switching transistor is suddenly turned off, thus protecting the third switching transistor. This is beneficial to improving the stability and reliability of the control circuit of the magnetic latching relay.

[0023] The control circuit of the magnetic latching relay mentioned above also includes a first resistor and a second resistor. Another switch pin of the second switch transistor is also connected to one end of the first resistor, and another switch pin of the third switch transistor is also connected to one end of the second resistor. The other ends of the first resistor and the other ends of the second resistor are both connected to the positive terminal of the first capacitor.

[0024] In this embodiment, by setting a first resistor, when the second switch is turned off, the voltage at the positive terminal of the first capacitor is applied to the fourth and seventh switches, thereby turning off the fourth and seventh switches. By setting a second resistor, when the third switch is turned off, the voltage at the positive terminal of the first capacitor is applied to the fifth and sixth switches, thereby turning off the fifth and sixth switches. This helps to ensure the reliability of the control circuit of the magnetic latching relay.

[0025] In the control circuit of the magnetic latching relay described above, the first switching transistor, the second switching transistor, and the third switching transistor are NPN transistors.

[0026] In this embodiment, since both the first and second switching transistors are NPN transistors, the second switching transistor can be turned on when the first switching transistor is turned on, thereby resetting the magnetic latching relay. In addition, since the third switching transistor is an NPN transistor, when the set control terminal receives the set signal, the third switching transistor can be turned on, thereby closing the magnetic latching relay.

[0027] In the control circuit of the magnetic latching relay described above, the voltage sampling module includes a third resistor and a fourth resistor. The DC power supply terminal is connected to one end of the third resistor, the other end of the third resistor is connected to one end of the fourth resistor, the other end of the fourth resistor is grounded, and the connection point of the third resistor and the fourth resistor is connected to the reference terminal of the voltage reference element.

[0028] In this embodiment, the third and fourth resistors are both voltage divider resistors, and the third and fourth resistors are connected in series. The voltage at the DC power supply terminal is divided by the third and fourth resistors and then output to the reference terminal of the voltage reference element. Voltage detection is simple and convenient. When the circuit is powered off, the voltage output by the voltage sampling module to the reference terminal of the voltage reference element is lower than the reference voltage of the voltage reference element, thereby changing the on / off state of the voltage reference element, which facilitates the reset control of the magnetic latching relay.

[0029] Secondly, embodiments of the present invention provide a circuit board including the control circuit described in the first aspect embodiment above. The circuit board provided by the embodiments of the present invention has at least the following beneficial effects: when the circuit is normally powered on, the DC power supply terminal provides DC power, and the first capacitor can store electrical energy. After the circuit is powered off, the voltage sampling module detects a drop in the DC power supply terminal voltage and outputs a voltage signal to the power-off reset control module. Under the control of the power-off reset control module, the voltage at the positive terminal of the first capacitor can be applied to the magnetic latching relay, thereby resetting the magnetic latching relay. This control circuit can automatically reset the magnetic latching relay when the circuit is powered off, avoiding a large surge current to the load when the circuit is powered on again after a power outage, and improving the reliability of the circuit.

[0030] Thirdly, embodiments of the present invention provide an air conditioner, including the control circuit described in the first aspect embodiment above or the circuit board described in the second aspect embodiment above.

[0031] The air conditioner provided according to the embodiments of the present invention has at least the following beneficial effects: When the circuit is normally powered on, the DC power supply terminal provides DC power, and the first capacitor can store electrical energy. After the circuit is powered off, the voltage sampling module detects the voltage drop at the DC power supply terminal and outputs a voltage signal to the power-off reset control module. Under the control of the power-off reset control module, the voltage at the positive terminal of the first capacitor can be applied to the magnetic latching relay, thereby resetting the magnetic latching relay. This control circuit can realize the automatic reset of the magnetic latching relay when the circuit is powered off, avoiding a large surge current to the load when the circuit is powered on again after being powered off, and improving the working reliability of the circuit.

