Anti-reverse input protection circuit and power electronic conversion device
By designing an anti-reverse input protection circuit including relays, resistors and transistors, the problem of ineffective preventing electrical devices from accessing reverse voltage in the prior art is solved, and efficient power input and normal power supply of electrical devices are achieved.
Patent Information
- Application Number
- CN202421365690.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-14
- Publication Date
- 2025-04-18
- Estimated Expiration
- 2034-06-14
AI Technical Summary
The existing anti-reverse input circuit cannot effectively prevent the electrical devices from being connected to the reverse voltage, resulting in a decrease in the input power supply efficiency and abnormal power supply of electrical devices.
An anti-reverse input protection circuit is designed, including a relay, a first resistor, a second resistor and a transistor. By using the voltage divider structure of the first resistor and a transistor when inputting an external power supply, the opening and closing state of the relay is controlled to ensure that the electrical devices are only connected to the power supply at the positive voltage.
Effectively prevent the electrical devices from being connected to the reverse voltage, improve the efficiency of the input power supply, and ensure the normal power supply of the electrical devices.
Smart Images
Figure CN222775976U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of power electronics, in particular to an anti-reverse input protection circuit and a power electronics conversion device. Background Art
[0002] With the rapid development of power electronics technology, in existing power electronic converters, weak current driving signals are often used to control the power switch to work. Furthermore, in terms of power control, an external switching power supply is set to provide a stable low-voltage power supply to the power electronic converter, and then a low-voltage DC-to-DC conversion (DC-to-DC, DCDC) is performed as needed to power the microcontroller unit (MCU) and other electrical devices of the power electronic converter. Considering the reliability and flexibility of the power supply, a 24V (±20%) DC power supply is generally selected in the control power supply scheme. Furthermore, in order to prevent the positive and negative polarity of the input voltage of the DC power supply from being reversed, an anti-reverse input circuit is generally required.
[0003] At present, the reverse input protection circuit mostly adopts the input full-bridge rectifier circuit. However, the voltage drop generated when the two diodes in the full-bridge rectifier circuit are forward-conducted will cause the input voltage of the DC power supply to decrease. Especially under the condition of high current supply, the loss of the diode will increase by the square of the current, which brings challenges to the thermal design of the power supply voltage and the input circuit. In the full-bridge rectifier circuit, the voltage drop range of the general diode is 0.3V~1.2V, and the input voltage drop of the full bridge is 0.6V~2.4V. At this time, the heating of the diode will cause the efficiency of the input power supply to decrease, and even cause the power supply of the electrical device to be abnormal and unable to start. Therefore, the existing reverse input protection circuit cannot effectively prevent the electrical device from connecting to the reverse voltage, and the effect of preventing reverse connection is poor. Utility Model Content
[0004] In view of this, the utility model provides an anti-reverse input protection circuit and a power electronic conversion device, the main purpose of which is to solve the technical problem that the existing anti-reverse input circuit has a poor reverse connection prevention effect.
[0005] To achieve the above object, the utility model first provides an anti-reverse input protection circuit, which is used to connect to an external power supply to power an electrical device, and the anti-reverse input protection circuit includes a relay, a first resistor, a second resistor and a transistor;
[0006] The first end of the first resistor and the first end of the second resistor are respectively connected to the positive terminal of the external power supply, the second end of the first resistor is connected to the base of the transistor, the collector of the transistor is connected to the second end of the second resistor, and the emitter of the transistor is respectively connected to the negative terminal of the external power supply and the negative electrode access terminal of the electrical device;
[0007] The relay coil of the relay is connected in parallel with the second resistor, and the normally open contact of the relay is connected in series between the first end of the second resistor and the positive electrode access terminal of the electrical device.
[0008] In one embodiment of the utility model, the anti-reverse input protection circuit also includes a first voltage regulator diode; the cathode end of the first voltage regulator diode is connected to the second end of the first resistor, and the anode end of the first voltage regulator diode is connected to the base of the transistor.
