Power supply protection circuit, power supply protection device and low-voltage direct current equipment

Abstract

The invention discloses a power supply protection circuit, a power supply protection device and low-voltage direct current equipment, and relates to the technical field of power supply circuits. The power supply protection device comprises a power supply input end and a power supply output end, and the power supply protection circuit comprises a rectification circuit with an input end electrically connected with the power supply input end; the rectifying circuit is used for converting an input first voltage into a second voltage and outputting the second voltage; the input end of the voltage stabilizing circuit is electrically connected with the output end of the rectifying circuit; the voltage stabilizing circuit is used for outputting a corresponding voltage detection signal according to the second voltage; the input end of the switch control circuit is electrically connected with the output end of the rectifying circuit, the controlled end of the switch control circuit is electrically connected with the output end of the voltage stabilizing circuit, and the power output end of the switch control circuit is electrically connected; the switch control circuit is used for connecting or disconnecting a path between the power supply input end and the power supply output end according to a voltage detection signal. The invention aims to improve the power supply input safety of the low-voltage direct-current equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply circuits, and in particular to a power supply protection circuit, a power supply protection device and a low-voltage direct current device. Background Art

[0002] In the existing power access technology, different input sockets are mainly distinguished by foolproof design to avoid the DC and AC terminals from being plugged in together. However, in actual applications, there is still the problem that DC and AC interfaces are easily confused, resulting in the actual client application of mutual plugging and causing damage to DC equipment. In addition, in actual applications, there is also the problem that DC high voltage, AC high voltage and DC low voltage interfaces are easily confused, resulting in the actual client application of mutual plugging and causing damage to DC low voltage equipment. Summary of the invention

[0003] The main purpose of the present invention is to provide a power supply protection circuit, a power supply protection device and a low-voltage DC device, aiming to improve the safety of the power supply input of the low-voltage DC device.

[0004] To achieve the above object, the present invention provides a power protection circuit, which is applied to a power protection device, wherein the power protection device includes a power input terminal for connecting to a power source and a power output terminal for outputting power. The power protection circuit includes:

[0005] A rectifier circuit, wherein the input end of the rectifier circuit is electrically connected to the power input end; the rectifier circuit is used to convert the input first voltage into a second voltage and output it;

[0006] a voltage stabilizing circuit, wherein an input end of the voltage stabilizing circuit is electrically connected to an output end of the rectifier circuit; the voltage stabilizing circuit is used to output a corresponding voltage detection signal according to the second voltage;

[0007] A switch control circuit, wherein the input end of the switch control circuit is electrically connected to the power input end, the controlled end of the switch control circuit is electrically connected to the output end of the voltage stabilizing circuit, and the power output end of the switch control circuit is electrically connected; the switch control circuit is used to turn on or off the path between the power input end and the power output end according to the voltage detection signal.

[0008] In one embodiment, the rectifier circuit includes a first diode, a second diode, a third diode, and a fourth diode;

[0009] Among them, the anode of the first diode is electrically connected to the first end of the power input terminal and the cathode of the fourth diode, and the cathode of the first diode is electrically connected to the voltage stabilizing circuit and the cathode of the second diode; the anode of the second diode is electrically connected to the second end of the power input terminal and the cathode of the third diode; the anode of the third diode is electrically connected to the voltage stabilizing circuit and the anode of the fourth diode.

[0010] In one embodiment, the voltage stabilizing circuit includes a first resistor, a second resistor, and a voltage stabilizing diode;

[0011] Among them, the first end of the first resistor is electrically connected to the output end of the rectifier circuit, the second end of the first resistor is electrically connected to the first end of the second resistor and the cathode of the Zener diode; the second end of the second resistor is electrically connected to the ground end; the anode of the Zener diode is electrically connected to the switch control circuit.

[0012] In one embodiment, the switch control circuit includes:

[0013] An auxiliary power supply circuit, the auxiliary power supply circuit being used to output a switch control signal according to the wake-up signal;

[0014] a first switch circuit, wherein a first end of the first switch circuit is electrically connected to the power input end, a controlled end of the first switch circuit is electrically connected to the auxiliary power circuit, and a second end of the first switch circuit is electrically connected to the power output end; the first switch circuit is used to turn on or off a path between the power input end and the power output end according to the switch control signal;

[0015] a second switch circuit, wherein a first end of the second switch circuit is electrically connected to the output end of the rectifier circuit, a controlled end of the second switch circuit is electrically connected to the output end of the voltage stabilizing circuit, and a second end of the second switch circuit is electrically connected to the ground end; the second switch circuit is used to turn on or off the path between the output end of the rectifier circuit and the ground end according to the voltage detection signal;

