Overvoltage protection circuit and power supply

Abstract

The utility model provides an overvoltage protection circuit and a power supply. The overvoltage protection circuit comprises an acquisition circuit, a voltage stabilizing circuit and an adjusting circuit. The input end of the acquisition circuit is connected with the output end of a pre-stage circuit of the power supply; one input end of the voltage stabilizing circuit is connected with the output end of the acquisition circuit, and the output end of the voltage stabilizing circuit is grounded; the adjusting circuit comprises a primary circuit and a secondary circuit, the input end of the primary circuit is connected with the output end of the pre-stage circuit, the output end of the primary circuit is connected with the other input end of the voltage stabilizing circuit, and the secondary circuit is connected with a control chip of the pre-stage circuit. According to the utility model, the overvoltage protection circuit can be simplified, and the cost can be lower.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply, in particular to an overvoltage protection circuit and a power supply. Background Art

[0002] A power supply is usually provided with an overvoltage protection circuit to ensure the safety of the chip inside the power supply to prevent the chip from being damaged due to a high voltage. However, the overvoltage protection circuit of most power supplies is not only complex in structure, but also expensive. Utility Model Content

[0003] The utility model provides an overvoltage protection circuit and a power supply, aiming to solve the problems of complex structure and high cost of the current overvoltage protection circuit.

[0004] In a first aspect, the utility model provides an overvoltage protection circuit, which includes an acquisition circuit, a voltage stabilizing circuit and an adjustment circuit; the input end of the acquisition circuit is connected to the output end of the front-stage circuit of the power supply; an input end of the voltage stabilizing circuit is connected to the output end of the acquisition circuit, and the output end of the voltage stabilizing circuit is grounded; the adjustment circuit includes a primary circuit and a secondary circuit, the input end of the primary circuit is connected to the output end of the front-stage circuit, the output end of the primary circuit is connected to another input end of the voltage stabilizing circuit, and the secondary circuit is connected to the control chip of the front-stage circuit.

[0005] Furthermore, the adjustment circuit includes a photosensitive component, which includes a primary device and a secondary device; the primary device is connected to the output end of the previous circuit and the input end of the voltage stabilizing circuit as the primary circuit of the adjustment circuit, and the secondary device is connected to the control chip as the secondary circuit of the adjustment circuit.

[0006] Furthermore, the primary device is a light emitting diode, the anode of the light emitting diode is connected to the output end of the front-stage circuit, and the cathode of the light emitting diode is connected to the voltage stabilizing circuit.

[0007] Furthermore, the secondary device is a phototransistor, the collector of the phototransistor is connected to the control chip, and the emitter of the phototransistor is grounded.

[0008] Furthermore, the adjustment circuit further includes a first resistor, one end of the first resistor is connected to the output end of the previous stage circuit, and the other end of the first resistor is connected to the primary device.

[0009] Furthermore, the voltage stabilizing circuit includes a voltage stabilizing element, one input end of the voltage stabilizing element is connected to the primary device, the other input end of the voltage stabilizing element is connected to the output end of the acquisition circuit, and the output end of the voltage stabilizing element is grounded.

[0010] Furthermore, the acquisition circuit includes a voltage divider circuit, one end of the voltage divider circuit is connected to the front-stage circuit, and the other end of the voltage divider circuit is connected to the voltage stabilizing circuit.

[0011] Furthermore, the voltage divider circuit includes a second resistor and a third resistor; one end of the second resistor is connected to the previous stage circuit, the other end of the second resistor is respectively connected to the voltage stabilizing circuit and one end of the third resistor, and the other end of the third resistor is grounded.

[0012] Furthermore, the acquisition circuit further includes a first capacitor, one end of the first capacitor is connected to the second resistor, and the other end of the first capacitor is grounded.

[0013] In a second aspect, the utility model further provides a power supply, which includes a control chip and any of the above-mentioned overvoltage protection circuits.

