Circuit device for automatically switching low-voltage standby power supply

Abstract

The utility model discloses a circuit device for automatically switching a low-voltage standby power supply, which comprises a power supply switching circuit and an auxiliary power supply circuit, one end of the power supply switching circuit is respectively connected to a main power supply output end and a standby power supply output end, and the other end of the power supply switching circuit is connected to one end of the auxiliary power supply circuit and load equipment; and the other end of the auxiliary power supply circuit is connected to load equipment. According to the utility model, few devices are used, automatic switching of the standby power supply is realized with extremely low cost, meanwhile, uninterruptible power supply of load equipment is realized, the system structure is simple, and the system reliability is high in a pure hardware scheme; and meanwhile, the standby power supply can be automatically charged.

Description

Technical Field

[0001] The utility model belongs to the field of power switching circuit devices, and in particular relates to a circuit device for automatic switching of a low-voltage standby power supply. Background Art

[0002] Currently, automatic switching of backup power sources is mostly achieved by relays. This type of automatic power switching is only applicable to devices with uninterrupted power or their own batteries. It cannot achieve switching of load devices without power failure. It is limited to 24V and cannot charge backup batteries. Utility Model Content

[0003] The utility model provides a circuit device for automatically switching a low-voltage standby power supply, which realizes automatic switching of power supply by utilizing the power-off automatic recovery function of a single-pole double-throw relay, realizes automatic switching between a gapless standby power supply and a main power supply, and the working state of load equipment is not affected.

[0004] In order to achieve the above objectives, the utility model provides a circuit device for automatic switching of a low-voltage standby power supply;

[0005] It includes a power switching circuit and an auxiliary power supply circuit, one end of the power switching circuit is respectively connected to the main power output end and the backup power output end, and the other end is connected to one end of the auxiliary power supply circuit and the load device; the other end of the auxiliary power supply circuit is connected to the load device.

[0006] Furthermore, the power switching circuit includes a single-pole double-throw relay, whose normally open contact is connected to the output end of the main power supply, the normally closed contact is connected to the output end of the backup power supply, and the common output port is connected to the load device.

[0007] Furthermore, the auxiliary power supply circuit includes a capacitor or multiple energy storage capacitors connected in parallel, one end of the energy storage capacitor is connected to the first drive pin of the power switching circuit, and the other end is respectively connected to the common output end of the power switching circuit and the load device; when the main and standby power supplies are switched, the energy storage capacitor supplies power to the load device.

[0008] The power supply of the driving control part of the relay is provided by the main power supply. The normally open contact of the relay is connected to the main power input, and the normally closed contact is connected to the backup power input. When the main power is powered off, the relay simultaneously disconnects the normally open contact and closes the normally closed contact to connect the backup power supply to power the load equipment; when the main power is powered on, it will drive the relay to disconnect the normally closed contact and close the normally open contact to connect the main power supply to power the load equipment. At the same time, the main power supply automatically charges the battery of the backup power supply and automatically stops when it is fully charged; at the moment when the relay action contact is actuated, the large-capacity energy storage capacitor of the auxiliary power supply circuit is discharged to provide power to the load equipment.

[0009] Furthermore, the auxiliary power supply circuit includes an energy storage capacitor C1, one end of which is connected to the first drive pin of the power switching circuit, and the other end of which is respectively connected to the common output terminal of the power switching circuit and the load device.

[0010] Furthermore, the auxiliary power supply circuit includes an energy storage capacitor C2, one end of which is connected to the first drive pin of the power switching circuit, and the other end of which is respectively connected to the common output terminal of the power switching circuit and the load device.

[0011] Furthermore, it also includes a diode D1, whose anode is connected to the main power supply and whose cathode is connected to the second drive pin of the single-pole double-throw relay; it is used to prevent the self-inductance electromotive force of the coil in the single-pole double-throw relay from flowing back.

[0012] Furthermore, it also includes a diode D2, whose anode is connected to the main power supply and whose cathode is connected to the second drive pin of the single-pole double-throw relay; it is used to make the single-pole relay jump faster and suppress the self-induced electromotive force.

[0013] Furthermore, a capacitor or a plurality of parallel capacitors are connected between the anode of the diode D2 and the main power supply, and are used to filter the output of the main power supply.

