CN209881667U

CN209881667U - Switching power supply circuit for preventing BRO restart

Info

Publication number: CN209881667U
Application number: CN201920779861.2U
Authority: CN
Inventors: 林伟涛
Original assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd
Current assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd
Priority date: 2019-05-27
Filing date: 2019-05-27
Publication date: 2019-12-31
Anticipated expiration: 2029-05-27

Abstract

The utility model relates to a prevent switching power supply circuit that BRO restarted, its characterized in that: the power circuit comprises a transformer and a power circuit, wherein the power circuit is connected with a primary winding of the transformer; the power loop comprises a first rectifying circuit, the first rectifying circuit is connected with the input of the L line and the N line power supply, and the first rectifying circuit is connected with an electrolytic capacitor; the L line and the N line are also externally connected with a second rectifying circuit, and the output end of the second rectifying circuit is grounded after passing through a connecting resistor. The utility model discloses a prevent switching power supply circuit that BRO restarted can prevent that circuit IC's BRO from restarting.

Description

Switching power supply circuit for preventing BRO restart

Technical Field

The utility model relates to the field of electronic technology, especially, relate to a prevent switching power supply circuit that BRO restarted.

Background

The switch power supply is a power supply which directly controls an inductive element (an inductor or a transformer) connected with the switch power supply by a switch tube and realizes voltage or current conversion through the energy storage and discharge processes of the inductive element. The switching-on and switching-off time ratio of the main switching tube is adjusted to maintain stable output signals, and the switching-on and switching-off time ratio control circuit is widely applied to various electronic equipment such as industrial control, communication office, home consumption and the like.

In the power circuit of the existing switching power supply circuit, an electrolytic capacitor is connected behind an AC rectifier bridge for filtering, so that when the BRO test is carried out, the voltage on the aluminum electrolytic capacitor is high, the AC is reduced, a rectifier diode cannot be conducted, the AC is separated from a rectified grounding network, and the BRI of a power supply IC is triggered by mistake and restarted due to the fact that the AC and the power supply IC are not grounded. The BRO test is a process of simulating instability of a power grid and continuously reducing voltage for safety consideration.

SUMMERY OF THE UTILITY MODEL

Based on this, the utility model aims at providing a prevent switching power supply circuit that BRO restarted, it can prevent that circuit IC's BRO from restarting.

A switching power supply circuit for preventing BRO restart comprises a transformer, a power loop connected with a primary winding of the transformer; the power loop comprises a first rectifying circuit, the first rectifying circuit is connected with the input of the L line and the N line power supply, and the first rectifying circuit is connected with an electrolytic capacitor;

the L line and the N line are also externally connected with a second rectifying circuit, and the output end of the second rectifying circuit is grounded after passing through a connecting resistor.

Compared with the prior art, the utility model discloses a prevent that switching power supply circuit that BRO restarted is the external second rectifier circuit of AC, connecting resistance thereafter, because do not connect any capacitive load after the second rectifier circuit, guarantee that any time L line, N line and switching power supply circuit's IC's reference ground is communicating, avoided appearing the condition of spurious triggering.

Further, the second rectifying circuit is a bridge rectifying circuit comprising 4 diodes connected in a bridge form; the resistor is connected between the common cathode and the common anode of the bridge rectifier circuit; and the L line and the N line are respectively connected with the joints of the rest diodes.

Further, the resistors include a first resistor and a second resistor, and the first resistor and the second resistor are connected in series.

Further, the circuit also comprises an X capacitor, and the X capacitor is connected between the L line and the N line.

Furthermore, the transformer further comprises an auxiliary winding, the power loop further comprises a control circuit and a power supply circuit, the power supply circuit obtains energy from the auxiliary winding of the transformer to supply power to the control circuit, the output end of the control circuit is connected to the first end of the primary winding of the transformer, and the output end of the first rectification circuit is further connected to the second end of the primary winding.

For a better understanding and an implementation, the present invention is described in detail below with reference to the accompanying drawings.

Drawings

Fig. 1 is a circuit diagram of a switching power supply circuit for preventing a BRO restart according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to preferred embodiments and accompanying drawings. It is apparent that the examples described below are only for explaining the present invention, and are not limitative of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention. It should be understood that although the terms "first", "second", etc. are used hereinafter to describe various information, these information should not be limited to these terms, which are used only to distinguish one type of information from another. For example, "first" information may also be referred to as "second" information, and similarly, "second" information may also be referred to as "first" information, without departing from the scope of the present invention. It should be further noted that, for the convenience of description, only some but not all of the relevant portions of the present invention are shown in the drawings.

