CN202721436U - A high-voltage discharge protection circuit at the output end of an inverter - Google Patents

Abstract

The utility model discloses an inverter output end high-voltage discharge protection circuit, which comprises an inverter output circuit and a master control IC, wherein the high-voltage output end of the inverter output circuit is connected with the high-voltage end of an electric appliance, a first voltage divider is connected between the low-voltage end of the electric appliance and the enabling end of the master control IC, and a voltage-dividing rectification circuit and an overvoltage protection control circuit are sequentially connected between the high-voltage output end of the inverter output circuit and the enabling end of the master control IC in series; when the main control IC works normally, the output signal of the first voltage divider controls the main control IC to work; when high voltage occurs, the voltage division rectifying circuit and the overvoltage protection control circuit enable the enabling end of the main control IC to be grounded, and the inverter stops working; the protection circuit can accurately monitor the AC high voltage output by the inverter, and can protect the inverter in time once the discharge phenomenon of the output end occurs.

Description

A high-voltage discharge protection circuit at the output end of an inverter

technical field

The utility model relates to an overvoltage protection technology, in particular to an overvoltage protection circuit of a power supply.

Background technique

As the power supply equipment of all electronic products, the power supply must not only meet the requirements of power supply products, but also its own protection measures are also very important, such as overvoltage, overcurrent protection, etc. Once the electronic product fails, the power supply must be able to Corresponding protection measures should be taken to protect products and output devices from being burned in a timely manner. If a fault occurs without corresponding protection measures, it may cause more serious consequences, such as electric shock to the operator and fire.

When the high-voltage output of the inverter causes discharge due to damaged wires, insufficient safety distance, or abnormal input, the AC high voltage output by the inverter will rise sharply. If this discharge is not stopped in time, it will be very likely Damage to inverter-related parts, LCD Panel, or even harm to human body.

Utility model content

In view of the deficiencies in the prior art, the purpose of this utility model is to provide a high-voltage discharge protection circuit at the output end of the inverter. This protection circuit can accurately monitor and protect the AC high voltage output by the inverter, and prevent damage to the inverter. Inverter-related parts or LCD Panel. the

In order to solve the above technical problems, the technical solution of the present invention is: a high-voltage discharge protection circuit at the output end of the inverter, including an output circuit of the inverter and a main control IC for controlling the opening or closing of the inverter. The high-voltage output terminal of the output circuit is connected to the high-voltage terminal of the consumer, and a first voltage divider is connected between the low-voltage terminal of the consumer and the enabling terminal of the main control IC. The high-voltage output terminal of the inverter output circuit is connected to the A voltage dividing and rectifying circuit and an overvoltage protection control circuit are sequentially connected in series between the enabling terminals of the main control IC.

As a preferred technical solution, the voltage divider rectifier circuit includes a second voltage divider, a rectifier and a third voltage divider connected in series in sequence, the signal input end of the second voltage divider is connected to the output of the inverter The high voltage output terminal of the circuit is connected, and the signal output terminal of the third voltage divider is connected with the signal input terminal of the overvoltage protection control circuit.

As a preferred technical solution, the overvoltage protection control circuit includes a Zener diode, an ordinary diode and a transistor connected in series in sequence, and the anode of the Zener diode is connected to the signal output terminal of the third voltage divider, so The cathode of the ordinary diode is connected to the base of the transistor, the emitter of the transistor is grounded, and the collector of the transistor is connected to the enabling terminal of the main control IC.

The inverter output terminal high-voltage discharge protection circuit described in the utility model includes an inverter output circuit and a main control IC for controlling the inverter to be turned on or off. The first voltage divider is connected between the low-voltage terminal of the consumer and the enabling terminal of the main control IC, and the high-voltage output terminal of the inverter output circuit is connected to the enabling terminal of the main control IC. A voltage divider rectifier circuit and an overvoltage protection control circuit are sequentially connected in series; in normal operation, the output signal of the first voltage divider controls the operation of the main control IC; when high voltage occurs, the voltage divider rectifier circuit and the overvoltage protection control circuit control The enabling terminal of the control IC is grounded to stop the inverter; the protection circuit can accurately monitor the AC high voltage output by the inverter, and it can be protected in time if there is a discharge phenomenon at the output terminal. It has the advantages of high sensitivity, good accuracy, wide application range, simple circuit structure, low cost, etc., and can be widely used in the design of inverter products.

Description of drawings

Fig. 1 is the circuit schematic diagram of the utility model embodiment;

In the figure: 1-first voltage divider; 2-second voltage divider; 3-third voltage divider; 4-rectifier; 5-overvoltage protection control circuit; low voltage side.

