CN204928078U - Intelligent ammeter working power supply with short -circuit protection circuit - Google Patents

Abstract

The utility model discloses a working power supply for an intelligent electric energy meter provided with a short-circuit protection circuit. Each short-circuit protection circuit is respectively arranged between the output terminal of the power supply and the corresponding load. Each short-circuit protection circuit includes a start-up circuit and a control circuit connected in parallel. The circuit is used to disconnect the output of the power supply to the load when the load is short-circuited, to prevent the power supply from being damaged due to the short circuit, and to achieve the purpose of short-circuit protection power supply. When the load is short-circuited, the utility model prevents the power supply that provides the output of the power supply from also being damaged by short-circuit, so as to achieve the purpose of protecting the power supply, and can automatically restore the power supply circuit to the normal power supply state after the short-circuit fault is removed. The advantages of low cost and easy maintenance have good application prospects.

Description

A kind of working power supply of smart electric energy meter provided with short-circuit protection circuit

technical field

The utility model belongs to the technical field of protection circuits of intelligent electric energy meters, and in particular relates to a working power supply of an intelligent electric energy meter provided with a short circuit protection circuit.

Background technique

With the development of science and technology, the improvement of industrial production and people's living standards, the smart energy meter, an important part of the smart grid, has more and more functions, which involve multiple working modules such as measurement, calculation, and communication. The working power supply, which can be used without causing any danger, if any abnormality occurs in any working power supply circuit, it will not affect the work of other working power supplies. Although most of the working power supplies of smart energy meters on the market are multi-output, when a short circuit occurs in one of the working power supplies, it will cause damage to the entire working power supply and affect the function of the entire smart energy meter. To solve the above problems, the use of power chips with short-circuit protection function in the prior art will greatly increase the cost of smart energy meters on the one hand, and on the other hand, it will also lead to limitations in the selection of power chips, high cost, and is not conducive to smart energy meters. promotional use of the table.

Utility model content

The technical problem solved by the utility model is to overcome the problems of the intelligent electric energy meter power supply in the prior art. The working power supply of the smart electric energy meter provided with the short-circuit protection circuit of the utility model enables the intelligent electric energy meter to work. It can return to normal work, has strong versatility, does not need to use a dedicated power chip, has the advantages of low cost and easy maintenance, and has a good application prospect.

In order to solve the problems of the technologies described above, the technical solution adopted in the utility model is:

A working power supply for an intelligent electric energy meter provided with a short-circuit protection circuit, including a power supply, the power supply is provided with multiple power supply output terminals, and each power supply output terminal is connected to a corresponding load, and is characterized in that it also includes multiple short-circuit protection circuits , each short-circuit protection circuit is respectively arranged between the output end of the power supply and the corresponding load, and each short-circuit protection circuit includes a start-up circuit and a control circuit connected in parallel, and the start-up circuit is used to provide work for the load connected to it when the power supply is powered on. Voltage; the control circuit is used to disconnect the output of the power supply to the load when the load is short-circuited, to prevent the power supply from being damaged due to a short circuit, and to achieve the purpose of short-circuit protection power supply,

The starting circuit includes a resistor R5, and the resistor R5 is connected in series between one power supply output terminal of the power supply and the corresponding load;

The control circuit includes a first triode Q1, a second triode Q2, a resistor R1, a resistor R2 and a resistor R3, the emitter of the first triode Q1 is connected to a power supply output end of the power supply, so A resistor R5 of the starting circuit is connected between the emitter and the collector of the first triode Q1, and the base of the first triode Q1 is connected to the collector of the second triode Q2 through the resistor R1, so The base of the second transistor Q2 is connected to the collector of the first transistor Q1 through a resistor R2, and the base of the second transistor Q2 is also connected to the emitter of the second transistor Q2 through a resistor R3. The poles are connected, and the collector of the first triode Q1 is connected to the load as the output terminal of the control circuit.

The aforementioned working power supply for the smart energy meter provided with a short-circuit protection circuit is characterized in that: the resistor R5 is a metal film resistor or a wire wound resistor.

The aforementioned working power supply for the smart energy meter provided with a short-circuit protection circuit is characterized in that: the resistance value of the resistor R5 is between 200Ω-800Ω, and the power is greater than 1W.

The aforementioned working power supply of the smart electric energy meter provided with a short-circuit protection circuit is characterized in that: the control circuit also includes a capacitor C1 and a capacitor C2, the capacitor C2 is connected in parallel to one power supply output end of the power supply, and the capacitor C1 is connected in parallel to the control between the output terminal of the circuit and the load.