[0032] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0033] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0035] Figure 1 This is a schematic diagram of the control circuit of the magnetic latching relay provided in Embodiment 1 of the present invention;

[0036] Figure 2 This is a schematic diagram of the control circuit of the magnetic latching relay provided in Embodiment 2 of the present invention;

[0037] Figure 3 This is a schematic diagram of the control circuit of the magnetic latching relay provided in Embodiment 3 of the present invention; Detailed Implementation

[0038] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0039] In the description of the embodiments of the present invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the number itself, while "above," "below," "within," etc. are understood to include the number itself. "At least one" refers to one or more, and "at least one of the following" and similar expressions refer to any combination of these items, including any combination of single or multiple items. If "first," "second," etc., are used in the description, they are only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0040] It should be noted that the terms "setting," "installing," and "connecting" in the embodiments of this invention should be interpreted broadly. Those skilled in the art can reasonably determine the specific meaning of the above terms in the embodiments of this invention in conjunction with the specific content of the technical solution. For example, the term "connection" can be a mechanical connection, an electrical connection, or a connection that allows for mutual communication; it can be a direct connection or an indirect connection through an intermediate medium.

[0041] It should be noted that the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0042] In related technologies, magnetic latching relays allow for the relay to maintain its controlled state even after power is cut off. However, if a sudden power outage occurs and the relay retains its original state, undesirable results may occur upon power restoration. For example, if an air conditioner's indoor unit uses a magnetic latching relay to control the power supply to the outdoor unit, a sudden power outage and subsequent power restoration will cause the outdoor unit's electrical control to be directly energized, resulting in a surge current more than 10 times larger than normal, thus reducing circuit reliability.

[0043] Based on the above, embodiments of the present invention provide a control circuit, circuit board, and air conditioner for a magnetic latching relay. The control circuit for the magnetic latching relay includes a DC power supply terminal, a first capacitor, a voltage sampling module, and a power-off reset control module. The positive terminal of the first capacitor is connected to the DC power supply terminal and the magnetic latching relay, while the negative terminal is grounded. The voltage sampling module is connected to the DC power supply terminal. The input terminal of the power-off reset control module is connected to the output terminal of the voltage sampling module, and the output terminal is connected to the magnetic latching relay. In response to the voltage sampling module detecting a power outage at the DC power supply terminal, the power-off reset control module controls the magnetic latching relay to reset. According to the technical solution of the present invention, when the circuit is normally powered on, the DC power supply terminal provides DC power, and the first capacitor can store electrical energy. After the circuit is powered off, the voltage sampling module detects a drop in the DC power supply terminal voltage and outputs a voltage signal to the power-off reset control module. Under the control of the power-off reset control module, the voltage at the positive terminal of the first capacitor can be applied to the magnetic latching relay, thereby resetting the magnetic latching relay. This control circuit can achieve automatic reset of the magnetic latching relay when the circuit is powered off, avoiding a large surge current to the load when the circuit is powered on again after a power outage, and improving the reliability of the circuit.

[0044] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0045] like Figure 1 As shown, a first aspect embodiment of the present invention provides a control circuit for a magnetic latching relay, including a DC power supply terminal 100, a first capacitor C1, a voltage sampling module 200, and a power-off reset control module 300, wherein: the positive terminal of the first capacitor C1 is connected to the DC power supply terminal 100 and the magnetic latching relay K1, and the negative terminal is grounded; the voltage sampling module 200 is connected to the DC power supply terminal 100; the input terminal of the power-off reset control module 300 is connected to the output terminal of the voltage sampling module 200, and the output terminal is connected to the magnetic latching relay K1; in response to the voltage sampling module 200 detecting that the DC power supply terminal 100 is de-energized, the power-off reset control module 300 controls the magnetic latching relay K1 to reset.

[0046] The control circuit for the magnetic latching relay provided in the first aspect embodiment above provides DC power to the DC power supply terminal 100 when the circuit is normally powered on, and the first capacitor C1 can store electrical energy. After the circuit is powered off, the voltage sampling module 200 detects the voltage drop at the DC power supply terminal 100 and outputs a voltage signal to the power-off reset control module 300. Under the control of the power-off reset control module 300, the voltage at the positive terminal of the first capacitor C1 can be applied to the magnetic latching relay K1, thereby resetting the magnetic latching relay K1. This control circuit can automatically reset the magnetic latching relay K1 when the circuit is powered off, avoiding a large surge current to the load when the circuit is powered on again after being powered off, and improving the reliability of the circuit.

[0047] It should be noted that if the DC power supply terminal 100 is de-energized, i.e., the circuit is de-energized, the controller will not have power to operate. In the prior art, it is difficult to achieve the reset control of the magnetic latching relay K1 in the event of a power failure. Unlike the solutions in the prior art, the embodiment of the present invention sets up a first capacitor C1, which can store electrical energy when the circuit is normally energized, so as to provide power to the components in the control circuit after the power failure. The voltage sampling module 200 is used to detect the voltage of the DC power supply terminal 100. When the DC power supply terminal 100 is de-energized, the voltage sampling module 200 outputs a voltage signal to the power failure reset control module 300, so that the power failure reset control module 300 can realize the reset control of the magnetic latching relay K1.

