WO2021022957A1

WO2021022957A1 - Power source switching circuit and electronic apparatus

Info

Publication number: WO2021022957A1
Application number: PCT/CN2020/100436
Authority: WO
Inventors: 苏小燕; 蔡辉
Original assignee: 百富计算机技术（深圳）有限公司
Priority date: 2019-08-05
Filing date: 2020-07-06
Publication date: 2021-02-11
Also published as: CN210246387U

Abstract

The present invention is applicable to the technical field of power source circuit designs. Provided are a power source switching circuit and an electronic apparatus. The power source switching circuit comprises a primary power supply unit and at least one secondary power supply unit. When the primary power supply unit and the secondary power supply unit are simultaneously connected to external power sources, the power source switching circuit outputs electrical energy via an output end of the primary power supply unit. When any one of the primary power supply unit and the secondary power supply unit is connected to an external power source, the power source switching circuit outputs electrical energy via an output end of the power supply unit connected to the external power source. A power source switching circuit provided in an embodiment of the present invention allows a primary power supply unit and respective secondary power supply units to be simultaneously connected to external power sources, thereby solving the problem in the art in which a power supply circuit does not support simultaneous connection to multiple charging devices.

Description

Power switching circuit and electronic equipment

Technical field

This application belongs to the technical field of power supply circuit design, and in particular relates to a power switching circuit and electronic equipment.

Background technique

Many electrical equipment, such as POS machines, are often equipped with multiple charging methods. The electric equipment can be charged through the charging base, and the electric equipment can also be charged through the USB interface on the electric equipment. Generally, an electric device can only select one charging method for charging at a certain time, and cannot connect to multiple charging devices at the same time. Connecting multiple charging devices at the same time will cause greater adverse effects on electrical equipment.

When many users use electric equipment, they often hope that the electric equipment can be fully charged at all times for the convenience of use. This requires simultaneous access to multiple different charging devices for electrical equipment to ensure that at least one charging device can effectively charge the electrical equipment; however, the power supply circuits commonly used on electrical equipment do not support simultaneous access to multiple Charging device.

technical problem

In view of this, the embodiments of the present application provide a power switching circuit and electronic equipment to solve the problem that the current power supply circuit cannot support simultaneous access to multiple charging devices.

Technical solutions

According to the first aspect, an embodiment of the present application provides a power switching circuit, including: a main power supply unit and at least one auxiliary power supply unit; when the main power supply unit and the auxiliary power supply unit are simultaneously connected to external power, the The power switching circuit outputs electric energy through the output terminal of the main power supply unit; when any one of the main power supply unit and the auxiliary power supply unit is connected to an external power supply, the power supply switching circuit passes through the power supply unit connected to the external power supply The output terminal outputs electric energy.

With reference to the first aspect, in some embodiments of the present application, the main power supply unit includes: a resistor R794, a transistor Q29, a resistor R812, and a dual PMOS chip Q56; the resistor R794 is connected to the external power and the power supply of the main power supply unit. Between the bases of the transistor Q29; the emitter of the transistor Q29 is grounded, the collector of the transistor Q29 is connected to the first end of the resistor R812, and the second end of the resistor R812 is connected to the dual PMOS The first gate, the second gate, the first source and the second source of the chip Q56 are connected; the first drain of the dual PMOS chip Q56 is electrically connected to the outside of the main power supply unit, and the dual PMOS chip The second drain of Q56 is used to output electrical energy when the main power supply unit is powered on.

With reference to the first aspect, in some embodiments of the present application, the main power supply unit further includes: a resistor R809 and a capacitor C764; the first end of the resistor R809 is connected to the second end of the resistor R812, and the resistor The second end of R809 is respectively connected to the first source and the second source of the dual PMOS chip Q56; the capacitor C764 is connected in parallel to both ends of the resistor R809.

With reference to the first aspect, in some embodiments of the present application, the main power supply unit further includes: a resistor R795, a transistor Q41, and a resistor R968; the first end of the resistor R795 is electrically connected to the external power supply unit, so The second end of the resistor R795 is connected to the base of the transistor Q41; the emitter of the transistor Q41 is grounded, the collector of the transistor Q41 is connected to the first end of the resistor R968, and the first end of the resistor R968 The two ends are connected with a DC power supply; the collector of the transistor Q41 is also used to output a signal for indicating whether the external power of the main power supply unit is powered on.

