CN216121905U

CN216121905U - Power supply switching circuit and electronic equipment

Info

Publication number: CN216121905U
Application number: CN202121896630.3U
Authority: CN
Inventors: 杨磊; 宋苏晨; 董金昭; 王海贤
Original assignee: Shanghai Junzheng Network Technology Co Ltd
Current assignee: Shanghai Junzheng Network Technology Co Ltd
Priority date: 2020-09-22
Filing date: 2021-08-13
Publication date: 2022-03-22
Anticipated expiration: 2031-08-13

Abstract

The utility model discloses a power supply switching circuit, comprising: the first input end of the voltage comparison module is connected with the main power supply, and the second input end of the voltage comparison module is connected with the auxiliary power supply; the first end of the switching module is connected with the auxiliary power supply, and the second end of the switching module is connected with the output end of the voltage comparison module; the switching module is configured to close an output path of the secondary power supply when the voltage comparison module outputs a first level; and when the voltage comparison module outputs a second level, opening an output path of the secondary power supply. The utility model also provides electronic equipment using the circuit. The power supply switching circuit ensures that the system voltage is stable in the switching process, the reset or restart of the main control chip can not occur, the switching process is completed by pure hardware, software access is not needed, and the leakage current between the main power supply and the auxiliary power supply is extremely small.

Description

Power supply switching circuit and electronic equipment

Technical Field

The utility model relates to the field of electric devices powered by multiple power supplies, in particular to a power supply switching circuit and electronic equipment using the same.

Background

At present, many electric devices are powered by two-way power supplies, such as smart meters, GPS positioning and the like, and these devices can be powered by a main power supply and a standby power supply, wherein the main power supply can be a device capable of supplying power for a long time, such as a mains supply, a lithium battery pack and the like, and the standby power supply can be a device capable of supplying power for a short time, such as a battery, a super capacitor and the like.

In the actual use process, the main power supply may stop supplying power due to some special conditions, and at this time, the power supply needs to be automatically switched to the standby power supply to ensure that the equipment can continue to work normally for a period of time.

At present, the input voltage and output current ranges of the power supply path management chip on the market are fixed and not adjustable, the circuit compatibility is poor, the power supply path management chip cannot be applied to multiple scenes, and the cost is high.

Therefore, those skilled in the art are dedicated to develop a power switching circuit, which ensures that the system voltage is stable in the switching process, the reset or restart of the main control chip does not occur, the switching process is completed by pure hardware, software access is not required, and the leakage current between the main power supply and the auxiliary power supply is very small.

SUMMERY OF THE UTILITY MODEL

In view of the above defects in the prior art, the technical problem to be solved by the present invention is to provide a power switching circuit, in which the switching process is completed by pure hardware, software access is not required, the system voltage is stable in the switching process, and the reset or restart of the main control chip does not occur.

To achieve the above object, the present invention provides a power switching circuit, including:

the first input end of the voltage comparison module is connected with the main power supply, and the second input end of the voltage comparison module is connected with the auxiliary power supply;

the first end of the switching module is connected with the auxiliary power supply, and the second end of the switching module is connected with the output end of the voltage comparison module;

the switching module is configured to close an output path of the secondary power supply when the voltage comparison module outputs a first level; and when the voltage comparison module outputs a second level, opening an output path of the secondary power supply.

In some embodiments, preferably, the voltage comparison module includes a comparator, a non-inverting input terminal of the comparator is connected to the primary power supply, and an inverting input terminal of the comparator is connected to the secondary power supply.

In some embodiments, preferably, the switching module includes a PMOS transistor and a driving circuit connected to the PMOS transistor, an S pole of the PMOS transistor is connected to the secondary power supply, a G pole of the PMOS transistor is connected to one end of the driving circuit, and the other end of the driving circuit is connected to the output terminal of the voltage comparator.

In some embodiments, preferably, the main power supply is connected directly to the load circuit.

In some embodiments, preferably, a diode is provided between the main power supply and the load circuit.

In some embodiments, preferably, the primary power supply is configured such that, when powered, the voltage of the primary power supply is higher than the voltage of the secondary power supply.

In some embodiments, preferably, the main power supply includes a power supply device and a voltage reduction module connected to the power supply device.

In some embodiments, preferably, the secondary power source comprises a 4.2V or 3V battery.

In some embodiments, preferably, the power supply device includes 220V commercial power, and the voltage reduction module is a switching circuit composed of a transformer, a rectifier bridge and a switching chip; or, the power supply device comprises a 48V battery pack, and the voltage reduction module is a BUCK conversion (BUCK) circuit.

The utility model also provides electronic equipment comprising the power supply switching circuit.