[0048] like Figure 2 and Figure 3 As shown, in the control circuit of the magnetic latching relay described above, the power-off reset control module 300 includes a voltage reference element IC, a first switch Q1, and a second switch Q2; the output terminal of the voltage sampling module 200 is connected to the reference terminal of the voltage reference element IC, and the voltage reference element IC is connected to the control pin of the first switch Q1; one switch pin of the first switch Q1 is connected to the positive terminal of the first capacitor C1, and the other switch pin is connected to the control pin of the second switch Q2; one switch pin of the second switch Q2 is grounded, and the other switch pin is connected to the magnetic latching relay K1, so as to reset the magnetic latching relay K1 when the second switch Q2 is turned on.

[0049] In this embodiment, when the circuit is powered off, the voltage sampling module 200 detects a drop in the voltage at the DC power supply terminal 100. The voltage output by the voltage sampling module 200 to the reference terminal of the voltage reference element IC is lower than the reference voltage of the voltage reference element IC, causing the on / off state of the voltage reference element IC to change. This causes the first switch Q1 to turn on, and the voltage at the positive terminal of the first capacitor C1 is applied to the second switch Q2 through the first switch Q1, thereby turning on the second switch Q2. This enables the magnetic latching relay K1 to automatically reset when the power is off, which helps to improve the reliability of the circuit.

[0050] It should be noted that the change in the on / off state of the voltage reference element IC refers to the change in the on and off states between the two pins of the voltage reference element IC. Specifically, pin 1 of the voltage reference element IC is the reference terminal. When the DC power supply terminal 100 is de-energized, the voltage detected by pin 1 of the voltage reference element IC is lower than the reference voltage inside the voltage reference element IC, causing pins 2 and 3 of the voltage reference element IC to turn off. This causes the voltage at the positive terminal of the first capacitor C1 to be applied to the first switching transistor Q1, making the first switching transistor Q1 conduct. At the same time, the voltage at the positive terminal of the first capacitor C1 is applied to the second switching transistor Q2 through the first switching transistor Q1, at which point the second switching transistor Q2 is energized and conducts. It should be noted that when the second switching transistor Q2 is conducting, the voltage at the positive terminal of the first capacitor C1 can be applied to the magnetic latching relay K1, so that the magnetic latching relay K1 is reset. The control circuit of the magnetic latching relay in this embodiment can realize the function of automatic reset of the magnetic latching relay K1 when the power is off, thereby protecting the load.

[0051] In one embodiment, the DC power supply terminal 100 can provide +12V DC power to meet the power supply requirements of the components in the control circuit, and the reference voltage can be set to 2.5V. It should be noted that the voltage provided by the DC power supply terminal 100 and the reference voltage can be set according to actual conditions, and this embodiment of the invention does not impose specific limitations.

[0052] like Figure 2 and Figure 3 As shown, in one embodiment, the control circuit of the magnetic latching relay further includes a fifth resistor R5 and a sixth resistor R6. One end of the sixth resistor R6 is connected to the positive terminal of the first capacitor C1, and the other end is connected to the control pin of the first switching transistor Q1. One end of the fifth resistor R5 is connected to another switching pin of the first switching transistor Q1, and the other end is connected to the control pin of the second switching transistor Q2. When the DC power supply terminal 100 is de-energized, the on / off state of the voltage reference element IC changes. The voltage at the positive terminal of the first capacitor C1 is applied to the first switching transistor Q1 through the sixth resistor R6, causing the first switching transistor Q1 to conduct. By setting the sixth resistor R6, the first switching transistor Q1 can be protected. The voltage at the positive terminal of the first capacitor C1 is applied to the second switching transistor Q2 through the first switching transistor Q1 and the fifth resistor R5, causing the second switching transistor Q2 to conduct. By setting the fifth resistor R5, the second switching transistor Q2 can be protected.

