WO2022111416A1

WO2022111416A1 - Extended-time reset circuit of switching power supply, printed circuit board, and electronic device

Info

Publication number: WO2022111416A1
Application number: PCT/CN2021/132126
Authority: WO
Inventors: 王吉信
Original assignee: 中兴通讯股份有限公司
Priority date: 2020-11-27
Filing date: 2021-11-22
Publication date: 2022-06-02
Also published as: CN114567310A

Abstract

An extended-time reset circuit of a switching power supply, a printed circuit board, and an electronic device. The extended-time reset circuit of the switching power supply comprises: a power supply switching circuit (100), a reset signal holding circuit (200), and a power supply energy-storage circuit (300). A power supply input end, the power supply switching circuit (100), and a power supply pin of a chip are connected in sequence. The reset signal holding circuit (200) is connected to the power supply switching circuit (100). The power supply energy-storage circuit (300) is connected respectively to the power supply input end and the reset signal holding circuit (200). When a reset signal is received by the reset signal holding circuit (200), a shutdown signal is outputted to the power supply switching circuit (100), thus allowing the power supply switching circuit (100) to be shut down, thereby cutting off the power supply to the chip, the power supply energy-storage circuit (300) is discharged via the reset signal holding circuit (200), when discharged, the reset signal holding circuit (200) stops outputting the shutdown signal, and the power supply switching circuit (100) is reconnected so as to supply power to the power supply pin of the chip.

Description

Long-time reset circuit of switching power supply, printed circuit board and electronic equipment

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on the Chinese patent application with the application number of 202011362072.2 and the filing date of November 27, 2020, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is incorporated herein by reference.

technical field

The present application relates to the technical field of switching power supplies, and in particular, to a long-term reset circuit, a printed circuit board and an electronic device of a switching power supply.

Background technique

In current electronic products, the load of switching power supply often contains key chips. The key chip needs to be reset and restarted at some point, and the most effective and common way to reset the chip is to cut off the power supply for a period of time, and then power on again, the chip will restart naturally. This requires that when the chip needs to be reset, the system sends an instruction to the reset circuit. After the reset circuit receives the instruction, the power supply to the load such as the chip is turned off for a period of time.

For small and medium-sized systems and power supplies with small and medium power, it is difficult to realize the reset function due to the simple circuit function and no management system in the power supply. Adding switches at the power output end, configuring the control circuit with the energy storage circuit or using an independent auxiliary power supply will make the structure of the power supply circuit not simple enough, resulting in a large board area. Management, there is a complex control, resulting in a decline in power efficiency, reducing the reliability of the switching power supply.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a long-term reset circuit of a switching power supply, a printed circuit board, and an electronic device.

In a first aspect, an embodiment of the present application provides a long-term reset circuit of a switching power supply, including: a power supply switch circuit, the input end of the power supply switch circuit is connected to the power supply input end, and the output end of the power supply switch circuit is connected to the chip. a power supply pin; a reset signal maintenance circuit, the reset signal maintenance circuit is connected to the power supply switch circuit, and the reset signal maintenance circuit is configured to output a shutdown signal to the power supply switch circuit in the case of receiving the reset signal; a power supply energy storage circuit, the power supply energy storage circuit is respectively connected to the power input terminal and the reset signal maintenance circuit, the power supply energy storage circuit is set to be maintained by the reset signal when the power supply switch circuit is turned off The circuit is discharged, so that the reset signal maintaining circuit stops outputting the shutdown signal after the power supply energy storage circuit is discharged.

In a second aspect, embodiments of the present application provide a printed circuit board, including the long-term reset circuit of a switching power supply as described in the embodiments of the first aspect.

In a third aspect, embodiments of the present application provide an electronic device, including the long-term reset circuit of the switching power supply described in the first embodiment of the first aspect or the printed circuit board described in the second embodiment of the second aspect.

Other features and advantages of the present application will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the description, claims and drawings.

Description of drawings

The application is further described below in conjunction with the accompanying drawings and embodiments;

1 is a schematic diagram of a long-term reset circuit of a switching power supply provided in Embodiment 1 of the present application;

2 is a schematic diagram of a long-term reset circuit of a switching power supply provided in Embodiment 2 of the present application;

3 is a schematic diagram of a long-term reset circuit of a switching power supply provided in Embodiment 3 of the present application;

4 is a schematic diagram of a long-term reset circuit of a switching power supply provided in Embodiment 4 of the present application;

FIG. 5 is a schematic diagram of a long-term reset circuit of a switching power supply provided in Embodiment 5 of the present application.