Detailed ways

Below in conjunction with Fig. 1 and embodiment, further set forth the utility model. In the following detailed description, certain exemplary embodiments of the present invention are described by way of illustration only. Needless to say, those skilled in the art would realize that the described embodiments may be modified in various different ways, all without departing from the spirit and scope of the present invention. Accordingly, Figure 1 and the description are illustrative in nature and not intended to limit the scope of the claims.

As shown in Figure 1, a high-voltage discharge protection circuit at the output end of an inverter includes an output circuit of the inverter and a main control IC for controlling the opening or closing of the inverter, and the high-voltage output end of the output circuit of the inverter is connected to the The high-voltage terminal 61 of the electrical appliance is connected, the first voltage divider 1 is connected between the low-voltage terminal 62 of the consumer and the enable terminal of the main control IC, and the high-voltage output terminal of the inverter output circuit is connected to the main control IC. A voltage divider rectifier circuit and an overvoltage protection control circuit 5 are sequentially connected in series between the enabling terminals, and the voltage divider rectifier circuit includes a second voltage divider 2, a rectifier 4 and a third voltage divider 3 connected in series in sequence. The signal input end of the second voltage divider 2 is connected to the high voltage output end of the inverter output circuit, and the signal output end of the third voltage divider 3 is connected to the signal input end of the overvoltage protection control circuit 5 , the overvoltage protection control circuit 5 includes a Zener diode, an ordinary diode and a transistor connected in series in sequence, the anode of the Zener diode is connected to the signal output terminal of the third voltage divider 3, and the cathode of the ordinary diode It is connected with the base of the transistor, the emitter of the transistor is grounded, and the collector of the transistor is connected with the enabling terminal of the main control IC.

Working principle: As shown in Figure 1, during normal operation: The high-voltage output terminal of the inverter passes through the voltage division of R1, R2, R3, the full-wave rectification of D1, and the voltage division of R4 and R5 in sequence, to obtain the voltage Va, and through the ratio The resistance values of the resistors R1, R2, R3, R4, and R5 can be used to obtain an appropriate Va value, which satisfies all normal conditions. The Va value is not enough to break down the Zener diode D2, and the transistor Q1 is in a cut-off state. Through the voltage division of R7 and R8, the enabling terminal of the main control IC obtains a feedback signal from the low-voltage terminal 62 of the consumer, and different output currents can be obtained by adjusting the magnitude of this signal.

When an abnormality occurs: When the high-voltage output end of the inverter is discharged due to damaged wires, insufficient safety distance, or abnormal input, the AC high voltage output by the inverter will rise sharply, and the Va voltage value will also rise sharply. As a result, Zener diode D2 breaks down the voltage regulation, triggers transistor Q1 to turn on, and the enable terminal signal of the main control IC is pulled to ground, and the main control IC will automatically shut down, so that the inverter stops working to prevent accidents.

The key points of the protection circuit are the voltage value of Va and the voltage regulation value of Zener diode D2. When the voltage regulation value of Zener diode D2 is constant, increasing the voltage value of Va can increase the sensitivity of the protection circuit, and at the same time, it also increases the hidden danger of misoperation of the line. Therefore, in the application, it needs to be debugged according to the actual situation.

The basic principles, main features and advantages of the present utility model have been shown and described above. Those skilled in the art should understand that the utility model is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model The new model also has various changes and improvements, and these changes and improvements all fall within the scope of the claimed utility model. The scope of protection required by the utility model is defined by the appended claims and their equivalents.

Claims (3)

1. A high-voltage discharge protection circuit at the output end of an inverter, characterized in that: it includes an inverter output circuit and a main control IC that controls the inverter to be turned on or off, and the high-voltage output end of the inverter output circuit is connected with the user The high-voltage terminal of the electrical appliance is connected, and a first voltage divider is connected between the low-voltage terminal of the consumer and the enabling terminal of the main control IC, and the high-voltage output terminal of the inverter output circuit is connected to the enabling terminal of the main control IC. A voltage dividing rectification circuit and an overvoltage protection control circuit are sequentially connected in series. 2. The high-voltage discharge protection circuit at the output end of the inverter according to claim 1, wherein the voltage dividing and rectifying circuit comprises a second voltage divider, a rectifier and a third voltage divider connected in series in sequence, and the first The signal input end of the second voltage divider is connected to the high voltage output end of the inverter output circuit, and the signal output end of the third voltage divider is connected to the signal input end of the overvoltage protection control circuit. 3. The high-voltage discharge protection circuit at the output end of the inverter according to claim 2, wherein the overvoltage protection control circuit includes a Zener diode, an ordinary diode and a transistor connected in series in sequence, and the anode of the Zener diode It is connected with the signal output terminal of the third voltage divider, the cathode of the common diode is connected with the base of the transistor, the emitter of the transistor is grounded, and the collector of the transistor is connected with the main control IC. Enable connection.

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