Door status monitoring circuit and refrigerator

Abstract

The embodiment of the application provides a door state monitoring circuit and a refrigerator. The door state monitoring circuit comprises: a detection circuit connected with a door switch, the detection circuit being used for detecting an opening state of the door switch and outputting an opening signal; a delay circuit, an input end of the delay circuit being connected with an output end of the detection circuit, the delay circuit being used for outputting the opening signal after a delay setting time length; a lighting lamp and an alarm; a control circuit, an input end of the control circuit being connected with an output end of the delay circuit, output ends of the control circuit being connected with the lighting lamp and the alarm respectively, the control circuit being used for cutting off the lighting lamp when the opening signal after the delay setting time length is received, and controlling the alarm to alarm. The alarm is performed only after the door is opened for the setting time length, the risk of false alarm caused by normal use of the refrigerator by a user can be reduced, and precise alarm on an adverse problem caused by long-time opening of the door switch can be realized.

Description

Technical Field

[0001] This application belongs to the field of refrigerator technology, and particularly relates to a door status monitoring circuit and a refrigerator. Background Technology

[0002] Users often open the refrigerator door to take out food, but due to improper operation or incorrect door switch settings, the door may not close properly, which can lead to increased energy consumption of the refrigerator or spoilage of the food.

[0003] Current refrigerator door status monitoring mainly relies on solutions such as mechanical microswitches, infrared sensors, and gravity sensing modules. Mechanical microswitches are triggered by door compression; infrared sensors detect door status by utilizing beam obstruction; and gravity sensing modules determine the open / closed state by changes in door weight. However, the performance of existing door status monitoring solutions is unsatisfactory. Utility Model Content

[0004] This application provides a door status monitoring circuit and a refrigerator to improve the effectiveness of door status monitoring.

[0005] In a first aspect, embodiments of this application provide a door status monitoring circuit for monitoring the door open / close status, wherein the door switch is a magnetic switch, and the door status monitoring circuit includes:

[0006] A detection circuit is connected to the door switch, and the detection circuit is used to detect the open state of the door switch and output an open signal;

[0007] A delay circuit, wherein the input terminal of the delay circuit is connected to the output terminal of the detection circuit, and the delay circuit is used to output the start signal after a set delay time;

[0008] Lighting and alarms;

[0009] A control circuit is provided, the input of which is connected to the output of the delay circuit, and the output of which is connected to the lighting lamp and the alarm respectively. The control circuit is used to turn off the lighting lamp and control the alarm to sound when it receives the turn-on signal after a set delay time.

[0010] Optionally, the gate state monitoring circuit further includes:

[0011] Indicator light;

[0012] A protection circuit is provided, wherein the input terminal of the protection circuit is connected to the output terminal of the detection circuit, and the output terminal of the protection circuit is connected to the indicator light. The protection circuit is used to detect the voltage signal of the detection circuit and output a fault signal when the voltage signal is greater than a preset voltage, thereby turning on the indicator light.

[0013] Optionally, the protection circuit includes:

[0014] A sampling resistor, one end of which is connected to the output terminal of the detection circuit, and the other end of which is connected to a power supply, is used to detect the voltage signal of the detection circuit;

[0015] A differential amplifier, wherein the non-inverting input terminal and the inverting input terminal of the differential amplifier are respectively connected to the two ends of the sampling resistor, and the differential amplifier is used to amplify the voltage signal;

[0016] A first comparator is connected to the output of the differential amplifier, and its output is connected to the indicator light. The first comparator is used to output a fault signal when the amplified voltage signal is greater than a preset voltage, thereby turning on the indicator light.

[0017] Optionally, the gate state monitoring circuit further includes:

[0018] A reset control circuit is provided, wherein the input terminal of the reset control circuit is connected to the delay circuit, and the output terminal of the reset control circuit is connected to the input terminal of the control circuit. The reset control circuit includes a reset switch, which is used to turn off the alarm and turn on the lighting when the reset switch is closed.

[0019] Optionally, the door status monitoring circuit further includes a discharge circuit, the input terminal of which is connected to the output terminal of the detection circuit, and the output terminal of which is connected to the input terminal of the control circuit. The discharge circuit is used to discharge the electrical signal of the delay circuit when the door is closed.

[0020] Optionally, the discharge circuit includes:

[0021] A bleed resistor is connected at one end to the output terminal of the detection circuit and at the other end to the delay circuit;

[0022] A bleeder diode, the anode of which is connected to the input terminal of the control circuit, and the cathode of which is connected to the other end of the bleeder resistor.