Detailed ways

This section will describe the specific embodiments of the present application in detail, and the preferred embodiments of the present application are shown in the accompanying drawings. Each technical feature and overall technical solution of the application should not be construed as a limitation on the protection scope of the application.

In the description of this application, if the first and second are described only for the purpose of distinguishing technical features, they should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating The order of the indicated technical features.

In the description of this application, unless otherwise clearly defined, words such as setting, installation, and connection should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in this application in combination with the specific content of the technical solution.

The embodiments of the present application provide a long-term reset circuit, a printed circuit board and an electronic device of a switching power supply, which are simple in circuit, simple in reset control and low in cost.

The embodiments of the present application will be further described below with reference to the accompanying drawings.

Referring to FIG. 1 , an embodiment of the first aspect of the present application provides a long-term reset circuit of a switching power supply, including a power supply switch circuit 100 , a reset signal maintenance circuit 200 and a power supply energy storage circuit 300 , wherein:

The input end of the power supply switch circuit 100 is connected to the power input end, and the output end of the power supply switch circuit 100 is connected to the power supply pin of the chip;

The reset signal maintaining circuit 200 is connected to the power supply switch circuit 100, and the reset signal maintaining circuit 200 is configured to output a shutdown signal to the power supply switch circuit 100 in the case of receiving the reset signal;

The power supply energy storage circuit 300 is respectively connected to the power input terminal and the reset signal maintenance circuit 200. The power supply energy storage circuit 300 is configured to discharge through the reset signal maintenance circuit 200 when the power supply switch circuit 100 is turned off, so as to make the reset signal maintenance circuit 200 discharge. After the power supply energy storage circuit 300 is discharged, the output of the shutdown signal is stopped.

In the long-term reset circuit of the switching power supply provided by this embodiment, after the reset signal maintenance circuit 200 receives the reset signal, it outputs a shutdown signal to the power supply switch circuit 100, so that the power supply switch circuit 100 is turned off, and the power supply pin of the chip is cut off. Power is supplied, and then the power supply energy storage circuit 300 discharges through the reset signal maintenance circuit 200. After the power supply energy storage circuit 300 is discharged, the reset signal maintenance circuit 200 stops outputting the shutdown signal, and the power supply switch circuit 100 is reconnected to supply power to the power supply of the chip. Through the cooperation between the reset signal maintenance circuit 200 and the power supply energy storage circuit 300, the long-term reset of the power supply switch circuit 100 is realized, and then the long-term reset of the chip is realized. It is necessary to configure an independent auxiliary power supply, and there is no need to add a switch on the main circuit of the power supply output, which can reduce the board area and cost.

2, in the long-term reset circuit of the above-mentioned switching power supply, the power supply switch circuit 100 includes a first switch tube Q1 and a first diode D1, the reset circuit takes power from the primary winding of the transformer T1, and the lead of the transformer T1 As the power input terminal of the reset circuit, pin 6 is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to one switch pin of the first switch tube Q1, and the other one of the first switch tube Q1 The switch pin is connected to the power supply pin of the chip M1 , and the control pin of the first switch transistor Q1 is connected to the reset signal maintaining circuit 200 . It can be understood that when the power supply switch circuit 100 is turned on, that is, when the first switch tube Q1 is turned on, the electric energy provided by the primary winding of the transformer T1 is transmitted to the power supply lead of the chip M1 through the first diode D1 and the first switch tube Q1. pin to make the chip M1 work normally; if the reset signal maintenance circuit 200 receives the reset signal RESET, it will output a low-level turn-off signal to the base of the first switch tube Q1, so that the first switch tube Q1 is turned off, thereby Cut off the power supply to the power pin of chip M1. The first switch tube Q1 in FIG. 2 is an NPN transistor, that is, the cathode of the first diode D1 is connected to the collector of the first switch tube Q1, and the emitter of the first switch tube Q1 is connected to the power supply of the chip M1 pin, the base of the first switch transistor Q1 is connected to the reset signal maintaining circuit 200 .

Referring to FIG. 2, in the long-term reset circuit of the switching power supply, the reset signal maintaining circuit 200 includes a reset signal input terminal, a shutdown signal output terminal, a second switch transistor Q2, a third switch transistor Q3, a second resistor R2 and a third switch transistor Q3. Two capacitors C2, the reset signal input terminal is respectively connected to one end of the second resistor R2, one end of the second capacitor C2, a switch pin of the second switch Q2 and the control pin of the third switch Q3, the second resistor R2 The other end of the second capacitor C2 and one switch pin of the third switch tube Q3 are grounded, the other switch pin of the third switch tube Q3 is connected to the control pin of the second switch tube Q2, and the second switch tube Q3 is connected to the control pin of the second switch tube Q2. The other switch pin of the transistor Q2 is used as an output terminal of the turn-off signal and is connected to the control pin of the first switch transistor Q1.