[0053] like Figure 2 and Figure 3As shown, the control circuit of the magnetic latching relay also includes a third switch Q3, a set control terminal 400, and a reset control terminal 500. The reset control terminal 500 is connected to the control pin of the second switch Q2 to control the second switch Q2 to conduct when a reset signal is received. One switch pin of the third switch Q3 is grounded, and the other switch pin is connected to the magnetic latching relay K1 to set the magnetic latching relay K1 when the third switch Q3 is conducted. The set control terminal 400 is connected to the control pin of the third switch Q3 to control the third switch Q3 to conduct when a set signal is received.

[0054] In this embodiment, by connecting the third switch Q3 to the magnetic latching relay K1, the third switch Q3 can be turned on, causing the magnetic latching relay K1 to be set, thus closing the magnetic latching relay K1. When the circuit is normally powered on, i.e., when the DC power supply terminal 100 is energized, if it is necessary to control the magnetic latching relay K1 to close, the set control terminal 400 receives a set signal and can then control the third switch Q3 to turn on, thereby achieving the closing of the magnetic latching relay K1. When the DC power supply terminal 100 is energized and it is necessary to control the magnetic latching relay K1 to reset, the reset control terminal 500 receives a reset signal and can then control the second switch Q2 to turn on, thereby achieving the reset of the magnetic latching relay K1. By setting the set control terminal 400 and the reset control terminal 500, the magnetic latching relay K1 can be set and reset according to actual needs when the circuit is normally powered on, achieving efficient control of the control circuit.

[0055] Specifically, the control circuit of the magnetic latching relay also includes a controller. A set control terminal 400 and a reset control terminal 500 are set on the controller. The controller can set the magnetic latching relay K1 through the set control terminal 400. In addition, the controller can reset the magnetic latching relay K1 through the reset control terminal 500.

[0056] It is understood that the magnetic latching relay K1 can be a dual-coil magnetic latching relay or a single-coil magnetic latching relay. The following will introduce the embodiments of dual-coil magnetic latching relays and single-coil magnetic latching relays respectively.

[0057] like Figure 2 As shown, in the control circuit of the magnetic latching relay described above, the magnetic latching relay K1 is a dual-coil magnetic latching relay. The common pin of the dual-coil magnetic latching relay is connected to the positive terminal of the first capacitor C1. The other switch pin of the second switch transistor Q2 is connected to the reset pin of the dual-coil magnetic latching relay, and the other switch pin of the third switch transistor Q3 is connected to the set pin of the dual-coil magnetic latching relay.

[0058] In this embodiment, the magnetic latching relay K1 is a dual-coil magnetic latching relay. One coil of the dual-coil magnetic latching relay is a set coil, i.e., the coil between the common pin and the set pin, which is responsible for closing the contacts of the magnetic latching relay K1. The other coil of the dual-coil magnetic latching relay is a reset coil, i.e., the coil between the common pin and the reset pin, which is responsible for opening the contacts of the magnetic latching relay K1. It can be understood that by connecting the second switch Q2 to the reset pin of the dual-coil magnetic latching relay, the dual-coil magnetic latching relay can be reset when the second switch Q2 is turned on. By connecting the third switch Q3 to the set pin of the dual-coil magnetic latching relay, the dual-coil magnetic latching relay can be set when the third switch Q3 is turned on. When the circuit is de-energized, the first switch Q1 and the second switch Q2 are turned on, and the voltage at the positive terminal of the first capacitor C1 can be applied to the reset coil of the dual-coil magnetic latching relay, causing the reset coil to energize and operate, thereby realizing the function of resetting the magnetic latching relay K1 when de-energized.

[0059] like Figure 3 As shown, in the control circuit of the magnetic latching relay described above, the magnetic latching relay K1 is a single-coil magnetic latching relay. The control circuit also includes a fourth switch Q4, a fifth switch Q5, a sixth switch Q6, and a seventh switch Q7. One switch pin of the fourth switch Q4 and one switch pin of the sixth switch Q6 are both connected to the positive terminal of the first capacitor C1. The other switch pin of the fourth switch Q4 and one switch pin of the fifth switch Q5 are both connected to one end of the coil of the single-coil magnetic latching relay. The other switch pin of the sixth switch Q6 and one switch pin of the seventh switch Q7 are both connected to the other end of the coil of the single-coil magnetic latching relay. The other switch pins of the fifth switch Q5 and the seventh switch Q7 are grounded. The other switch pin of the second switch Q2 is connected to the control pins of the fourth switch Q4 and the seventh switch Q7. The other switch pin of the third switch Q3 is connected to the control pins of the fifth switch Q5 and the sixth switch Q6.