[0014] The power supply disclosed by the utility model comprises an overvoltage protection circuit and a control chip. The overvoltage protection circuit comprises a collection circuit, a voltage stabilizing circuit and an adjustment circuit. The collection circuit collects the output voltage of the front-stage circuit and outputs it to the voltage stabilizing circuit. Meanwhile, the primary circuit of the adjustment circuit is respectively connected to the voltage stabilizing circuit and the front-stage circuit, and the secondary circuit is connected to the control chip. When the output voltage of the front-stage circuit increases, the resistance of the voltage stabilizing circuit decreases, and the current of the primary circuit increases, so that the resistance value of the secondary circuit decreases, thereby lowering the voltage of the control chip, and performing overvoltage protection on the control chip. The entire circuit structure is relatively simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a block diagram of an overvoltage protection circuit provided by an embodiment of the utility model;

[0017] Figure 2 It is a circuit diagram of an overvoltage protection circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0019] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, operations, elements, components and / or groups thereof.

[0020] It should also be understood that the terms used in this utility model specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model. As used in the utility model specification and the appended claims, the singular forms of "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in the utility model specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0021] In addition, the directional terms mentioned in the present invention, such as "upper", "lower", "front", "back", "left", "right", "inner", "outer", "side", etc., are only for reference to the directions of the attached drawings and the use status of the product. Therefore, the directional terms used are used to illustrate and understand the present invention, but not to limit the present invention. In addition, in the drawings, structures with similar or identical structures are represented by the same reference numerals.

[0022] See also Figure 1 to Figure 2 , Figure 1 1 is a block diagram of an overvoltage protection circuit 100 provided in one embodiment of the present utility model; Figure 2 FIG. 1 is a circuit diagram of an overvoltage protection circuit 100 provided in an embodiment of the present invention. Figure 1As shown, the overvoltage protection circuit 100 includes a collection circuit 10, a voltage stabilizing circuit 20 and an adjustment circuit 30; the input end of the collection circuit 10 is connected to the output end of the front-stage circuit 200 of the power supply; an input end of the voltage stabilizing circuit 20 is connected to the output end of the collection circuit 10, and the output end of the voltage stabilizing circuit 20 is grounded; the adjustment circuit 30 includes a primary circuit 31 and a secondary circuit 32, the input end of the primary circuit 31 is connected to the output end of the front-stage circuit 200, the output end of the primary circuit 31 is connected to the other input end of the voltage stabilizing circuit 20, and the secondary circuit 32 is connected to the control chip 300 of the front-stage circuit 200.

[0023] Specifically, the overvoltage protection circuit 100 may include a collection circuit 10, a voltage stabilizing circuit 20, and an adjustment circuit 30. The input end of the collection circuit 10 is connected to the output end of the front-stage circuit 200, and is used to collect the output voltage of the front-stage circuit 200. The collection circuit 10 may include a voltage dividing circuit composed of voltage dividing resistors, which divides the collected voltage and sends it to the voltage stabilizing circuit 20.

[0024] One input end of the voltage stabilizing circuit 20 is connected to the output end of the acquisition circuit 10, and is used to receive the output voltage output by the acquisition circuit 10. Another input end of the voltage stabilizing circuit 20 is connected to the output end of the primary circuit 31, and the output end of the voltage stabilizing circuit 20 is grounded. The voltage stabilizing circuit 20 may be provided with a reference voltage. The voltage stabilizing circuit 20 adjusts the resistance value of the voltage stabilizing circuit 20 according to the difference between the received output voltage output by the comparison circuit and the reference voltage, thereby controlling the current of the adjustment circuit 30.

[0025] The adjustment circuit 30 includes a primary circuit 31 and a secondary circuit 32. The secondary circuit 32 can change accordingly according to the current change of the primary circuit 31. For example, the resistance of the secondary circuit 32 can change accordingly according to the current of the primary circuit 31. The input end of the primary circuit 31 is connected to the output end of the pre-stage circuit 200, the output end of the primary circuit 31 is connected to the input end of the voltage stabilizing circuit 20, and the secondary circuit 32 is connected to the control chip 300.