[0009] In one embodiment of the utility model, the anti-reverse input protection circuit also includes a third resistor, a fourth resistor and a controllable precision voltage-stabilizing source; the first end of the third resistor is connected to the positive terminal of the external power supply, the second end of the third resistor is respectively connected to the first end of the fourth resistor and the reference electrode of the controllable precision voltage-stabilizing source, and the second end of the fourth resistor is connected to the negative terminal of the external power supply; the cathode terminal of the controllable precision voltage-stabilizing source is connected to the second end of the first resistor, and the anode terminal of the controllable precision voltage-stabilizing source is connected to the negative terminal of the external power supply.
[0010] In one embodiment of the utility model, the anti-reverse input protection circuit also includes a bidirectional transient voltage suppression tube; the first end of the bidirectional transient voltage suppression tube is connected to the positive terminal of the external power supply, and the second end of the bidirectional transient voltage suppression tube is connected to the negative terminal of the external power supply.
[0011] In one embodiment of the utility model, the anti-reverse input protection circuit also includes a filter capacitor; the first end of the filter capacitor is connected to the positive access terminal of the electrical device, and the second end of the filter capacitor is connected to the negative access terminal of the electrical device.
[0012] In one embodiment of the utility model, the anti-reverse input protection circuit also includes a normal state prompt circuit; the first end of the normal state prompt circuit is connected to the positive access terminal of the electrical device, and the second end of the normal state prompt circuit is connected to the negative access terminal of the electrical device, and is used to issue a normal state prompt information when the electrical device obtains power.
[0013] In one embodiment of the utility model, the normal state prompt circuit includes a fifth resistor and a first light-emitting diode; the first end of the fifth resistor is connected to the positive access terminal of the electrical device, the second end of the fifth resistor is connected to the anode end of the first light-emitting diode, and the cathode end of the first light-emitting diode is connected to the negative access terminal of the electrical device.
[0014] In one embodiment of the utility model, the anti-reverse input protection circuit also includes an abnormal prompt circuit; the first end of the abnormal prompt circuit is connected to the second end of the second resistor, and the second end of the abnormal prompt circuit is connected to the negative electrode access terminal of the electrical device, which is used to issue an abnormal prompt information when the voltage of the external power supply input is undervoltage or overvoltage.
[0015] In one embodiment of the utility model, the abnormal warning circuit includes a second light-emitting diode and a second voltage-stabilizing diode; the anode terminal of the second light-emitting diode is connected to the second end of the second resistor, the cathode terminal of the second light-emitting diode is connected to the cathode terminal of the second voltage-stabilizing diode, and the anode terminal of the second voltage-stabilizing diode is connected to the negative electrode access terminal of the electrical device.
[0016] In addition, to achieve the above-mentioned purpose, the utility model also proposes a power electronic conversion device, including the above-mentioned anti-reverse input protection circuit.
[0017] The utility model provides a reverse input protection circuit and power electronic conversion device. When the voltage polarity of the external power supply input is correct, the first resistor will generate a voltage division, so that the base of the transistor receives a positive voltage, thereby turning on the transistor; further, after the transistor is turned on, the second resistor is connected to the circuit loop, so that the relay coil of the relay connected in parallel with the second resistor generates a current, thereby turning on the normally open contact of the relay, and the positive access end of the electric device is connected to the positive end of the external power supply, so that the electric device is powered. On the contrary, when the voltage polarity of the external power supply input is reversed, the first resistor will not generate a voltage division, so that the transistor is disconnected because the base cannot receive a positive voltage, and then the second resistor cannot be connected to the circuit loop, so that the relay coil of the relay will not generate a current, thereby disconnecting the normally open contact of the relay, and disconnecting the electric device from the external power supply, ensuring that the electric device will not be connected to the reverse voltage. The technical solution provided by the present application can prevent the formation of a reverse polarity loop when the input voltage of the external power supply is reversed, and effectively prevent the electric device from being connected to the reverse voltage.