[0023] Optionally, the detection circuit includes a pull-up resistor and a first capacitor. One end of the pull-up resistor is connected to one end of the door switch, and the other end of the pull-up resistor is connected to a power supply. One end of the first capacitor is connected to the other end of the door switch, and the other end of the first capacitor is connected to one end of the pull-up resistor.

[0024] The delay circuit includes a first resistor and a second capacitor. One end of the first resistor is connected to one end of the pull-up resistor, and the other end of the first resistor is connected to one end of the second capacitor. The other end of the second capacitor is connected to the input terminal of the control circuit.

[0025] Optionally, the control circuit includes:

[0026] A comparator circuit, one input of which is connected to the output of the delay circuit, is used to output a comparison signal based on the enable signal after a set delay time.

[0027] The driving sub-circuit has its input terminal connected to the output terminal of the comparator sub-circuit, and its output terminal connected to the lighting lamp and the alarm respectively. The driving sub-circuit is used to cut off the lighting lamp according to the comparison signal and control the alarm to sound.

[0028] Optionally, the comparator circuit includes:

[0029] The second comparator has its non-inverting input connected to the output of the delay circuit.

[0030] The second resistor has one end grounded and the other end connected to the inverting input of the second comparator.

[0031] The third resistor has one end connected to the inverting input of the second comparator and the other end connected to the power supply.

[0032] A fourth resistor, one end of which is connected to the output of the second comparator, and the other end of which is connected to the driving sub-circuit;

[0033] The driving sub-circuit includes:

[0034] A switching transistor, the gate of which is connected to the other end of the fourth resistor, and the source of which is grounded;

[0035] A relay, wherein the input terminal of the relay is connected to the drain of the switching transistor, the normally open contact of the relay is connected to the lighting lamp, and the normally closed contact of the relay is connected to the alarm.

[0036] A freewheeling diode, wherein the positive terminal of the freewheeling diode is connected to the power supply, and the negative terminal of the freewheeling diode is connected to the drain of the switching transistor.

[0037] Secondly, embodiments of this application also provide a refrigerator, comprising:

[0038] A door switch, the door switch including a reed switch;

[0039] A door status monitoring circuit is connected to the door switch, and the door status monitoring circuit is as described in any of the preceding claims.

[0040] In the door status monitoring circuit and refrigerator of this application embodiment, by using a magnetic switch as the door switch, mechanical wear can be eliminated and the service life of the door switch can be improved; by setting a delay circuit, the alarm is triggered only after the door has been open for a set period of time, which can reduce the risk of false alarms caused by normal use of the refrigerator by the user, and achieve accurate alarm for problems caused by prolonged opening of the door switch; in addition, the lighting is turned off at the same time as the alarm, thereby reducing energy consumption; thus, excellent monitoring of the door status is achieved in a comprehensive manner. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings. In the following description, the same reference numerals denote the same parts.

[0043] Figure 1 This is a structural block diagram of the gate state monitoring circuit provided in an embodiment of this application.

[0044] Figure 2 This is a schematic diagram of the refrigerator door opening / closing state and reed switch state provided in an embodiment of this application.

[0045] Figure 3 A circuit diagram of a gate state monitoring circuit provided in an embodiment of this application.

[0046] Figure 4 Another circuit diagram of the gate state monitoring circuit provided in the embodiments of this application. Detailed Implementation

[0047] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0048] To improve the door status monitoring effect, this application provides a door status monitoring circuit and a refrigerator, which will be described below with reference to the accompanying drawings.

[0049] For example, please refer to Figure 1 and Figure 2 As shown, Figure 1 This is a structural block diagram of the gate state monitoring circuit provided in an embodiment of this application. Figure 2 This is a schematic diagram of the refrigerator door open / close state and reed switch state structure provided in an embodiment of this application. The door state monitoring circuit 100 includes a detection circuit 110, a delay circuit 120, a light 130, an alarm 140, and a control circuit 150.