[0060] In this embodiment, the magnetic latching relay K1 is a single-coil magnetic latching relay. When a forward current is applied, the single-coil magnetic latching relay closes; when a reverse current is applied, the single-coil magnetic latching relay opens. It can be understood that the second switch Q2 is connected to the control pins of the fourth switch Q4 and the seventh switch Q7, respectively. After the circuit is powered off, when the second switch Q2 is turned on, it enables the fourth switch Q4 and the seventh switch Q7 to conduct, thereby causing the voltage at the positive terminal of the first capacitor C1 to be applied in reverse to the single-coil magnetic latching relay, achieving the power-off reset function. The third switch Q3 is connected to the control pins of the fifth switch Q5 and the sixth switch Q6, respectively. When the third switch Q3 is turned on, it enables the sixth switch Q6 and the fifth switch Q5 to conduct, thereby causing the voltage at the positive terminal of the first capacitor C1 to be applied in the forward direction to the single-coil magnetic latching relay, achieving the closing control of the magnetic latching relay K1.

[0061] like Figure 3 As shown, in one embodiment, the control circuit of the magnetic latching relay further includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, and a twelfth resistor R12. One end of the ninth resistor R9 is connected to the control pin of the fourth switch Q4, and the other end is connected to another switch pin of the second switch Q2. One end of the tenth resistor R10 is connected to the control pin of the fifth switch Q5, and the other end is connected to another switch pin of the third switch Q3. One end of the eleventh resistor R11 is connected to the control pin of the sixth switch Q6, and the other end is connected to another switch pin of the third switch Q3. One end of the twelfth resistor R12 is connected to the control pin of the seventh switch Q7, and the other end is connected to another switch pin of the second switch Q2.

[0062] like Figure 3 As shown, in the control circuit of the magnetic latching relay, the fourth switch Q4, the fifth switch Q5, the sixth switch Q6 and the seventh switch Q7 are PNP type transistors.

[0063] In this embodiment, the control pins of the fourth switch Q4, the fifth switch Q5, the sixth switch Q6, and the seventh switch Q7 are the bases; one switch pin of the fourth switch Q4, one switch pin of the fifth switch Q5, one switch pin of the sixth switch Q6, and one switch pin of the seventh switch Q7 are the emitters; and the other switch pins of the fourth switch Q4, the fifth switch Q5, the sixth switch Q6, and the seventh switch Q7 are the collectors.

[0064] Specifically, the emitters of the fourth switch Q4 and the sixth switch Q6 are both connected to the positive terminal of the first capacitor C1; the collector of the fourth switch Q4 and the emitter of the fifth switch Q5 are both connected to one end of the coil of the single-coil magnetic latching relay; the collector of the sixth switch Q6 and the emitter of the seventh switch Q7 are both connected to the other end of the coil of the single-coil magnetic latching relay; and the collectors of the fifth switch Q5 and the seventh switch Q7 are grounded. The other switch pin of the second switch Q2 is connected to the base of the fourth switch Q4 and the base of the seventh switch Q7. Because the fourth switch... Transistor Q4 and the seventh switch Q7 are PNP transistors. When the second switch Q2 is turned on, the fourth switch Q4 and the seventh switch Q7 can be turned on, thereby realizing the reset control of the magnetic latching relay K1. The other switch pin of the third switch Q3 is connected to the base of the fifth switch Q5 and the base of the sixth switch Q6. Since the fifth switch Q5 and the sixth switch Q6 are PNP transistors, when the third switch Q3 is turned on, the fifth switch Q5 and the sixth switch Q6 can be turned on, thereby realizing the closing control of the magnetic latching relay K1.

[0065] It is understandable that the parameters of the fourth switch Q4, the fifth switch Q5, the sixth switch Q6, and the seventh switch Q7 can be selected according to the actual situation, and no specific restrictions are made here.

[0066] like Figure 2 and Figure 3 As shown, the control circuit of the magnetic latching relay also includes a first diode D1, with the DC power supply terminal 100 connected to the positive terminal of the first diode D1 and the negative terminal of the first diode D1 connected to the positive terminal of the first capacitor C1.

[0067] In this embodiment, the DC power supply terminal 100 is connected to the positive terminal of the first capacitor C1 through the first diode D1. By utilizing the unidirectional conductivity of the first diode D1, it can be ensured that the electrical energy stored in the first capacitor C1 is only used by the components in the control circuit, and that the voltage of the positive terminal of the first capacitor C1 can be normally applied to the magnetic latching relay K1 to realize the automatic reset of the magnetic latching relay K1.