[0016] a third switch circuit, wherein a controlled end of the third switch circuit is electrically connected to a first end of the second switch circuit and the auxiliary power supply circuit, and a second end of the third switch circuit is electrically connected to a ground end; the third switch circuit is used to turn on or off a path between the first end of the third switch circuit and the ground end according to the wake-up signal and / or the switch control signal;

[0017] a fourth switch circuit, wherein a first end of the fourth switch circuit is electrically connected to the output end of the rectifier circuit, a controlled end of the fourth switch circuit is electrically connected to the first end of the third switch circuit, and a second end of the fourth switch circuit is electrically connected to the controlled end of the third switch circuit and the auxiliary power supply circuit; the fourth switch circuit is used to turn on or off a path between the output end of the rectifier circuit and the controlled end of the third switch circuit and the auxiliary power supply circuit according to a working state of the third switch circuit;

[0018] When the fourth switch circuit turns on the path between the output end of the rectifier circuit and the controlled end of the third switch circuit and the auxiliary power supply circuit, the auxiliary power supply circuit receives the wake-up signal and outputs a switch control signal to the first switch circuit and the third switch circuit.

[0019] In one embodiment, the third switch circuit includes a unidirectional conduction circuit, and the unidirectional conduction circuit is connected in series to a path between the controlled end of the third switch circuit and the auxiliary power supply circuit.

[0020] In one embodiment, the first switch circuit includes a third resistor and a switch device; the second switch circuit includes a fourth resistor and a first switch tube; the third switch circuit includes a fifth resistor, a sixth resistor, a seventh resistor, a fifth diode, and a second switch tube; the fourth switch circuit includes an eighth resistor and a third switch tube;

[0021] Wherein, the first end of the third resistor is electrically connected to the controlled end of the switch device, and the second end of the third resistor is electrically connected to the auxiliary power supply circuit, the second end of the third switch tube, and the anode of the fifth diode; the first end of the switch device is electrically connected to the power input end, and the second end of the switch device is electrically connected to the power output end; the first end of the fourth resistor is electrically connected to the output end of the rectifier circuit and the first end of the third switch tube, and the second end of the fourth resistor is electrically connected to the first end of the first switch tube and the first end of the fifth resistor; the controlled end of the first switch tube is electrically connected to the output end of the voltage stabilizing circuit, and the second end of the first switch tube is electrically connected to the ground end; the second end of the fifth resistor is electrically connected to the controlled end of the second switch tube, the first end of the sixth resistor, and the second end of the seventh resistor; the first end of the second switch tube is electrically connected to the second end of the eighth resistor, and the second end of the second switch tube is electrically connected to the ground end; the second end of the sixth resistor is electrically connected to the ground end; the first end of the seventh resistor is electrically connected to the cathode of the fifth diode; the controlled end of the third switch tube is electrically connected to the first end of the eighth resistor.

[0022] In one embodiment, the switch control circuit also includes a light emitting diode, an anode of the light emitting diode is electrically connected to the second end of the first switch tube, and a cathode of the light emitting diode is electrically connected to the ground end; the light emitting diode is used to work when the first switch tube is turned on.

[0023] In one embodiment, the power protection circuit further includes:

[0024] a first filter circuit, wherein an input end of the first filter circuit is electrically connected to an output end of the rectifier circuit, and an output end of the first filter circuit is electrically connected to an input end of the switch circuit; the first filter circuit is used to filter and output a second voltage output by the rectifier circuit;

[0025] A second filtering circuit, the second filtering circuit is electrically connected to the auxiliary power supply circuit; the second filtering circuit is used to filter the wake-up signal input to the auxiliary power supply circuit and then output it, and / or to filter the switch control signal output to the first switching circuit and the third switching circuit and then output it.

[0026] The present invention further provides a power supply protection device, which includes a power supply input terminal for connecting to a power supply, a power supply output terminal for outputting a power supply, and a power supply protection circuit as described in any one of the above items.

[0027] The present invention further provides a low-voltage DC device, which includes the power supply protection device as described above.