After the reset signal maintenance circuit 200 receives the reset signal RESET from the reset signal input terminal, it triggers the third switch transistor Q3 to conduct, and then triggers the second switch transistor Q2 to conduct after the third switch transistor Q3 is conducted, thereby pulling down the first switch transistor. The potential of the base of Q1 turns off the first switch transistor Q1.

Among them, in the long-term reset circuit of the switching power supply shown in FIG. 2 , the second switch Q2 in the reset signal maintenance circuit 200 adopts an NPN transistor, and the third switch Q3 adopts a PNP transistor; The second switch transistor Q2 and the third switch transistor Q3 can also be used in combination with an N-type MOS transistor and a P-type MOS transistor, or a triode and a MOS transistor can be used in combination.

In addition, the reset signal maintenance circuit 200 can also use the method in FIG. 4 to realize its function. The reset signal maintenance circuit 200 includes a reset signal input terminal, a shutdown signal output terminal, a second resistor R2, a second capacitor C2 and a thyristor Q4, the reset signal input terminal is respectively connected to one end of the second resistor R2, one end of the second capacitor C2 and the control electrode of the thyristor Q4, the other end of the second resistor R2, the other end of the second capacitor C2 and the thyristor The cathode of Q4 is grounded, and the anode of the thyristor Q4 is used as the output terminal of the turn-off signal and is connected to the control pin of the first switch tube Q1.

After receiving the reset signal RESET from the reset signal input terminal, the reset signal maintaining circuit 200 triggers the thyristor Q4 to be turned on, and pulls down the potential of the base of the first switch transistor Q1, so that the first switch transistor Q1 is turned off.

3 and 4, the power supply tank circuit 300 includes a first capacitor C1 and a first resistor R1, one end of the first capacitor C1 and one end of the first resistor R1 are both connected to the cathode of the first diode D1, and the first capacitor C1 is connected to the cathode of the first diode D1. The other end of C1 is grounded, and the other end of the first resistor R1 is connected to the control pin of the first switch transistor Q1.

When the first switch tube Q1 is turned on, the transformer T1 supplies power to the chip M1 through the first diode D1 and the first switch tube Q1. After receiving the reset signal RESET, the reset signal maintaining circuit 200 outputs a turn-off signal to the first switch tube. Q1, so that the first switch tube Q1 is turned off, and the power supply to the power supply pin of the chip M1 is cut off; after the chip M1 stops working, the power supply of the transformer T1 is also cut off accordingly. After the charging is completed, after the first switch Q1 is turned off, the first capacitor C1 is discharged through the first resistor R1 and the reset signal maintaining circuit 200. When the first capacitor C1 is discharged to a certain extent, the discharge current of the first capacitor C1 Small enough to maintain the conduction of the second switch Q2 and the third switch Q3 in FIG. 3 or insufficient to maintain the conduction of the thyristor Q4 in FIG. 4 , the reset signal maintenance circuit 200 no longer outputs a turn-off signal to The first switch tube Q1 is turned on again, so that the chip M1 is reset. The size of the discharge current can be adjusted by the size of the first capacitor C1 and the first resistor R1, thereby adjusting the reset time, and selecting appropriate parameters to make the reset time meet the long-term reset requirement in seconds.

3 and 5, the long-term reset circuit of the switching power supply further includes a reset signal filter circuit 400, the reset signal filter circuit 400 includes a third resistor R3 and a third capacitor C3, and one end of the third resistor R3 is used to receive the reset signal, The other end of the third resistor R3 is connected to one end of the third capacitor C3, the other end of the third capacitor C3 is grounded, and the other end of the third resistor R3 and one end of the third capacitor C3 are also connected to the reset signal input end, that is, the second The connection point between the resistor R2 and the second capacitor C2. Setting the reset signal filter circuit 400 can filter out the ripple signal in the reset signal and reduce interference.

