CN209389773U - A kind of switching circuit of main power source and stand-by power source - Google Patents

Abstract

This utility model discloses a switching circuit for main power supply and backup power supply, which includes a DC input source, a first switch, a second switch, a first positive logic optocoupler, a first negative logic optocoupler, a second negative logic optocoupler, a first DC-DC converter, and a second DC-DC converter. The circuit uses switching elements, current limiting elements, and optocoupler elements in parallel and series to achieve the switching between the main and backup DC outputs, controlling the output of the main and backup power supplies. It allows manual selection of the main power supply or backup power supply output, and also allows monitoring of the main power supply output when it is working. When the main power supply fails, it automatically switches to the backup power supply to ensure the continuous and reliable operation of important loads.

Description

A switching circuit of main power supply and backup power supply

technical field

The utility model relates to the technical field of power supply switching, in particular to a switching circuit for a main power supply and a backup power supply, which is suitable for a DC input switching power supply.

Background technique

In an important power supply system, it is generally necessary to provide stable and reliable power supply equipment for important equipment to ensure the normal and uninterrupted operation of the system. In the current situation, the most commonly used mode is to adopt the dual power supply mode of the main power supply and the backup power supply to improve the output quality of the power supply.

In the actual use of the main and backup power supply circuits, one scheme is to control the output of the main power supply and the backup power supply respectively through two switches, and when one of the power supplies fails, manually switch to another power supply for power supply through the switch; the other The solution is to detect the output of the main power supply through the detection circuit, and automatically switch to the backup power supply when the main power supply fails. The former method can only manually control the output of the main power supply or the backup power supply, while the latter method only works when the main power supply fails, and the backup power supply cannot be selected artificially. The disadvantages of these two control methods are obvious .

Contents of the invention

In order to solve the above problems, the purpose of the utility model is to provide a simple structure, low cost, precise control switching circuit of the main power supply and the backup power supply.

In order to realize the above-mentioned purpose of the invention, the utility model adopts the following technical solutions:

A switching circuit for a main power supply and a backup power supply, which includes a DC input source, a first switch, a second switch, a first positive logic optocoupler, a first negative logic optocoupler, a second negative logic optocoupler, a first DC- DC converter and the second DC-DC converter, the positive input terminal of the DC input source is connected to the positive input terminal of the first DC-DC converter and the second DC-DC converter, and is also connected to the first negative input terminal through the second resistor. The positive input terminal of the logic optocoupler is connected, the negative input terminal of the first inverse logic optocoupler is connected with the positive input terminal of the second inverse logic optocoupler, and the input of the DC input source is also connected through the fourth resistor in series, the second switch and the DC input source The negative terminal is connected, the negative input terminal of the second inverse logic optocoupler is connected to the input negative terminal of the DC input source through the third resistor in series and the first switch, the positive and negative output terminals of the first inverse logic optocoupler are respectively connected to the first The enabling terminal and the negative input terminal of the DC-DC converter are connected, and the positive and negative output terminals of the second inverse logic optocoupler are respectively connected to the enabling terminal and the negative input terminal of the second DC-DC converter; the first DC- The enabling terminal and the negative input terminal of the DC converter are respectively connected to the positive and negative output terminals of the first positive logic optocoupler, and the positive input terminal of the first positive logic optocoupler is connected to the second DC-DC converter through the first resistor. The positive output terminal is connected, the negative input terminal is connected to the negative output terminal of the second DC-DC converter; the positive and negative output terminals of the first DC-DC converter are connected to the backup power supply, and the positive and negative terminals of the second DC-DC converter are connected The output terminal is connected to the main power supply.

Due to the adoption of the above-mentioned technical scheme, the utility model has the following advantages:

The switching circuit of the main power supply and the backup power supply has high efficiency, low power consumption, low cost, convenient use, precise control, repeatable operation, and high reliability. The method realizes the main-standby switching of two DC outputs, and controls the output of the main and standby power supplies. It can not only artificially select the output of the main power supply or the standby power supply, but also monitor the output of the main power supply when the main power supply is working. When the main power supply appears In case of failure, it will automatically switch to the backup power supply to ensure continuous and reliable operation of important loads.