[0014] Furthermore, two capacitors C3 and C4 connected in parallel are included, one end of which is connected to the positive electrode of the main power supply, and the other end of which is connected to the positive electrode of the diode D2.

[0015] Furthermore, a diode D3 is included, a positive electrode of which is connected to the output end of the main power supply, and a negative electrode of which is connected to the output end of the backup power supply.

[0016] Furthermore, the backup power supply is a storage battery.

[0017] The beneficial effects of the utility model include:

[0018] 1. Low power consumption: Since the backup power supply is powered by a storage battery with limited power, this circuit device does not need to consume any additional power from the backup power supply when using the backup power supply;

[0019] 2. Low cost: Automatic switching of backup power supply is realized at a very low cost, and the load equipment is switched without power failure;

[0020] 3. Small size: Based on this circuit, a small-volume reliable backup power automatic switching solution can be realized under the corresponding voltage application scenario; and the backup power automatically charges and stops automatically when it is full;

[0021] 4. The system has a simple structure and powerful functions: the system uses few devices and realizes uninterrupted power supply for load equipment. The system has a simple structure and the pure hardware solution has high system reliability.

[0022] 5. Flexible application scenarios: By replacing similar devices of different specifications based on this circuit, it can adapt to different DC low-voltage load equipment application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0024] The specific implementation methods of the utility model are further described below in conjunction with the accompanying drawings. It should be noted that the description of these implementation methods is used to help understand the utility model, but does not constitute a limitation of the utility model. Based on this embodiment, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] like Figure 1 As shown, the embodiment of the utility model provides a circuit device for automatic switching of low-voltage backup power supply; it includes a power switching circuit and an auxiliary power supply circuit, one end of the power switching circuit is respectively connected to the main power supply output end and the backup power supply output end, and the other end is connected to one end of the auxiliary power supply circuit and the load device; the other end of the auxiliary power supply circuit is connected to the load device. The backup power supply is an energy storage battery.

[0026] The power switching circuit includes a single-pole double-throw relay K1, whose normally open contact 3 is connected to the output end of the main power supply, the normally closed contact 2 is connected to the output end of the backup power supply, and the common output port 5 is connected to the load device.

[0027] The auxiliary power supply circuit includes two parallel energy storage capacitors C1 and C2, one end of which is connected to the first drive pin 1 of the single-pole double-throw relay K1, and the other end is connected to the common output terminal 5 of the single-pole double-throw relay K1 and the load device respectively.

[0028] In order to prevent the self-induced electromotive force of the coil in the single-pole double-throw relay from flowing back, a diode D1 is also included, whose positive electrode is connected to the main power supply and whose negative electrode is connected to the second drive pin 4 of the single-pole double-throw relay K1.

[0029] In order to make the single-pole relay jump faster and suppress the self-induced electromotive force, a diode D2 is also included, whose positive electrode is connected to the main power supply and whose negative electrode is connected to the second drive pin 4 of the single-pole double-throw relay K1.

[0030] In order to filter the output of the main power supply, two parallel capacitors C3 and C4 are connected between the anode of the diode D2 and the main power supply.

[0031] In order to automatically charge the backup power supply, a diode D3 is connected between the output end of the main power supply and the output end of the backup power supply, with the positive electrode of the diode D3 connected to the main power supply and the negative electrode of the diode D3 connected to the backup power supply.

[0032] The working principle of the utility model is as follows:

[0033] (1) When the main power supply is normal: the main power supply output drives the relay K1 through the diode D2 so that the normally open contact (pin 2) of the relay K1 is closed, so that the main power supply is connected; the normally closed contact (pin 3) is disconnected, so that the backup power supply is disconnected; the power is supplied from the normally open contact (pin 2) of the relay K1 to the common output port (pin 5) to the equipment; at this time, the backup power supply and the load equipment are disconnected, and the main power supply can charge the backup power supply at the same time. After the backup power supply is fully charged, the voltage is the same as the main power supply and the charging stops automatically.