[0018] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:
[0020] Figure 1 A schematic diagram of the structure of an anti-reverse input protection circuit provided by an embodiment of the utility model is shown;
[0021] Figure 2 A schematic diagram of the structure of another anti-reverse input protection circuit provided by an embodiment of the utility model is shown;
[0022] Figure 3 A structural schematic diagram of yet another anti-reverse input protection circuit provided by an embodiment of the utility model is shown. DETAILED DESCRIPTION
[0023] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.
[0024] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.
[0025] At present, the reverse input protection circuit mostly adopts the input full-bridge rectifier circuit. However, the voltage drop generated when the two diodes in the full-bridge rectifier circuit are forward-conducted will cause the input voltage of the DC power supply to decrease. Especially under the condition of high current supply, the loss of the diode will increase by the square of the current, which brings challenges to the thermal design of the power supply voltage and the input circuit. In the full-bridge rectifier circuit, the voltage drop range of the general diode is 0.3V~1.2V, and the input voltage drop of the full bridge is 0.6V~2.4V. At this time, the heating of the diode will cause the efficiency of the input power supply to decrease, and even cause the power supply of the electrical device to be abnormal and unable to start. Therefore, the existing reverse input protection circuit cannot effectively prevent the electrical device from connecting to the reverse voltage, and the effect of preventing reverse connection is poor.
[0026] Furthermore, the anti-reverse input circuit also adopts the scheme of adding a fuse to the positive end of the input and a voltage regulator diode between the positive and negative ends. When the input voltage polarity is reversed, the voltage regulator diode is forward-conducted, a large current passes through the fuse, the fuse is blown, and the reverse circuit is open, which plays a reverse protection function. At the same time, the voltage regulator diode connected to the input end can also play an input voltage overvoltage protection role. However, when the power supply circuit with correct polarity works with a large current, the voltage drop of the fuse is still a problem that cannot be ignored. In addition, when the polarity of the power supply is reversed, if the voltage regulator diode fails first, the reverse-conducted voltage will cause damage to the polarity capacitor. Further, a P-MOS tube is used as a conduction switch at the input end of the circuit. When the polarity of the input power supply is reversed, the switch tube will not be turned on. However, the price of P-MOS is generally high, and the control circuit is complicated. Further, using a positive series diode at the input end of the circuit will also have the problems of conduction voltage drop and thermal design under large current, resulting in poor anti-reverse effect.
[0027] In view of the above problems, the following Figures 1 to 3 The invention describes an anti-reverse input protection circuit and a power electronic conversion device according to some embodiments of the invention.
[0028] like Figure 1 As shown, an anti-reverse input protection circuit proposed in an embodiment of the utility model is used to connect to an external power supply (not shown in the figure) to power an electrical device (not shown in the figure), wherein the external power supply can be a DC power supply for powering a power electronic conversion device, which can output a 24V (±20%) DC power supply, and the electrical device can be an MCU and other components of the power electronic conversion device.
[0029] Furthermore, the anti-reverse input protection circuit includes a relay, a first resistor R1, a second resistor R2 and a transistor Q1. Here, the switch device of the anti-reverse input protection circuit is a relay. Since the contact resistance of the relay is small, the voltage drop on the line can be reduced, and the thermal design and conduction voltage drop of the switch device can be avoided when working with a large current, thereby improving the power supply efficiency of the input power supply.
[0030] Specifically, the first end of the first resistor R1 and the first end of the second resistor R2 are respectively connected to the positive terminal Vin+ of the external power supply, the second end of the first resistor R1 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the second end of the second resistor R2, and the emitter of the transistor Q1 is respectively connected to the negative terminal Vin- of the external power supply and the negative electrode access terminal Vout- of the electrical device. Specifically, the first end of the first resistor R1 can be connected between the first end of the second resistor R2 and the positive terminal Vin+ of the external power supply, the emitter of the transistor Q1 can be connected between the negative terminal Vin- of the external power supply and the negative electrode access terminal Vout- of the electrical device, and the emitter of the transistor Q1 can also be grounded.
