CN213602557U

CN213602557U - Starting-up impact current protection circuit of alternating current and direct current power supply

Info

Publication number: CN213602557U
Application number: CN202023132392.7U
Authority: CN
Inventors: 王萌; 张妹雄
Original assignee: Wuxi Mingxin Microelectronics Co Ltd
Current assignee: Wuxi Mingxin Microelectronics Co Ltd
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2021-07-02
Anticipated expiration: 2030-12-23

Abstract

The application discloses alternating current direct current power supply start-up impulse current protection circuit relates to integrated circuit technical field, protection circuit includes: the circuit comprises a first resistor, a Silicon Controlled Rectifier (SCR), an optocoupler, a second resistor, a third resistor and a fourth resistor; two ends of the first resistor are respectively connected with the first end and the second end of the SCR; the third end of the SCR is connected with the third end of the optocoupler; two ends of the second resistor are connected with the first end of the SCR and the fourth end of the optocoupler; two ends of the third resistor are connected with the second end of the SCR and the first end of the optocoupler; and two ends of the fourth resistor are connected with the first end of the optical coupler and the second end of the optical coupler. The problem that the service life of the fuse is influenced due to the fact that the fuse and the capacitor are likely to be impacted due to large impact current during starting in the existing scheme is solved, and the effect of restraining the starting current is achieved.

Description

Starting-up impact current protection circuit of alternating current and direct current power supply

Technical Field

The utility model relates to a direct current power supply start impulse current protection circuit belongs to integrated circuit technical field.

Background

When the AC/DC or DC/DC power supply is started, a relatively large rush current is generated, the excessive rush current can bring unstable power supply voltage to cause resetting of other power supplies connected in parallel, and the service life of the power supplies can be influenced by impact on a fuse and a capacitor.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an alternating current direct current power supply start impulse current protection circuit for solve the problem that exists among the prior art.

In order to achieve the above purpose, the utility model provides a following technical scheme:

according to a first aspect, the embodiment of the utility model provides an alternating current direct current power supply start-up impulse current protection circuit, the circuit includes:

the circuit comprises a first resistor, a Silicon Controlled Rectifier (SCR), an optocoupler, a second resistor, a third resistor and a fourth resistor;

two ends of the first resistor are respectively connected with the first end and the second end of the SCR; the third end of the SCR is connected with the third end of the optocoupler;

two ends of the second resistor are connected with the first end of the SCR and the fourth end of the optocoupler;

two ends of the third resistor are connected with the second end of the SCR and the first end of the optocoupler;

and two ends of the fourth resistor are connected with the first end of the optical coupler and the second end of the optical coupler.

Optionally, the first end of the optocoupler is an anode of a light emitting diode, the second end of the optocoupler is a cathode of the light emitting diode, the third end of the optocoupler is a main port 1, and the fourth end of the optocoupler is a main port 2.

Optionally, the first end of the SCR is a gate, the second end of the SCR is an anode, and the third end of the SCR is a cathode.

Optionally, the first end of the SCR is connected to a power supply.

Optionally, the second end of the SCR is an output end.

Optionally, the current obtained after voltage division by the third resistor and the fourth resistor is smaller than the minimum trigger current of the optocoupler.

Optionally, a resistance value of the first resistor is smaller than a resistance value of the load resistor.

Optionally, the circuit further includes a filter capacitor, and two ends of the filter capacitor are connected to the second end of the SCR and the second end of the optocoupler.

The protection circuit comprises a first resistor, a Silicon Controlled Rectifier (SCR), an optical coupler, a second resistor, a third resistor and a fourth resistor; two ends of the first resistor are respectively connected with the first end and the second end of the SCR; the third end of the SCR is connected with the third end of the optocoupler; two ends of the second resistor are connected with the first end of the SCR and the fourth end of the optocoupler; two ends of the third resistor are connected with the second end of the SCR and the first end of the optocoupler; and two ends of the fourth resistor are connected with the first end of the optical coupler and the second end of the optical coupler. Also through setting up the circuit of above-mentioned structure for impulse current when starting can be suppressed through the cooperation of opto-coupler and SCR, the problem that impulse current is great when having avoided starting in the current scheme can cause the impact and then influence its life-span to fuse and electric capacity, has reached the effect that can suppress starting current.

The above description is only an overview of the technical solution of the present invention, and in order to make the technical means of the present invention clearer and can be implemented according to the content of the description, the following detailed description is made with reference to the preferred embodiments of the present invention and accompanying drawings.

Drawings

Fig. 1 is a schematic circuit diagram of a start-up inrush current protection circuit of an ac/dc power supply according to an embodiment of the present invention;

fig. 2 is a schematic circuit diagram of a start-up inrush current protection circuit of an ac/dc power supply according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a rush current when 110V AC is powered on in a conventional scheme;

FIG. 4 is a schematic diagram of the voltage variation of a conventional scheme when 110V AC is powered;

fig. 5 is a schematic diagram of an impulse current when the 110V ac power is applied when the protection circuit is set according to an embodiment of the present invention;

fig. 6 is a schematic diagram of a change of voltage when the 110V ac is powered on when the protection circuit is provided according to an embodiment of the present invention.