The power supply switching circuit provided by the utility model has the following technical effects:

1. the switching process of the main power supply and the auxiliary power supply is completed by a circuit formed by pure hardware, software intervention is not needed, the system voltage stability in the switching process is ensured, and the reset or restart condition of the main control chip can not occur.

2. And a power path management chip is not needed, the number of used electronic components is small, and the cost is low.

3. Due to the action of the PMOS tube and the diode, the leakage current between the main power supply and the auxiliary power supply is extremely small and can be ignored.

4. The used components are less affected by temperature, and the working temperature range can reach minus 40 ℃ to 85 ℃.

The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.

Drawings

FIG. 1 is a block diagram of a power switching circuit of the present invention;

fig. 2 is a schematic circuit diagram of the power switching circuit of the present invention.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The utility model is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.

Some exemplary embodiments of the utility model have been described for illustrative purposes, and it is to be understood that the utility model may be practiced otherwise than as specifically described.

As shown in fig. 1, the power switching circuit provided by the present invention includes a voltage comparing module 50 and a switching module 40. The voltage comparison module 50 has a first input connected to the primary power source 10 and a second input connected to the secondary power source 20. The switching module 40 has a first terminal connected to the secondary power source 20 and a second terminal connected to an output terminal of the voltage comparison module 50. The voltage of the main power source 10 is compared with the voltage of the secondary power source 20 by the voltage comparison module 50 to determine whether the main power source 10 is operating normally, and if the main power source 10 is operating normally, the voltage comparison module 50 outputs a first level, which can prompt the switching module 40 to close the output path of the secondary power source 20. If the main power supply 10 cannot work normally, the voltage comparison module 50 outputs a second level, which enables the switching module 40 to open the output path of the secondary power supply 20, so that the secondary power supply 20 can supply power normally. The voltage comparison module 50 and the switching module 40 can be implemented in a pure hardware manner to perform the voltage determination and automatic switching functions without software intervention.

In some embodiments, as shown in fig. 2, the voltage comparison module 50 may employ a voltage comparator 51. The main power supply 10 is connected to the inverting input terminal of the voltage comparator 51, and the sub power supply 20 is connected to the inverting input terminal of the voltage comparator 51. In the case where the main power supply 10 is normally operated, the voltage of the main power supply 10 is higher than the voltage of the subsidiary power supply 20. In the presence of the main power supply 10, that is, the main power supply 10 can supply power normally, the level output by the output terminal of the voltage comparator 51 is a high level, so that the switching module 40 closes the path of the secondary power supply 20, and the secondary power supply 20 does not discharge to the outside. When the main power supply 10 is absent, the main power supply 10 cannot normally supply power, and at this time, the secondary power supply 20 needs to be started to supply power to the load circuit 30, at this time, the level output by the output end of the voltage comparator 51 is a low level, so that the switching module 40 opens the path of the secondary power supply 20, and the secondary power supply 20 discharges to the outside. When the main power supply 10 is normally used, the high level output from the voltage comparator 51 is equal to the voltage of the main power supply 10. When the main power supply 10 is absent or cannot normally supply power, the voltage comparator 51 outputs a low level (close to 0V). It should be understood that other devices with voltage comparison function may be used to implement voltage comparison, so that different levels are output according to different voltages of the primary and secondary power supplies 20 to trigger the switching function of the switching module 40.

In some embodiments, the switching module 40 includes a PMOS transistor 41, wherein the S pole of the PMOS transistor 41 is connected to the secondary power supply 20, the G pole is connected to the output terminal of the voltage comparator 51, and the D pole is connected to the load circuit 30. A driving circuit 42 may be further disposed between the G-pole of the PMOS transistor 41 and the output terminal of the voltage comparator 51, for controlling the on and off of the PMOS transistor 41. The driving circuit 42 may be any one of the driving circuits 42 used in the prior art for the PMOS transistor 41, and two resistors are selected to divide the voltage, thereby forming the driving circuit 42.

In use, when the voltage comparator 51 outputs a high level, the voltage at the control G pole of the PMOS transistor 41 is pulled high, and the voltage between the G, S poles is greater than the turn-on voltage of the PMOS transistor 41, so as to turn off the PMOS transistor 41, at which time the output path of the secondary power supply 20 is turned off, and the primary power supply 10 does not generate a leakage current at the secondary power supply 20. When the main power supply 10 cannot supply power or the voltage is lower than the voltage of the secondary power supply 20 due to an abnormality of the main power supply 10, such as a power failure, a battery pack stolen or an abnormality, the main power supply 10 cannot normally supply power, the voltage comparator 51 outputs a low level (close to 0V) to the driving circuit 42, the voltage of the control G pole of the PMOS transistor 41 is pulled to 0V, the voltage between the G, S poles is lower than the starting voltage of the PMOS transistor 41, the PMOS transistor 41 is opened, the secondary power supply 20 is switched to supply power to a load, and the voltage of the load circuit 30 does not drop in the switching process, so that the system can normally operate. It should be understood that the switching module 40 is not limited to the PMOS transistor 41, and other devices capable of performing the switching function at different levels can also perform the functions of the present invention.