[0031] Further, the relay coil L1 of the relay is connected in parallel with the second resistor R2. Specifically, the first end of the relay coil L1 of the relay can be connected to the first end of the second resistor R2, and the second end of the relay coil L1 of the relay can be connected to the second end of the second resistor R2. Further, the normally open contact S1 of the relay is connected in series between the first end of the second resistor R2 and the positive access terminal Vout+ of the electrical device. Specifically, the first end of the normally open contact S1 is connected to the first end of the second resistor R2, and the second end of the normally open contact S1 is connected to the positive access terminal Vout+ of the electrical device. Here, the relay coil L1 is used to control the normally open contact S1 to be turned on or off based on the magnetic force generated by its own power supply.
[0032] Furthermore, in the actual working process, the positive terminal Vin+ of the external power supply can be connected to the first end of the first resistor R1 and the first end of the second resistor R2, the negative terminal Vin- of the external power supply can be connected to the emitter of the transistor Q1, and the positive access terminal Vout+ of the electrical device can be connected to the normally open contact S1 of the relay, and the negative access terminal Vout- of the electrical device can be connected to the emitter of the transistor Q1, so as to obtain electrical energy from the external power supply through the anti-reverse input protection circuit and power the electrical device.
[0033] The utility model embodiment proposes a reverse input protection circuit. When the voltage polarity of the external power supply input is correct, that is, a positive voltage is input from the positive terminal of the external power supply, and a negative voltage is input from the negative terminal of the external power supply, the first resistor will generate a voltage division, so that the base of the transistor receives the positive voltage, and then the transistor is turned on; further, after the transistor is turned on, the second resistor is connected to the circuit loop, so that the relay coil of the relay connected in parallel with the second resistor generates current, and then the normally open contact of the relay is turned on, and the positive access end of the electric device is connected to the positive terminal of the external power supply, and the electric device is powered. Conversely, when the voltage polarity of the external power supply input is reversed, that is, a negative voltage is input from the positive terminal of the external power supply, and a positive voltage is input from the negative terminal of the external power supply, the first resistor will not generate a voltage division, so that the transistor is disconnected because the base cannot receive the positive voltage, and then the second resistor cannot be connected to the circuit loop, so that the relay coil of the relay will not generate current, so that the normally open contact of the relay is disconnected, and the electric device is disconnected from the external power supply, ensuring that the electric device will not be connected to the reverse voltage. The technical solution provided in the present application can prevent the formation of a reverse polarity loop when the input voltage of the external power supply is reversely connected, and effectively prevent electrical devices from being connected to reverse voltage.
[0034] In one embodiment, Figure 2 As shown, the anti-reverse input protection circuit also includes a first zener diode D1; specifically, the cathode end of the first zener diode D1 is connected to the second end of the first resistor R1, and the anode end of the first zener diode D1 is connected to the base of the transistor Q1. In the actual working process, the first zener diode D1 plays a role in preventing undervoltage in the anti-reverse input protection circuit. Here, a zener diode with a specific breakdown voltage can be selected as the first zener diode D1. When the input voltage of the external power supply is less than the breakdown voltage of the first zener diode D1, it can be determined that the input voltage of the external power supply is undervoltage. The model selection of the first zener diode D1 can be determined according to the actual situation and is not limited here.
[0035] In the actual working process, when the input voltage polarity of the external power supply is correct, but the voltage amplitude is lower than the breakdown voltage of the first voltage zener diode D1, the first voltage zener diode D1 will not break down, so that the base of the transistor Q1 cannot get voltage, the transistor Q1 will not be turned on, and the relay cannot be closed, which can play the undervoltage protection function; Conversely, when the input voltage polarity of the external power supply is correct and the voltage amplitude is higher than the breakdown voltage of the first voltage zener diode D1, the first voltage zener diode D1 is broken down, so that the base of the transistor Q1 gets voltage, the transistor Q1 is turned on, so that the relay is closed, and the electrical device is connected to the external power supply. The embodiment provided by the present application can make the anti-reverse input protection circuit have the function of undervoltage protection, improve the power supply capacity of the anti-reverse input protection circuit, and prevent damage to the devices of the subsequent circuit.