[0028] The technical solution of the present invention uses a rectifier circuit to rectify the possible input AC voltage and output it to a voltage stabilizing circuit and a switch control circuit. The voltage stabilizing circuit is electrically connected to the output end of the rectifier circuit to receive the second voltage output by the rectifier circuit. The voltage stabilizing circuit compares the input second voltage with the threshold voltage and outputs a corresponding voltage detection signal to the switch control circuit. The switch control circuit will turn on or off the path between the power input end and the power output end according to the voltage detection signal, thereby ensuring that the power output end can stably output low-voltage DC power. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0030] Figure 1 It is a module schematic diagram of the power protection circuit of the present invention;

[0031] Figure 2 A schematic diagram of a module of an embodiment of a power protection circuit of the present invention;

[0032] Figure 3 FIG. 1 is a circuit diagram of an embodiment of a power protection circuit of the present invention.

[0033] Description of Figure Numbers:

[0034] 10. Rectification circuit; 20. Voltage stabilizing circuit; 30. Switch control circuit; 31. Auxiliary power supply circuit; 32. First switch circuit; 33. Second switch circuit; 34. Third switch circuit; 35. Fourth switch circuit; 40. First filter circuit; 50. Second filter circuit; R1-R9, first resistor - ninth resistor; D1-D5, first diode - fifth diode; D6, light emitting diode; Q1-Q3, first switch tube - third switch tube; RY, switch device; ZD, voltage stabilizing diode; C1-C2, first capacitor - second capacitor.

[0035] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0038] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0039] In the existing power access technology, different input sockets are mainly distinguished by foolproof design to avoid the DC and AC terminals from being plugged in together. However, in actual applications, there is still the problem that DC and AC interfaces are easily confused, resulting in the actual client application of mutual plugging and causing damage to DC equipment. In addition, in actual applications, there is also the problem that DC high voltage, AC high voltage and DC low voltage interfaces are easily confused, resulting in the actual client application of mutual plugging and causing damage to DC low voltage equipment.

[0040] To solve the above problems, refer to Figures 1 to 3 The present invention provides a power protection circuit, which is applied to a power protection device, wherein the power protection device includes a power input terminal for connecting to a power source and a power output terminal for outputting a power source, and the power protection circuit includes:

[0041] A rectifier circuit 10, wherein the input end of the rectifier circuit 10 is electrically connected to the power input end; the rectifier circuit 10 is used to convert the input first voltage into a second voltage and output it;

[0042] A voltage stabilizing circuit 20, wherein the input end of the voltage stabilizing circuit 20 is electrically connected to the output end of the rectifier circuit 10; the voltage stabilizing circuit 20 is used to output a corresponding voltage detection signal according to the second voltage;

[0043] A switch control circuit 30, wherein the input end of the switch control circuit 30 is electrically connected to the power input end, the controlled end of the switch control circuit 30 is electrically connected to the output end of the voltage stabilizing circuit 20, and the power output end of the switch control circuit 30 is electrically connected; the switch control circuit 30 is used to turn on or off the path between the power input end and the power output end according to the voltage detection signal.

[0044] In this embodiment, the rectifier circuit 10 can be implemented by a half-wave rectifier circuit 10, a full-wave rectifier circuit 10, or a voltage doubler rectifier circuit 10. Among them, the full-wave rectifier circuit 10 can be implemented by a center-tapped transformer full-wave rectifier, a bridge rectifier, etc. The most commonly used full-wave rectifier is a bridge rectifier, which consists of four diodes to form a "bridge". Regardless of the polarity of the AC input voltage, the bridge rectifier can make the current always flow through the load in the same direction, so the full-wave rectification effect can be obtained, and no special center-tapped transformer is required. Specifically, the rectifier circuit 10 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4; wherein the anode of the first diode D1 is electrically connected to the first end of the power input terminal and the cathode of the fourth diode D4, and the cathode of the first diode D1 is electrically connected to the voltage stabilizing circuit 20 and the cathode of the second diode D2; the anode of the second diode D2 is electrically connected to the second end of the power input terminal and the cathode of the third diode D3; the anode of the third diode D3 is electrically connected to the voltage stabilizing circuit 20 and the anode of the fourth diode D4.

[0045] In this embodiment, the voltage stabilizing circuit 20 can be implemented by a voltage stabilizing diode ZD, a voltage detection circuit, etc. Among them, the voltage detection circuit is implemented by using a voltage divider circuit, a comparison circuit, and a main control circuit. It can be understood that the voltage stabilizing circuit 20 receives the second voltage output by the rectifier circuit 10, and determines whether the input second voltage reaches the threshold voltage through its own circuit structure, thereby confirming whether the input second voltage is high voltage. Among them, the setting of the threshold voltage can be set according to the maximum voltage that the low-voltage DC device can receive. Taking the voltage stabilizing circuit 20 using a voltage detection circuit as an example, the second voltage output by the rectifier circuit 10 is detected by the voltage detection circuit and a voltage detection signal is output to the MCU. The MCU compares the received voltage detection signal with the preset threshold voltage therein, thereby confirming whether the second voltage output by the rectifier circuit 10 reaches the threshold circuit, and then outputs a corresponding control signal to the switch control circuit 30, so that the switch control circuit 30 turns on or turns off the path between the power input terminal and the power output terminal.

