Isolation type high-voltage protection circuit, power supply control system and electric appliance

Abstract

The utility model provides an isolation type high-voltage protection circuit, a power supply control system and an electric appliance, in the isolation type high-voltage protection circuit, when a normal voltage is input into a power supply, a switch unit and an isolation unit are not conducted, a working voltage controls a relay to be closed, and the power supply is transmitted to a post-stage circuit through the relay; when an abnormal voltage is input into the power supply, the switch unit and the isolation unit are conducted, the working voltage is pulled down and grounded, the relay is disconnected, the power supply is transmitted to a post-stage circuit through the PTC thermistor, and the abnormal voltage is higher than the normal voltage. Therefore, the isolation type high-voltage protection circuit detects the voltage state input by the power supply in real time and switches the relay and the PTC thermistor to transmit the power supply according to the voltage state, so that the purpose of protecting the whole circuit is achieved, and the safety and the stability of the circuit are improved; and strong and weak current isolation of the power supply and the working voltage is realized through the isolation unit, so that the power supply safety and reliability of a post-stage circuit are ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of high-voltage protection, in particular to an isolated high-voltage protection circuit, a power supply control system and an electrical appliance. Background Art

[0002] During the operation of the air conditioner, the input voltage increases due to power grid fluctuations, lightning strikes and other reasons. If there are no effective protection measures, it will cause abnormal heating or even damage of internal components such as capacitors, semiconductor components, motors, etc., which will seriously affect the normal operation and service life of the air conditioner. At present, the high-voltage protection measures are mainly used in combination with varistors and discharge tubes, but this measure mainly protects the subsequent load by short-circuiting, and the protection voltage is designed to be high, mainly used for spike impacts, but it cannot effectively protect against voltage fluctuations, which is likely to cause damage to the previous circuit. Utility Model Content

[0003] In view of this, the purpose of the utility model is to provide an isolated high-voltage protection circuit, a power supply control system and an electrical appliance to alleviate the above-mentioned problems. It not only serves the purpose of protecting the entire circuit and improving the circuit safety and stability, but also realizes the strong and weak electrical isolation of the power supply and the working voltage through the isolation unit, thereby ensuring the safety and reliability of the power supply of the subsequent circuit.

[0004] In the first aspect, an embodiment of the utility model provides an isolated high-voltage protection circuit, comprising: a power supply, a rectifier and a voltage divider unit, a switch unit, an isolation unit, a relay and a positive temperature coefficient (PTC) thermistor; wherein the power supply is connected to the isolation unit via the rectifier and the voltage divider unit and the switch unit, the isolation unit is also connected to the first contact and the second contact of the relay, and the working voltage is connected between the isolation unit and the first contact of the relay; the fourth contact of the relay and one end of the PTC thermistor are both connected to the power supply, and the third contact of the relay and the other end of the PTC thermistor are both connected to the subsequent circuit of the appliance; when the power supply inputs a normal voltage, the switch unit and the isolation unit are both not turned on, the working voltage controls the relay to be attracted, and the power supply is transmitted to the subsequent circuit via the relay; when the power supply inputs an abnormal voltage, the switch unit and the isolation unit are both turned on, the working voltage is pulled down to ground, the relay is disconnected, and the power supply is transmitted to the subsequent circuit via the PTC thermistor; wherein the abnormal voltage is higher than the normal voltage.

[0005] The above-mentioned isolated high-voltage protection circuit detects the voltage state of the power supply input in real time and switches the relay and PTC thermistor to transmit the power supply according to the voltage state. It not only protects the entire circuit and improves the circuit safety and stability, but also realizes the strong and weak electrical isolation of the power supply and the working voltage through the isolation unit, ensuring the safety and reliability of the power supply of the subsequent circuit.

[0006] Preferably, the above-mentioned rectifier voltage-dividing unit includes a first diode, a first voltage-dividing resistor, a second voltage-dividing resistor and a third voltage-dividing resistor; wherein, the anode of the first diode is connected to one end of the power supply, the cathode of the first diode, the first voltage-dividing resistor, the second voltage-dividing resistor and the third voltage-dividing resistor are connected in sequence, and the third voltage-dividing resistor is also connected to the other end of the power supply.

