Overvoltage protection circuit and refrigerator

Abstract

The utility model discloses an overvoltage protection circuit and a refrigerator, the overvoltage protection circuit comprises a voltage detection module, a protection module and a voltage output module, the detection module is connected with the protection module, the protection module is connected with the voltage output module, and the voltage output module is connected with a display panel. Wherein the voltage detection module is used for accessing a power supply voltage and outputting an overvoltage detection signal when the power supply voltage is greater than a preset reference voltage; the protection module is used for outputting an overvoltage protection signal according to the overvoltage detection signal; the voltage output module is used for accessing power supply voltage and being connected with the display panel, and the voltage output module is further used for controlling the display panel to be powered off according to the overvoltage protection signal, so that the phenomenon that the display panel is burnt out due to the fact that the power supply voltage of the display panel is larger than the voltage needed by the display panel is avoided, and overvoltage protection on the display panel is achieved.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, specifically to an overvoltage protection circuit and a refrigerator. Background Technology

[0002] The current display board has a power input of +5V and +12V. During the assembly and power-on process of the display board, since the input voltage is fixed, there is no problem when the input voltage is +12V. However, when the display board is installed with +5V, it will cause overvoltage and burn out the display board.

[0003] Therefore, the technology still needs to be improved and enhanced. Utility Model Content

[0004] This application provides an overvoltage protection circuit and a refrigerator, which can effectively alleviate the problem of damage to the display panel in the refrigerator due to excessive input voltage.

[0005] This application provides an overvoltage protection circuit for use in a refrigerator, which includes a display panel. The overvoltage protection circuit includes:

[0006] The voltage detection module is used to connect to the supply voltage and outputs an overvoltage detection signal when the supply voltage is greater than the preset reference voltage.

[0007] The protection module is connected to the voltage detection module and is used to output an overvoltage protection signal based on the overvoltage detection signal.

[0008] The voltage output module is connected to the protection module and is used to connect to the power supply voltage and the display panel. The voltage output module is also used to control the power off of the display panel according to the overvoltage protection signal.

[0009] In some embodiments of the overvoltage protection circuit, the voltage detection module includes a voltage divider unit, a detection unit, and a reference voltage output unit. The voltage divider unit and the reference voltage output unit are both connected to the detection unit, and the detection unit is also connected to the protection module.

[0010] The voltage divider unit is used to input the power supply voltage, and after sampling the power supply voltage, it outputs the sampled voltage.

[0011] The reference voltage output unit is used to input the supply voltage and convert the supply voltage to output a preset reference voltage;

[0012] The detection unit is used to compare the sampled voltage with a preset reference voltage. When the sampled voltage is greater than the preset reference voltage, an overvoltage detection signal is output.

[0013] In some embodiments of the overvoltage protection circuit, the voltage divider unit includes a first resistor and a second resistor. One end of the first resistor is used to connect to the power supply voltage, and the other end of the first resistor and one end of the second resistor are both connected to the detection unit. The other end of the second resistor is grounded.

[0014] In some embodiments of the overvoltage protection circuit, the reference voltage output unit includes a first capacitor, a second capacitor, and a voltage regulator. The input terminal of the voltage regulator is used to connect to the power supply voltage, and the output terminal of the voltage regulator is connected to the detection unit. One end of the first capacitor is connected to the input terminal of the voltage regulator, and one end of the second capacitor is connected to the output terminal of the voltage regulator. The ground terminal of the voltage regulator, one end of the first capacitor, and one end of the second capacitor are all grounded.

[0015] In some embodiments of the overvoltage protection circuit, the detection unit includes a third resistor and a comparator. The non-inverting input of the comparator is connected to the output of the voltage regulator, the inverting input of the comparator is connected to the other end of the first resistor, the output of the comparator is connected to the protection module, one end of the third resistor is energized, and the other end of the third resistor is connected to the output of the comparator.