The aforementioned working power supply for the smart energy meter provided with a short-circuit protection circuit is characterized in that: the first transistor Q1 is a PNP transistor, and the second transistor Q2 is an NPN transistor.

The aforementioned working power supply for the smart energy meter provided with a short-circuit protection circuit is characterized in that: the capacitors C1 and C2 are both ceramic capacitors with a capacitance of 0.1 μF.

The beneficial effects of the utility model are: the working power supply of the smart electric energy meter provided with the short-circuit protection circuit of the present utility model adds a short-circuit protection circuit between the output of each power supply of the intelligent electric energy meter and the load, and prevents the The power supply that provides the output of this power supply is also damaged by a short circuit, so as to achieve the purpose of protecting the power supply, and can automatically restore the power supply circuit to the normal power supply state after the short circuit fault is removed. It has strong versatility and does not need to use a dedicated power supply chip. , has the advantages of low cost and easy maintenance, and has a good application prospect.

Description of drawings

Fig. 1 is the system block diagram of the working power supply of the smart electric energy meter provided with the short-circuit protection circuit of the utility model.

Fig. 2 is a circuit diagram of the short circuit protection circuit of the present invention.

Fig. 3 is a simulation circuit diagram when the working power supply of the smart electric energy meter of the utility model works normally.

Fig. 4 is a simulation circuit diagram when a short circuit occurs at the load end of the smart electric energy meter of the present invention.

Detailed ways

The utility model will be further described below in conjunction with the accompanying drawings of the description.

As shown in Figure 1, the working power supply of the smart electric energy meter provided with the short-circuit protection circuit of the utility model includes a power supply, and the power supply is provided with multiple power supply output terminals, and each power supply output terminal is connected with the corresponding load, and also includes multiple short-circuit power supply terminals. Protection circuit, each short-circuit protection circuit is set between the output terminal of the power supply and the corresponding load, each short-circuit protection circuit includes a start-up circuit and a control circuit connected in parallel, the start-up circuit is used to provide work for the load connected to it when the power supply is powered on Voltage; the control circuit is used to disconnect the direct output of the power supply to the load when the load is short-circuited, to prevent the power supply from being damaged due to the short circuit, and to achieve the purpose of short-circuit protection power supply.

As shown in Figure 2, the start-up circuit includes a resistor R5, the resistor R5 is connected in series between one power supply output terminal of the power supply and the corresponding load, when the power supply is just powered on, the voltage of one power supply output terminal of the power supply is transmitted to the For the load corresponding to the rear end, the resistance value of resistor R5 should fully consider the impedance of the rear end load and the power of the resistor itself. If the resistance value of R5 is too large, the voltage obtained by the rear end load will drop, which will affect the stability of the startup state; If the resistance value of R5 is too small, the power consumption consumed on R5 will become larger. At this time, if the power of the resistor itself is too small, the resistor will be damaged, and then the entire power circuit will be affected. In the short circuit protection circuit of the present invention Therefore, the resistor R5 is a metal film resistor or a wire wound resistor with a resistance value between 200Ω-800Ω and a power greater than 1W.

The control circuit includes a first triode Q1, a second triode Q2, a resistor R1, a resistor R2 and a resistor R3, the emitter of the first triode Q1 is connected to a power supply output end of the power supply, so A resistor R5 of the starting circuit is connected between the emitter and the collector of the first triode Q1, and the base of the first triode Q1 is connected to the collector of the second triode Q2 through the resistor R1, so The base of the second transistor Q2 is connected to the collector of the first transistor Q1 through a resistor R2, and the base of the second transistor Q2 is also connected to the emitter of the second transistor Q2 through a resistor R3. The poles are connected, and the collector of the first triode Q1 is connected to the load as the output terminal of the control circuit.

The control circuit further includes a capacitor C1 and a capacitor C2, the capacitor C2 is connected in parallel to one power supply output end of the power supply, and the capacitor C1 is connected in parallel between the output end of the control circuit and the load.

The first transistor Q1 is a PNP transistor, and the second transistor Q2 is an NPN transistor.

The capacitors C1 and C2 are ceramic capacitors with a capacitance of 0.1 μF.