[0036] In one embodiment, Figure 2 As shown, the anti-reverse input protection circuit also includes a third resistor R3, a fourth resistor R4 and a controllable precision voltage regulator TL; wherein the controllable precision voltage regulator TL can be a TL431 voltage regulator, and the third resistor R3, the fourth resistor R4 and the controllable precision voltage regulator TL play the role of an overvoltage protection circuit in the anti-reverse input protection circuit.
[0037] Specifically, the first end of the third resistor R3 is connected to the positive terminal Vin+ of the external power supply, the second end of the third resistor R3 is respectively connected to the first end of the fourth resistor R4 and the reference electrode of the controllable precision voltage stabilizing source TL, and the second end of the fourth resistor R4 is connected to the negative terminal Vin- of the external power supply. Further, the cathode terminal of the controllable precision voltage stabilizing source TL is connected to the second end of the first resistor R1, and the anode terminal of the controllable precision voltage stabilizing source TL is connected to the negative terminal Vin- of the external power supply.
[0038] Specifically, when the voltage polarity of the external power supply input is correct, but the input voltage amplitude is high, the input voltage of the external power supply is compared with the reference voltage of the controllable precision voltage stabilizing source TL through the voltage division of the third resistor R3 and the fourth resistor R4. When the voltage division through the third resistor R3 and the fourth resistor R4 is greater than the reference voltage, the controllable precision voltage stabilizing source TL will break down, causing the anode voltage of the first voltage stabilizing diode D1 to be pulled down, so that the first voltage stabilizing diode D1 will not break down, and then the relay of the subsequent stage will not be closed, thereby playing an overvoltage protection role. Conversely, when the voltage division through the third resistor R3 and the fourth resistor R4 is not greater than the reference voltage, the controllable precision voltage stabilizing source TL will not break down, causing the anode voltage of the first voltage stabilizing diode D1 to be raised, causing the first voltage stabilizing diode D1 to break down, and then the relay of the subsequent stage will be closed to connect the electrical device to the external power supply. The embodiment provided by the application can enable the anti-reverse input protection circuit to have the function of overvoltage protection, improve the power supply capacity of the anti-reverse input protection circuit, and prevent damage to the devices of the subsequent circuit.
[0039] In one embodiment, Figure 3As shown, the anti-reverse input protection circuit also includes a bidirectional transient voltage suppressor D2; wherein, the bidirectional transient voltage suppressor (TVS) is an overvoltage protection device with bidirectional voltage stabilization characteristics and bidirectional negative resistance characteristics, similar to a varistor. It is used in various AC and DC power supply circuits to suppress instantaneous overvoltage. When a surge pulse voltage appears instantly in the protected circuit, the bidirectional breakdown diode can quickly break down, changing from a high resistance state to a low resistance state, shunting and clamping the surge voltage, thereby protecting the components in the circuit from being damaged by the instantaneous surge pulse voltage.
[0040] Specifically, the first end of the bidirectional transient voltage suppressor D2 is connected to the positive terminal Vin+ of the external power supply, and the second end of the bidirectional transient voltage suppressor D2 is connected to the negative terminal Vin- of the external power supply. In the embodiment provided by the present application, a bidirectional transient voltage suppressor is provided in the circuit, so that surge voltage spikes can be discharged when power is turned on. Here, the parameters of the bidirectional transient voltage suppressor should be selected to be slightly larger than the upper limit of the input voltage.
[0041] In one embodiment, the anti-reverse input protection circuit further includes a filter capacitor C; specifically, the first end of the filter capacitor C is connected to the positive access terminal Vout+ of the electrical device, and the second end of the filter capacitor C is connected to the negative access terminal Vout- of the electrical device. The embodiment provided by the present application can filter the anti-reverse input protection circuit based on the filter capacitor, thereby improving the stability of the anti-reverse input protection circuit.