[0026] When the output voltage received by the voltage stabilizing circuit 20 and output by the acquisition circuit 10 increases and is greater than its reference voltage, the resistance of the voltage stabilizing circuit 20 decreases, and the current of the front-stage circuit 200 flowing through the primary circuit 31 increases. The secondary circuit 32 detects the increase in the current of the primary circuit 31, and its resistance decreases accordingly, thereby lowering the voltage of the relevant pins of the control chip 300, causing the control chip 300 to turn off the output, thereby completing the overvoltage protection of the control chip 300.

[0027] See also Figure 2As a further embodiment, the adjustment circuit 30 includes a photosensitive component U1, and the photosensitive component U1 includes a primary device and a secondary device; the primary device is connected to the output end of the pre-stage circuit 200 and the input end of the voltage stabilizing circuit 20 as the primary circuit 31 of the adjustment circuit 30, and the secondary device is connected to the control chip 300 as the secondary circuit 32 of the adjustment circuit 30.

[0028] The photosensitive component U1 may include a primary device and a secondary device, the primary device may be a light emitting component, and the secondary device may be a photosensitive component. The primary device is connected between the front stage circuit 200 and the voltage stabilizing circuit 20. That is, the input end of the primary device is connected to the front stage circuit 200, the output end of the primary circuit 31 is connected to the voltage stabilizing circuit 20, and the secondary device is connected to the pin of the control chip 300.

[0029] When the output voltage received by the voltage stabilizing circuit 20 increases, the resistance of the voltage stabilizing circuit 20 decreases, the current flowing through the primary device of the front-stage circuit 200 increases, the brightness of the primary device increases, and after the secondary device senses the increase in the brightness of the primary device, its internal resistance decreases, thereby lowering the voltage of the control chip 300.

[0030] As a further embodiment, the primary device is a light emitting diode, the positive electrode of the light emitting diode is connected to the output end of the pre-stage circuit 200 , and the negative electrode of the light emitting diode is connected to the voltage stabilizing circuit 20 .

[0031] The primary device may be a light emitting diode, the positive electrode of the light emitting diode is connected to the front stage circuit 200, and the negative electrode of the light emitting diode is connected to the voltage stabilizing circuit 20. When the output voltage received by the voltage stabilizing circuit 20 increases, the internal resistance of the voltage stabilizing circuit 20 decreases, the current flowing through the light emitting diode of the front stage circuit 200 increases, the brightness of the light emitting diode increases, and the internal resistance of the secondary device decreases, thereby lowering the voltage of the control chip 300.

[0032] As a further embodiment, the secondary device is a phototransistor, the collector of the phototransistor is connected to the control chip 300, and the emitter of the phototransistor is grounded.

[0033] Among them, the secondary device can be a phototransistor, the gate of which can sense the change in the brightness of the light-emitting diode. When the brightness of the light-emitting diode increases, the internal resistance of the phototransistor decreases, thereby lowering the voltage of the control chip 300. The light-emitting diode and the phototransistor can improve the accuracy of the overvoltage protection circuit 100, and further improve the protection capability of the control chip 300.

[0034] As a further embodiment, the adjustment circuit 30 further includes a first resistor R1 , one end of the first resistor R1 is connected to the output end of the pre-stage circuit 200 , and the other end of the first resistor R1 is connected to the primary device.

[0035] The first resistor R1 is used as a current limiting resistor, one end of which is connected to the front-stage circuit 200 and the other end of which is connected to the primary device, so as to protect the primary device and prevent the primary device from being damaged by excessive current.

[0036] As a further embodiment, the voltage stabilizing circuit 20 includes a voltage stabilizing element U2, one input end of the voltage stabilizing element U2 is connected to the primary device, the other input end of the voltage stabilizing element U2 is connected to the output end of the acquisition circuit 10, and the output end of the voltage stabilizing element U2 is grounded.

[0037] The voltage stabilizing circuit 20 may include a voltage stabilizing element U2, which is a voltage stabilizing source. One input end of the voltage stabilizing element U2 is connected to the primary device, and the other input end of the voltage stabilizing element U2 is connected to the output end of the acquisition circuit 10. The voltage stabilizing element U2 receives the output voltage output by the acquisition circuit 10. When the output voltage increases, the internal resistance of the voltage stabilizing element U2 decreases, so that the current of the primary device increases, thereby reducing the internal resistance of the secondary device and pulling down the voltage of the control chip 300.