[0050] It should be noted that the door status monitoring circuit 100 in this embodiment is used to monitor the door opening and closing status, such as preventing high energy consumption caused by prolonged door opening. The door switch can be a magnetic switch, such as a combination of a reed switch SW1 and a permanent magnet, which can eliminate mechanical wear and improve the service life of the door switch. For example, the reed switch SW1 is installed in the sealing groove of the refrigerator door frame, and the permanent magnet can be a neodymium iron boron permanent magnet, which is embedded in the corresponding position of the door. When the door is closed, the distance between the permanent magnet and the reed switch SW1 is less than or equal to 2 mm, at which time the reed switch SW1 is open and the contact resistance is greater than 10 MΩ; when the door is open, the permanent magnet moves away from the reed switch SW1, therefore, the reed switch SW1 is closed, at which time the contact resistance is less than 0.5 Ω. This embodiment utilizes this property to detect the door status.

[0051] The detection circuit 110 is connected to the door switch and is used to detect the open state of the door switch and output an open signal. Of course, the detection circuit 110 is also used to detect the closed state of the door switch and output a closed signal. Since the embodiments of this application mainly describe the monitoring scheme when the door switch is open, the description takes the detection circuit 110 detecting the open state of the door switch as an example, and should not be construed as a limitation on the detection circuit 110.

[0052] The reed switch SW1 in the door switch can be set in the detection circuit 110. The opening and closing of the door switch can be detected according to the opening and closing state of the reed switch SW1. For example, when the reed switch SW1 is open, it can be determined that the door switch is in the closed state, and when the reed switch SW1 is closed, it can be determined that the door switch is in the open state.

[0053] The input terminal of the delay circuit 120 is connected to the output terminal of the detection circuit 110. The delay circuit 120 is used to output an opening signal after a set delay period. It is understood that the opening signal is not transmitted immediately upon opening the door. This could be due to a brief opening of the refrigerator door by the user. To reduce misjudgments of the refrigerator door opening caused by user activity, this embodiment of the application sets the delay circuit 120 to transmit the opening signal only after a set delay period. The set duration can be determined based on experience. For example, a user's brief use of the refrigerator to retrieve items typically lasts for tens of seconds, so the set duration can be one minute. Since a brief opening of the refrigerator door does not affect the refrigerator's operation and has little impact on its power consumption, this approach is suitable.

[0054] The light 130 can be installed inside the refrigerator, such as in the refrigerator compartment. The light 130 is used for illumination. For example, when the refrigerator door is opened, if the ambient light outside the refrigerator is dim, it will affect the user's experience of taking items out. Therefore, the light 130 can illuminate the refrigerator when the user takes items out of the refrigerator, thus improving the user's experience of using the refrigerator.

[0055] The alarm 140 can be installed on the outside of the refrigerator door, for example, to remind the user that the refrigerator door has been open for too long. The alarm 140 can be a device that emits an alarm sound, a device that emits a light warning, or a device that can emit both an alarm sound and a light warning simultaneously; there are no restrictions on this.

[0056] The input terminal of the control circuit 150 is connected to the output terminal of the delay circuit 120. The output terminal of the control circuit 150 is connected to the lighting lamp 130 and the alarm 140 respectively. The control circuit 150 is used to turn off the lighting lamp 130 and control the alarm 140 to sound when it receives the turn-on signal after the set delay time.

[0057] In the door status monitoring circuit 100 of this application embodiment, by using a magnetic switch as the door switch, mechanical wear can be eliminated and the service life of the door switch can be improved; by setting a delay circuit 120, an alarm is triggered only after the door has been open for a set period of time, which can reduce the risk of false alarms caused by normal use of the refrigerator by the user, and achieve accurate alarm for problems caused by prolonged opening of the door switch; in addition, the lighting is turned off at the same time as the alarm, thereby reducing energy consumption; thus, a comprehensive and excellent monitoring of the door status is achieved.

[0058] For example, please refer to Figure 1 and Figure 2 And see Figure 3 As shown, Figure 3This is a circuit diagram of a door status monitoring circuit provided in an embodiment of this application. The detection circuit 110 includes a pull-up resistor R11 and a first capacitor C1. One end of the reed switch SW1 in the door switch is grounded to GND, and the other end of the reed switch SW1 is connected to one end of the pull-up resistor R11, which is connected to the power supply VCC. One end of the first capacitor C1 is grounded to GND, and the other end of the first capacitor C1 is connected to the other end of the reed switch SW1, that is, the first capacitor C1 is connected in parallel across the two ends of the reed switch SW1. The first capacitor C1 is used to filter out contact bounce of the reed switch SW1. The reed switch SW1 can be normally open, and is closed when the refrigerator door is opened. A current-limiting resistor R12 is also provided between the reed switch SW1 and the pull-up resistor R11.