With reference to the first aspect, in some embodiments of the present application, the auxiliary power supply unit includes: a resistor R714, a transistor Q31, a resistor R796, a dual PMOS chip U40, and a transistor Q55; the base of the transistor Q55 and the main power supply unit The external electrical connection of the unit, the emitter of the transistor Q55 is grounded, the collector of the transistor Q55 is connected to the base of the transistor Q31; the resistor R714 is connected between the external electrical of the auxiliary power supply unit and the transistor Q31 Between the bases; the emitter of the transistor Q31 is grounded, the collector of the transistor Q31 is connected to the first end of the resistor R796, and the second end of the resistor R796 is respectively connected to the first end of the dual PMOS chip U40 A gate, a second gate, a first source and a second source are connected; the first drain of the dual PMOS chip U40 is electrically connected to the outside of the auxiliary power supply unit, and the second of the dual PMOS chip U40 The drain is used to output electrical energy when only the external power of the auxiliary power supply unit is powered on.

With reference to the first aspect, in some embodiments of the present application, the auxiliary power supply unit further includes: a resistor R810 and a capacitor C267; a first end of the resistor R810 is connected to a second end of the resistor R796, and the resistor The second end of R810 is connected to the first source and the second source of the dual PMOS chip U40, respectively; the capacitor C267 is connected in parallel to both ends of the resistor R810.

With reference to the first aspect, in some embodiments of the present application, the auxiliary power supply unit further includes: a resistor R1001 and a capacitor C978; the resistor R1001 is connected between the base of the transistor Q55 and the external power supply of the main power supply unit The capacitor C978 is connected between the base of the transistor Q55 and ground.

With reference to the first aspect, in some embodiments of the present application, the auxiliary power supply unit further includes: a resistor R769 and a transistor Q32; the first end of the resistor R769 receives a control for controlling whether the auxiliary power supply unit is enabled Signal, the second end of the resistor R769 is connected to the base of the transistor Q32; the emitter of the transistor Q32 is grounded, and the collector of the transistor Q32 is connected to the base of the transistor Q31.

According to the second aspect, an embodiment of the present application provides an electronic device including the power switching circuit as described in the first aspect or any one of the first aspect.

Beneficial effect

In the power switching circuit provided by the embodiment of the present application, the main power supply unit and each auxiliary power supply unit are allowed to be connected to external power at the same time, and when the main power supply unit and each auxiliary power supply unit are connected to the external power at the same time, only the main power supply unit is controlled. Therefore, the power switching circuit provided in the embodiments of the present application can realize charging when multiple power supply units are powered on at the same time, which solves the problem that the current power supply circuit cannot support simultaneous access to multiple charging devices.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only of the present application. For some embodiments, for those of ordinary skill in the art, other drawings can be obtained from these drawings without creative labor.

FIG. 1 is a schematic diagram of the system structure of a power switching circuit provided by an embodiment of the present application;

2 is a circuit schematic diagram of a power switching circuit provided by an embodiment of the present application;

Fig. 3 is a schematic diagram of an electronic device provided by an embodiment of the present application.

Embodiments of the invention

In the following description, for the purpose of illustration rather than limitation, specific details such as a specific system structure and technology are proposed for a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from obstructing the description of this application.

In order to illustrate the technical solutions described in the present application, specific embodiments are used for description below.

An embodiment of the present application provides a power switching circuit. As shown in FIG. 1, the power switching circuit may include: a main power supply unit and at least one auxiliary power supply unit.

When the main power supply unit and each auxiliary power supply unit are simultaneously connected to external power, the power switching circuit outputs electric energy through the output terminal of the main power supply unit.

When any one of the main power supply unit and the auxiliary power supply unit is connected to external power, the power switching circuit outputs electric energy through the output terminal of the power supply unit connected to the external power.

In the power switching circuit shown in Figure 1, a main power supply unit and an auxiliary power supply unit are schematically drawn. In practical applications, the user can freely set the number of auxiliary power supply units as needed, which is not limited in the embodiment of the present application.

In a specific real-time mode, as shown in FIG. 2, the main power supply unit may include: a resistor R794, a transistor Q29, a resistor R812, and a dual PMOS chip Q56.