[0016] In some embodiments of the overvoltage protection circuit, the protection module includes a fourth resistor, a fifth resistor, and a first switching transistor. One end of the fourth resistor is connected to the output terminal of the comparator, and the other end of the fourth resistor and one end of the fifth resistor are both connected to the first terminal of the first switching transistor. The second terminal of the first switching transistor and the other end of the fifth resistor are both grounded, and the third terminal of the first switching transistor is connected to the voltage output module.

[0017] In some embodiments of the overvoltage protection circuit, the voltage output module includes a sixth resistor, a seventh resistor, and a second switching transistor. One end of the sixth resistor is connected to the third end of the first switching transistor, and the other end of the sixth resistor and one end of the seventh resistor are both connected to the first end of the second switching transistor. The second end of the second switching transistor and the other end of the seventh resistor are used to connect to the power supply voltage, and the third end of the second switching transistor is used to connect to the display panel.

[0018] In some embodiments of the overvoltage protection circuit, the overvoltage protection circuit further includes a filtering unit connected to the voltage divider unit, and the filtering unit is used to filter the sampled voltage.

[0019] In some embodiments of the overvoltage protection circuit, the filter unit includes a third capacitor, one end of which is connected to the voltage divider unit, and the other end of which is grounded.

[0020] This application also discloses a refrigerator, which includes a display panel and the overvoltage protection circuit described above, with the overvoltage protection circuit connected to the display panel.

[0021] This application provides an overvoltage protection circuit and a refrigerator. The voltage detection module in the overvoltage protection circuit compares the supply voltage with a preset reference voltage. When the supply voltage is greater than the preset reference voltage, it outputs an overvoltage detection signal. The protection module outputs an overvoltage protection signal based on the overvoltage detection signal. The voltage output module controls the display panel to cut off power based on the overvoltage protection signal, thereby preventing the supply voltage of the display panel from exceeding the voltage required by the display panel and burning out the display panel, thus achieving overvoltage protection for the display panel. Attached Figure Description

[0022] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0023] Figure 1 This is a structural block diagram of the overvoltage protection circuit provided in an embodiment of this application.

[0024] Figure 2 A circuit diagram of an overvoltage protection circuit provided in an embodiment of this application. Detailed Implementation

[0025] 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.

[0026] Furthermore, 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. Features thus defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0027] Please see Figure 1 This embodiment provides an overvoltage protection circuit, which is applied in a refrigerator. The refrigerator includes a display panel 10. The overvoltage protection circuit is used to detect the power supply voltage VCC of the display panel 10 in order to realize overvoltage protection for the display panel 10.

[0028] Specifically, the overvoltage protection circuit includes a voltage detection module 100, a protection module 200, and a voltage output module 300. The detection module is connected to the protection module 200, the protection module 200 is connected to the voltage output module 300, and the voltage output module 300 is connected to the display panel 10. The voltage detection module 100 is used to connect to the supply voltage VCC and outputs an overvoltage detection signal when the supply voltage VCC exceeds a preset reference voltage. The protection module 200 is used to output an overvoltage protection signal based on the overvoltage detection signal. The voltage output module 300 is connected to the supply voltage VCC and the display panel 10. The voltage output module 300 also controls the display panel 10 to power off based on the overvoltage protection signal, thereby preventing the supply voltage VCC of the display panel 10 from exceeding the voltage required by the display panel 10 and burning out the display panel 10, thus achieving effective protection for the display panel 10.

[0029] Please see Figure 2 In some embodiments, the voltage detection module 100 includes a voltage divider unit 110, a detection unit 120, and a reference voltage output unit 130. The voltage divider unit 110 and the reference voltage output unit 130 are both connected to the detection unit 120, and the detection unit 120 is also connected to the protection module 200.