In addition, the long-term reset circuit of the switching power supply further includes a reset signal isolation circuit, and the other end of the third resistor R3 and one end of the third capacitor C3 are connected to the reset signal input terminal through the reset signal isolation circuit. If the reset signal RESET comes from the secondary winding of the transformer T1, it is necessary to set the reset signal isolation circuit to avoid interference between the primary and secondary sides. The reset signal isolation circuit is not shown in the circuits in FIGS. 3 and 5, but does not affect the understanding of the present application. The reset signal isolation circuit may use relay isolation, optocoupler isolation, or isolation by other methods, which will not be repeated here.

3 and 5 , the long-term reset circuit of the switching power supply further includes a reset start auxiliary circuit 500. The reset start auxiliary circuit 500 includes an auxiliary power supply terminal BUS, a fourth resistor R4 and a fourth capacitor C4, and the auxiliary power supply terminal BUS is connected to the first power supply terminal BUS. One end of the four resistors R4 and the other end of the fourth resistor R4 are respectively connected to one end of the fourth capacitor C4, the power supply pin of the chip M1 and the output end of the power supply switch circuit 100, and the other end of the fourth capacitor C4 is grounded.

The reset start-up auxiliary circuit 500 is provided. When the first switch tube Q1 is turned on again, the auxiliary power supply terminal BUS charges the fourth capacitor C4 through the fourth resistor R4, thereby increasing the voltage of the power supply pin of the chip M1, and the auxiliary chip M1 starts again. .

3 and 5, in the long-term reset circuit of the switching power supply, the reset start auxiliary circuit 500 further includes a second diode D2, and the other end of the fourth resistor R4 is also connected to the anode of the second diode D2, and the first The cathodes of the two diodes D2 are connected to the reset signal maintaining circuit 200 .

The second diode D2 is set. When the first switch tube Q1 is turned off, the auxiliary power supply terminal BUS and the fourth capacitor C4 can be discharged through the second diode D2 and the reset signal maintaining circuit 200, so as to prevent the fourth capacitor C4 from being in a constant state. fully charged state.

In a second aspect, the embodiments of the present application provide a printed circuit board including the long-term reset circuit of the switching power supply of the embodiments of the first aspect of the present application. After the reset signal maintenance circuit 200 receives the reset signal, it outputs a shutdown signal to the power supply switch circuit 100, so that the power supply switch circuit 100 is turned off, cutting off the power supply to the power supply pins of the chip, and then the power supply energy storage circuit 300 maintains the circuit through the reset signal 200 is discharged. After the power supply energy storage circuit 300 is discharged, the reset signal maintaining circuit 200 stops outputting the shutdown signal, and the power supply switch circuit 100 is reconnected to supply power to the power pins of the chip. The reset circuit has simple reset control, simple structure, and no It is necessary to configure an independent auxiliary power supply, and there is no need to add a switch on the main circuit of the power supply output, which can reduce the board area and cost.

In a third aspect, the embodiments of the present application provide an electronic device, including the long-term reset circuit of the switching power supply of the first aspect of the present application or the printed circuit board of the second aspect of the present application. After the reset signal maintenance circuit 200 receives the reset signal, it outputs a shutdown signal to the power supply switch circuit 100, so that the power supply switch circuit 100 is turned off, cutting off the power supply to the power supply pins of the chip, and then the power supply energy storage circuit 300 maintains the circuit through the reset signal 200 is discharged. After the power supply energy storage circuit 300 is discharged, the reset signal maintaining circuit 200 stops outputting the shutdown signal, and the power supply switch circuit 100 is reconnected to supply power to the power pins of the chip. The reset circuit has simple reset control, simple structure, and no It is necessary to configure an independent auxiliary power supply, and there is no need to add a switch on the main circuit of the power supply output, which can reduce the board area and cost.

The embodiment of the present application includes: a long-term reset circuit of a switching power supply, a printed circuit board, and an electronic device. After the reset signal maintenance circuit receives the reset signal, it outputs a shutdown signal to the power supply switch circuit, so that the power supply switch circuit is turned off and the power supply switch circuit is cut off. Then the power supply energy storage circuit discharges through the reset signal maintenance circuit. After the power supply energy storage circuit is discharged, the reset signal maintenance circuit stops outputting the shutdown signal, and the power supply switch circuit is reconnected to supply power to the chip's power supply lead. Through the reset signal maintaining the cooperation between the circuit and the power supply energy storage circuit, the long-term reset of the power supply switch circuit is realized, and then the long-term reset of the chip is realized. The reset control of the reset circuit is simple, the structure is simple, and no independent configuration is required. The auxiliary power supply does not need to add a switch on the main output circuit of the power supply, which can reduce the board area and cost.