Specifically, the resistor R794 is connected between the external power of the main power supply unit and the base of the transistor Q29. The emitter of the transistor Q29 is grounded, the collector of the transistor Q29 is connected to the first end of the resistor R812, and the second end of the resistor R812 is respectively connected to the first gate, the second gate, the first source and the first terminal of the dual PMOS chip Q56. Two source connections.

The first drain of the dual PMOS chip Q56 is electrically connected to the external power supply unit, and the second drain of the dual PMOS chip Q56 is used to output electric energy when the external power of the main power supply unit is powered on.

Optionally, a resistor R809 and a capacitor C764 can be added to the main power supply unit.

Specifically, the first end of the resistor R809 is connected to the second end of the resistor R812, and the second end of the resistor R809 is connected to the first source and the second source of the dual PMOS chip Q56, respectively. The capacitor C764 is connected in parallel across the resistor R809.

The resistor R809 and the capacitor C764 form an RC delay circuit, which can make the voltage on the first gate and the second gate of the dual PMOS chip Q56 slowly drop, so that the dual PMOS chip Q56 is slowly turned on, realizing a slow start of power supply.

Optionally, a resistor R795, a transistor Q41, and a resistor R968 can be added to the main power supply unit.

Specifically, the first end of the resistor R795 is electrically connected to the outside of the main power supply unit, and the second end of the resistor R795 is connected to the base of the transistor Q41. The emitter of the transistor Q41 is grounded, the collector of the transistor Q41 is connected to the first end of the resistor R968, and the second end of the resistor R968 is connected to the DC power supply. The collector of the transistor Q41 is also used to output a signal indicating whether the external power of the main power supply unit is powered on.

When the external power of the main power supply unit is powered on, the BASE_PWR in Figure 2 is high, the transistor Q41 is turned on, and the signal AP_BASE output by the collector of the transistor Q41 is a low-level signal; when the external power of the main power supply unit is powered off, the signal in Figure 2 BASE_PWR is low, Q41 is turned off, and transistor Q41 is turned off, so that AP_BASE output by the collector of transistor Q41 is a high level signal. The signal AP_BASE output by the collector of the transistor Q41 can reflect whether the main power supply unit is powered on.

In another specific embodiment, as shown in FIG. 2, the auxiliary power supply unit may include a resistor R714, a transistor Q31, a resistor R796, a dual PMOS chip U40, and a transistor Q55.

Specifically, the base of the transistor Q55 is electrically connected to the outside of the main power supply unit, the emitter of the transistor Q55 is grounded, and the collector of the transistor Q55 is connected to the base of the transistor Q31. The resistor R714 is connected between the external power of the auxiliary power supply unit and the base of the transistor Q31. The emitter of the transistor Q31 is grounded, the collector of the transistor Q31 is connected to the first end of the resistor R796, and the second end of the resistor R796 is respectively connected to the first gate, the second gate, the first source and the first terminal of the dual PMOS chip U40. Two sources are connected.

The first drain of the dual PMOS chip U40 is electrically connected to the external power supply unit, and the second drain of the dual PMOS chip U40 is used to output electrical energy when only the external power supply of the auxiliary power supply unit is powered on.

Only when the external power of the main power supply unit is powered off and the auxiliary power supply unit is powered on, that is, when BASE_PWR in Figure 2 is low and USB_VCC is high, the transistor Q31 will be turned on, thus turning on the dual PMOS chip U40. In turn, the output terminal of the auxiliary power supply unit outputs electric energy.

Optionally, a resistor R810 and a capacitor C267 can be added to the auxiliary power supply unit.

The first end of the resistor R810 is connected to the second end of the resistor R796, and the second end of the resistor R810 is connected to the first source and the second source of the dual PMOS chip U40, respectively. The capacitor C267 is connected in parallel across the resistor R810.

The resistor R810 and the capacitor C267 form an RC delay circuit, which can make the voltage on the first and second gates of the dual PMOS chip U40 slowly drop, so that the dual PMOS chip U40 is slowly turned on, realizing the slow start of the power supply, and When the external power of the auxiliary power supply unit is suddenly powered on, that is, when the USB_VCC in Figure 2 is inserted instantaneously, the excessively high and fast pulse voltage may damage the back-end circuit.