The operating power supply of the smart electric energy meter provided with the short-circuit protection circuit of the utility model has the following working principle,

As shown in Figure 3, the simulation circuit diagram of the working power supply of the smart electric energy meter is working normally. During normal operation, the output voltage of one output terminal of the working power supply of the smart electric energy meter is U1, which is divided by the resistor R2 and the resistor R3, and the second triode The base voltage of Q2 is high level, the second triode Q2 is in the conduction state, at this time the base of the first triode Q1 is directly grounded through the resistor R1, the base voltage is low level, the first triode Q1 The tube Q1 is also in the conduction state, and the power supply voltage is transmitted to the load side through the channel of the first triode Q1. At this time, the voltage on the load side is U2, and U2=U1;

As shown in Figure 4, the simulation circuit diagram when the load end of the smart energy meter is short-circuited, the upper end of the resistor R2 is directly grounded to a low level, causing the base of the second transistor Q2 to be obtained by dividing the voltage through the resistor R2 and the resistor R3 The voltage of the second triode Q2 is also in the cut-off state. At this time, the base of the first triode Q1 is disconnected from the ground, the first triode Q1 is in the cut-off state, and the working power of the smart energy meter The voltage of one output terminal of the power supply cannot be transmitted to the load side through the channel of the first triode Q1, so as to prevent the power supply from being damaged due to a short circuit. The resistor R5 in the circuit has a limited value, therefore, it will not damage the power supply. When the load side is released from the short circuit and returns to normal, the working state of the circuit returns to the working state shown in Figure 3 and returns to normal operation. state.

To sum up, the working power supply of the smart electric energy meter provided with the short-circuit protection circuit of the utility model adds a short-circuit protection circuit between the output of each power supply of the intelligent electric energy meter and the load, and prevents the supply of the short-circuit protection circuit when the load is short-circuited. The power output of the power supply is also damaged by a short circuit, so as to achieve the purpose of protecting the power supply, and can automatically restore the power supply circuit to the normal power supply state after the short circuit fault is removed. It has strong versatility and does not need to use a dedicated power chip. The advantages of cost and easy maintenance have good application prospects.

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 (6)

1. A working power supply of an intelligent electric energy meter provided with a short-circuit protection circuit, comprising a power supply, the power supply is provided with multiple power supply output terminals, each power supply output terminal is connected with a corresponding load, and is characterized in that: it also includes a multi-channel short circuit Protection circuit, each short-circuit protection circuit is respectively arranged between the output end of the power supply and the corresponding load, and each short-circuit protection circuit includes a start-up circuit and a control circuit connected in parallel, and the start-up circuit is used to provide the load connected to it when the power supply is powered on. Provide working voltage; the control circuit is used to disconnect the output of the power supply to the load when the load is short-circuited, so as to realize the purpose of short-circuit protection power supply, The starting circuit includes a resistor R5, and the resistor R5 is connected in series between one power supply output terminal of the power supply and the corresponding load; The control circuit includes a first triode Q1, a second triode Q2, a resistor R1, a resistor R2 and a resistor R3, the emitter of the first triode Q1 is connected to a power supply output end of the power supply, so A resistor R5 of the starting circuit is connected between the emitter and the collector of the first triode Q1, and the base of the first triode Q1 is connected to the collector of the second triode Q2 through the resistor R1, so The base of the second transistor Q2 is connected to the collector of the first transistor Q1 through a resistor R2, and the base of the second transistor Q2 is also connected to the emitter of the second transistor Q2 through a resistor R3. The poles are connected, and the collector of the first triode Q1 is connected to the load as the output terminal of the control circuit. 2. The working power supply of the smart energy meter provided with a short-circuit protection circuit according to claim 1, wherein the resistor R5 is a metal film resistor or a wire wound resistor. 3. The working power supply of the smart energy meter provided with a short-circuit protection circuit according to claim 1 or 2, characterized in that: the resistance value of the resistor R5 is between 200Ω-800Ω, and the power is greater than 1W. 4. The working power supply of an intelligent electric energy meter provided with a short-circuit protection circuit according to claim 1, characterized in that: the control circuit also includes a capacitor C1 and a capacitor C2, and the capacitor C2 is connected in parallel to one power supply output end of the power supply, The capacitor C1 is connected in parallel between the output terminal of the control circuit and the load. 5. The working power supply of the smart energy meter provided with a short-circuit protection circuit according to claim 1, wherein the first triode Q1 is a PNP triode, and the second triode Q2 is an NPN triode. 6 . The working power supply of the smart energy meter provided with a short-circuit protection circuit according to claim 4 , wherein the capacitors C1 and C2 are both ceramic capacitors with a capacitance of 0.1 μF.