[0046] Optionally, the voltage stabilizing circuit 20 includes a first resistor R1, a second resistor R2, and a voltage stabilizing diode ZD;

[0047] Among them, the first end of the first resistor R1 is electrically connected to the output end of the rectifier circuit 10, the second end of the first resistor R1 is electrically connected to the first end of the second resistor R2 and the cathode of the Zener diode ZD; the second end of the second resistor R2 is electrically connected to the ground end; the anode of the Zener diode ZD is electrically connected to the switch control circuit 30.

[0048] In this embodiment, the voltage stabilizing circuit 20 is implemented by a voltage stabilizing diode ZD. Among them, the voltage stabilizing diode ZD will produce the so-called "Zener effect" or "avalanche breakdown" under a certain reverse voltage. At this time, even if the input voltage fluctuates greatly, the voltage across the diode will remain relatively stable. In this technical solution, the "avalanche breakdown" of the voltage stabilizing diode ZD is mainly used. When the voltage stabilizing diode ZD faces a higher reverse voltage, the carriers obtain enough energy to generate more electron-hole pairs, thereby forming a large current, and output to the switch control circuit 30 through the anode of the voltage stabilizing diode ZD. It can be understood that the voltage signal output through the anode of the voltage stabilizing diode ZD is the voltage detection signal. When the first voltage input to the power input end is a high voltage DC and a high voltage AC, the second voltage is output after rectification by the rectifier circuit 10, and the second voltage is output to the cathode of the voltage stabilizing diode ZD after the voltage division processing of the first resistor R1 and the second resistor R2, and breaks down, so that the voltage stabilizing diode ZD outputs a voltage detection signal. When the first voltage inputted to the power input terminal is a low voltage DC or a low voltage AC, the second voltage is outputted after being rectified by the rectifier circuit 10, and the second voltage is outputted to the cathode of the voltage zener diode ZD after being divided by the first resistor R1 and the second resistor R2. At this time, the voltage zener diode ZD will not be broken down. Therefore, the switch control circuit 30 will not receive the voltage detection signal.

[0049] In this embodiment, the switch control circuit 30 can be implemented by at least one switch tube, such as a MOS tube, an IGBT tube, a thyristor, a triode, a power tube, etc., and / or by at least one switch device RY, such as a contactor, a circuit breaker, and a relay. Among them, the input end of the switch control circuit 30 is electrically connected to the power input end, the controlled end of the switch control circuit 30 is electrically connected to the output end of the voltage stabilizing circuit 20, and the output end of the switch circuit is electrically connected to the power output end. Therefore, the control signal output to the controlled end of the switch control circuit 30 satisfies the on or off condition of the switch control circuit 30, and the path between the power input end and the power output end can be turned on or off.

[0050] The rectifier circuit 10 is used to rectify the possible input AC voltage and output it to the voltage stabilizing circuit 20 and the switch control circuit 30. The voltage stabilizing circuit 20 is electrically connected to the output end of the rectifier circuit 10, thereby receiving the second voltage output by the rectifier circuit 10. The voltage stabilizing circuit 20 compares the input second voltage with the threshold voltage and outputs the corresponding voltage detection signal to the switch control circuit 30. The switch control circuit 30 will turn on or off the path between the power input end and the power output end according to the voltage detection signal, thereby ensuring that the power output end can stably output low-voltage DC power.