Optionally, a resistor R1001 and a capacitor C978 can be added to the auxiliary power supply unit.

Specifically, the resistor R1001 is connected between the base of the transistor Q55 and the external power of the main power supply unit. The capacitor C978 is connected between the base of the transistor Q55 and ground.

When the external power of the main power supply unit and the external power of the auxiliary power supply unit are powered on at the same time, that is, when both BASE_PWR and USB_VCC in Figure 2 are high, the main power supply unit needs to give priority to external power supply.

The BASE_PWR in FIG. 2 can control the cut-off or conduction of the transistor Q31 through the transistor Q55. When both BASE_PWR and USB_VCC in FIG. 2 are high, the transistor Q55 is turned on, so that the transistor Q31 is turned off, and the dual PMOS chip U40 is turned off, and the auxiliary power supply unit is turned off. At the same time, the transistor Q29 is turned on, so that the dual PMOS chip Q56 is turned on, and the main power supply unit is turned on.

When the external power of the main power supply unit and the auxiliary power supply unit are powered on at the same time, and the main power supply unit gives priority to power supply, if the main power supply unit is suddenly removed, ensure that the dual PMOS chip Q56 is turned off first, and then the dual PMOS chip U40 is turned on. The power switching circuit provided by the embodiment of the present application can prevent the dual PMOS chip U40 and the dual PMOS chip Q56 from being turned on at the same time, and prevent the output power of the auxiliary power supply unit from being poured back into the main power supply unit. Since the dual PMOS chip is in an incomplete conduction state, when the dual PMOS chip U40 and the dual PMOS chip Q56 are turned on at the same time, the voltage of the output V_CHG of the main power supply unit and the auxiliary power supply unit in the power switching circuit is clamped below 5V, and the power supply cannot be normal. .

In addition, by increasing the resistance R794, reducing the resistance R1001, and increasing the capacitor C978, it can be ensured that the dual PMOS chip Q56 is turned off first, and then the dual PMOS chip U40 is turned on again, which can solve the above problem.

Optionally, a resistor R769 and a transistor Q32 can be added to the auxiliary power supply unit.

The first end of the resistor R769 receives a control signal for controlling whether the auxiliary power supply unit is enabled, and the second end of the resistor R769 is connected to the base of the transistor Q32. The emitter of the transistor Q32 is grounded, and the collector of the transistor Q32 is connected to the base of the transistor Q31.

When the auxiliary power supply unit adopts the USB adapter as the external power, the use state management of the USB can be realized through the resistor R769 and the transistor Q32.

In Figure 2, AP_USB can be used to switch the status of USB. Generally, the usage status of USB can include USB HOST and USB Charge. Among them, USB HOST indicates that the USB setting is in the host device state, and the corresponding peripheral device can be a mouse, keyboard, hard disk, U disk, MP3 or USB gamepad, and the peripheral device can read the corresponding data in the USB HOST state information. USB Charge indicates that the USB setting is in the USB charger state.

When AP_USB is high in Figure 2, USB HOST is enabled; when AP_USB is low in Figure 2, USB Charge is enabled.

The embodiment of the present application also provides an electronic device. As shown in FIG. 3, the electronic device 200 includes the power switching circuit 100 as described in FIG. 1 or FIG. 2. In the electronic device 200 shown in FIG. 3, the structure of the electronic device 200 is schematically described according to the power switching circuit shown in FIG. In use, the user can also select the power switching circuit shown in FIG. 2 in the electronic device 200 according to needs, and the embodiment of the present application does not limit this.

The above-mentioned embodiments are only used to illustrate the technical solutions of the present application, not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still implement the foregoing The technical solutions recorded in the examples are modified, or some of the technical features are equivalently replaced; these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application, and should be included in Within the scope of protection of this application.

