Power failure detection circuit and electronic equipment

Abstract

The embodiment of the utility model provides a power failure detection circuit and electronic equipment, and the power failure detection circuit comprises a detection module which is used for being coupled to commercial power and generating an induction current when the commercial power is in a power-on state; and the amplification module is connected with the detection module, and the amplification module is used for carrying out amplification processing on the induction current and outputting a square wave signal. According to the technical scheme, the non-contact detection module is used for current induction of the commercial power instead of contact type power failure detection performed by using a resistor and an optocoupler in the prior art, so that the power failure state of the commercial power can be detected according to the existence of square wave signals, the loss of the detection module caused by the fluctuation of the commercial power can be reduced, and the service life of the detection module can be further prolonged.

Description

Technical Field

[0001] This application belongs to the field of electronic equipment technology, and in particular relates to a power failure detection circuit and an electronic device. Background Technology

[0002] In electronic devices such as home appliances, the power-off memory function is one of the selling points. To realize the power-off memory function, the microcontroller unit (MCU) needs to save the data after sensing the mains power failure.

[0003] The conventional approach to sensing mains power is to use a high-power resistor connected in series with an optocoupler and then to the mains power. However, the resistor and optocoupler are subject to current fluctuations due to mains power fluctuations, leading to wear and tear on the sensing devices and affecting their lifespan. Utility Model Content

[0004] This application provides a power failure detection circuit and electronic device that can reduce the damage to the detection device caused by mains power fluctuations, thereby improving the service life of the detection device.

[0005] In a first aspect, embodiments of this application provide a power-down detection circuit, applied to an electronic device, the power-down detection circuit comprising:

[0006] The detection module is used to be coupled to the mains power and to generate an induced current when the mains power is powered on.

[0007] An amplification module is connected to the detection module. The amplification module is used to amplify the induced current and output a square wave signal.

[0008] Optionally, the detection module includes:

[0009] An induction coil is electromagnetically coupled to a mains power line to generate the induced current.

[0010] Optionally, the amplification module includes:

[0011] A first amplification unit has one input terminal connected to the induction coil and the other input terminal grounded and connected to the output terminal of the first amplification unit. The first amplification unit is used to amplify the induced current.

[0012] Optionally, the amplification module further includes:

[0013] The second amplification unit is connected between the induction coil and an input terminal of the first amplification unit. The second amplification unit is used to amplify the induced current and then input it into the first amplification unit for further amplification.

[0014] A level inversion unit is connected between the first amplification unit and the second amplification unit. The level inversion unit is used to convert the induced current into a square wave signal that is in phase with the sine wave.

[0015] Optionally, the first amplification unit includes:

[0016] An operational amplifier, wherein the non-inverting input terminal of the operational amplifier is connected to the level inversion unit, and the inverting input terminal of the operational amplifier is grounded and connected to the output terminal of the operational amplifier.

[0017] Optionally, the second amplification unit includes:

[0018] The first transistor has its base connected to the induction coil, its collector connected to a power supply, and its emitter grounded.

[0019] Optionally, the second amplification unit further includes:

[0020] The base of the second transistor is connected to the emitter of the first transistor, the collector of the second transistor is connected to the power supply, and the emitter of the second transistor is grounded.

[0021] Optionally, the level inversion unit includes:

[0022] The third transistor has its base connected to the collector of the second transistor, its emitter connected to a power supply, and its collector connected to the non-inverting input of the operational amplifier.

[0023] Optionally, the detection module further includes:

[0024] A first resistor, one end of which is connected to the induction coil;

[0025] A diode, wherein the positive terminal of the diode is connected to the other end of the first resistor, and the negative terminal of the diode is connected to a power source.

[0026] Secondly, embodiments of this application also provide an electronic device, including the power-down detection circuit as described in any of the preceding claims.

[0027] In the power failure detection circuit and electronic device of this application embodiment, a non-contact detection module is used to sense the current of the mains power, instead of the existing contact-type power failure detection using resistors and optocouplers. The power failure status of the mains power can be detected based on the presence or absence of a square wave signal, and the loss of the detection module due to mains power fluctuations can be reduced, thereby improving the service life of the detection module. Attached Figure Description

[0028] 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.

[0029] 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.

[0030] Figure 1 This is a first structural block diagram of the power-down detection circuit provided in an embodiment of this application.

[0031] Figure 2 This is a second structural block diagram of the power-down detection circuit provided in an embodiment of this application.

[0032] Figure 3 This is a schematic diagram of the detection module in the power-down detection circuit provided in an embodiment of this application.

[0033] Figure 4 The circuit diagram is provided for the power-down detection circuit in the embodiments of this application. Detailed Implementation

[0034] 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.