[0051] refer to Figures 2 to 3In one embodiment of the present invention, the switch control circuit 30 includes:

[0052] An auxiliary power supply circuit 31, wherein the auxiliary power supply circuit 31 is used to output a switch control signal according to the wake-up signal;

[0053] a first switch circuit 32, wherein a first end of the first switch circuit 32 is electrically connected to the power input end, a controlled end of the first switch circuit 32 is electrically connected to the auxiliary power circuit 31, and a second end of the first switch circuit 32 is electrically connected to the power output end; the first switch circuit 32 is used to turn on or off the path between the power input end and the power output end according to the switch control signal;

[0054] a second switch circuit 33, wherein a first end of the second switch circuit 33 is electrically connected to the output end of the rectifier circuit 10, a controlled end of the second switch circuit 33 is electrically connected to the output end of the voltage stabilizing circuit 20, and a second end of the second switch circuit 33 is electrically connected to the ground end; the second switch circuit 33 is used to turn on or off the path between the output end of the rectifier circuit 10 and the ground end according to the voltage detection signal;

[0055] a third switch circuit 34, wherein a controlled end of the third switch circuit 34 is electrically connected to a first end of the second switch circuit 33 and the auxiliary power supply circuit 31, and a second end of the third switch circuit 34 is electrically connected to a ground end; the third switch circuit 34 is configured to switch on or off a path between the first end of the third switch circuit 34 and the ground end according to the wake-up signal and / or the switch control signal;

[0056] a fourth switch circuit 35, wherein a first end of the fourth switch circuit 35 is electrically connected to the output end of the rectifier circuit 10, a controlled end of the fourth switch circuit 35 is electrically connected to a first end of the third switch circuit 34, and a second end of the fourth switch circuit 35 is electrically connected to the controlled end of the third switch circuit 34 and the auxiliary power supply circuit 31; the fourth switch circuit 35 is used to turn on or off the path between the output end of the rectifier circuit 10 and the controlled end of the third switch circuit 34 and the auxiliary power supply circuit 31 according to the working state of the third switch circuit 34;

[0057] Among them, when the fourth switch circuit 35 turns on the path between the output end of the rectifier circuit 10 and the controlled end of the third switch circuit 34 and the auxiliary power supply circuit 31, the auxiliary power supply circuit 31 receives the wake-up signal and outputs a switch control signal to the first switch circuit 32 and the third switch circuit 34.

[0058] In this embodiment, the auxiliary power supply circuit 31 can be implemented by the internal power supply and related interface circuit of the low-voltage DC device, or a separate power supply circuit can be set as an auxiliary circuit in the switch control circuit 30. Among them, the auxiliary power supply circuit 31 can be further electrically connected to the power input terminal by setting a corresponding voltage conversion circuit to realize charging when the power input terminal has power input, so as to avoid the inability to work normally when receiving the wake-up signal due to insufficient power. It can be understood that the wake-up signal is the second voltage output by the rectifier circuit 10. The auxiliary power supply circuit 31 receives the second voltage output by the rectifier circuit 10, thereby confirming that the voltage output by the power output terminal meets the maximum voltage that the low-voltage DC device can receive, and then outputs a switch control signal to the first switch circuit 32, so that the first switch circuit 32 conducts the path between the power input terminal and the power output terminal.

[0059] In this embodiment, the first switch circuit 32, the second switch circuit 33, the third switch circuit 34 and the fourth switch circuit 35 can all be implemented by at least one switch tube, such as a MOS tube, an IGBT tube, a thyristor, a triode, a power tube, etc., and / or by at least one switch device, such as a contactor, a circuit breaker and a relay.

[0060] Among them, the controlled end of the first switch circuit 32 is electrically connected to the auxiliary power supply circuit 31, and the path between the power input end and the power output end is turned on or off by receiving the switch control signal output by the auxiliary power supply circuit 31. It should be understood that the first end of the first switch circuit 32 is directly electrically connected to the power input end, rather than to the output end of the rectifier circuit 10, which can effectively reduce the loss of the input power due to passing through the rectifier circuit 10. In addition, there are a few cases where the voltage input to the power input end is low-voltage AC. At this time, a corresponding freewheeling diode can be set at the power output end to avoid damaging the low-voltage DC device, and it can be realized as a low-voltage DC device under the condition of suitable voltage.

