CN115065143A - USB power supply switching circuit, method, device and chip - Google Patents

Abstract

The invention provides a USB power supply switching circuit, a method, a device and a chip. The USB power supply switching circuit provided by the invention comprises a voltage control module, a system power supply module and a standby power supply module; the voltage control module is used for inputting a low level to the system power supply module or inputting a low level to the standby power supply module; the system power supply module is used for outputting system voltage when receiving the low level input by the voltage control module; and the standby power supply module is used for outputting standby voltage when receiving the low level input by the voltage control module. The USB power supply switching circuit realizes the switching of the USB power supply output between the system voltage and the standby voltage, and solves the problem of insufficient power supply of the USB to external equipment.

Description

USB power supply switching circuit, method, device and chip

Technical Field

The invention relates to the technical field of USB power supply, in particular to a USB power supply switching circuit, a method, a device and a chip.

Background

USB is a serial bus standard for connecting a computer system and external devices, and is also a technical specification of input/output interfaces, which can be connected to a variety of peripheral devices. In view of the advantages of USB supporting hot plug, portability, unified standards, and being capable of connecting multiple devices, USB is widely used in communication products such as personal computers and mobile devices, and is expanded to related fields such as video equipment, digital televisions, game machines, and the like. The USB on the computer motherboard is generally powered by a 5V Standby voltage. The Standby voltage is a Standby voltage of +5V reserved after the system is turned off, so as to be used for power supply and wake-up service of the system, and is generally used as a power supply for starting a mouse, a keyboard and a network.

The current corresponding to the standby voltage of the USB is generally small, and when the rated current of the connected external device is large, the external device cannot work normally, and then system voltage (system voltage) is required to supply power to the external device. The standby voltage and the system voltage can provide different power consumptions, and the power consumption provided by the latter is larger than that provided by the former.

When the external devices are high-power-consumption devices such as a camera and a scanner, sufficient power supply electric energy needs to be provided for the external devices, but the output of the USB interface of the existing product is generally standby voltage, so that different power supply modes cannot be well selected, which may cause the USB to supply insufficient power to the external devices.

Disclosure of Invention

The invention aims to provide a USB power supply switching circuit, a method, a device and a chip, which are used for solving the technical problem that the USB supplies power to external equipment insufficiently in the prior art.

The technical scheme of the invention is that a USB power supply switching circuit is provided, which comprises a voltage control module, a system power supply module and a standby power supply module;

the voltage control module is used for inputting a low level to the system power supply module or inputting a low level to the standby power supply module; the system power supply module is used for outputting system voltage when receiving the low level input by the voltage control module; and the standby power supply module is used for outputting standby voltage when receiving the low level input by the voltage control module.

Further, the voltage control module comprises a voltage switching unit and a voltage input unit;

the voltage switching unit is used for receiving a high level or a low level and enabling the voltage input unit to input the low level to the system power supply module when receiving the high level,

and when receiving a low level, enabling the voltage input unit to input the low level to the standby power supply module.

Further, the voltage input unit comprises a first field effect transistor, a second field effect transistor, a first power supply and a second power supply; the first field effect transistor is connected with the first power supply source, and the second field effect transistor is connected with the second power supply source;

the voltage switching unit is also used for enabling the first field effect transistor to be conducted when receiving a high level and enabling the second field effect transistor to be conducted when receiving a low level; the first power supply is used for inputting low level to the system power supply module when the first field effect transistor is conducted; and the second power supply is used for inputting low level to the standby power supply module when the second field effect transistor is conducted.

Further, the circuit further comprises a fifth power supply, the voltage switching unit comprises a diode, the voltage input unit further comprises a sixth power supply, a first resistor and a second resistor, the fifth power supply is connected with the cathode of the diode, the anode of the diode is respectively connected with one end of the first resistor, one end of the second resistor and the grid electrode of the first field effect transistor, the other end of the first resistor is connected with the sixth power supply, the other end of the second resistor is grounded, the drain electrode of the first field effect transistor is connected with the first power supply, and the source electrode of the first field effect transistor is grounded.

Further, the voltage input unit further includes a capacitor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor;

the positive electrode of the diode is also connected with one end of the capacitor, the other end of the capacitor is grounded, the drain electrode of the first field effect transistor is connected with the first power supply source through the third resistor, and the drain electrode of the first field effect transistor is also grounded through the fourth resistor;

the source electrode of the second field effect transistor is grounded, the grid electrode of the second field effect transistor is respectively connected with the first power supply through a third resistor and grounded through a fourth resistor, and the drain electrode of the second field effect transistor is respectively connected with the second power supply through a fifth resistor and grounded through a sixth resistor.