[0035] In electronic devices such as air conditioners, refrigerators, and washing machines, power-down memory is a key selling point. Implementing this function requires the MCU to save data after sensing a power outage. Currently, the conventional approach to sensing mains power involves connecting a high-power resistor in series with an optocoupler and then to the mains power. However, the resistor experiences power fluctuations due to voltage variations, leading to significant heat generation. Furthermore, the current fluctuations experienced by the optocoupler and resistor with mains power fluctuations cause wear and tear on the sensing devices, impacting their lifespan.

[0036] To improve the lifespan of detection devices, this application provides a power-down detection circuit and electronic device, which will be described below with reference to the accompanying drawings.

[0037] For example, please refer to Figure 1 As shown, Figure 1This is a first structural block diagram of a power-off detection circuit provided in an embodiment of this application. This application provides a power-off detection circuit 100, applied to electronic devices, such as air conditioners, refrigerators, washing machines, and other household appliances with power-off memory functions.

[0038] The power failure detection circuit 100 includes a detection module 110 and an amplification module 120. The detection module 110 is coupled to the mains power and generates an induced current when the mains power is on. The amplification module 120 is connected to the detection module 110 and amplifies the induced current, outputting a square wave signal.

[0039] It should be noted that when the mains power is on, the detection module 110 can detect the induced current, and the amplification module 120 outputs a square wave signal accordingly. When the mains power is off, the detection module 110 cannot detect the induced current, and the amplification module 120 outputs no electrical signal. Therefore, the mains power failure can be determined when the square wave signal of the amplification module 120 disappears. At this time, the electronic device can activate the power failure memory function to save the data.

[0040] In the power failure detection circuit 100 provided in this application embodiment, the current sensing of the mains power is performed by using a non-contact detection module 110, instead of the existing contact-type power failure detection using resistors and optocouplers. The power failure status of the mains power can be detected based on the presence or absence of a square wave signal, and the loss of the detection module 110 due to mains power fluctuations can be reduced, thereby improving the service life of the detection module 110.

[0041] For example, please refer to Figure 2 As shown, Figure 2 This is a second structural block diagram of the power-off detection circuit provided in the embodiments of this application. The detection module 110 includes an induction coil L1, which is electromagnetically coupled to the mains power line and generates an induced current. The induction coil L1 can also be understood as an antenna, as one end of the induction coil L1 is connected to the amplification module 120, and the other end of the induction coil L1 is a free end. The induction coil L1 is mainly used for electromagnetic coupling with the mains power line to generate an induced current.

[0042] It should be noted that, in order to increase the signal coupling strength, another induction coil L2 can be installed on the mains power line; in other words, the other induction coil L2 is an inductance loop formed by the mains power circuit board traces. Furthermore, the distance between the other induction coil L2 and the induction coil L1 is a fixed value.

[0043] In this regard, please combine Figure 2 And see Figure 3 As shown, Figure 3This is a schematic diagram of the detection module in the power-down detection circuit provided in an embodiment of this application. The winding methods of induction coil L1 and another induction coil L2 can be found in [reference needed]. Figure 3 As shown in the image.

[0044] For example, please continue reading Figure 2 As shown, the amplification module 120 includes a first amplification unit 121, a second amplification unit 122, and a level inversion unit 123.

[0045] One input terminal of the first amplification unit 121 is connected to the induction coil L1, and the other input terminal of the first amplification unit 121 is grounded to GND and connected to the output terminal of the first amplification unit 121. The first amplification unit 121 is used to amplify the induced current.

[0046] The second amplification unit 122 is connected between the induction coil L1 and an input terminal of the first amplification unit 121. The second amplification unit 122 is used to amplify the induced current and then input it into the first amplification unit 121 for further amplification.

[0047] The level inversion unit 123 is connected between the first amplification unit 121 and the second amplification unit 122. The level inversion unit 123 is used to convert the induced current into a square wave signal that is in phase with the sine wave.

[0048] It should be noted that in this embodiment, the induced current is amplified by the first amplification unit 121 and the second amplification unit 122 respectively, which can balance the amplification factor and the voltage value, and prevent circuit imbalance caused by excessive voltage value. The level inversion unit 123 converts the induced current into a square wave signal in phase with the sine wave, which can be easily recognized by the MCU.

[0049] For example, please refer to Figure 4 As shown, Figure 4 This is a circuit diagram of the power-down detection circuit provided in an embodiment of this application. The first amplification unit 121 includes an operational amplifier U1. The non-inverting input terminal of the operational amplifier U1 is connected to the level inversion unit 123, and the inverting input terminal of the operational amplifier U1 is grounded to GND and connected to the output terminal of the operational amplifier U1.