[0007] Preferably, the switch unit comprises a voltage regulator tube, wherein the cathode of the voltage regulator tube is connected between the second voltage-dividing resistor and the third voltage-dividing resistor, and the anode of the voltage regulator tube is connected to the isolation unit.

[0008] Preferably, the above-mentioned isolation unit includes a photocoupler; wherein the first end of the photocoupler is connected to the anode of the voltage regulator tube, the second end of the photocoupler is grounded, the third end of the photocoupler is connected to the first contact of the relay, and the fourth end of the photocoupler is grounded.

[0009] Preferably, the second contact of the relay is connected to the fourth end of the photocoupler.

[0010] Preferably, the above-mentioned isolated high-voltage protection circuit also includes a pull-up resistor; wherein one end of the pull-up resistor is connected to the operating voltage, and the other end of the pull-up resistor is connected between the third end of the photocoupler and the first contact of the relay.

[0011] Preferably, the above-mentioned isolated high-voltage protection circuit further includes a second diode; wherein the anode of the second diode is connected to the second contact of the relay, and the cathode of the second diode is connected to the first contact of the relay.

[0012] In a second aspect, an embodiment of the utility model further provides a power supply control system, comprising: a post-stage circuit and the isolated high-voltage protection circuit of the first aspect.

[0013] In a third aspect, an embodiment of the utility model further provides an electrical appliance, which includes the power supply control system according to the second aspect.

[0014] Preferably, the above-mentioned electrical appliance is an air conditioner.

[0015] The embodiments of the present invention bring the following beneficial effects:

[0016] The embodiment of the utility model provides an isolated high-voltage protection circuit, a power supply control system and an electrical appliance. In the isolated high-voltage protection circuit, when the power supply inputs a normal voltage, the switch unit and the isolation unit are not turned on, the working voltage control relay is energized, and the power supply is transmitted to the subsequent circuit via the relay; when the power supply inputs an abnormal voltage, the switch unit and the isolation unit are both turned on, the working voltage is pulled down to ground, the relay is disconnected, and the power supply is transmitted to the subsequent circuit via the PTC thermistor; wherein the abnormal voltage is higher than the normal voltage. Therefore, the above-mentioned isolated high-voltage protection circuit detects the voltage state of the power supply input in real time, and switches the relay and the PTC thermistor to transmit the power supply according to the voltage state, thereby avoiding the circuit operation abnormality and device damage caused by the abnormally high level of the power supply input during the circuit operation, thereby achieving the purpose of protecting the entire circuit and improving the circuit safety and stability; in addition, the isolation unit also realizes the strong and weak electrical isolation of the power supply and the working voltage, ensuring the safety and reliability of the power supply of the subsequent circuit.

[0017] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by practicing the utility model. The purpose and other advantages of the utility model are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0018] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A circuit diagram of an isolated high-voltage protection circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. 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.

[0022] To facilitate understanding of this embodiment, the embodiment of the utility model is described in detail below.

[0023] The utility model embodiment provides an isolated high voltage protection circuit, such as Figure 1 As shown, it includes: a power supply AC, a rectifying and voltage dividing unit 11 , a switch unit 12 , an isolation unit 13 , a relay K and a PTC (Positive Temperature Coefficient) thermistor 14 .

[0024] Among them, the power supply AC is connected to the isolation unit 13 via the rectification and voltage division unit 11 and the switch unit 12, the isolation unit 13 is also connected to the first contact and the second contact of the relay K, and the working voltage VCC is connected between the isolation unit 13 and the first contact of the relay K; the fourth contact of the relay K and one end of the PTC thermistor 14 are both connected to the power supply AC, and the third contact of the relay K and the other end of the PTC thermistor 14 are both connected to the subsequent circuit of the appliance (not shown).