[0068] like Figure 2 and Figure 3 As shown, the control circuit of the magnetic latching relay also includes a second diode D2. The reset control terminal 500 is connected to the positive terminal of the second diode D2, and the negative terminal of the second diode D2 is connected to the control pin of the second switching transistor Q2.

[0069] In this embodiment, the reset control terminal 500 is connected to the control pin of the second switch Q2 through the second diode D2. By utilizing the unidirectional conductivity of the second diode D2, it can be ensured that the reset signal received by the reset control terminal 500 can be transmitted normally to the control pin of the second switch Q2, thereby realizing the reset control of the magnetic latching relay K1.

[0070] like Figure 2 and Figure 3 As shown, in one embodiment, if the DC power supply terminal 100 is energized and it is necessary to control the magnetic latching relay K1 to be reset, the second switch Q2 can be turned on through the reset control terminal 500, the second diode D2, and the fifth resistor R5, thereby realizing the reset of the magnetic latching relay K1. If the DC power supply terminal 100 is energized and it is necessary to control the magnetic latching relay K1 to be closed, the third switch Q3 can be turned on through the set control terminal 400 and the seventh resistor R7, thereby realizing the closure of the magnetic latching relay K1.

[0071] In one embodiment, the control circuit of the magnetic latching relay further includes an eighth resistor R8, one end of which is connected to another switch pin of the first switching transistor, and the other end is grounded.

[0072] like Figure 2 As shown, the control circuit of the magnetic latching relay also includes a third diode D3 and a fourth diode D4. The reset pin is connected to the positive terminal of the third diode D3, the set pin is connected to the positive terminal of the fourth diode D4, and the negative terminals of the third diode D3 and the fourth diode D4 are both connected to the positive terminal of the first capacitor C1.

[0073] In this embodiment, by setting a third diode D3 and connecting its positive terminal to the reset pin of the magnetic latching relay K1, a freewheeling circuit is provided for the reset coil of the magnetic latching relay K1. This prevents the current in the reset coil from impacting the second switch Q2 after it is suddenly turned off, thus protecting the second switch Q2. Similarly, by setting a fourth diode D4 and connecting its positive terminal to the set pin of the magnetic latching relay K1, a freewheeling circuit is provided for the closed coil of the magnetic latching relay K1. This prevents the current in the closed coil from impacting the third switch Q3 after it is suddenly turned off, thus protecting the third switch Q3. This improves the stability and reliability of the control circuit of the magnetic latching relay.

[0074] like Figure 3As shown, the control circuit of the magnetic latching relay also includes a first resistor R1 and a second resistor R2. Another switch pin of the second switch transistor Q2 is also connected to one end of the first resistor R1, and another switch pin of the third switch transistor Q3 is also connected to one end of the second resistor R2. The other ends of the first resistor R1 and the other ends of the second resistor R2 are both connected to the positive terminal of the first capacitor C1.

[0075] In this embodiment, by setting the first resistor R1, when the second switch Q2 is turned off, the voltage at the positive terminal of the first capacitor C1 is applied to the fourth switch Q4 and the seventh switch Q7, thereby turning off the fourth switch Q4 and the seventh switch Q7. By setting the second resistor R2, when the third switch Q3 is turned off, the voltage at the positive terminal of the first capacitor C1 is applied to the fifth switch Q5 and the sixth switch Q6, thereby turning off the fifth switch Q5 and the sixth switch Q6. This helps to ensure the reliability of the control circuit of the magnetic latching relay.

[0076] like Figure 2 and Figure 3 As shown, in the control circuit of the magnetic latching relay, the first switch Q1, the second switch Q2, and the third switch Q3 are NPN transistors.

[0077] In this embodiment, the control pin of the first switch Q1 is the base, one switch pin of the first switch Q1 is the collector, and the other switch pin is the emitter. The control pin of the second switch Q2 is the base, one switch pin of the second switch Q2 is the emitter, and the other switch pin is the collector. The control pin of the third switch Q3 is the base, one switch pin of the third switch Q3 is the emitter, and the other switch pin is the collector. Since both the first switch Q1 and the second switch Q2 are NPN transistors, the second switch Q2 can be turned on when the first switch Q1 is turned on, thereby resetting the magnetic latching relay K1. In addition, since the third switch Q3 is an NPN transistor, when the set control terminal 400 receives a set signal, it can be turned on, thereby closing the magnetic latching relay K1.