Detailed Description

The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments 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. In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art. Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

Referring to fig. 1, a circuit diagram of a protection circuit for power-on rush current of an ac/dc power supply according to an embodiment of the present application is shown, as shown in fig. 1, the protection circuit includes:

a first resistor R1, an SCR (Silicon Controlled Rectifier), an optocoupler, a second resistor R2, a third resistor R3 and a fourth resistor R4; wherein:

two ends of the first resistor R1 are respectively connected with the first end and the second end of the SCR; the third end of the SCR is connected with the third end of the optocoupler;

two ends of the second resistor R2 are connected with the first end of the SCR and the fourth end of the optocoupler;

two ends of the third resistor R3 are connected with the second end of the SCR and the first end of the optocoupler;

and two ends of the fourth resistor R4 are connected with the first end of the optical coupler and the second end of the optical coupler.

The first end of the optical coupler is an anode of the light emitting diode, the second end of the optical coupler is a cathode of the light emitting diode, the third end of the optical coupler is a main port 1, and the fourth end of the optical coupler is a main port 2.

The first end of the SCR is a gate pole, the second end of the SCR is an anode, and the third end of the SCR is a cathode.

And as shown in fig. 1, a first terminal of the SCR is connected to a power supply. And the second end of the SCR is an output end.

Optionally, as shown in fig. 2, the protection circuit may further include a filter capacitor, and two ends of the filter capacitor are connected to the second end of the SCR and the second end of the optocoupler. In practical implementation, the capacitance value of the filter capacitor C may be selected according to practical use, for example, may be 200uF, 330uF, 47uF, and the like, and different capacitance values may be selected according to different application scenarios, which is not limited herein.

The current after voltage division of the third resistor R3 and the fourth resistor R4 is smaller than the minimum trigger current of the optical coupler. In practical implementation, the resistance value of R3 may be 33k, and the resistance value of R4 may be 1 k.

The resistance value of the first resistor R1 is smaller than the resistance value of the load resistor. For example, R1 is 100. The resistance value of R2 is 1 k.

In the circuit, after a power supply is powered on, current charges a filter capacitor C through R1, an optical coupler is conducted after the filter capacitor C is charged to a preset voltage value, an SCR is conducted, and power can be supplied to a load after the SCR is conducted to play a role in restraining impact current during starting. The predetermined voltage value may be determined according to resistance values of R3 and R4, which is not limited in this embodiment.

In general, the larger the resistance value of R3 and the smaller the trigger current value of the opto-coupler, the smaller the on-current can be suppressed.

Referring to fig. 3, it shows that the surge current can reach 143.66a at the 110V ac power-on instant when the protection circuit is not provided, the pulse width is about 500uS, and referring to fig. 4, the voltage at the output terminal in the prior art scheme is initially kept unchanged and then rises steeply after the power is powered on, referring to fig. 5, it shows a schematic diagram of the surge current at the 110V ac power-on instant after the protection circuit is provided, as shown in fig. 5, the surge current is only 36.84A, the pulse width is 500uS, and in addition, referring to fig. 6, after the power is powered on, the filter capacitor C is charged through R1, the voltage value at the corresponding output terminal (i.e. at both ends of the filter capacitor) rises slowly, the power-on current is suppressed, the optical coupler is turned on when the voltage value of the filter capacitor reaches the predetermined voltage value, and the surge current of the filter capacitor is accordingly suppressed to be lower. In fig. 3 to 6, C1 is the voltage value at the output terminal, and C2 is the voltage value at both ends of the SCR. As known above, the protection circuit can significantly suppress the power-on current, thereby avoiding the problem that the impact current is large when the power-on is performed in the conventional scheme, which may cause impact to the fuse and the capacitor and further affect the service life of the fuse and the capacitor, and achieving the effect of suppressing the power-on current.

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 protection circuit for starting-up impact current of an AC/DC power supply is characterized by comprising:

2. The protection circuit according to claim 1, wherein a first end of the optocoupler is an anode of a light emitting diode, a second end of the optocoupler is a cathode of the light emitting diode, a third end of the optocoupler is a main port 1, and a fourth end of the optocoupler is a main port 2.

3. The protection circuit of claim 1, wherein the first terminal of the SCR is a gate, the second terminal of the SCR is an anode, and the third terminal of the SCR is a cathode.

4. The protection circuit of claim 1, wherein the first terminal of the SCR is coupled to a power supply.

5. The protection circuit of claim 1, wherein the second terminal of the SCR is an output terminal.

6. The protection circuit according to any one of claims 1 to 5, wherein the current after voltage division by the third resistor and the fourth resistor is less than the minimum trigger current of the optocoupler.

7. The protection circuit according to any one of claims 1 to 5, wherein a resistance value of the first resistor is smaller than a resistance value of the load resistor.

8. The protection circuit according to any one of claims 1 to 5, wherein the circuit further comprises a filter capacitor, and two ends of the filter capacitor are connected with the second end of the SCR and the second end of the optocoupler.