[0059] It should be noted that for the door status monitoring circuit 100, the power input can be directly connected to the 5V DC power supply provided by the refrigerator mainboard. To protect the power supply VCC, this embodiment also includes a fuse F1, a first diode D1, and an electrolytic capacitor C11 between the power input and the pull-up resistor R11. One end of the fuse F1 is connected to the power supply VCC, and the other end is connected to one end of the electrolytic capacitor C11. The fuse F1 can be a resettable fuse, connected in series at the power supply VCC input terminal, with an operating current of 500mA. The fuse F1 is used for overcurrent protection. The other end of the electrolytic capacitor C11 is connected to the other end of the pull-up resistor R11, and the electrolytic capacitor C11 is used to filter power supply noise. The anode of the first diode D1 is connected to one end of the fuse F1, and the cathode of the first diode D1 is connected to the other end of the fuse F1. The first diode D1 can be used to prevent the power supply VCC from being reversed.

[0060] For example, the delay circuit 120 can be an RC charging circuit. The delay circuit 120 includes a first resistor R1 and a second capacitor C2. One end of the first resistor R1 is connected to one end of the pull-up resistor R11, and the other end of the first resistor R1 is connected to one end of the second capacitor C2. The other end of the second capacitor C2 is connected to the input terminal of the control circuit 150 and grounded (GND). The first resistor R1 is an adjustable resistor, and its resistance value can be determined according to a preset duration. The resistance value of the first resistor R1 and the capacitance value of the second capacitor C2 are related to the calculation of the preset duration, and can be determined according to the preset duration.

[0061] For example, the control circuit 150 includes a comparator sub-circuit 151 and a driver sub-circuit 152. One input terminal of the comparator sub-circuit 151 is connected to the output terminal of the delay circuit 120, and the comparator sub-circuit 151 outputs a comparison signal based on an on signal after a set delay period. The input terminal of the driver sub-circuit 152 is connected to the output terminal of the comparator sub-circuit 151, and the output terminal of the driver sub-circuit 152 is connected to the lighting lamp 130 and the alarm 140, respectively. The driver sub-circuit 152 is used to turn off the lighting lamp 130 based on the comparison signal and control the alarm 140 to sound an alarm.

[0062] For example, the comparator circuit 151 includes a second comparator U2, a second resistor R2, a third resistor R3, and a fourth resistor R4.

[0063] The non-inverting input of the second comparator U2 is connected to the output of the delay circuit 120 and grounded to GND. One end of the second resistor R2 is grounded to GND, and the other end is connected to the inverting input of the second comparator U2. One end of the third resistor R3 is connected to the inverting input of the second comparator U2, and the other end is connected to the power supply VCC. The resistance values ​​of the second resistor R2 and the third resistor R3 can be equal, and there is a voltage divider point between the second resistor R2 and the third resistor R3 to divide the power supply voltage. The inverting input of the second comparator U2 is connected to the voltage divider point to obtain the reference voltage. One end of the fourth resistor R4 is connected to the output of the second comparator U2, and the other end is connected to the driver sub-circuit 152.

[0064] The comparator circuit 151 also includes a fifth resistor R5. One end of the fifth resistor R5 is connected to the output terminal of the second comparator U2, and the other end of the fifth resistor R5 is connected to the power supply VCC. The fifth resistor R5 is a pull-up resistor.

[0065] For example, the driver sub-circuit 152 includes a switch Q1, a relay K1, and a freewheeling diode D22.

[0066] The switching transistor Q1 can be a MOSFET. The gate G of Q1 is connected to the other end of the fourth resistor R4, and the source S of Q1 is grounded to GND. The input terminal, i.e., the coil, of relay K1 is connected to the drain D of switching transistor Q1. The normally open contact NO of relay K1 is connected to the lighting lamp 130, and the normally closed contact NC of relay K1 is connected to the alarm 140. Relay K1 can have a first input terminal A and a second input terminal B, both of which are connected to the drain of switching transistor Q1. The anode of freewheeling diode D22 is connected to the power supply VCC, and the cathode of freewheeling diode D22 is connected to the drain of switching transistor Q1. Furthermore, freewheeling diode D22 is connected between the first input terminal A and the second input terminal B of relay K1.