Claims

A power supply switching circuit, characterized by comprising: a main power supply unit and at least one auxiliary power supply unit;

When the main power supply unit and the auxiliary power supply unit are simultaneously connected to external power, the power supply switching circuit outputs electric energy through the output terminal of the main power supply unit;

When any one of the main power supply unit and the auxiliary power supply unit is connected to external power, the power switching circuit outputs electric energy through the output terminal of the power supply unit connected to the external power.
The power switching circuit according to claim 1, wherein the main power supply unit comprises: a resistor R794, a transistor Q29, a resistor R812, and a dual PMOS chip Q56;

The resistor R794 is connected between the external power of the main power supply unit and the base of the transistor Q29;

The emitter of the transistor Q29 is grounded, the collector of the transistor Q29 is connected to the first end of the resistor R812, and the second end of the resistor R812 is respectively connected to the first gate and the first gate of the dual PMOS chip Q56. The second gate, the first source and the second source are connected;

The first drain of the dual PMOS chip Q56 is electrically connected to the external power supply unit, and the second drain of the dual PMOS chip Q56 is used to output electric energy when the external power supply of the main power supply unit is powered on.
3. The power switching circuit of claim 2, wherein the main power supply unit further comprises: a resistor R809 and a capacitor C764;

The first end of the resistor R809 is connected to the second end of the resistor R812, and the second end of the resistor R809 is respectively connected to the first source and the second source of the dual PMOS chip Q56;

The capacitor C764 is connected in parallel with both ends of the resistor R809.
The power switching circuit according to claim 2 or 3, wherein the main power supply unit further comprises: a resistor R795, a transistor Q41 and a resistor R968;

The first end of the resistor R795 is electrically connected to the outside of the main power supply unit, and the second end of the resistor R795 is connected to the base of the transistor Q41;

The emitter of the transistor Q41 is grounded, the collector of the transistor Q41 is connected to the first end of the resistor R968, and the second end of the resistor R968 is connected to a DC power supply;

The collector of the transistor Q41 is also used to output a signal indicating whether the external power of the main power supply unit is powered on.
The power switching circuit according to claim 1, wherein the auxiliary power supply unit comprises: a resistor R714, a transistor Q31, a resistor R796, a dual PMOS chip U40 and a transistor Q55;

The base of the transistor Q55 is electrically connected to the outside of the main power supply unit, the emitter of the transistor Q55 is grounded, and the collector of the transistor Q55 is connected to the base of the transistor Q31;

The resistor R714 is connected between the external power of the auxiliary power supply unit and the base of the transistor Q31;

The emitter of the transistor Q31 is grounded, the collector of the transistor Q31 is connected to the first end of the resistor R796, and the second end of the resistor R796 is respectively connected to the first gate and the first gate of the dual PMOS chip U40. The second gate, the first source and the second source are connected;

The first drain of the dual PMOS chip U40 is electrically connected to the external power supply unit, and the second drain of the dual PMOS chip U40 is used to output electrical energy when only the external power supply of the auxiliary power supply unit is powered on.
8. The power switching circuit of claim 5, wherein the auxiliary power supply unit further comprises: a resistor R810 and a capacitor C267;

The first end of the resistor R810 is connected to the second end of the resistor R796, and the second end of the resistor R810 is connected to the first source and the second source of the dual PMOS chip U40, respectively;

The capacitor C267 is connected in parallel with both ends of the resistor R810.
8. The power switching circuit according to claim 5 or 6, wherein the auxiliary power supply unit further comprises: a resistor R1001 and a capacitor C978;

The resistor R1001 is connected between the base of the transistor Q55 and the external power of the main power supply unit;

The capacitor C978 is connected between the base of the transistor Q55 and ground.
8. The power switching circuit according to claim 5 or 6, wherein the auxiliary power supply unit further comprises: a resistor R769 and a transistor Q32;

The first end of the resistor R769 receives a control signal for controlling whether the auxiliary power supply unit is enabled, and the second end of the resistor R769 is connected to the base of the transistor Q32;

The emitter of the transistor Q32 is grounded, and the collector of the transistor Q32 is connected to the base of the transistor Q31.
8. The power switching circuit of claim 7, wherein the auxiliary power supply unit further comprises: a resistor R769 and a transistor Q32;

The first end of the resistor R769 receives a control signal for controlling whether the auxiliary power supply unit is enabled, and the second end of the resistor R769 is connected to the base of the transistor Q32;

The emitter of the transistor Q32 is grounded, and the collector of the transistor Q32 is connected to the base of the transistor Q31.
An electronic device comprising the power switch circuit according to any one of claims 1 to 9.