[0061] The controlled end of the second switch circuit 33 is electrically connected to the output end of the voltage stabilizing circuit 20, so as to turn on or off the path between the output end and the ground end of the rectifier circuit 10 according to whether the voltage stabilizing diode ZD in the voltage stabilizing circuit 20 is broken down. When the voltage stabilizing diode ZD in the voltage stabilizing circuit 20 is broken down, the voltage stabilizing diode ZD will be turned on, thereby turning on the second switch circuit 33. At this time, the path between the output end and the ground end of the rectifier circuit 10 is turned on. When the voltage stabilizing diode ZD in the voltage stabilizing circuit 20 is not broken down, the voltage stabilizing diode ZD will not be turned on, and the second switch circuit 33 is in the off state. At this time, the path between the output end and the ground end of the rectifier circuit 10 is not turned on. The controlled end of the third switch circuit 34 is electrically connected to the output end of the rectifier circuit 10 and the first end of the second switch circuit 33. When the second switch circuit 33 is turned on, the voltage of the controlled end of the third switch circuit 34 is pulled down, and then it is in the off state. When the second switch circuit 33 is not turned on, the voltage of the controlled end of the third switch circuit 34 receives the second voltage output by the rectifier circuit 10, and is in a conducting state. When the third switch circuit 34 is in a conducting state, the path between the controlled end of the fourth switch circuit 35 and the ground end is turned on. At this time, the controlled end of the fourth switch circuit 35 will be pulled down, thereby turning on the path between the output end of the rectifier circuit 10 and the auxiliary power supply circuit 31. It can be understood that when the path between the output end of the rectifier circuit 10 and the auxiliary power supply circuit 31 is turned on, the auxiliary power supply circuit 31 will receive the second voltage output by the rectifier circuit 10, that is, the wake-up signal. Further, after the auxiliary power supply circuit 31 receives the second voltage output by the rectifier circuit 10, it will output a switch control signal to the first switch circuit 32 and the third switch circuit 34, so that the first switch circuit 32 turns on the path between the power input end and the power output end, and controls the third switch circuit 34 to be in a conducting state until the auxiliary power supply circuit 31 no longer receives the wake-up signal.

[0062] Optionally, the third switch circuit 34 includes a unidirectional conduction circuit, which is connected in series to a path between a controlled end of the third switch circuit 34 and the auxiliary power supply circuit 31 .

[0063] Further, the first switch circuit 32 includes a third resistor R3 and a switch device RY; the second switch circuit 33 includes a fourth resistor R4 and a first switch tube Q1; the third switch circuit 34 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a fifth diode D5, and a second switch tube Q2; the fourth switch circuit 35 includes an eighth resistor R8 and a third switch tube Q3;

[0064] Wherein, the first end of the third resistor R3 is electrically connected to the controlled end of the switch device RY, and the second end of the third resistor R3 is electrically connected to the auxiliary power supply circuit 31, the second end of the third switch tube Q3, and the anode of the fifth diode D5; the first end of the switch device RY is electrically connected to the power input end, and the second end of the switch device RY is electrically connected to the power output end; the first end of the fourth resistor R4 is electrically connected to the output end of the rectifier circuit 10 and the first end of the third switch tube Q3, and the second end of the fourth resistor R4 is electrically connected to the first end of the first switch tube Q1 and the first end of the fifth resistor R5; the first switch tube Q 1 is electrically connected to the output end of the voltage stabilizing circuit 20, and the second end of the first switch tube Q1 is electrically connected to the ground end; the second end of the fifth resistor R5 is electrically connected to the controlled end of the second switch tube Q2, the first end of the sixth resistor R6, and the second end of the seventh resistor R7; the first end of the second switch tube Q2 is electrically connected to the second end of the eighth resistor R8, and the second end of the second switch tube Q2 is electrically connected to the ground end; the second end of the sixth resistor R6 is electrically connected to the ground end; the first end of the seventh resistor R7 is electrically connected to the cathode of the fifth diode D5; the controlled end of the third switch tube Q3 is electrically connected to the first end of the eighth resistor R8.

[0065] In this embodiment, the unidirectional conduction circuit is used to limit the second voltage output by the rectifier circuit 10 from being output to the auxiliary power supply circuit 31 through the branch of the controlled end of the third switch circuit 34, so that the auxiliary power supply circuit 31 outputs a switch control signal through the negative feedback of the fifth diode D5 and the seventh resistor R7, so that the third switch circuit 34 is in a conducting state.

[0066] refer to Figure 3 In one embodiment of the present invention, the switch control circuit 30 further includes a light emitting diode D6, an anode of the light emitting diode D6 is electrically connected to the second end of the first switch tube Q1, and a cathode of the light emitting diode D6 is electrically connected to the ground end; the light emitting diode D6 is used to work when the first switch tube Q1 is turned on.

[0067] In this embodiment, the light-emitting diode D6 is a prompt circuit. When the first switch tube Q1 is in the on state, it indicates that the voltage-stabilizing diode ZD in the voltage-stabilizing circuit 20 is in the breakdown state, which means that the first voltage inputted by the power input terminal is a high-voltage direct current or a high-voltage alternating current. At this time, the light-emitting diode D6 will be in the power-on state, thereby prompting the user that the power input terminal is connected to the wrong power source.