[0025] Specifically, for the above-mentioned isolated high-voltage protection circuit, the working principle is as follows: when the power supply AC inputs a normal voltage, the switch unit 12 and the isolation unit 13 are both not turned on, the working voltage VCC controls the relay K to be attracted, and the power supply AC is transmitted to the subsequent circuit (i.e., AC-L1) via the relay K; when the power supply AC inputs an abnormal voltage, the switch unit 12 and the isolation unit 13 are both turned on, the working voltage VCC is pulled down to ground, the relay K is disconnected, and the power supply AC is transmitted to the subsequent circuit via the PTC thermistor 14; wherein, the abnormal voltage is higher than the normal voltage.

[0026] Therefore, no matter it is an abnormal voltage caused by a spike impact or an abnormal voltage caused by a voltage fluctuation, the above-mentioned isolated high-voltage protection circuit transmits the power supply by switching the PTC thermistor, thereby avoiding abnormal circuit operation and device damage caused by the abnormally high level of voltage input by the power supply during circuit operation, thereby protecting the entire circuit and improving the circuit safety and stability.

[0027] The isolated high-voltage protection circuit provided by the embodiment of the utility model detects the voltage state of the power supply input in real time, and switches the relay and the PTC thermistor to transmit the power supply according to the voltage state, thereby avoiding abnormal circuit operation and device damage caused by the abnormally high voltage level of the power supply input during circuit operation, thereby protecting the entire circuit and improving the circuit safety and stability; in addition, the isolation unit realizes the strong and weak electrical isolation of the power supply and the working voltage, ensuring the safety and reliability of the power supply of the subsequent circuit.

[0028] Preferably, if Figure 1 As shown, the above-mentioned rectifier voltage-dividing unit 11 includes a first diode D1, a first voltage-dividing resistor R1, a second voltage-dividing resistor R2 and a third voltage-dividing resistor R3; wherein, the anode of the first diode D1 is connected to one end (i.e., AC-L) of the power supply AC, the cathode of the first diode D1, the first voltage-dividing resistor R1, the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3 are connected in sequence, and the third voltage-dividing resistor R3 is also connected to the other end (AC-N) of the power supply AC.

[0029] It should be noted that, in addition to using the first diode D1 to perform half-wave rectification on the AC input voltage of the power supply, full-wave rectification may also be used in some scenarios, which will not be described in detail in the embodiments of the utility model.

[0030] In addition, the switch unit 12 includes a voltage regulator tube Q1 , wherein the cathode of the voltage regulator tube Q1 is connected between the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3 , and the anode of the voltage regulator tube Q1 is connected to the isolation unit 13 .

[0031] In actual application, when the power supply AC inputs a normal voltage, the voltage divided at the third voltage-dividing resistor R3 does not meet the conduction condition of the voltage-stabilizing tube Q1, and at this time, the switch unit 12 and the isolation unit 13 are both not conducting; when the power supply AC inputs an abnormal voltage, since the abnormal voltage is higher than the normal voltage, the voltage divided at the third voltage-dividing resistor R3 meets the conduction condition of the voltage-stabilizing tube Q1, and at this time, the switch unit 12 and the isolation unit 13 are both conducting. Therefore, during the operation of the electrical appliance, by real-time detection of the state of the power supply AC input voltage (such as normal voltage or abnormally high voltage), the conduction state of the switch unit 12 and the isolation unit 13 can be controlled, thereby realizing the switching relay and the PTC thermistor to transfer the power supply, which plays a role in protecting the entire circuit.

[0032] Preferably, the isolation unit 13 includes a photocoupler IC1, wherein a first end of the photocoupler IC1 is connected to the anode of the voltage regulator tube Q1, a second end of the photocoupler IC1 is grounded, a third end of the photocoupler IC1 is connected to a first contact of the relay K, and a fourth end of the photocoupler IC1 is grounded. In addition, a second contact of the relay K is connected to a fourth end of the photocoupler IC1.

[0033] Therefore, for the above-mentioned isolated high-voltage protection circuit, the power supply AC and the operating voltage VCC are isolated by the photocoupler IC1; wherein, for the operating voltage VCC, after the appliance is powered on, the power supply AC-L first passes through the PTC thermistor 14 to the subsequent circuit, and is obtained after filtering, sorting and power conversion. Therefore, the operating voltage VCC must be lower than the power supply AC, thereby achieving strong and weak electrical isolation through the photocoupler IC1 to ensure the safety and reliability of the power supply of the subsequent circuit.