Furthermore, the system power supply module comprises a third power supply and a third field effect transistor, wherein the third power supply is connected with the electrical drain of the third field effect transistor, and the grid of the third field effect transistor is connected with the drain of the first field effect transistor;

the third field effect transistor is used for being switched on when receiving a low level input by the voltage control module, and the third power supply is used for outputting system voltage when the third field effect transistor is switched on.

Further, the standby power supply module includes a fourth power supply and a fourth field effect transistor, the fourth power supply is connected to a drain of the fourth field effect transistor, and a gate of the fourth field effect transistor is connected to a drain of the second field effect transistor;

the fourth field effect transistor is used for being switched on when receiving a low level input by the voltage control module, and the fourth power supply is used for outputting standby voltage when the fourth field effect transistor is switched on.

Another technical solution of the present invention is as follows, and provides a USB power supply switching method, which is applied to the USB power supply switching circuit according to any one of the above technical solutions, and includes:

inputting a low level to a system power supply module or inputting a low level to a standby power supply module; the system power supply module outputs system voltage when receiving corresponding low level; and the standby power supply module outputs standby voltage when receiving the corresponding low level.

Another technical solution of the present invention is to provide a USB power supply switching apparatus, including the USB power supply switching circuit according to any one of the above technical solutions.

Another technical solution of the present invention is to provide a chip, including the USB power supply switching circuit according to any one of the above technical solutions.

The invention has the beneficial effects that: inputting a low level to a system power supply module or inputting a low level to a standby power supply module through a voltage control module; outputting system voltage when the system power supply module receives the low level input by the voltage control module; outputting standby voltage when receiving the low level input by the voltage control module through the standby power supply module; the switching of the USB power supply output between the system voltage and the standby voltage is realized, and the problem of insufficient power supply of the USB to the external equipment is solved.

Drawings

FIG. 1 is a block diagram of a USB power switching circuit according to an embodiment of the present invention;

FIG. 2 is a schematic circuit diagram of a voltage control module according to an embodiment of the present invention;

FIG. 3 is a circuit schematic of a jumper cap according to an embodiment of the invention;

FIG. 4 is a schematic circuit diagram of a system power supply module and a standby power supply module according to an embodiment of the present invention;

fig. 5 is a flowchart illustrating a USB power supply switching method according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

In order to make the technical solutions of the present application better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the embodiments of the present application, at least one means one or more; plural means two or more. In the description of the present application, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance, nor order.

Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, the terms "including," "comprising," "having," and variations thereof in this specification mean "including, but not limited to," unless expressly specified otherwise.

It is to be noted that "connected" in the embodiments of the present application may be understood as an electrical connection, and the connection of two electrical components may be a direct or indirect connection between the two electrical components. For example, a and B may be connected directly, or indirectly through one or more other electrical components.

Fig. 1 is a block diagram of a USB power supply switching circuit according to an embodiment of the present invention. It should be noted that, if the result is substantially the same, the USB power switching circuit provided in the present invention does not have the structural block diagram shown in fig. 1. As shown in fig. 1, the USB power switching circuit 100 includes a voltage control module 101, a system power supply module 102, and a standby power supply module 103;

the voltage control module 101 is configured to input a low level to the system power supply module 102 or input a low level to the standby power supply module 103; the system power supply module 102 is configured to output a system voltage when receiving a low level input by the voltage control module 101; the standby power supply module 103 is configured to output a standby voltage when receiving a low level input by the voltage control module 101.

In the embodiment of the invention, a low level is input to a system power supply module 102 or a standby power supply module 103 through a voltage control module 101; when receiving a low level input by the voltage control module 101, the system power supply module 102 outputs a system voltage; when receiving a low level input by the voltage control module 101, the standby power supply module 103 outputs a standby voltage; the switching of the USB power supply output between the system voltage and the standby voltage is realized, and the problem of insufficient power supply of the USB to the external equipment is solved.

As an embodiment, the voltage control module includes a voltage switching unit and a voltage input unit;

the voltage switching unit is used for receiving a high level or a low level, enabling the voltage input unit to input the low level to the system power supply module when the high level is received, and enabling the voltage input unit to input the low level to the standby power supply module when the low level is received.

In a specific embodiment, as shown in fig. 2, in the circuit schematic diagram of the voltage control module, when the voltage switching unit 111 receives a high level, the voltage input unit 121 inputs a low level to the system power supply module, and when the voltage switching unit 111 receives a low level, the voltage input unit 121 inputs a low level to the standby power supply module; wherein, a jumper cap or a GPIO (general purpose input output) of an MCU (micro control unit) is used to provide a high level or a low level for the voltage switching unit 111.