[0067] The alarm 140 includes a circuit connected to the normally closed contact NC of relay K1. Exemplarily, the alarm circuit includes transistor Q2, a sixth resistor R6, the alarm 140, and a third capacitor C3. The base of transistor Q2 is connected to the normally closed contact NC of relay K1 via the sixth resistor R6. The collector of transistor Q2 is connected to the positive terminal of alarm 140. Alarm 140 can be a buzzer, such as a 3V active buzzer. The emitter of transistor Q2 is grounded to GND. The negative terminal of alarm 140 is grounded to GND. A reverse protection diode D33 is connected in parallel between the positive terminal of alarm 140 and transistor Q2. One end of the third capacitor C3 is connected to the negative terminal of alarm 140, and the other end of the third capacitor C3 is grounded to GND.

[0068] The process of gate status monitoring and the operation of the gate status monitoring circuit 100 can be described as follows:

[0069] When the refrigerator door is opened, the reed switch SW1 closes. At this time, the voltage at the node between the pull-up resistor R11 and the current-limiting resistor R12, or the output node of the detection circuit 110, is 0. The second capacitor C2 begins to charge. When the second capacitor C2 is charged to a voltage greater than 2.5V, the second comparator U2 outputs a high level, the switching transistor Q1 is turned on, and the relay K1 is energized. As a result, the normally open contact NO of the relay K1 opens, turning off the light 130. At the same time, the normally closed contact NC of the relay K1 closes, and the alarm 140 sounds.

[0070] When the refrigerator door is closed, the reed switch SW1 is disconnected. At this time, the voltage at the node between the pull-up resistor R11 and the current-limiting resistor R12, or the output node of the detection circuit 110, is 5V. The second capacitor C2 begins to discharge. When the voltage of the second capacitor C2 is less than 2.5V, the second comparator U2 outputs a low level, the switching transistor Q1 is turned off, and the relay K1 is released. As a result, the normally open contact NO of the relay K1 closes, and the lighting lamp 130 resumes illumination. At the same time, the normally closed contact NC of the relay K1 opens, and the alarm 140 stops alarming.

[0071] It should be noted that, in addition to automatically shutting off when the refrigerator door is closed, alarm 140 can also be stopped by manual reset.

[0072] For example, please refer to Figure 4 As shown, Figure 4This is another circuit diagram of the door status monitoring circuit provided in the embodiments of this application. The door status monitoring circuit 100 also includes a reset control circuit 160. The input terminal of the reset control circuit 160 is connected to the delay circuit 120, and the output terminal of the reset control circuit 160 is connected to the input terminal of the control circuit 150. The reset control circuit 160 includes a reset switch SW2. The reset control circuit 160 is used to turn off the alarm 140 and turn on the lighting lamp 130 through the control circuit 150 when the reset switch SW2 is closed.

[0073] For example, the reset switch SW2 can be connected in parallel with the second capacitor C2. The reset switch SW2 is a normally open button. When the user operates the reset switch SW2, the reset switch SW2 closes, at which time the second capacitor C2 discharges. When the voltage of the second capacitor C2 is less than 2.5V, the second comparator U2 outputs a low level, the switching transistor Q1 is turned off, and the relay K1 is released, thereby stopping the alarm 140. In order to prevent short circuit damage to the second capacitor C2, the reset control circuit 160 also includes a reset resistor R21. One end of the reset resistor R21 is connected to the reset switch SW2, and the other end of the reset resistor R21 is connected to the other end of the second capacitor C2.

[0074] In order to discharge the electrical signal of the second capacitor C2, the door state monitoring circuit 100 of this application embodiment further includes a discharge circuit 170. The input terminal of the discharge circuit 170 is connected to the output terminal of the detection circuit 110, and the output terminal of the discharge circuit 170 is connected to the input terminal of the control circuit 150. The discharge circuit 170 is used to discharge the electrical signal of the delay circuit 120 when the door switch is closed. Therefore, the discharge circuit 170 can also be called an automatic discharge circuit.

[0075] For example, the discharge circuit 170 includes a discharge resistor R31 and a discharge diode D31. One end of the discharge resistor R31 is connected to the output terminal of the detection circuit 110, and the other end of the discharge resistor R31 is connected to the delay circuit 120, such as between the first resistor R1 and the second capacitor C2. The discharge resistor R31 is used to limit the discharge current. The positive terminal of the discharge diode D31 is connected to the input terminal of the control circuit 150, and the negative terminal of the discharge diode D31 is connected to the other end of the discharge resistor R31. The discharge diode D31 is used to guide the direction of the discharged charge. The discharge circuit 170 of this embodiment can achieve bidirectional discharge, ensuring reset at the moment of closing and eliminating malfunctions caused by residual current in traditional RC circuits.