[0034] It should be noted that in some scenarios, if there is no need to isolate strong and weak electricity, the above-mentioned photocoupler IC1 can also be replaced by a transistor to realize the switching of the relay and the PTC thermistor through the voltage regulator Q1 and the transistor, thereby realizing the protection of the subsequent circuit under high voltage conditions and ensuring the reliable operation of the electrical appliance.

[0035] Preferably, the above-mentioned isolated high-voltage protection circuit further includes a pull-up resistor R4; wherein one end of the pull-up resistor R4 is connected to the working voltage VCC, and the other end of the pull-up resistor R4 is connected between the third end of the photocoupler IC1 and the first contact of the relay K. Therefore, by setting the pull-up resistor R4, the reliable conduction of the relay K is guaranteed, thereby ensuring the stability of the circuit.

[0036] Preferably, the above-mentioned isolated high-voltage protection circuit further includes a second diode D2; wherein, the anode of the second diode D2 is connected to the second contact of the relay K, and the cathode of the second diode D2 is connected to the first contact of the relay K.

[0037] In summary, for the above-mentioned isolated high-voltage protection circuit, its working principle is as follows:

[0038] (1) After the appliance is powered on, the power supply AC-L first passes through the PTC thermistor 14 to the subsequent circuit, and then obtains the working voltage VCC after filtering and power conversion;

[0039] (2) After the power supply AC-L is half-wave rectified by the first diode D1, the first voltage-dividing resistor R1, the second voltage-dividing resistor R2 and the third voltage-dividing resistor R3 are used for voltage division;

[0040] (3) When the power supply AC inputs a normal voltage, the appliance works at a normal voltage. The voltage divided by the third voltage-dividing resistor R3 does not meet the conduction condition of the voltage-stabilizing tube Q1, the photocoupler IC1 is not turned on, the working voltage VCC controls the relay K to be attracted, and the power supply AC-L is transmitted to the subsequent circuit through the relay K, so that the appliance works normally.

[0041] (4) When the power supply AC inputs an abnormal voltage (i.e., a high voltage), at this time, the voltage divided at the third voltage-dividing resistor R3 meets the conduction condition of the voltage-stabilizing tube Q1, the photocoupler IC1 is turned on, the working voltage VCC is pulled down to the ground, the relay K is disconnected, and the power supply AC-L is again transmitted to the subsequent circuit through the PTC thermistor 14 to enable the electrical appliance to work normally.

[0042] Under abnormal voltage, due to the large current, the heat of the PTC thermistor 14 becomes more serious as the resistance increases, causing the resistance of the PTC thermistor 14 to rapidly increase to the maximum resistance; at this time, due to the sharp increase in resistance, the current passing through the component is greatly reduced, thereby limiting the impact of excessive current on the subsequent circuit, reducing the circuit failure rate, and achieving the purpose of protecting the entire circuit.

[0043] In addition, the above-mentioned isolated high-voltage protection circuit adds a hardware protection function on the basis of the original relay charging circuit, thereby improving the utilization rate of the original circuit; and by real-time detection of the voltage state of the power supply input, and switching the relay and PTC thermistor to transmit the power supply according to the voltage state, it avoids the circuit operation abnormality and device damage caused by the abnormally high level of the power supply input voltage during circuit operation. It not only serves the purpose of protecting the entire circuit and improving the circuit safety and stability, but also has the advantages of low cost and easy implementation, which is convenient for promotion and implementation in practical applications.

[0044] Furthermore, based on the above-mentioned isolated high-voltage protection circuit, an embodiment of the utility model also provides a power supply control system, which includes: a subsequent circuit and the above-mentioned isolated high-voltage protection circuit.

[0045] The power supply control system provided in the embodiment of the utility model has the same technical features as the isolated high-voltage protection circuit provided in the above embodiment, so it can also solve the same technical problems and achieve the same technical effects.