As an embodiment, the voltage input unit includes a first field effect transistor, a second field effect transistor, a first power supply, and a second power supply; the first field effect transistor is connected with the first power supply, and the second field effect transistor is connected with the second power supply;

the voltage switching unit is also used for enabling the first field effect transistor to be conducted when receiving a high level, and enabling the second field effect transistor to be conducted when receiving a low level; the first power supply is used for inputting low level to the system power supply module when the first field effect transistor is conducted; and the second power supply is used for inputting low level to the standby power supply module when the second field effect transistor is conducted.

According to the embodiment of the invention, smooth switching of system voltage output and standby voltage output can be realized by providing a high level or a low level for the voltage switching unit.

In some embodiments, when the voltage switching unit receives a high level, the first field effect transistor is turned on, the second field effect transistor is turned off, and the first power supply supplies a low level to the system power supply module; and when the voltage switching unit receives a low level, the second field effect transistor is switched on, the first field effect transistor is switched off, and at the moment, the second power supply supplies a low level to the standby power supply module.

As an implementation manner, the circuit further includes a fifth power supply, the voltage switching unit includes a diode, the voltage input unit further includes a sixth power supply, a first resistor, and a second resistor, the fifth power supply is connected to a negative electrode of the diode, an anode of the diode is respectively connected to one end of the first resistor, one end of the second resistor, and a gate of the first field effect transistor, another end of the first resistor is connected to the sixth power supply, another end of the second resistor is grounded, a drain of the first field effect transistor is connected to the first power supply, and a source of the first field effect transistor is grounded.

In some embodiments, a jumper cap is used to provide a high level or a low level for the voltage switching unit, and a circuit schematic diagram of the jumper cap is shown in fig. 3, pin 1 of the jumper cap J6C7 is connected to the fifth power supply, pin 2 of the jumper cap is connected to the voltage switching unit, and pin 3 of the jumper cap is connected to ground; setting a high level or a low level through a jumper cap J6C7 to switch whether the USB power supply switching circuit outputs a system voltage of V5S or a standby voltage of V5 SB; the jumper cap J6C7 can also be cancelled, and the switching of the USB power supply mode is controlled by the GPIO of the MCU, so that the backward flow of the power supply can be effectively prevented.

In another embodiment, as shown in fig. 2, the voltage input unit includes a sixth power supply, a first resistor R2872 and a second resistor R2873, the fifth power supply is connected to a cathode of a diode D73, an anode of the diode D73 is respectively connected to one end of the first resistor R2872, one end of the second resistor R2873 and a gate of the first field effect transistor, another end of the first resistor R2872 is connected to the sixth power supply, another end of the second resistor R2873 is grounded, a drain of the first field effect transistor is connected to the first power supply, and a source of the first field effect transistor is grounded.

As an embodiment, the voltage input unit further includes a capacitor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor;

the anode of the diode is also connected with one end of the capacitor, the other end of the capacitor is grounded, the drain electrode of the first field effect transistor is connected with the first power supply source through the third resistor, and the drain electrode of the first field effect transistor is also grounded through the fourth resistor;

the source electrode of the second field effect transistor is grounded, the grid electrode of the second field effect transistor is respectively connected with the first power supply through a third resistor and grounded through a fourth resistor, and the drain electrode of the second field effect transistor is respectively connected with the second power supply through a fifth resistor and grounded through a sixth resistor.

In some embodiments, in the voltage control module shown in fig. 2, the drain of the first field effect transistor is connected to the first power supply through the third resistor R2874, and the drain of the first field effect transistor is also connected to ground through the fourth resistor R2875; the grid electrode of the second field effect transistor is respectively connected with the first power supply through a third resistor R2874 and is grounded through a fourth resistor R2875, and the drain electrode of the second field effect transistor is respectively connected with the second power supply through a fifth resistor R2877 and is grounded through a sixth resistor R2876; the fifth power supply is connected with the negative electrode of the diode D73, the model of the diode D73 is 1N4148W, the field effect transistor unit Q245 comprises a first field effect transistor and a second field effect transistor, when V5USB _ EN is high, namely, the negative electrode input of the diode D73 is high, the first field effect transistor (front MOS transistor) of the field effect transistor unit Q245 is turned on, the level at PG _ # + V5 is pulled low, the second field effect transistor (rear MOS transistor) of the field effect transistor unit Q245 is turned off, the level at EN _ + V5SB is pulled high, and the system power supply module outputs system voltage. When the V5USB _ EN is at a low level, that is, the negative input of the diode D73 is at a low level, the first fet of the fet unit Q245 is turned off, the level at PG # + V5 is pulled high, the second fet of the fet unit Q245 is turned on, the level at EN _ + V5SB is pulled low, and the standby power module outputs a standby voltage.