[0050] The second amplification unit 122 includes a first transistor Q1 and a second transistor Q2. The base of the first transistor Q1 is connected to the induction coil L1, the collector of the first transistor Q1 is connected to the power supply, and the emitter of the first transistor Q1 is connected to the base of the second transistor Q2. The collector of the second transistor Q2 is connected to the power supply, and the emitter of the second transistor Q2 is grounded to GND. The first transistor Q1 and the second transistor Q2 are of the same type, which simplifies the arrangement of the components.

[0051] The level inversion unit 123 includes a third transistor Q3. The base of the third transistor Q3 is connected to the collector of the second transistor Q2, the emitter of the third transistor Q3 is connected to a power supply, and the collector of the third transistor Q3 is connected to the non-inverting input of the operational amplifier U1. The third transistor Q3 is of a different type than the first transistor Q1, because the third transistor Q3 is mainly used to achieve level inversion, while the first transistor Q1 is used to amplify the current.

[0052] The following will describe the components that provide circuit protection in each module or unit.

[0053] For example, the detection module 110 further includes a first resistor R1 and a diode D1. One end of the first resistor R1 is connected to the induction coil L1, the anode of the diode D1 is connected to the other end of the first resistor R1, and the cathode of the diode D1 is connected to the power supply. The diode D1 serves as overvoltage protection, and the first resistor R1 is a current-limiting resistor.

[0054] For example, the second amplification unit 122 also includes a second resistor R2 and a third resistor R3.

[0055] One end of the second resistor R2 is connected to the collector of the first transistor Q1, and the other end of the second resistor R2 is connected to the power supply. The second resistor R2 is a current-limiting resistor.

[0056] One end of the third resistor R3 is connected to the collector of the second transistor Q2, and the other end of the third resistor R3 is connected to the power supply. The third resistor R3 is also a current-limiting resistor.

[0057] For example, the level inversion unit 123 further includes a fourth resistor R4 and a first capacitor C1. One end of the fourth resistor R4 is connected to the collector of the third transistor Q3, and the other end of the fourth resistor R4 is connected to one end of the first capacitor C1, the other end of the first capacitor C1 being grounded (GND). The fourth resistor R4 and the first capacitor C1 form a low-pass filter unit for filtering out high-frequency noise.

[0058] For example, the first amplification unit 121 also includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a second capacitor C2.

[0059] One end of the fifth resistor R5 is connected to the non-inverting input of operational amplifier U1, and the other end of the fifth resistor R5 is grounded (GND). The fifth resistor R5 is a pull-down resistor.

[0060] One end of the sixth resistor R6 is connected to the inverting input of operational amplifier U1, and the other end is grounded (GND). One end of the seventh resistor R7 is connected to one end of the sixth resistor R6, and the other end is connected to the output of operational amplifier U1. The second capacitor C2 is connected in parallel with the seventh resistor R7. The sixth resistor R6, the seventh resistor R7, and the second capacitor C2 together form a non-inverting amplifier.

[0061] One end of the eighth resistor R8 is connected to the output of operational amplifier U1, and the other end of the eighth resistor R8 is used to connect to a device such as an MCU or controller to transmit the square wave signal output by the amplifier module 120 to the MCU or controller for processing. The eighth resistor R8 is also a current-limiting resistor.

[0062] It should be noted that the detection principle of this application embodiment is based on the principle of electric field induction. When voltage passes through a wire, an induced electric field is formed around it. If a wire is placed near the wire, it will be affected by the induced electric field and generate a voltage. In this application embodiment, an induction coil L1 is formed through circuit board traces, thereby detecting whether the mains power is on. After two stages of amplification by the first transistor Q1 and the second transistor Q2, and then three stages of amplification by the operational amplifier U1, a pulse voltage that can be used for detection by a microcontroller is finally formed.

[0063] For example, the operation of the power-down detection circuit 100 in this application embodiment is as follows: the induction coil L1 receives the induced voltage and current, causing the first transistor Q1 to enter the amplification operating region and be slightly turned on. The collector of the first transistor Q1 forms a voltage difference with the base of the second transistor Q2, so that the second transistor Q2 also enters the amplification region or saturation region. The third transistor Q3, through level inversion, can make the microcontroller receive a square wave in phase with the sine wave, which is beneficial for detection. After the induced noise is filtered out by the low-pass filter composed of the fourth resistor R4 and the first capacitor C1, it is input to the operational amplifier U1. Since the input impedance of the operational amplifier U1 is theoretically infinite, it can effectively reduce the signal attenuation of the pre-amplifier circuit. After amplification such as 50 times in phase, a square wave signal can be obtained. The duration of the square wave signal can be such as 7ms, and the voltage is greater than half of the power supply voltage, which can be detected by the main control board MCU. When the mains power fails, or when the power failure detection circuit 100 fails, the induced voltage or induced current disappears, and the square wave signal disappears accordingly. The MCU detects the disappearance of the square wave signal and then enters the power failure memory data, thus realizing the power failure detection function.