[0078] Specifically, the voltage reference element IC is connected to the base of the first switching transistor Q1, the collector of the first switching transistor Q1 is connected to the positive terminal of the first capacitor C1, and the emitter of the first switching transistor Q1 is connected to the base of the second switching transistor Q2. The emitter of the second switching transistor Q2 is grounded, and the collector of the second switching transistor Q2 is connected to the magnetic latching relay K1. The reset control terminal 500 is connected to the base of the second switching transistor Q2, and can control the second switching transistor Q2 to conduct when a reset signal is received, thereby realizing the reset control of the magnetic latching relay K1. The set control terminal 400 is connected to the base of the third switching transistor Q3, and can control the third switching transistor Q3 to conduct when a set signal is received. The emitter of the third switching transistor Q3 is grounded, and the collector of the third switching transistor Q3 is connected to the magnetic latching relay K1, and can set the magnetic latching relay K1 when the third switching transistor Q3 is conducting, thereby realizing the closing control of the magnetic latching relay K1.

[0079] It is understandable that the specific parameters of the first switch Q1, the second switch Q2, and the third switch Q3 can be selected according to the actual situation, and no specific restrictions are made here.

[0080] like Figure 2 and Figure 3 As shown, in the control circuit of the magnetic latching relay, the voltage sampling module 200 includes a third resistor R3 and a fourth resistor R4. The DC power supply terminal 100 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is grounded, and the connection point of the third resistor R3 and the fourth resistor R4 is connected to the reference terminal of the voltage reference element IC.

[0081] In this embodiment, the third resistor R3 and the fourth resistor R4 are both voltage divider resistors connected in series. The voltage at the DC power supply terminal 100 is divided by the third resistor R3 and the fourth resistor R4 and then output to the reference terminal of the voltage reference element IC. Voltage detection is simple and convenient. When the circuit is powered off, the voltage output by the voltage sampling module 200 to the reference terminal of the voltage reference element IC is lower than the reference voltage of the voltage reference element IC, thereby changing the on / off state of the voltage reference element IC and facilitating the reset control of the magnetic latching relay K1.

[0082] It will be understood by those skilled in the art that Figures 1 to 3 The control circuit of the magnetic latching relay shown does not constitute a limitation on the embodiments of the present invention. It may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0083] A second aspect of the present invention provides a circuit board including the control circuit described in the first aspect embodiment above.

[0084] According to the circuit board provided in the embodiment of the present invention, when the circuit is normally powered on, the DC power supply terminal 100 provides DC power, and the first capacitor C1 can store electrical energy. After the circuit is powered off, the voltage sampling module 200 detects the voltage drop at the DC power supply terminal 100 and outputs a voltage signal to the power-off reset control module 300. Under the control of the power-off reset control module 300, the voltage at the positive terminal of the first capacitor C1 can be applied to the magnetic latching relay K1, thereby resetting the magnetic latching relay K1. This control circuit can realize the automatic reset of the magnetic latching relay K1 when the circuit is powered off, avoiding a large surge current to the load when the circuit is powered on again after being powered off, and improving the working reliability of the circuit.

[0085] A third aspect of the present invention provides an air conditioner, including the control circuit of the first aspect embodiment above or the circuit board of the second aspect embodiment above.

[0086] According to the air conditioner provided in the embodiment of the present invention, when the circuit is normally powered on, the DC power supply terminal 100 provides DC power, and the first capacitor C1 can store electrical energy. After the circuit is powered off, the voltage sampling module 200 detects the voltage drop at the DC power supply terminal 100 and outputs a voltage signal to the power-off reset control module 300. Under the control of the power-off reset control module 300, the voltage at the positive terminal of the first capacitor C1 can be applied to the magnetic latching relay K1, thereby resetting the magnetic latching relay K1. This control circuit can realize the automatic reset of the magnetic latching relay K1 when the circuit is powered off, avoiding a large surge current to the load when the circuit is powered on again after being powered off, improving the working reliability of the circuit, and helping to improve the stability and reliability of the air conditioner.

[0087] It is understood that the air conditioner in the embodiments of the present invention can be a central air conditioner, a wall-mounted air conditioner, a floor-standing air conditioner, or other types of air conditioners.