[0030] The voltage divider unit 110 is used to connect to the power supply voltage VCC, sample the power supply voltage VCC, and output a sampled voltage. The reference voltage output unit 130 is used to connect to the power supply voltage VCC, convert the power supply voltage VCC, and output a preset reference voltage. The detection unit 120 is used to compare the sampled voltage with the preset reference voltage. When the sampled voltage is greater than the preset reference voltage, an overvoltage detection signal is output. The protection module 200 outputs an overvoltage protection signal to the voltage output module 300 based on the overvoltage detection signal. The voltage output module 300 then disconnects the display panel 10 from the power supply voltage VCC based on the overvoltage protection signal, thereby de-energizing the display panel 10 and protecting it. The detection unit 120 compares the sampled voltage with the preset reference voltage. When the sampled voltage is not greater than the preset reference voltage, a detection signal is output. The protection module 200 outputs a feedback signal to the voltage output module 300, causing the voltage output module 300 to connect the power supply voltage VCC to the display panel 10 to supply power.

[0031] Please continue reading. Figure 2In one embodiment, the voltage divider unit 110 includes a first resistor R1 and a second resistor R2. One end of the first resistor R1 is connected to the supply voltage VCC, and the other end of the first resistor R1 and one end of the second resistor R2 are both connected to the detection unit 120. The other end of the second resistor R2 is grounded. In this embodiment, a voltage divider circuit is formed by the first resistor R1 and the second resistor R2 to sample the supply voltage VCC and obtain a sampled voltage, so as to realize the detection of the magnitude of the supply voltage VCC.

[0032] In one embodiment, the reference voltage output unit 130 includes a first capacitor C1, a second capacitor C2, and a voltage regulator LDO. The input terminal of the voltage regulator LDO is connected to the supply voltage VCC, and the output terminal of the voltage regulator LDO is connected to the detection unit 120. One end of the first capacitor C1 is connected to the input terminal of the voltage regulator LDO, and one end of the second capacitor C2 is connected to the output terminal of the voltage regulator LDO. The ground terminal of the voltage regulator LDO, one end of the first capacitor C1, and one end of the second capacitor C2 are all grounded. In this embodiment, the voltage regulator LDO is used to convert the output supply voltage VCC and output a preset reference voltage, which is lower than the supply voltage VCC. The first capacitor C1 and the second capacitor C2 are decoupling capacitors used to filter the input supply voltage VCC and the output preset reference voltage to improve circuit stability.

[0033] As one embodiment, the detection unit 120 includes a third resistor R3 and a comparator OP1. The non-inverting input of the comparator OP1 is connected to the output of the voltage regulator LDO, the inverting input of the comparator OP1 is connected to the other end of the first resistor R1, the output of the comparator OP1 is connected to the protection module 200, one end of the third resistor R3 is energized, and the other end of the third resistor R3 is connected to the output of the comparator OP1.

[0034] When the sampled voltage is greater than the preset reference voltage, comparator OP1 outputs a low-level signal as an overvoltage detection signal; when the sampled voltage is not greater than the preset reference voltage, comparator OP1 outputs a high-level signal as a detection signal, thereby detecting the magnitude of the supply voltage VCC. The third resistor R3 is a pull-up resistor, which enables the overvoltage detection signal and the detection signal output by comparator OP1 to serve as control signals for the protection module 200, facilitating subsequent overvoltage protection.

[0035] In one embodiment, the protection module 200 includes a fourth resistor R4, a fifth resistor R5, and a first switching transistor Q1. One end of the fourth resistor R4 is connected to the output terminal of comparator OP1. The other end of the fourth resistor R4 and one end of the fifth resistor R5 are both connected to the first terminal of the first switching transistor Q1. The second terminal of the first switching transistor Q1 and the other end of the fifth resistor R5 are both grounded. The third terminal of the first switching transistor Q1 is connected to the voltage output module 300. In this embodiment, the first switching transistor Q1 can be a transistor. The first terminal of the first switching transistor Q1 is the base of the transistor, the second terminal of the first switching transistor Q1 is the emitter of the transistor, and the third terminal of the first switching transistor Q1 is the collector of the transistor. When comparator OP1 outputs a low-level signal, the first switching transistor Q1 is turned off to output an overvoltage protection signal to the voltage output module 300; when comparator OP1 outputs a high-level signal, the first switching transistor Q1 is turned on to output a feedback signal to the voltage output module 300.