[0038] As a further embodiment, the acquisition circuit 10 includes a voltage divider circuit 11 , one end of the voltage divider circuit 11 is connected to the pre-stage circuit 200 , and the other end of the voltage divider circuit 11 is connected to the voltage stabilizing circuit 20 .

[0039] Among them, one end of the voltage divider circuit 11 is connected to the previous stage circuit 200, and the other end of the voltage divider circuit 11 is connected to the voltage stabilizing circuit 20, and the voltage divider circuit 11 is also grounded, which is used to divide the collected voltage and send the divided voltage to the voltage stabilizing circuit 20.

[0040] As a further embodiment, the voltage divider circuit 11 includes a second resistor R2 and a third resistor R3; one end of the second resistor R2 is connected to the pre-stage circuit 200, the other end of the second resistor R2 is respectively connected to the voltage stabilizing circuit 20 and one end of the third resistor R3, and the other end of the third resistor R3 is grounded.

[0041] Among them, one end of the second resistor R2 is connected to the front-stage circuit 200, and the other end of the second resistor R2 is respectively connected to the third resistor R3 and the voltage stabilizing circuit 20, and the third resistor R3 is grounded. The second resistor R2 and the third resistor R3 are used as a voltage divider circuit 11 to divide the collected voltage. In addition, the trigger threshold of the overvoltage protection circuit 100 can also be adjusted by adjusting the resistance values ​​of the second resistor R2 and the third resistor R3. The trigger threshold of the overvoltage protection circuit 100 = (R2 / R3+1)*the reference voltage of the voltage stabilizer U2. For example, if the reference voltage of the voltage stabilizer U2 is 2.5V, the trigger threshold of the overvoltage protection circuit 100 = (R2 / R3+1)*2.5.

[0042] As a further embodiment, the acquisition circuit 10 further includes a first capacitor C1 , one end of the first capacitor C1 is connected to the second resistor R2 , and the other end of the first capacitor C1 is grounded.

[0043] The utility model also provides a power supply, which includes a control chip 300 and an overvoltage protection circuit 100 described in any one of the above embodiments; the overvoltage protection circuit 100 includes a collection circuit 10, a voltage stabilizing circuit 20 and an adjustment circuit 30; the input end of the collection circuit 10 is connected to the output end of the front-stage circuit 200 of the power supply; an input end of the voltage stabilizing circuit 20 is connected to the output end of the collection circuit 10, and the output end of the voltage stabilizing circuit 20 is grounded; the adjustment circuit 30 includes a primary circuit 31 and a secondary circuit 32, the input end of the primary circuit 31 is connected to the output end of the front-stage circuit 200, the output end of the primary circuit 31 is connected to the other input end of the voltage stabilizing circuit 20, and the secondary circuit 32 is connected to the control chip 300 of the front-stage circuit 200.

[0044] Specifically, the overvoltage protection circuit 100 may include a collection circuit 10, a voltage stabilizing circuit 20, and an adjustment circuit 30. The input end of the collection circuit 10 is connected to the output end of the front-stage circuit 200, and is used to collect the output voltage of the front-stage circuit 200. The collection circuit 10 may include a voltage dividing circuit 11 composed of voltage dividing resistors, which divides the collected voltage and sends it to the voltage stabilizing circuit 20.

[0045] One input end of the voltage stabilizing circuit 20 is connected to the output end of the acquisition circuit 10, and is used to receive the output voltage output by the acquisition circuit 10. Another input end of the voltage stabilizing circuit 20 is connected to the output end of the primary circuit 31, and the output end of the voltage stabilizing circuit 20 is grounded. The voltage stabilizing circuit 20 may be provided with a reference voltage. The voltage stabilizing circuit 20 adjusts the resistance value of the voltage stabilizing circuit 20 according to the difference between the received output voltage output by the comparison circuit and the reference voltage, thereby controlling the current of the adjustment circuit 30.