[0064] In the power failure detection circuit 100 provided in this application embodiment, a non-contact detection module 110 is used to sense the mains current, replacing the existing contact-based power failure detection using resistors and optocouplers. This allows for the detection of the mains power failure state based on the presence or absence of a square wave signal, reducing the losses to the detection module 110 caused by mains power fluctuations, thereby extending the lifespan of the detection module 110. Furthermore, the coupling current is smaller during surge impacts, reducing the impact on the current in the power failure detection circuit 100.

[0065] In some embodiments, the amplification module may include only a first amplification unit and a level inversion unit. The level inversion unit can be referred to the above description and will not be repeated here. The first amplification unit includes an operational amplifier. The non-inverting input terminal of the operational amplifier is connected to the induction coil through the level inversion unit, and the inverting input terminal of the operational amplifier is grounded and connected to the output terminal of the operational amplifier. Using an operational amplifier for one-stage amplification is sufficient, resulting in a simpler circuit structure and saving on the installation of electrical components.

[0066] In some embodiments, the amplification module may include a first amplification unit, a second amplification unit, and a level inversion unit. The first amplification unit and the level inversion unit are as described above and will not be repeated here. The second amplification unit may consist of only one transistor; for example, the second amplification unit may include a first transistor, with the base of the first transistor connected to the induction coil, the collector of the first transistor connected to the power supply through a current-limiting resistor, and the emitter of the first transistor connected to the first amplification unit through the level inversion unit. The induced current undergoes a first-stage amplification through the second amplification unit, and then a second-stage amplification through the first amplification unit, which can also save on the number of electrical components.

[0067] This application also provides an electronic device, which can be a household appliance such as an air conditioner, refrigerator, or washing machine. The electronic device includes the power failure detection circuit described above. The specific structure of the power failure detection circuit is as described in the above embodiments. Since this electronic device 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.

[0068] 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.

[0069] 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.

[0070] The power-down detection circuit and electronic device 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 power-down detection circuit, applied to electronic devices, characterized in that, The power failure detection circuit includes: The detection module is used to be coupled to the mains power and to generate an induced current when the mains power is powered on. An amplification module is connected to the detection module. The amplification module is used to amplify the induced current and output a square wave signal.

2. The power failure detection circuit according to claim 1, characterized in that, The detection module includes: An induction coil is electromagnetically coupled to a mains power line to generate the induced current.

3. The power failure detection circuit according to claim 2, characterized in that, The amplification module includes: A first amplification unit has one input terminal connected to the induction coil and the other input terminal grounded and connected to the output terminal of the first amplification unit. The first amplification unit is used to amplify the induced current.

4. The power failure detection circuit according to claim 3, characterized in that, The amplification module also includes: The second amplification unit is connected between the induction coil and an input terminal of the first amplification unit. The second amplification unit is used to amplify the induced current and then input it into the first amplification unit for further amplification. A level inversion unit is connected between the first amplification unit and the second amplification unit. The level inversion unit is used to convert the induced current into a square wave signal that is in phase with the sine wave.

5. The power failure detection circuit according to claim 4, characterized in that, The first amplification unit includes: An operational amplifier, wherein the non-inverting input terminal of the operational amplifier is connected to the level inversion unit, and the inverting input terminal of the operational amplifier is grounded and connected to the output terminal of the operational amplifier.

6. The power failure detection circuit according to claim 5, characterized in that, The second amplification unit includes: The first transistor has its base connected to the induction coil, its collector connected to a power supply, and its emitter grounded.

7. The power failure detection circuit according to claim 6, characterized in that, The second amplification unit also includes: The base of the second transistor is connected to the emitter of the first transistor, the collector of the second transistor is connected to the power supply, and the emitter of the second transistor is grounded.

8. The power failure detection circuit according to claim 7, characterized in that, The level inversion unit includes: The third transistor has its base connected to the collector of the second transistor, its emitter connected to a power supply, and its collector connected to the non-inverting input of the operational amplifier.

9. The power failure detection circuit according to claim 2, characterized in that, The detection module also includes: A first resistor, one end of which is connected to the induction coil; A diode, wherein the positive terminal of the diode is connected to the other end of the first resistor, and the negative terminal of the diode is connected to a power source.

10. An electronic device, characterized in that, Includes the power failure detection circuit as described in any one of claims 1 to 9.

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