[0036] In one embodiment, the voltage output module 300 includes a sixth resistor R6, a seventh resistor R7, and a second switch Q2. One end of the sixth resistor R6 is connected to the third terminal of the first switch Q1, and the other end of the sixth resistor R6 and one end of the seventh resistor R7 are both connected to the first terminal of the second switch Q2. The second terminal of the second switch Q2 and the other end of the seventh resistor R7 are used to connect to the power supply voltage VCC. The third terminal of the second switch Q2 is used to connect to the display panel 10. In this embodiment, the second switch Q2 is a MOSFET. The first terminal of the second switch Q2 is the gate of the MOSFET, the second terminal of the second switch Q2 is the source of the MOSFET, and the third terminal of the second switch Q2 is the drain of the MOSFET. When the first switch Q1 is off, the second switch Q2 is off, thus disconnecting the power supply voltage VCC from the display panel 10; when the first switch Q1 is on, the second switch Q2 is on, thus connecting the power supply voltage VCC to the display panel 10, ensuring that the display panel 10 is powered.

[0037] In one embodiment, the overvoltage protection circuit further includes a filtering unit 140, which is connected to the voltage divider unit 110. The filtering unit 140 is used to filter the sampled voltage. The filtering unit 140 includes a third capacitor C3, one end of which is connected to the voltage divider unit 110, and the other end of which is grounded. In this embodiment, the third capacitor C3 is a decoupling capacitor. The filtering of the sampled voltage by the third capacitor C3 achieves noise reduction, thereby improving the stability of the circuit.

[0038] To explain the working principle of this overvoltage protection circuit in detail, the following describes the working process of the overvoltage protection circuit in conjunction with a specific embodiment:

[0039] If display panel 10 is powered by +5V, when the supply voltage VCC is 12V, the inverting input of comparator OP1 is the sampling voltage of the voltage divider between the first resistor R1 and the second resistor R2. After the +12V input voltage is divided by the first resistor R1 and the second resistor R2, the voltage sampled by the inverting input of comparator OP1 is 6V. The voltage regulator LDO converts the supply voltage VCC to a voltage of +3.3V. At this time, the voltage sampled by the non-inverting input of comparator OP1 is +3.3V. Since the non-inverting input voltage of comparator OP1 is less than the inverting input voltage, comparator OP1 outputs a low-level signal. Because the base of the transistor is connected to the output of comparator OP1, the base level of the transistor is low, the transistor does not conduct, the MOSFET does not conduct, and the supply voltage VCC cannot reach the display panel 10 through the MOSFET, protecting the display panel 10 from damage by high voltage.

[0040] When the supply voltage VCC is +5V, the sampling voltage obtained by the voltage division of the first resistor R1 and the second resistor R2 is 2.5V. The inverting input of comparator OP1 receives a voltage of 2.5V. The LDO regulator converts the supply voltage VCC to obtain a preset reference voltage, which is +3.3V. Therefore, the non-inverting input of comparator OP1 receives a voltage of +3.3V. Since the non-inverting input voltage of comparator OP1 (+3.3V) is greater than the inverting input voltage (+2.5V), comparator OP1 is forward biased and outputs a high-level signal. Because the base of the transistor is connected to the output of comparator OP1, the base of the transistor is at a high level, the transistor conducts, the MOSFET conducts, and the +5V supply voltage VCC reaches the display panel 10 through the MOSFET, allowing the display panel 10 to operate normally.

[0041] This application also provides a refrigerator that includes the overvoltage protection circuit described above. Since the overvoltage protection circuit has been described in detail above, it will not be repeated here.

[0042] 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.