As an embodiment, the system power supply module includes a third power supply and a third field effect transistor, the third power supply is connected to a drain of the third field effect transistor, and a gate of the third field effect transistor is connected to a drain of the first field effect transistor;

the third field effect transistor is used for being switched on when receiving a low level input by the voltage control module, and the third power supply is used for outputting system voltage when the third field effect transistor is switched on. Wherein electric power is output from a source of the third field effect transistor.

As an embodiment, the standby power supply module includes a fourth power supply and a fourth field effect transistor, the fourth power supply is connected to a drain of the fourth field effect transistor, and a gate of the fourth field effect transistor is connected to a drain of the second field effect transistor;

the fourth field effect transistor is used for being switched on when receiving a low level input by the voltage control module, and the fourth power supply is used for outputting standby voltage when the fourth field effect transistor is switched on. Wherein electric power is output from a source of the fourth field effect transistor.

In some embodiments, as shown in fig. 4, the system power supply module 102 further includes a seventh resistor R3G69, the third power supply is connected to the drain of the third fet through the seventh resistor R3G69, the standby power supply module 103 further includes an eighth resistor R3G72, and the fourth power supply is connected to the drain of the fourth fet through the eighth resistor R3G 72; when the level at EN _ + V5SB is pulled high and the level at PG _ # + V5 is pulled low, the third fet Q246 is turned on, the fourth fet Q247 is turned off, the system voltage of + V5 is supplied to + V5DUAL, and + V5DUAL is the output of the USB power switching circuit; when the level at PG # + V5 is pulled high and the level at EN _ + V5SB is pulled low, the third fet Q246 is turned off, the fourth fet Q247 is turned on, and the + V5DUAL is given the standby voltage of + V5 SB.

It should be noted that, in the entire USB power supply switching circuit, the third field effect transistor and the fourth field effect transistor are controlled to be turned on or off by turning on or off the field effect transistor unit Q245. When the level signal of the V5USB _ EN changes from low level to high level, or from high level to low level, the power supply of the + V5DUAL can be perfectly switched by the diode D73 according to different voltage division of the + V5SB power supply (standby power supply) and the + V5 power supply (system power supply), and switching of on or off of the first field effect transistor, the second field effect transistor, the third field effect transistor and the fourth field effect transistor, without current backflow or voltage drop.

Wherein the types of the third field effect transistor Q246 and the fourth field effect transistor Q247 can be selected according to passing different currents; in specific implementation, FDS4435 field effect transistors can be selected, and the maximum current which can be passed through the transistors is 8.8A; the field effect transistor with larger leakage current value can be selected, or the field effect transistor with FDS4435 connected in parallel can be added to meet the requirement of larger current.

The embodiment of the invention provides a USB power supply switching circuit, which inputs low level to a system power supply module or inputs low level to a standby power supply module through a voltage control module; outputting system voltage when the system power supply module receives the low level input by the voltage control module; outputting standby voltage when receiving the low level input by the voltage control module through the standby power supply module; the switching of the USB power supply output between the system voltage and the standby voltage is realized, and the problem of insufficient power supply of the USB to the external equipment is solved.

The embodiment of the invention can meet the requirements of different devices by switching the power supply mode of the USB. The power supply standard of the common USB cannot meet the development requirements of various existing applications, and different applications have different requirements on the USB power supply, which involves using a standby voltage or a system voltage. The computer system is powered by default with a 5V standby voltage, while some devices require a 5V system voltage. In the application of a computer, the power consumption which can be provided by the standby voltage and the system voltage are different, when a USB is used for connecting a plurality of cameras or other high-power-consumption equipment, the power consumption which can be provided by the standby voltage is possibly insufficient, and at the moment, the mode selection can be carried out through the USB power supply switching circuit of the embodiment of the invention, and the system voltage is selected for power supply; when a device such as a keyboard and mouse is connected to the USB, the standby voltage can be used for supplying power. Because the magnitude of the required current of the USB external device cannot be very clear, only 4 paths of current of USB3.0 need to be satisfied as a standard design, and the USB power supply switching circuit can be expanded appropriately.

It should be noted that, in the prior art, when the operating current of the external device is large, the standby voltage is increased to support the device operation, which increases the circuit design cost. The USB power supply switching circuit provided by the embodiment of the invention realizes the switching of the USB power supply output between the system voltage and the standby voltage, meets the power supply requirement of external equipment and can also reduce the design cost of the circuit.