The power supply switching circuit of the utility model switches the power supply path by the PMOS tube 41 and the voltage comparator 51, is a switching circuit consisting of pure hardware and does not need software intervention. When the main power supply 20 and the auxiliary power supply 20 are switched, the leakage current is extremely small and can be ignored. In addition, the power supply switching circuit has fewer peripheral devices and low cost; the working temperature range can reach minus 40 ℃ to 85 ℃, and the device is particularly suitable for some electronic equipment working outdoors for a long time, such as a GPS positioning device.

In some embodiments, the main power supply 10 may be directly connected to the load circuit 30. In some embodiments, as shown in fig. 2, a diode 12 may be further connected in series between the main power source 10 and the load circuit 30, and the diode 12 may prevent the leakage of the main power source 10 from the secondary power source 20. In the above embodiment, the main power source 10 is a low voltage (generally 5V) converted by the power supply device through the voltage reduction module 11. The power supply device and the voltage reduction module 11 can be selected according to actual requirements. For example, in some embodiments, 220V commercial power may be selected at the VIN end shown in fig. 2, and then a voltage-reducing module 11 for 220V commercial power existing in the prior art is selected to convert the 220V commercial power into a suitable low voltage, where the voltage-reducing module 11 may be a switching circuit composed of a transformer, a rectifier bridge, and a switching chip; in some embodiments, the VIN terminal shown in fig. 2 may select a battery pack (generally 48V) composed of a lithium battery, a lead storage battery, and the like, and then select a BUCK conversion (BUCK) circuit or a BUCK chip to convert the voltage of the battery pack into a low voltage. Under normal conditions, the load circuit 30 is always powered by the main power supply 10. It should be understood that the power supply device of the main power supply 10 can be selected according to actual requirements, and the low voltage of the main power supply 10 referred to herein can be selected according to actual requirements, and is not limited to 5V, which do not constitute a limitation of the present invention.

The voltage of the secondary power source 20 may be slightly lower than that of the primary power source 10, a single battery of 4.2V or 3V may be used, or other power sources with lower voltage than that of the primary power source 10. The secondary power supply 20 is connected to the load circuit 30 through the switching module 40, and in a normal condition, the voltage comparator 51 and the switching module 40 act to turn off the power-on path of the secondary power supply 20, so that no power is supplied to the load circuit 30. When the main power supply 10 fails to supply power or the voltage of the main power supply 10 is lower than the voltage of the secondary power supply 20 due to an abnormality, the power-on path of the secondary power supply 20 is activated to discharge the power to the outside. It should be understood that the specific implementation form of the secondary power supply 20 can be selected according to actual requirements, and is not limited to the 4.2V or 3V battery, but can also be selected from devices such as super capacitor.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the utility model. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. A power switching circuit, comprising:

2. The power switching circuit of claim 1, wherein the voltage comparison module comprises a comparator having a non-inverting input connected to the primary power source and an inverting input connected to the secondary power source.

3. The power switching circuit according to claim 2, wherein the switching module comprises a PMOS transistor and a driving circuit connected to the PMOS transistor, an S-pole of the PMOS transistor is connected to the secondary power supply, a G-pole of the PMOS transistor is connected to one end of the driving circuit, and the other end of the driving circuit is connected to the output terminal of the voltage comparator.

4. The power switching circuit of claim 1, wherein the main power source is directly connected to the load circuit.

5. The power switching circuit of claim 1, wherein a diode is disposed between the main power supply and the load circuit.

6. The power switching circuit of claim 2, wherein the primary power source is configured such that, when powered, a voltage of the primary power source is higher than a voltage of the secondary power source.

7. The power switching circuit of claim 6, wherein the main power supply comprises a power supply and a voltage reduction module connected to the power supply.

8. The power switching circuit of claim 6, wherein the secondary power source comprises a 4.2V or 3V battery.

9. The power switching circuit according to claim 7, wherein the power supply device comprises 220V commercial power, and the voltage reduction module is a switching circuit composed of a transformer, a rectifier bridge and a switching chip; or, the power supply device comprises a 48V battery pack, and the voltage reduction module is a BUCK circuit.

10. An electronic device comprising the power switching circuit according to any one of claims 1 to 9.