Power supply switching circuit, power supply switching system and multi-path power supply equipment

Abstract

The utility model discloses a power supply switching circuit, a power supply switching system and multi-path power supply equipment, and belongs to the technical field of power supply switching. The power supply switching circuit comprises a power supply module and a switching protection module, the power supply module comprises at least two power supply units, and each power supply unit is used for supplying power to target equipment; the power supply module is electrically connected with the switching protection module, the switching protection module comprises at least two switching protection units, each switching protection unit is electrically connected with the corresponding power supply unit, different switching protection units are electrically connected, and the at least two switching protection units are used for switching the switching protection units when one power supply unit supplies power to target equipment. And cutting off the power supply of other power supply units. The power supply switching circuit of the utility model can effectively avoid the problem of backward flow of the power supply during power supply switching, realize stable switching under the condition of simultaneous power supply of multiple power supplies, and ensure stable operation of electronic equipment.

Description

Technical Field

[0001] The utility model relates to the technical field of power switching, and in particular to a power switching circuit, a power switching system and multi-channel power supply equipment. Background Art

[0002] At present, the power supply system of most electronic devices can usually support a variety of different power supply modes, such as pluggable built-in batteries, external adapter power supply, etc. In practice, electronic devices usually only use one power supply mode to provide power for the operation of the device, so it is necessary to switch between different power supply modes through a power switching circuit in the power supply system of the electronic device. However, since the power supply voltages of different power supply modes may be different, the related technology is prone to the problem of power backflow when implementing power switching, that is, the power supply current may flow from the power supply with higher potential to the power supply with lower potential, thereby affecting the normal operation of the electronic device and causing damage to the electronic device. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a power switching circuit, a power switching system and a multi-way power supply device, which can effectively avoid the problem of power backflow during power switching, realize stable switching when multiple power supplies are supplied at the same time, and ensure the stable operation of electronic equipment.

[0004] A power switching circuit according to an embodiment of the first aspect of the utility model includes:

[0005] A power supply module, the power supply module comprising at least two power supply units, each of the power supply units being used to supply power to the target device;

[0006] A switching protection module, wherein the power supply module is electrically connected to the switching protection module, and the switching protection module includes at least two switching protection units, each of which is electrically connected to the corresponding power supply unit, and different switching protection units are electrically connected, and the at least two switching protection units are used to cut off the power supply of other power supply units when one power supply unit supplies power to the target device.

[0007] A power switching circuit according to an embodiment of the utility model has at least the following beneficial effects: by setting a power module of at least two power supply units and a switching protection module of at least two switching protection units, wherein the power module is electrically connected to the switching protection module, and each switching protection unit is electrically connected to the corresponding power supply unit. When one power supply unit supplies power to a device, the power supply to other power supply units will be cut off by the corresponding switching protection module. Therefore, the present application utilizes multiple switching protection units to cut off the power supply to other power supply units when multiple power supply units are supplying power at the same time, which can effectively prevent power conflicts, and can also effectively avoid the problem of power backflow that occurs when power is switched in the related art, thereby achieving stable switching when multiple power supplies are supplied at the same time, thereby ensuring the stable operation of the electronic device.

[0008] According to some embodiments of the present utility model, the at least two switching protection units include a first switching protection unit and a second switching protection unit, and the first switching protection unit is electrically connected to the second switching protection unit;

[0009] The at least two power supply units include a first power supply unit and a second power supply unit, the first power supply unit is electrically connected to the second power supply unit and the first switching protection unit, and the second power supply unit is electrically connected to the second switching protection unit.

[0010] According to some embodiments of the present invention, the first switching protection unit includes:

[0011] a first switching switch subunit, the first switching switch subunit comprising a first transistor and a second resistor, a gate of the first transistor being electrically connected to one end of the second resistor, a source of the first transistor being electrically connected to the other end of the second resistor, and a drain of the first transistor being electrically connected to the second switching protection unit;

[0012] A first switching conduction subunit, the first switching conduction subunit includes a first transistor and a fourth resistor, the base of the first transistor is electrically connected to one end of the fourth resistor, the collector of the first transistor is electrically connected to the gate of the first transistor, the emitter of the first transistor is grounded, and the other end of the fourth resistor is electrically connected to the first power supply unit.

[0013] According to some embodiments of the present invention, the second switching protection unit includes:

[0014] a second switching subunit, the second switching subunit comprising a second transistor and a third resistor, the gate of the second transistor being electrically connected to one end of the third resistor, the source of the second transistor being electrically connected to the other end of the third resistor, and the drain of the second transistor being electrically connected to the drain of the first transistor;

[0015] A second switching conduction subunit, the second switching conduction subunit includes a second transistor and a fifth resistor, the base of the second transistor is electrically connected to one end of the fifth resistor, the collector of the second transistor is electrically connected to the gate of the second transistor, the emitter of the second transistor is grounded, and the other end of the fifth resistor is electrically connected to the other end of the fourth resistor.