Fig. 1 is a circuit diagram of a switching power supply circuit for preventing a BRO restart according to an embodiment of the present invention, as shown in fig. 1, the switching power supply circuit for preventing a BRO restart in this embodiment includes a transformer, and a power loop connected to a primary winding of the transformer; the power loop comprises a first rectifying circuit, the first rectifying circuit is connected with the input of the L line and the N line power supply, and the first rectifying circuit is connected with an electrolytic capacitor;

Specifically, the second rectification circuit is a bridge rectification circuit B2 including 4 diodes connected in a bridge form; the resistor is connected between the common cathode and the common anode of the bridge rectifier circuit; and the L line and the N line are respectively connected with the joints of the rest diodes. The rectifier bridge is different from the first rectifier circuit of the power loop, one difference is that the current of the rectifier bridge is very small, only a very small diode can meet the requirement, and the other difference is that no capacitive load is connected behind the rectifier bridge, so that the AC line and the reference ground of the IC are enabled at any time. The condition of false triggering is avoided.

The resistor can be a single resistor or a plurality of resistors connected in series. In an alternative embodiment, the resistors include a first resistor R6 and a second resistor R7, and the first resistor R6 and the second resistor R7 are connected in series. In particular, the resistance is a high impedance resistance.

Optionally, the display device further comprises an X capacitor connected between the L line and the N line. The L line and the N line can be connected to the X capacitor, and then R6 and R7 can be used as discharge resistors of the X capacitor.

It can be understood that the utility model discloses a prevent switching power supply circuit that BRO restarted can be based on carrying out the improvement on current various switching power supply circuit, including flyback converter topological structure and forward converter topological structure's switching power supply circuit, all can connect big impedance resistance through L line and the external rectification circuit of N line at switching power supply circuit's power return circuit power input end, the postgrafting can prevent that BRO from restarting.

In an alternative implementation manner, referring to fig. 1, referring to a conventional primary circuit structure of a flyback converter, a primary circuit of a transformer in this embodiment is divided into three parts, namely a control circuit 100, a rectifying and filtering circuit 200 and a power supply circuit 300, where the power supply circuit 300 obtains energy from an auxiliary winding of the transformer to supply power to the control circuit 100, an output terminal of the control circuit 100 is connected to a first end (i.e., a dotted terminal 3 shown in fig. 1) of the primary winding of the transformer, and an output terminal of the rectifying and filtering circuit 200 is connected to a second end (i.e., a dotted terminal 1 shown in fig. 1) of the primary winding. The control circuit 100 mainly generates the PWM control signal, and the rectifying and filtering circuit 200 can inject energy into the primary winding of the transformer. The rectifying and filtering circuit 200 here includes a first rectifying circuit and an electrolytic capacitor, and the output end of the rectifying and filtering circuit 200 is also the output end of the first rectifying circuit; in the field of switching power supplies, the primary side circuit of the flyback converter is mature, and the circuit structure is also multiple, and the detailed description is omitted here.

For convenience of description, the operation principle of the present invention will be described in detail by taking the circuit diagram of fig. 1 as an example.

Because the L line and the N line are externally connected with a rectifying circuit, and then are connected with a first resistor R6 and a second resistor R7 with large impedance, the impedance is pure resistance and is not connected with any capacitive load, the L line, the N line and the reference ground of the IC of the switching power supply circuit are ensured to be communicated at any time, and the condition of BRO false triggering is avoided.

And the first resistor R6 and the second resistor R7 can also be used as discharge resistors of the X capacitor, so that the cost is saved, and the standby power consumption is not influenced.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A switch power supply circuit for preventing BRO restart is characterized in that: the power circuit comprises a transformer and a power circuit, wherein the power circuit is connected with a primary winding of the transformer; the power loop comprises a first rectifying circuit, the first rectifying circuit is connected with the input of the L line and the N line power supply, and the first rectifying circuit is connected with an electrolytic capacitor;

2. The switching power supply circuit for preventing BRO restart of claim 1, wherein: the second rectifying circuit is a bridge rectifying circuit and comprises 4 diodes connected in a bridge mode; the resistor is connected between the common cathode and the common anode of the bridge rectifier circuit; and the L line and the N line are respectively connected with the joints of the rest diodes.

3. The switching power supply circuit for preventing BRO restart according to claim 1 or 2, wherein: the resistors comprise a first resistor and a second resistor, and the first resistor and the second resistor are connected in series.

4. The switching power supply circuit for preventing BRO restart of claim 1, wherein: the circuit further comprises an X capacitor, and the X capacitor is connected between the L line and the N line.

5. The switching power supply circuit for preventing BRO restart of claim 1, wherein: the transformer further comprises an auxiliary winding, the power loop further comprises a control circuit and a power supply circuit, the power supply circuit obtains energy from the auxiliary winding of the transformer to supply power to the control circuit, the output end of the control circuit is connected to the first end of the primary winding of the transformer, and the output end of the first rectifying circuit is further connected to the second end of the primary winding.