Description of drawings

Fig. 1 is the principle diagram of the switching circuit of the main power supply and the backup power supply of the utility model.

Detailed ways

The technical solution of the utility model will be described in further detail below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, the switching circuit between the main power supply and the backup power supply includes a DC input source UI, a first switch S1, a second switch S2, a first positive logic optocoupler V1, a first negative logic optocoupler V2, a first Two anti-logic optocouplers V3, the first DC-DC converter N1 and the second DC-DC converter N2, the input positive terminal (+IN) of the DC input source UI and the first DC-DC converter N1, the second DC -The positive input terminal (+IN) of the DC converter N2 is connected, and also connected to the positive input terminal (pin 1) of the first inverse logic optocoupler V2 through the second resistor R2, and the negative input terminal of the first inverse logic optocoupler V2 (pin 2) is connected to the positive input terminal (pin 1) of the second inverse logic optocoupler V3, and is also connected to the negative input terminal (-IN) of the DC input source through the fourth resistor R4 in series and the second switch S2, The negative input terminal (pin 2) of the second inverse logic optocoupler V3 is connected to the input negative terminal (-IN) of the DC input source through the third resistor R3 in series and the first switch S1, and the positive input terminal of the first inverse logic optocoupler V2 The output terminal (pin 3) and the negative output terminal (pin 4) are respectively connected to the enable terminal (EN) and the negative input terminal (-IN) of the first DC-DC converter N1, and the positive terminal (-IN) of the second inverse logic optocoupler V3 The output terminal (pin 3) and the negative output terminal (pin 4) are respectively connected to the enable terminal (EN) and the negative input terminal (-IN) of the second DC-DC converter N2; the first DC-DC converter N1 The enable terminal (EN) and the negative input terminal (-IN) are respectively connected to the positive output terminal (pin 3) and the negative output terminal (pin 4) of the first positive logic optocoupler V1, and the positive output terminal (pin 4) of the first positive logic optocoupler V1 The input terminal (pin 1) is connected to the positive output terminal (+OUT) of the second DC-DC converter N2 through the first resistor R1, and the negative input terminal (pin 2) is connected to the negative output terminal of the second DC-DC converter N2 (-OUT) connection; the positive output terminal (+OUT) and negative output terminal (-OUT) of the first DC-DC converter N1 are connected to the backup power supply, and the positive output terminal (+OUT) of the second DC-DC converter N2 , The negative output terminal (-OUT) is connected to the main power supply.

The switching circuit of the main power supply and the backup power supply of the utility model has the following working methods:

When the first switch S1 and the second switch S2 are turned off at the same time, the input positive terminal (+IN) and the input negative terminal (-IN) of the DC input source UI are blocked, and the first inverting logic optocoupler V2 and the second inverse logic optocoupler The positive and negative input terminals of the coupling V3 are not conducting; the positive and negative output terminals of the first anti-logic optocoupler V2 are low impedance, resulting in no output from the positive and negative output terminals of the first DC-DC converter N1, The backup power supply has no output; at the same time, the positive and negative output terminals of the second anti-logic optocoupler V3 are low impedance, so that the enabling terminal of the second DC-DC converter N2 is connected to the negative input terminal, resulting in the second DC-DC The positive and negative output terminals of the converter N2 have no output, and the main power supply has no output.

When the first switch S1 is turned off and the second switch S2 is turned on, the DC input voltage is connected between the input positive terminal (+IN) and the input negative terminal (-IN) of the DC input source UI, through the second resistor R2, the second An anti-logic optocoupler V2, the fourth resistor R4, and the second switch S2 are turned on, the positive and negative input terminals of the first anti-logic optocoupler V2 are turned on, and the positive and negative output terminals of the first anti-logic optocoupler V2 are connected. It is high impedance, so that the enabling terminal of the first DC-DC converter N1 is disconnected from the negative input terminal, the positive and negative output terminals of the first DC-DC converter N1 have output, and the backup power supply has output; at the same time, because of the second The positive and negative input terminals of the anti-logic optocoupler V3 are not conducting, and the positive and negative output terminals are low impedance. Connect the enabling terminal of the second DC-DC converter N2 to the negative input terminal, resulting in the second DC - The positive and negative output terminals of the DC converter N2 have no output, and the main power supply has no output.