[0068] refer to Figure 3 In one embodiment of the present invention, the power protection circuit further includes:

[0069] a first filter circuit 40, wherein the input end of the first filter circuit 40 is electrically connected to the output end of the rectifier circuit 10, and the output end of the first filter circuit 40 is electrically connected to the input end of the switch circuit; the first filter circuit 40 is used for filtering and outputting the second voltage output by the rectifier circuit 10;

[0070] The second filter circuit 50 is electrically connected to the auxiliary power supply circuit 31; the second filter circuit 50 is used to filter the wake-up signal input to the auxiliary power supply circuit 31 and then output it, and / or to filter the switch control signal output to the first switch circuit 32 and the third switch circuit 34 and then output it.

[0071] In this embodiment, the first filter circuit 40 and the second filter circuit 50 can be implemented by filter circuits such as RC filter circuit, LC filter circuit, RL filter circuit, etc. Among them, the input end of the first filter circuit 40 is electrically connected to the output end of the rectifier circuit 10, and is implemented by the first capacitor C1 and the ninth resistor R9, so that the second voltage output by the rectifier circuit 10 is stable, thereby ensuring that the awakening of the auxiliary power supply circuit 31 and the conduction or disconnection of the switch tube are in a stable control state. The second filter circuit 50 is electrically connected to the auxiliary power supply circuit 31, and is implemented by the second capacitor C2 to stabilize the wake-up signal it receives or the switch control signal it outputs.

[0072] The present invention further proposes a power supply protection device, the power supply protection device comprising a power supply input terminal for connecting to a power supply, a power supply output terminal for outputting a power supply, and a power supply protection circuit as described in any one of the above items. It is worth noting that since the power supply protection device of the present invention is based on the above power supply protection circuit, the embodiments of the power supply protection device of the present invention include all technical solutions of all embodiments of the above power supply protection circuit, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0073] The present invention further provides a low-voltage DC device, which includes the power supply protection device as described above. It is worth noting that since the low-voltage DC device of the present invention is based on the power supply protection device as described above, the embodiments of the low-voltage DC device of the present invention include all technical solutions of all embodiments of the power supply protection device as described above, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0074] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A power protection circuit, applied to a power protection device, characterized in that: The power protection device includes a power input terminal for connecting to a power source and a power output terminal for outputting power. The power protection circuit includes: A rectifier circuit, wherein the input end of the rectifier circuit is electrically connected to the power input end; the rectifier circuit is used to convert the input first voltage into a second voltage and output it; a voltage stabilizing circuit, wherein an input end of the voltage stabilizing circuit is electrically connected to an output end of the rectifier circuit; the voltage stabilizing circuit is used to output a corresponding voltage detection signal according to the second voltage; A switch control circuit, wherein the input end of the switch control circuit is electrically connected to the power input end, the controlled end of the switch control circuit is electrically connected to the output end of the voltage stabilizing circuit, and the power output end of the switch control circuit is electrically connected; the switch control circuit is used to turn on or off the path between the power input end and the power output end according to the voltage detection signal.

2. The power protection circuit according to claim 1, characterized in that: The rectifier circuit includes a first diode, a second diode, a third diode, and a fourth diode; Among them, the anode of the first diode is electrically connected to the first end of the power input terminal and the cathode of the fourth diode, and the cathode of the first diode is electrically connected to the voltage stabilizing circuit and the cathode of the second diode; the anode of the second diode is electrically connected to the second end of the power input terminal and the cathode of the third diode; the anode of the third diode is electrically connected to the voltage stabilizing circuit and the anode of the fourth diode.

3. The power protection circuit according to claim 1, characterized in that: The voltage stabilizing circuit comprises a first resistor, a second resistor, and a voltage stabilizing diode; Among them, the first end of the first resistor is electrically connected to the output end of the rectifier circuit, the second end of the first resistor is electrically connected to the first end of the second resistor and the cathode of the Zener diode; the second end of the second resistor is electrically connected to the ground end; the anode of the Zener diode is electrically connected to the switch control circuit.