[0042] In one embodiment, Figure 3 As shown, the anti-reverse input protection circuit also includes a normal state prompt circuit; specifically, the first end of the normal state prompt circuit is connected to the positive access terminal Vout+ of the electrical device, and the second end of the normal state prompt circuit is connected to the negative access terminal Vout- of the electrical device, for issuing a normal state prompt information when the electrical device obtains power.
[0043] Specifically, when there is voltage between the positive access terminal Vout+ of the electrical device and the negative access terminal Vout- of the electrical device, the warning light and other devices in the normal state prompt circuit will be powered to emit light. When the relevant operator finds that the warning light and other devices in the normal state prompt circuit are emitting light, it can be determined that the electrical device is receiving power. The embodiment provided by the present application can send out light prompt information when the electrical device receives power, so that the relevant operator can intuitively understand the operating status of the circuit.
[0044] In one embodiment, Figure 3As shown, the normal state prompt circuit includes a fifth resistor R5 and a first light emitting diode D5. Here, the first light emitting diode D5 can emit green light when powered on.
[0045] Specifically, the first end of the fifth resistor R5 is connected to the positive access terminal Vout+ of the electrical device, the second end of the fifth resistor R5 is connected to the anode end of the first light-emitting diode D5, and the cathode end of the first light-emitting diode D5 is connected to the negative access terminal Vout- of the electrical device.
[0046] Specifically, when a forward voltage is connected between the positive access terminal Vout+ of the electrical device and the negative access terminal Vout- of the electrical device, the first light-emitting diode D5 is turned on and emits green light, prompting the relevant operator that the electrical device is receiving power; conversely, when a reverse voltage is connected between the positive access terminal Vout+ of the electrical device and the negative access terminal Vout- of the electrical device, the first light-emitting diode D5 is turned off and stops emitting light. The embodiment provided by the present application can emit a light prompt message when the electrical device obtains the correct voltage, so that the relevant operator can intuitively understand the operating status of the circuit.
[0047] In one embodiment, Figure 3 As shown, the anti-reverse input protection circuit also includes an abnormal prompt circuit. Specifically, the first end of the abnormal prompt circuit is connected to the second end of the second resistor R2, and the second end of the abnormal prompt circuit is connected to the negative electrode access terminal Vout- of the electrical device, which is used to send out prompt information such as light information when the voltage of the external power input is undervoltage or overvoltage.
[0048] Specifically, when the relay coil L1 is not energized, the normally open contact S1 is disconnected, and the voltage of the external power supply directly acts on the second resistor R2, so that there is a large voltage between the second end of the second resistor R2 and the ground, the warning light and other equipment in the abnormal state prompt circuit will be powered to emit red light to prompt the relevant operator that the circuit is over-voltage or under-voltage. The embodiment provided by the present application can emit light prompt information when the voltage input by the external power supply is over-voltage or under-voltage, so as to prompt the relevant operator to handle it.
[0049] In one embodiment, Figure 3As shown, the abnormal prompt circuit includes a second light emitting diode D3 and a second voltage stabilizing diode D4, wherein the second light emitting diode D3 can be a diode that emits red light. Specifically, the anode end of the second light emitting diode D3 is connected to the second end of the second resistor R2, the cathode end of the second light emitting diode D3 is connected to the cathode end of the second voltage stabilizing diode D4, and the anode end of the second voltage stabilizing diode D4 is connected to the negative electrode access terminal Vout- of the electrical device. When the voltage provided by the external power supply is overvoltage or undervoltage, the voltage of the external power supply directly acts on the second voltage stabilizing diode D4, causing the second voltage stabilizing diode D4 to break down and conduct, thereby causing the second light emitting diode D3 to emit red light. The embodiment provided in the present application can emit a light prompt message by the second light emitting diode when the voltage provided by the external power supply is overvoltage or undervoltage, so that the relevant operating personnel can understand the abnormal situation in time and deal with it quickly.
[0050] On the other hand, an embodiment of the present invention provides a power electronic conversion device, comprising the above-mentioned anti-reverse input protection circuit. Here, the anti-reverse input protection circuit can be used as a power supply circuit of the power electronic conversion device.
[0051] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.