When the first switch S1 is turned on, no matter whether the second switch S2 is turned on or not, the DC input voltage is connected between the input positive terminal (+IN) and the input negative terminal (-IN) of the DC input source UI, and the second resistor R2 , the first anti-logic optocoupler V2, the second anti-logic optocoupler V3, the third resistor R3 and the first switch S1 conduct; The positive and negative input terminals of the coupling V3 are turned on, and the positive and negative output terminals of the second inverse logic optocoupler V3 are high impedance, and the enabling terminal of the second DC-DC converter N2 is disconnected from the negative input terminal, The positive and negative output terminals of the second DC-DC converter N2 have output, and the main power supply has output; because the main power supply has output, the first resistor R1 and the first positive logic optocoupler V1 are turned on, and the first positive logic optocoupler The positive and negative input terminals of V1 are turned on, and the positive and negative output terminals of the first positive logic optocoupler V1 have a low impedance, and the enable terminal of the first DC-DC converter N1 is connected to the negative input terminal, resulting in the first The positive and negative output terminals of a DC-DC converter N1 have no output, and the backup power supply has no output; only when the second DC-DC converter N2 fails, the positive and negative output terminals of the second DC-DC converter N2 have no output. output, when the main power supply has no output, the first resistor R1 and the first positive logic optocoupler V1 are not conducting, the positive and negative input terminals of the first positive logic optocoupler V1 are not conducting, and the positive input of the first positive logic optocoupler V1 , The negative output terminals are high impedance, the enabling terminal of the first DC-DC converter N1 is disconnected from the negative input terminal, the positive and negative output terminals of the first DC-DC converter N1 have output, and the backup power supply has output.

Through the above control methods, the main/standby switching of the two DC outputs is realized. When the first switch S1 is open and the second switch S2 is closed, only the backup power supply has output; when the first switch S1 is closed, no matter whether the second switch S2 is closed or not, only the main power supply has output, if and only when the main power supply fails When there is no output, the standby power supply has output.

In the switching circuit between the main power supply and the backup power supply of the utility model, the model of the first positive logic optocoupler V1 is M211, the models of the first inverse logic optocoupler V2 and the second inverse logic optocoupler V3 are both M212, and the first DC- The models of the DC converter N1 and the second DC-DC converter N2 are both V28C28T100BL.

The above descriptions are only preferred embodiments of the utility model, and are not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present utility model shall be included in the protection scope of the present utility model.

Claims (1)

1. the switching circuit of a kind of main power source and stand-by power source, it is characterized in that: it includes direct current input source, first switch, second opens Pass, the first positive logic optocoupler, the first antilogical optocoupler, the second antilogical optocoupler, the first DC-DC converter and the 2nd DC-DC turn The input anode of parallel operation, direct current input source is connect with the positive input terminal of the first DC-DC converter, the second DC-DC converter, also logical It crosses second resistance to connect with the positive input terminal of the first antilogical optocoupler, the negative input end and the second antilogical of the first antilogical optocoupler The positive input terminal of optocoupler connects, and is also connected by the input negative terminal of concatenated 4th resistance, second switch and direct current input source, The negative input end of second antilogical optocoupler is connected by the input negative terminal of concatenated 3rd resistor, first switch and direct current input source It connecing, the positive and negative output end of the first antilogical optocoupler is connect with the enable end of the first DC-DC converter, negative input end respectively, and second The positive and negative output end of antilogical optocoupler is connect with the enable end of the second DC-DC converter, negative input end respectively；First DC-DC turns The enable end of parallel operation, negative input end are connect with the positive and negative output end of the first positive logic optocoupler respectively, and the first positive logic optocoupler is just Input terminal is connect by first resistor with the positive output end of the second DC-DC converter, negative input end and the second DC-DC converter Negative output terminal connection；The positive and negative output of first DC-DC converter terminates stand-by power source, the positive and negative output of the second DC-DC converter Terminate main power source.