The embodiments of the present application have been described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned embodiments. Within the scope of knowledge possessed by those of ordinary skill in the technical field, various aspects can be made without departing from the purpose of the present application. kind of change.

Claims

A long-time reset circuit of a switching power supply, comprising:

a power supply switch circuit, the input end of the power supply switch circuit is connected to the power supply input end, and the output end of the power supply switch circuit is connected to the power supply pin of the chip;

a reset signal maintenance circuit, the reset signal maintenance circuit is connected to the power supply switch circuit, and the reset signal maintenance circuit is configured to output a shutdown signal to the power supply switch circuit in the case of receiving the reset signal;

a power supply energy storage circuit, the power supply energy storage circuit is respectively connected to the power input terminal and the reset signal maintenance circuit, the power supply energy storage circuit is set to be maintained by the reset signal when the power supply switch circuit is turned off The circuit is discharged, so that the reset signal maintaining circuit stops outputting the shutdown signal after the power supply energy storage circuit is discharged.
The long-time reset circuit of a switching power supply according to claim 1, wherein the power supply switching circuit comprises a first switch tube and a first diode, and the power supply input terminal is connected to the anode of the first diode , the cathode of the first diode is connected to one switch pin of the first switch tube, the other switch pin of the first switch tube is connected to the power supply pin of the chip, and the first switch tube The control pin is connected to the reset signal maintaining circuit.
The long-term reset circuit of a switching power supply according to claim 2, wherein the reset signal maintenance circuit comprises a reset signal input terminal, a shutdown signal output terminal, a second switch tube, a third switch tube, a second resistor and a second capacitor, the reset signal input terminal is respectively connected to one end of the second resistor, one end of the second capacitor, a switch pin of the second switch tube and the control of the third switch tube pin, the other end of the second resistor, the other end of the second capacitor and one switch pin of the third switch tube are grounded, and the other switch pin of the third switch tube is connected to the The control pin of the second switch tube, and the other switch pin of the second switch tube is used as the output end of the turn-off signal and is connected to the control pin of the first switch tube.
The long-term reset circuit of a switching power supply according to claim 2, wherein the reset signal maintenance circuit comprises a reset signal input terminal, a shutdown signal output terminal, a second resistor, a second capacitor and a thyristor, so The reset signal input end is respectively connected to one end of the second resistor, one end of the second capacitor and the control electrode of the thyristor, the other end of the second resistor, the other end of the second capacitor and the cathode of the thyristor is grounded, and the anode of the thyristor serves as the output terminal of the shutdown signal and is connected to the control pin of the first switch tube.
The long-time reset circuit of a switching power supply according to any one of claims 2 to 4, wherein the power supply energy storage circuit comprises a first capacitor and a first resistor, one end of the first capacitor and the first One end of a resistor is connected to the cathode of the first diode, the other end of the first capacitor is grounded, and the other end of the first resistor is connected to the control pin of the first switch tube.
The long-term reset circuit of a switching power supply according to claim 3 or 4, further comprising a reset signal filter circuit, the reset signal filter circuit comprising a third resistor and a third capacitor, one end of the third resistor for receiving a reset signal, the other end of the third resistor is connected to one end of the third capacitor, the other end of the third capacitor is grounded, the other end of the third resistor and one end of the third capacitor is also connected to the reset signal input terminal.
The long-term reset circuit of a switching power supply according to claim 6, further comprising a reset signal isolation circuit, and the other end of the third resistor and one end of the third capacitor are connected through the reset signal isolation circuit to the reset signal input terminal.
The long-term reset circuit of a switching power supply according to claim 1, further comprising a reset start auxiliary circuit, the reset start auxiliary circuit comprising an auxiliary power supply terminal, a fourth resistor and a fourth capacitor, the auxiliary power supply terminal Connected to one end of the fourth resistor, the other end of the fourth resistor is respectively connected to one end of the fourth capacitor, the power supply pin of the chip and the output end of the power supply switch circuit, the fourth capacitor The other end is grounded.
The long-time reset circuit of a switching power supply according to claim 8, wherein the reset start auxiliary circuit further comprises a second diode, and the other end of the fourth resistor is further connected to the second diode The anode of the tube and the cathode of the second diode are connected to the reset signal maintaining circuit.
A printed circuit board, comprising the long-time reset circuit of the switching power supply according to any one of claims 1 to 9.
An electronic device, comprising the long-time reset circuit of the switching power supply according to any one of claims 1 to 9 or comprising the printed circuit board according to claim 10 .