[0076] To protect the safety of the door status monitoring circuit 100, the door status monitoring circuit 100 in this embodiment further includes an indicator light D5 and a protection circuit 180. The indicator light D5 illuminates to alert the user when the door status monitoring circuit 100 malfunctions, thereby reducing the problem of poor door status monitoring caused by a fault in the door status monitoring circuit 100. The input terminal of the protection circuit 180 is connected to the output terminal of the detection circuit 110, and the output terminal of the protection circuit 180 is connected to the indicator light D5. The protection circuit 180 detects the voltage signal of the detection circuit 110 and outputs a fault signal when the voltage signal exceeds a preset voltage, causing the indicator light D5 to turn on.

[0077] For example, the protection circuit 180 includes a sampling resistor R41, a differential amplifier U3, and a first comparator U1. One end of the sampling resistor R41 is connected to the output of the detection circuit 110, and the other end of the sampling resistor R41 is connected to a power supply. The sampling resistor R41 is used to detect the voltage signal of the detection circuit 110. The non-inverting input and the inverting input of the differential amplifier U3 are respectively connected to the two ends of the sampling resistor R41, and the differential amplifier U3 is used to amplify the voltage signal. The input of the first comparator U1 is connected to the output of the differential amplifier U3, and the output of the first comparator U1 is connected to the indicator light D5. The first comparator U1 is used to output a fault signal when the amplified voltage signal is greater than a preset voltage, thereby turning on the indicator light D5. The protection circuit 180 also includes a first feedback resistor R51 and a second feedback resistor R52. One end of the first feedback resistor R51 is connected to the other end of the pull-up resistor R11, and the other end of the first feedback resistor R51 is connected to the inverting input of the differential amplifier U3. One end of the second feedback resistor R52 is connected to the other end of the first feedback resistor R51, and the other end of the second feedback resistor R52 is connected to the output terminal of the differential amplifier U3.

[0078] When the voltage signal detected by the sampling resistor R41 is greater than the preset voltage, it can be confirmed that the door status monitoring circuit 100 has malfunctioned, and the indicator light D5 will be turned on to remind the user to perform maintenance.

[0079] In the door status monitoring circuit 100 of this embodiment, the use of a magnetic switch as the door switch eliminates mechanical wear and extends the lifespan of the door switch. By setting a delay circuit 120, an alarm is triggered only after a set time has elapsed since the door was opened, reducing the risk of false alarms caused by normal user operation of the refrigerator and enabling accurate alarms for problems caused by prolonged door opening. Furthermore, the lighting 130 is switched off simultaneously with the alarm, thereby reducing energy consumption. Overall, this achieves excellent monitoring of the door status. In addition, the door status monitoring circuit 100 of this embodiment also includes a reset control circuit 160, allowing the user to manually reset the alarm 140. This provides flexible control of the alarm 140 and improves the user experience. The protection circuit 180 enables fault monitoring of the door status monitoring circuit 100 system, reducing the occurrence of poor door status monitoring due to malfunctions in the door status monitoring circuit 100. Moreover, the door status monitoring circuit 100 of this embodiment uses low-cost components and can achieve adaptive protection without network support, reducing the circuit's manufacturing cost.

[0080] This application also provides a refrigerator, which includes a door switch and a door status monitoring circuit. The door switch includes a reed switch, and the door status monitoring circuit is connected to the door switch. The structure and working principle of the door status monitoring circuit are the same as those in the above embodiments. Since this refrigerator adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0081] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0082] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0083] The door status monitoring circuit and refrigerator provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A gate state monitoring circuit, characterized in that, The door status monitoring circuit is used to monitor the status of a door switch, which is a magnetic switch. The door status monitoring circuit includes: A detection circuit is connected to the door switch, and the detection circuit is used to detect the open state of the door switch and output an open signal; A delay circuit, wherein the input terminal of the delay circuit is connected to the output terminal of the detection circuit, and the delay circuit is used to output the start signal after a set delay time; Lighting and alarms; A control circuit is provided, the input of which is connected to the output of the delay circuit, and the output of which is connected to the lighting lamp and the alarm respectively. The control circuit is used to turn off the lighting lamp and control the alarm to sound when it receives the turn-on signal after a set delay time.