Claims
1. A reverse input protection circuit, used to connect to an external power supply to power an electrical device, characterized in that: The anti-reverse input protection circuit includes a relay, a first resistor, a second resistor and a transistor; The first end of the first resistor and the first end of the second resistor are respectively connected to the positive terminal of the external power supply, the second end of the first resistor is connected to the base of the transistor, the collector of the transistor is connected to the second end of the second resistor, and the emitter of the transistor is respectively connected to the negative terminal of the external power supply and the negative electrode access terminal of the electrical device; The relay coil of the relay is connected in parallel with the second resistor, and the normally open contact of the relay is connected in series between the first end of the second resistor and the positive electrode access terminal of the electrical device.
2. The anti-reverse input protection circuit according to claim 1, characterized in that: The anti-reverse input protection circuit also includes a first voltage stabilizing diode; The cathode terminal of the first voltage stabilizing diode is connected to the second end of the first resistor, and the anode terminal of the first voltage stabilizing diode is connected to the base of the transistor.
3. The anti-reverse input protection circuit according to claim 2, characterized in that: The anti-reverse input protection circuit also includes a third resistor, a fourth resistor and a controllable precision voltage stabilizing source; The first end of the third resistor is connected to the positive terminal of the external power supply, the second end of the third resistor is respectively connected to the first end of the fourth resistor and the reference electrode of the controllable precision voltage-stabilizing source, and the second end of the fourth resistor is connected to the negative terminal of the external power supply; The cathode terminal of the controllable precision voltage-stabilizing source is connected to the second end of the first resistor, and the anode terminal of the controllable precision voltage-stabilizing source is connected to the negative terminal of the external power supply.
4. The anti-reverse input protection circuit according to claim 1, characterized in that: The anti-reverse input protection circuit also includes a bidirectional transient voltage suppression tube; The first end of the bidirectional transient voltage suppression tube is connected to the positive terminal of the external power supply, and the second end of the bidirectional transient voltage suppression tube is connected to the negative terminal of the external power supply.
5. The anti-reverse input protection circuit according to claim 1, characterized in that: The anti-reverse input protection circuit also includes a filter capacitor; The first end of the filter capacitor is connected to the positive electrode access terminal of the electrical device, and the second end of the filter capacitor is connected to the negative electrode access terminal of the electrical device.
6. The anti-reverse input protection circuit according to claim 1, characterized in that: The anti-reverse input protection circuit also includes a normal state prompt circuit; The first end of the normal state prompt circuit is connected to the positive access terminal of the electrical device, and the second end of the normal state prompt circuit is connected to the negative access terminal of the electrical device, and is used to issue normal state prompt information when the electrical device obtains power supply.
7. The anti-reverse input protection circuit according to claim 6, characterized in that: The normal state prompt circuit includes a fifth resistor and a first light emitting diode; The first end of the fifth resistor is connected to the positive access terminal of the electrical device, the second end of the fifth resistor is connected to the anode end of the first light-emitting diode, and the cathode end of the first light-emitting diode is connected to the negative access terminal of the electrical device.
8. The reverse input protection circuit according to claim 2, characterized in that: The anti-reverse input protection circuit also includes an abnormality prompt circuit; The first end of the abnormal prompt circuit is connected to the second end of the second resistor, and the second end of the abnormal prompt circuit is connected to the negative electrode access terminal of the electrical device, and is used to issue an abnormal prompt message when the voltage of the external power supply input is undervoltage or overvoltage.
9. The reverse input protection circuit according to claim 8, characterized in that: The abnormality prompt circuit includes a second light emitting diode and a second voltage stabilizing diode; The anode terminal of the second light emitting diode is connected to the second end of the second resistor, the cathode terminal of the second light emitting diode is connected to the cathode terminal of the second voltage stabilizing diode, and the anode terminal of the second voltage stabilizing diode is connected to the negative electrode access terminal of the electrical device.
10. A power electronic conversion device, characterized in that: The invention comprises the anti-reverse input protection circuit as claimed in any one of claims 1 to 9.