[0034] (2) When the main power fails: the coil of relay K1 also loses power at the same time, the normally open contact (pin 2) of relay K1 is disconnected, the main power is disconnected, the normally closed contact (pin 3) is closed, the backup power is connected, and the normally closed contact (pin 3) of relay K1 is connected to the common output port (pin 5) to power the device; at this time, the main power and the load device are disconnected. At the moment when the main power fails and the backup power is not connected, the load device is powered through capacitors C1 and C2.

[0035] (3) When the main power supply is powered on: the relay K1 coil is also powered on at the same time, the normally open contact (pin 2) of relay K1 is closed (main power supply connected), and the normally closed contact (pin 3) is disconnected (backup power supply disconnected). The main power supply supplies power to the device from the normally open contact (pin 2) of relay K1 to the common output port (pin 5); at this time, the backup power supply and the load device are disconnected, and the main power supply can charge the backup power supply at the same time. After the backup power supply is fully charged, the voltage is the same as the main power supply and charging stops automatically. When the backup power supply is powered off and the main power supply is not connected, the load device is powered through capacitors C1 and C2.

[0036] The utility model can be applied to a variety of low-voltage system working schemes, including but not limited to the following schemes:

[0037] 1. 3.3V system solution: The driving voltage of the single-pole double-throw relay K1 is 3.3V, and the withstand voltage of capacitors C1, C2, C3, and C4 is greater than 6V;

[0038] 2. 5V system solution: The driving voltage of the single-pole double-throw relay K1 is 5V, and the withstand voltage of capacitors C1, C2, C3, and C4 is greater than 10V;

[0039] 3. 12V system solution: The driving voltage of the single-pole double-throw relay K1 is 12V, and the withstand voltage of capacitors C1, C2, C3, and C4 is greater than 20V;

[0040] 4. 24V system solution: The driving voltage of the single-pole double-throw relay K1 is 24V, and the withstand voltage of capacitors C1, C2, C3, and C4 is greater than 35V;

[0041] 5. 36V system solution: The driving voltage of the single-pole double-throw relay K1 is 36V, and the withstand voltage of capacitors C1, C2, C3, and C4 is greater than 50V.

Claims

1. A circuit device for automatic switching of a low-voltage backup power supply, comprising a main power supply and a backup power supply, characterized in that: It includes a power switching circuit and an auxiliary power supply circuit, one end of the power switching circuit is connected to the main power output end and the backup power output end respectively, and the other end is connected to one end of the auxiliary power supply circuit and the load device; the other end of the auxiliary power supply circuit is connected to the load device; The power switching circuit includes a single-pole double-throw relay, whose normally open contact is connected to the output end of the main power supply, the normally closed contact is connected to the output end of the backup power supply, and the common output port is connected to the load device; The auxiliary power supply circuit includes an energy storage capacitor C1, one end of which is connected to the first drive pin of the single-pole double-throw relay of the power switching circuit, and the other end is respectively connected to the common output end of the single-pole double-throw relay of the power switching circuit and the load device; The auxiliary power supply circuit includes an energy storage capacitor C2, one end of which is connected to the first drive pin of the power switching circuit, and the other end is respectively connected to the common output end of the single-pole double-throw relay of the power switching circuit and the load device.

2. A circuit device for automatic switching of a low voltage backup power supply as claimed in claim 1, characterized in that: The device further comprises a diode D1 , an anode of which is connected to the main power supply, and a cathode of which is connected to the second driving pin of the single-pole double-throw relay.

3. A circuit device for automatic switching of a low voltage backup power supply as claimed in claim 1, characterized in that: The device further comprises a diode D2, an anode of which is connected to the main power supply, and a cathode of which is connected to the second driving pin of the single-pole double-throw relay.

4. A circuit device for automatic switching of a low voltage standby power supply as claimed in claim 3, characterized in that: A capacitor or a plurality of parallel capacitors are connected between the positive electrode of the diode D2 and the main power supply.

5. A circuit device for automatic switching of a low voltage standby power supply as claimed in claim 3, characterized in that: It also includes two parallel capacitors C3 and C4, one end of which is connected to the positive electrode of the main power supply, and the other end of which is connected to the positive electrode of the diode D2.

6. A circuit device for automatic switching of a low voltage backup power supply as claimed in claim 1, characterized in that: A diode D3 is also included, with an anode connected to the main power supply and a cathode connected to the backup power supply.

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