[0046] The adjustment circuit 30 includes a primary circuit 31 and a secondary circuit 32. The secondary circuit 32 can change accordingly according to the current change of the primary circuit 31. For example, the resistance of the secondary circuit 32 can change accordingly according to the current of the primary circuit 31. The input end of the primary circuit 31 is connected to the output end of the pre-stage circuit 200, the output end of the primary circuit 31 is connected to the input end of the voltage stabilizing circuit 20, and the secondary circuit 32 is connected to the control chip 300.

[0047] When the output voltage received by the voltage stabilizing circuit 20 and output by the acquisition circuit 10 increases and is greater than its reference voltage, the resistance of the voltage stabilizing circuit 20 decreases, and the current of the front-stage circuit 200 flowing through the primary circuit 31 increases. The secondary circuit 32 detects the increase in the current of the primary circuit 31, and its resistance decreases accordingly, thereby lowering the voltage of the relevant pins of the control chip 300, causing the control chip 300 to turn off the output, thereby completing the overvoltage protection of the control chip 300.

[0048] The overvoltage protection circuit 100 and the power supply disclosed in the present invention can simplify the overvoltage protection circuit 100 and reduce the cost of the overvoltage protection circuit 100.

[0049] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. An overvoltage protection circuit, characterized in that: Applicable to power supplies, including: A collection circuit, the input end of the collection circuit is connected to the output end of the front-stage circuit of the power supply; A voltage stabilizing circuit, wherein an input end of the voltage stabilizing circuit is connected to an output end of the acquisition circuit, and an output end of the voltage stabilizing circuit is grounded; The adjustment circuit includes a primary circuit and a secondary circuit, the input end of the primary circuit is connected to the output end of the previous circuit, the output end of the primary circuit is connected to another input end of the voltage stabilizing circuit, and the secondary circuit is connected to the control chip of the previous circuit.

2. The overvoltage protection circuit according to claim 1, characterized in that: The adjustment circuit includes a photosensitive element, and the photosensitive element includes a primary device and a secondary device; The primary device as the primary circuit of the adjustment circuit is connected to the output end of the previous circuit and the input end of the voltage stabilizing circuit respectively, and the secondary device as the secondary circuit of the adjustment circuit is connected to the control chip.

3. The overvoltage protection circuit according to claim 2, characterized in that: The primary device is a light emitting diode, the positive electrode of the light emitting diode is connected to the output end of the front-stage circuit, and the negative electrode of the light emitting diode is connected to the voltage stabilizing circuit.

4. The overvoltage protection circuit according to claim 3, characterized in that: The secondary device is a phototransistor, the collector of the phototransistor is connected to the control chip, and the emitter of the phototransistor is grounded.

5. The overvoltage protection circuit according to claim 2, characterized in that: The adjustment circuit further includes a first resistor, one end of which is connected to the output end of the front-stage circuit, and the other end of which is connected to the primary device.

6. The overvoltage protection circuit according to claim 2, characterized in that: The voltage stabilizing circuit comprises a voltage stabilizing element, one input end of the voltage stabilizing element is connected to the primary device, the other input end of the voltage stabilizing element is connected to the output end of the acquisition circuit, and the output end of the voltage stabilizing element is grounded.

7. The overvoltage protection circuit according to claim 2, characterized in that: The acquisition circuit includes a voltage divider circuit, one end of the voltage divider circuit is connected to the front-stage circuit, and the other end of the voltage divider circuit is connected to the voltage stabilizing circuit.

8. The overvoltage protection circuit according to claim 7, characterized in that: The voltage divider circuit includes a second resistor and a third resistor; One end of the second resistor is connected to the previous stage circuit, the other end of the second resistor is respectively connected to the voltage stabilizing circuit and one end of the third resistor, and the other end of the third resistor is grounded.

9. The overvoltage protection circuit according to claim 8, characterized in that: The acquisition circuit further includes a first capacitor, one end of the first capacitor is connected to the second resistor, and the other end of the first capacitor is grounded.

10. A power supply, characterized in that: It comprises a control chip and an overvoltage protection circuit as described in any one of claims 1 to 9.

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