[0043] The overvoltage protection circuit provided in the embodiments of this application has 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 technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An overvoltage protection circuit, characterized in that, Applied in a refrigerator, the refrigerator includes a display panel, and the overvoltage protection circuit includes: A voltage detection module is used to receive the power supply voltage, and when the power supply voltage is greater than a preset reference voltage, it outputs an overvoltage detection signal. A protection module is connected to a voltage detection module, and the protection module is used to output an overvoltage protection signal based on the overvoltage detection signal. A voltage output module is connected to the protection module and is used to connect to the power supply voltage and the display panel. The voltage output module is also used to control the power off of the display panel according to the overvoltage protection signal.

2. The overvoltage protection circuit according to claim 1, characterized in that, The voltage detection module includes a voltage divider unit, a detection unit, and a reference voltage output unit. The voltage divider unit and the reference voltage output unit are both connected to the detection unit, and the detection unit is also connected to the protection module. The voltage divider unit is used to receive the power supply voltage, and to sample the power supply voltage and output a sampled voltage. The reference voltage output unit is used to receive the supply voltage and convert the supply voltage to output the preset reference voltage; The detection unit is used to compare the sampled voltage with the preset reference voltage, and outputs the overvoltage detection signal when the sampled voltage is greater than the preset reference voltage.

3. The overvoltage protection circuit according to claim 2, characterized in that, The voltage divider unit includes a first resistor and a second resistor. One end of the first resistor is used to connect to the power supply voltage, and the other end of the first resistor and one end of the second resistor are both connected to the detection unit. The other end of the second resistor is grounded.

4. The overvoltage protection circuit according to claim 3, characterized in that, The reference voltage output unit includes a first capacitor, a second capacitor, and a voltage regulator. The input terminal of the voltage regulator is used to connect to the power supply voltage, and the output terminal of the voltage regulator is connected to the detection unit. One end of the first capacitor is connected to the input terminal of the voltage regulator, and one end of the second capacitor is connected to the output terminal of the voltage regulator. The ground terminal of the voltage regulator, one end of the first capacitor, and one end of the second capacitor are all grounded.

5. The overvoltage protection circuit according to claim 4, characterized in that, The detection unit includes a third resistor and a comparator. The non-inverting input of the comparator is connected to the output of the voltage regulator, the inverting input of the comparator is connected to the other end of the first resistor, the output of the comparator is connected to the protection module, one end of the third resistor is energized, and the other end of the third resistor is connected to the output of the comparator.

6. The overvoltage protection circuit according to claim 5, characterized in that, The protection module includes a fourth resistor, a fifth resistor, and a first switching transistor. One end of the fourth resistor is connected to the output terminal of the comparator. The other end of the fourth resistor and one end of the fifth resistor are both connected to the first terminal of the first switching transistor. The second terminal of the first switching transistor and the other end of the fifth resistor are both grounded. The third terminal of the first switching transistor is connected to the voltage output module.

7. The overvoltage protection circuit according to claim 6, characterized in that, The voltage output module includes a sixth resistor, a seventh resistor, and a second switching transistor. One end of the sixth resistor is connected to the third end of the first switching transistor, and the other end of the sixth resistor and one end of the seventh resistor are both connected to the first end of the second switching transistor. The second end of the second switching transistor and the other end of the seventh resistor are used to connect to the power supply voltage, and the third end of the second switching transistor is used to connect to the display panel.

8. The overvoltage protection circuit according to any one of claims 2-7, characterized in that, The overvoltage protection circuit further includes a filtering unit, which is connected to the voltage divider unit and is used to filter the sampled voltage.

9. The overvoltage protection circuit according to claim 8, characterized in that, The filtering unit includes a third capacitor, one end of which is connected to the voltage divider unit, and the other end of which is grounded.

10. A refrigerator, characterized in that, The refrigerator includes a display panel and an overvoltage protection circuit as described in any one of claims 1-9, wherein the overvoltage protection circuit is connected to the display panel.

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