[0046] Furthermore, the embodiment of the utility model also provides an electrical appliance, which includes the above-mentioned power supply control system. The electrical appliance includes but is not limited to an air conditioner, and the type of the specific electrical appliance can be set according to actual conditions.

[0047] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the above-described system and electrical appliance can refer to the corresponding process in the aforementioned isolated high-voltage protection circuit embodiment, and will not be repeated here.

[0048] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that can be executed by a processor. Based on this understanding, the technical solution of the utility model, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the utility model. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.

[0050] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0051] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the utility model, which are used to illustrate the technical solution of the utility model, rather than to limit it. The protection scope of the utility model is not limited thereto. Although the utility model is described in detail with reference to the above-mentioned embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solution recorded in the above-mentioned embodiments within the technical scope disclosed by the utility model, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiment of the utility model, and 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 isolated high voltage protection circuit, characterized in that: include: Power supply, rectifier and voltage divider unit, switch unit, isolation unit, relay and positive temperature coefficient PTC thermistor; The power supply is connected to the isolation unit via the rectifier voltage divider unit and the switch unit, the isolation unit is also connected to the first contact and the second contact of the relay, and the working voltage is connected between the isolation unit and the first contact of the relay; the fourth contact of the relay and one end of the PTC thermistor are both connected to the power supply, and the third contact of the relay and the other end of the PTC thermistor are both connected to the subsequent circuit of the electrical appliance; When the power supply inputs a normal voltage, the switch unit and the isolation unit are both off, the working voltage controls the relay to be energized, and the power supply is transmitted to the subsequent circuit via the relay; when the power supply inputs an abnormal voltage, the switch unit and the isolation unit are both on, the working voltage is pulled down to ground, the relay is disconnected, and the power supply is transmitted to the subsequent circuit via the PTC thermistor; wherein the abnormal voltage is higher than the normal voltage.

2. The isolated high voltage protection circuit according to claim 1, characterized in that: The rectifying and voltage-dividing unit comprises a first diode, a first voltage-dividing resistor, a second voltage-dividing resistor and a third voltage-dividing resistor; Among them, the anode of the first diode is connected to one end of the power supply, the cathode of the first diode, the first voltage-dividing resistor, the second voltage-dividing resistor and the third voltage-dividing resistor are connected in sequence, and the third voltage-dividing resistor is also connected to the other end of the power supply.

3. The isolated high voltage protection circuit according to claim 2, characterized in that: The switch unit includes a voltage regulator tube, wherein a cathode of the voltage regulator tube is connected between the second voltage-dividing resistor and the third voltage-dividing resistor, and an anode of the voltage regulator tube is connected to the isolation unit.

4. The isolated high voltage protection circuit according to claim 3, characterized in that: The isolation unit includes a photocoupler; wherein the first end of the photocoupler is connected to the anode of the voltage regulator tube, the second end of the photocoupler is grounded, the third end of the photocoupler is connected to the first contact of the relay, and the fourth end of the photocoupler is grounded.

5. The isolated high voltage protection circuit according to claim 4, characterized in that: The second contact of the relay is connected to the fourth end of the photocoupler.

6. The isolated high voltage protection circuit according to claim 4, characterized in that: The isolated high-voltage protection circuit also includes a pull-up resistor, wherein one end of the pull-up resistor is connected to the operating voltage, and the other end of the pull-up resistor is connected between the third end of the photocoupler and the first contact of the relay.

7. The isolated high voltage protection circuit according to claim 1, characterized in that: The isolated high-voltage protection circuit further includes a second diode; wherein an anode of the second diode is connected to the second contact of the relay, and a cathode of the second diode is connected to the first contact of the relay.

8. A power supply control system, characterized in that: include: A subsequent circuit and an isolated high-voltage protection circuit as described in any one of claims 1 to 7.

9. An electrical appliance, characterized in that: The electrical appliance comprises the power supply control system as described in claim 8 above.

10. The electrical appliance according to claim 9, characterized in that The electrical appliance is an air conditioner.

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