2. The gate state monitoring circuit according to claim 1, characterized in that, The gate status monitoring circuit also includes: Indicator light; A protection circuit is provided, wherein the input terminal of the protection circuit is connected to the output terminal of the detection circuit, and the output terminal of the protection circuit is connected to the indicator light. The protection circuit is used to detect the voltage signal of the detection circuit and output a fault signal when the voltage signal is greater than a preset voltage, thereby turning on the indicator light.

3. The gate state monitoring circuit according to claim 2, characterized in that, The protection circuit includes: A sampling resistor, one end of which is connected to the output terminal of the detection circuit, and the other end of which is connected to a power supply, is used to detect the voltage signal of the detection circuit; A differential amplifier, wherein the non-inverting input terminal and the inverting input terminal of the differential amplifier are respectively connected to the two ends of the sampling resistor, and the differential amplifier is used to amplify the voltage signal; A first comparator is connected to the output of the differential amplifier, and its output is connected to the indicator light. The first comparator is used to output a fault signal when the amplified voltage signal is greater than a preset voltage, thereby turning on the indicator light.

4. The gate state monitoring circuit according to claim 1, characterized in that, The gate status monitoring circuit also includes: A reset control circuit is provided, wherein the input terminal of the reset control circuit is connected to the delay circuit, and the output terminal of the reset control circuit is connected to the input terminal of the control circuit. The reset control circuit includes a reset switch, which is used to turn off the alarm and turn on the lighting when the reset switch is closed.

5. The gate state monitoring circuit according to claim 1, characterized in that, The door status monitoring circuit also includes a discharge circuit. The input terminal of the discharge circuit is connected to the output terminal of the detection circuit, and the output terminal of the discharge circuit is connected to the input terminal of the control circuit. The discharge circuit is used to discharge the electrical signal of the delay circuit when the door is closed.

6. The gate state monitoring circuit according to claim 5, characterized in that, The discharge circuit includes: A bleed resistor is connected at one end to the output terminal of the detection circuit and at the other end to the delay circuit; A bleeder diode, the anode of which is connected to the input terminal of the control circuit, and the cathode of which is connected to the other end of the bleeder resistor.

7. The gate state monitoring circuit according to claim 1, characterized in that, The detection circuit includes a pull-up resistor and a first capacitor. One end of the pull-up resistor is connected to one end of the door switch, and the other end of the pull-up resistor is connected to a power supply. One end of the first capacitor is connected to the other end of the door switch, and the other end of the first capacitor is connected to one end of the pull-up resistor. The delay circuit includes a first resistor and a second capacitor. One end of the first resistor is connected to one end of the pull-up resistor, and the other end of the first resistor is connected to one end of the second capacitor. The other end of the second capacitor is connected to the input terminal of the control circuit.

8. The gate state monitoring circuit according to claim 1, characterized in that, The control circuit includes: A comparator circuit, one input of which is connected to the output of the delay circuit, is used to output a comparison signal based on the enable signal after a set delay time. The driving sub-circuit has its input terminal connected to the output terminal of the comparator sub-circuit, and its output terminal connected to the lighting lamp and the alarm respectively. The driving sub-circuit is used to cut off the lighting lamp according to the comparison signal and control the alarm to sound.

9. The gate state monitoring circuit according to claim 8, characterized in that, The comparator circuit includes: The second comparator has its non-inverting input connected to the output of the delay circuit. The second resistor has one end grounded and the other end connected to the inverting input of the second comparator. The third resistor has one end connected to the inverting input of the second comparator and the other end connected to the power supply. A fourth resistor, one end of which is connected to the output of the second comparator, and the other end of which is connected to the driving sub-circuit; The driving sub-circuit includes: A switching transistor, the gate of which is connected to the other end of the fourth resistor, and the source of which is grounded; A relay, wherein the input terminal of the relay is connected to the drain of the switching transistor, the normally open contact of the relay is connected to the lighting lamp, and the normally closed contact of the relay is connected to the alarm. A freewheeling diode, wherein the positive terminal of the freewheeling diode is connected to the power supply, and the negative terminal of the freewheeling diode is connected to the drain of the switching transistor.

10. A refrigerator, characterized in that, include: A door switch, the door switch including a reed switch; A door status monitoring circuit is connected to the door switch, and the door status monitoring circuit is the door status monitoring circuit as described in any one of claims 1 to 9.

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