4. The power protection circuit according to claim 1, characterized in that: The switch control circuit comprises: An auxiliary power supply circuit, the auxiliary power supply circuit being used to output a switch control signal according to the wake-up signal; a first switch circuit, wherein a first end of the first switch circuit is electrically connected to the power input end, a controlled end of the first switch circuit is electrically connected to the auxiliary power circuit, and a second end of the first switch circuit is electrically connected to the power output end; the first switch circuit is used to turn on or off a path between the power input end and the power output end according to the switch control signal; a second switch circuit, wherein a first end of the second switch circuit is electrically connected to the output end of the rectifier circuit, a controlled end of the second switch circuit is electrically connected to the output end of the voltage stabilizing circuit, and a second end of the second switch circuit is electrically connected to the ground end; the second switch circuit is used to turn on or off the path between the output end of the rectifier circuit and the ground end according to the voltage detection signal; a third switch circuit, wherein a controlled end of the third switch circuit is electrically connected to a first end of the second switch circuit and the auxiliary power supply circuit, and a second end of the third switch circuit is electrically connected to a ground end; the third switch circuit is used to turn on or off a path between the first end of the third switch circuit and the ground end according to the wake-up signal and / or the switch control signal; a fourth switch circuit, wherein a first end of the fourth switch circuit is electrically connected to the output end of the rectifier circuit, a controlled end of the fourth switch circuit is electrically connected to the first end of the third switch circuit, and a second end of the fourth switch circuit is electrically connected to the controlled end of the third switch circuit and the auxiliary power supply circuit; the fourth switch circuit is used to turn on or off a path between the output end of the rectifier circuit and the controlled end of the third switch circuit and the auxiliary power supply circuit according to a working state of the third switch circuit; When the fourth switch circuit turns on the path between the output end of the rectifier circuit and the controlled end of the third switch circuit and the auxiliary power supply circuit, the auxiliary power supply circuit receives the wake-up signal and outputs a switch control signal to the first switch circuit and the third switch circuit.

5. The power protection circuit according to claim 4, characterized in that: The third switch circuit includes a unidirectional conduction circuit, and the unidirectional conduction circuit is connected in series to a path between a controlled end of the third switch circuit and the auxiliary power supply circuit.

6. The power protection circuit according to claim 5, characterized in that: The first switch circuit includes a third resistor and a switch device; the second switch circuit includes a fourth resistor and a first switch tube; the third switch circuit includes a fifth resistor, a sixth resistor, a seventh resistor, a fifth diode, and a second switch tube; the fourth switch circuit includes an eighth resistor and a third switch tube; Wherein, the first end of the third resistor is electrically connected to the controlled end of the switch device, and the second end of the third resistor is electrically connected to the auxiliary power supply circuit, the second end of the third switch tube, and the anode of the fifth diode; the first end of the switch device is electrically connected to the power input end, and the second end of the switch device is electrically connected to the power output end; the first end of the fourth resistor is electrically connected to the output end of the rectifier circuit and the first end of the third switch tube, and the second end of the fourth resistor is electrically connected to the first end of the first switch tube and the first end of the fifth resistor; the controlled end of the first switch tube is electrically connected to the output end of the voltage stabilizing circuit, and the second end of the first switch tube is electrically connected to the ground end; the second end of the fifth resistor is electrically connected to the controlled end of the second switch tube, the first end of the sixth resistor, and the second end of the seventh resistor; the first end of the second switch tube is electrically connected to the second end of the eighth resistor, and the second end of the second switch tube is electrically connected to the ground end; the second end of the sixth resistor is electrically connected to the ground end; the first end of the seventh resistor is electrically connected to the cathode of the fifth diode; the controlled end of the third switch tube is electrically connected to the first end of the eighth resistor.

7. The power protection circuit according to claim 6, characterized in that: The switch control circuit also includes a light emitting diode, an anode of the light emitting diode is electrically connected to the second end of the first switch tube, and a cathode of the light emitting diode is electrically connected to the ground end; the light emitting diode is used to work when the first switch tube is turned on.

8. The power protection circuit according to claim 4, characterized in that: The power protection circuit also includes: a first filter circuit, wherein an input end of the first filter circuit is electrically connected to an output end of the rectifier circuit, and an output end of the first filter circuit is electrically connected to an input end of the switch circuit; the first filter circuit is used to filter and output a second voltage output by the rectifier circuit; A second filtering circuit, the second filtering circuit is electrically connected to the auxiliary power supply circuit; the second filtering circuit is used to filter the wake-up signal input to the auxiliary power supply circuit and then output it, and / or to filter the switch control signal output to the first switching circuit and the third switching circuit and then output it.

9. A power supply protection device, characterized in that: The power protection device comprises a power input terminal for connecting to a power source, a power output terminal for outputting a power source, and a power protection circuit as claimed in any one of claims 1 to 8.

10. A low voltage DC device, characterized in that: The low voltage DC device comprises the power supply protection device as claimed in claim 9.

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