[0088] In the description of the embodiments of the present invention, the references to "one embodiment / implementation," "another embodiment / implementation," or "some embodiments / implementations," "in the above embodiments / implementations," etc., refer to specific features, structures, materials, or characteristics described in connection with embodiments or examples that are included in at least two embodiments or implementations of this disclosure. In this disclosure, the illustrative expressions of the above terms do not necessarily refer to the same illustrative embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.

[0089] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A control circuit for a magnetic latching relay, characterized in that, include: DC power supply terminal; The positive terminal of the first capacitor is connected to the DC power supply terminal and the magnetic latching relay, while the negative terminal is grounded. A voltage sampling module is connected to the DC power supply terminal; A power-off reset control module includes a voltage reference element, a first switching transistor, a second switching transistor, and a third switching transistor. The output terminal of the voltage sampling module is connected to the reference terminal of the voltage reference element, and the voltage reference element is connected to the control pin of the first switching transistor. One switching pin of the first switching transistor is connected to the positive terminal of the first capacitor, and the other switching pin is connected to the control pin of the second switching transistor. One switching pin of the second switching transistor is grounded, and the other switching pin is connected to the magnetic latching relay to reset the magnetic latching relay when the second switching transistor is turned on. The magnetic latching relay is a single-coil magnetic latching relay. The control circuit further includes a fourth, a fifth, a sixth, and a seventh switching transistor. One switching pin of the fourth and a switching pin of the sixth switching transistor are both connected to the positive terminal of the first capacitor. The other switching pin of the fourth and a switching pin of the fifth switching transistor are both connected to one end of the coil of the single-coil magnetic latching relay. The other switching pin of the sixth and a switching pin of the seventh switching transistor are both connected to the other end of the coil of the single-coil magnetic latching relay. The other switching pins of the fifth and seventh switching transistors are grounded. The other switching pin of the second switching transistor is connected to the control pins of the fourth and seventh switching transistors. The other switching pin of the third switching transistor is connected to the control pins of the fifth and sixth switching transistors.

2. The control circuit according to claim 1, characterized in that, It also includes a set control terminal and a reset control terminal. The reset control terminal is connected to the control pin of the second switch transistor. One switch pin of the third switch transistor is grounded, and the other switch pin is connected to the magnetic latching relay to set the magnetic latching relay when the third switch transistor is turned on. The set control terminal is connected to the control pin of the third switch transistor.

3. The control circuit according to claim 2, characterized in that, The magnetic latching relay is a dual-coil magnetic latching relay. The common pin of the dual-coil magnetic latching relay is connected to the positive terminal of the first capacitor. The other switch pin of the second switch is connected to the reset pin of the dual-coil magnetic latching relay. The other switch pin of the third switch is connected to the set pin of the dual-coil magnetic latching relay.

4. The control circuit according to claim 1, characterized in that, It also includes a first diode, with the DC power supply terminal connected to the positive terminal of the first diode and the negative terminal of the first diode connected to the positive terminal of the first capacitor.

5. The control circuit according to claim 2, characterized in that, It also includes a second diode, with the reset control terminal connected to the positive terminal of the second diode and the negative terminal of the second diode connected to the control pin of the second switching transistor.

6. The control circuit according to claim 3, characterized in that, It also includes a third diode and a fourth diode, the reset pin is connected to the positive terminal of the third diode, the set pin is connected to the positive terminal of the fourth diode, and the negative terminals of the third diode and the fourth diode are both connected to the positive terminal of the first capacitor.

7. The control circuit according to claim 1, characterized in that, The magnetic latching relay is a single-coil magnetic latching relay. The control circuit also includes a first resistor and a second resistor. Another switch pin of the second switch transistor is also connected to one end of the first resistor. Another switch pin of the third switch transistor is also connected to one end of the second resistor. The other ends of the first resistor and the other ends of the second resistor are both connected to the positive terminal of the first capacitor.

8. The control circuit according to claim 1, characterized in that, The first switching transistor, the second switching transistor, and the third switching transistor are NPN transistors.

9. The control circuit according to claim 1, characterized in that, The voltage sampling module includes a third resistor and a fourth resistor. The DC power supply terminal is connected to one end of the third resistor, the other end of the third resistor is connected to one end of the fourth resistor, the other end of the fourth resistor is grounded, and the connection point of the third resistor and the fourth resistor is connected to the reference terminal of the voltage reference element.

10. A circuit board, characterized in that, Includes the control circuit described in any one of claims 1 to 9.

11. An air conditioner, characterized in that, It includes the control circuit as described in any one of claims 1 to 9 or the circuit board as described in claim 10.

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