The embodiment of the present application provides a USB power supply switching method, which is applied to the USB power supply switching circuit described in any of the above embodiments, and a flow diagram of the USB power supply switching method is shown in fig. 5. The USB power supply switching method comprises the following steps:

s51, inputting low level to the system power supply module or inputting low level to the standby power supply module;

s52, the system power supply module outputs system voltage when receiving corresponding low level;

and S53, the standby power supply module outputs a standby voltage when receiving the corresponding low level.

The embodiment of the application provides a USB power supply switching device, which comprises the USB power supply switching circuit in any embodiment.

The embodiment of the application provides a chip, which comprises the USB power supply switching circuit in any one of the above embodiments.

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

The above examples only express the preferred embodiments of the present application, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A USB power supply switching circuit is characterized by comprising a voltage control module, a system power supply module and a standby power supply module;

the voltage control module is used for inputting a low level to the system power supply module or inputting a low level to the standby power supply module; the system power supply module is used for outputting system voltage when receiving the low level input by the voltage control module; and the standby power supply module is used for outputting standby voltage when receiving the low level input by the voltage control module.

2. The USB power supply switching circuit according to claim 1, wherein the voltage control module comprises a voltage switching unit and a voltage input unit;

the voltage switching unit is used for receiving a high level or a low level and enabling the voltage input unit to input the low level to the system power supply module when receiving the high level,

and when receiving a low level, enabling the voltage input unit to input the low level to the standby power supply module.

3. The USB power switching circuit according to claim 2, wherein the voltage input unit includes a first field effect transistor, a second field effect transistor, a first power supply, and a second power supply; the first field effect transistor is connected with the first power supply, and the second field effect transistor is connected with the second power supply;

the voltage switching unit is also used for enabling the first field effect transistor to be conducted when receiving a high level, and enabling the second field effect transistor to be conducted when receiving a low level; the first power supply is used for inputting low level to the system power supply module when the first field effect transistor is conducted; and the second power supply is used for inputting low level to the standby power supply module when the second field effect transistor is conducted.

4. The USB power supply switching circuit according to claim 3, wherein the circuit further comprises a fifth power supply, the voltage switching unit comprises a diode, the voltage input unit further comprises a sixth power supply, a first resistor and a second resistor, the fifth power supply is connected to a cathode of the diode, an anode of the diode is connected to one end of the first resistor, one end of the second resistor and a gate of the first field effect transistor, respectively, another end of the first resistor is connected to the sixth power supply, another end of the second resistor is connected to ground, a drain of the first field effect transistor is connected to the first power supply, and a source of the first field effect transistor is connected to ground.

5. The USB power supply switching circuit according to claim 4, wherein the voltage input unit further comprises a capacitor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor;

the anode of the diode is also connected with one end of the capacitor, the other end of the capacitor is grounded, the drain electrode of the first field effect transistor is connected with the first power supply source through the third resistor, and the drain electrode of the first field effect transistor is also grounded through the fourth resistor;

the source electrode of the second field effect transistor is grounded, the grid electrode of the second field effect transistor is respectively connected with the first power supply through a third resistor and grounded through a fourth resistor, and the drain electrode of the second field effect transistor is respectively connected with the second power supply through a fifth resistor and grounded through a sixth resistor.

6. The USB power supply switching circuit according to claim 3, wherein the system power supply module comprises a third power supply and a third field effect transistor, the third power supply is connected with a drain of the third field effect transistor, and a gate of the third field effect transistor is connected with a drain of the first field effect transistor;

the third field effect transistor is used for being switched on when receiving a low level input by the voltage control module, and the third power supply is used for outputting system voltage when the third field effect transistor is switched on.

7. The USB power supply switching circuit according to claim 3, wherein the standby power supply module comprises a fourth power supply and a fourth field effect transistor, the fourth power supply is electrically connected to a drain of the fourth field effect transistor, and a gate of the fourth field effect transistor is connected to a drain of the second field effect transistor;

the fourth field effect transistor is used for being switched on when receiving a low level input by the voltage control module, and the fourth power supply is used for outputting standby voltage when the fourth field effect transistor is switched on.

8. A USB power supply switching method applied to the USB power supply switching circuit of claim 1, comprising:

inputting a low level to a system power supply module or inputting a low level to a standby power supply module; the system power supply module outputs system voltage when receiving corresponding low level; and the standby power supply module outputs standby voltage when receiving the corresponding low level.

9. A USB power switching device comprising the USB power switching circuit of any one of claims 1 to 7.

10. A chip comprising the USB power switching circuit of any one of claims 1-7.

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