[0016] According to some embodiments of the present invention, the first power supply unit includes:

[0017] A first power supply, wherein a positive electrode of the first power supply is electrically connected to one end of a first resistor, a negative electrode of the first power supply is grounded, and the first power supply is used to supply power to the target device;

[0018] A first resistor, wherein the other end of the first resistor is electrically connected to the other end of the fourth resistor.

[0019] According to some embodiments of the present invention, the second power supply unit includes:

[0020] a power supply subunit, the power supply subunit being used to supply power to the target device;

[0021] A switching and isolating subunit, the switching and isolating subunit is electrically connected to the power supply subunit and the first switching protection unit, and is used to cut off the power supply of other power supply units when the power supply subunit supplies power to the target device.

[0022] According to some embodiments of the present invention, the sub-supply unit comprises:

[0023] A second power supply, wherein the second power supply is used to supply power to the target device;

[0024] a first diode, wherein an anode of the first diode is electrically connected to a positive electrode of the second power supply, and a cathode of the first diode is electrically connected to the target device;

[0025] A second diode, wherein an anode of the second diode is electrically connected to a negative electrode of the second power supply, and a cathode of the second diode is electrically connected to a positive electrode of the second power supply.

[0026] According to some embodiments of the present invention, the switching isolation subunit includes:

[0027] a third diode, wherein an anode of the third diode is electrically connected to the positive electrode of the second power supply, and a cathode of the third diode is electrically connected to one end of a sixth resistor;

[0028] a sixth resistor, the other end of which is electrically connected to the base of the third transistor;

[0029] a third triode, wherein the collector of the third triode is electrically connected to the first power supply unit, and the emitter of the third triode is grounded;

[0030] a seventh resistor, one end of the seventh resistor is electrically connected to the other end of the sixth resistor, and the other end of the seventh resistor is grounded.

[0031] According to a second aspect of an embodiment of the present utility model, a power switching system is provided, and the power switching system includes the power switching circuit as described in the first aspect of the embodiment.

[0032] A power switching system according to an embodiment of the utility model has at least the following beneficial effects: the power switching system includes the above-mentioned power switching circuit, which can effectively avoid the problem of power backflow during power switching, thereby realizing stable switching when multiple power supplies are supplied at the same time, thereby ensuring the stable operation of the electronic device.

[0033] According to a third aspect of the present invention, a multi-way power supply device comprises a power switching system as described in the second aspect of the present invention.

[0034] A multi-way power supply device according to an embodiment of the utility model has at least the following beneficial effects: the multi-way power supply device includes the above-mentioned power switching system, which can effectively avoid the problem of power backflow during power switching, thereby realizing stable switching when multiple power supplies are supplied at the same time, thereby ensuring the stable operation of this multi-way power supply device.

[0035] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0037] Figure 1 A schematic diagram of a power switching circuit provided by an embodiment of the utility model;

[0038] Figure 2 Another schematic diagram of the structure of the power switching circuit provided by the embodiment of the utility model;

[0039] Figure 3 A specific circuit diagram of a power switching circuit provided by an embodiment of the utility model;

[0040] Figure 4 A specific circuit diagram of a first working state of a power switching circuit provided by an embodiment of the utility model;

[0041] Figure 5 A specific circuit diagram of the second working state of the power switching circuit provided by the embodiment of the utility model;

[0042] Figure 6 A specific circuit diagram of the third working state of the power switching circuit provided by the embodiment of the utility model;

[0043] Figure 7 A specific circuit diagram of the fourth working state of the power switching circuit provided by an embodiment of the utility model.

[0044] Figure numerals: power supply module 100, switching protection module 200, first power supply unit 110, second power supply unit 120, power supply subunit 121, switching isolation subunit 122, first switching protection unit 210, second switching protection unit 220, first switching switch subunit 211, first switching conduction subunit 212, second switching switch subunit 221, second switching conduction subunit 222. DETAILED DESCRIPTION

[0045] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0046] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0047] In the description of the present utility model, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0048] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0049] In the description of the utility model, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0050] First, some nouns involved in this application are analyzed:

[0051] Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET): A semiconductor device that can control the flow of current between the source and drain by applying voltage to the gate.

[0052] Bipolar Junction Transistor (BJT): A semiconductor device that controls the current from the collector to the emitter by applying a voltage between the base and the emitter.

[0053] Transient Voltage Suppressor (TVS tube): a semiconductor device used to protect electronic circuits from damage by voltage spikes.

[0054] At present, the power supply system of most electronic devices can usually support a variety of different power supply modes, such as pluggable built-in batteries, external adapter power supply, etc. In practice, electronic devices usually only use one power supply mode to provide power for the operation of the device, so it is necessary to switch between different power supply modes through a power switching circuit in the power supply system of the electronic device. However, since the power supply voltages of different power supply modes may be different, the related technology is prone to the problem of power backflow when implementing power switching, that is, the power supply current may flow from the power supply with higher potential to the power supply with lower potential, thereby affecting the normal operation of the electronic device and causing damage to the electronic device.

[0055] Based on this, refer to Figure 1, an embodiment of the present application provides a structural schematic diagram of a power switching circuit. The power switching circuit may include: a power module 100 and a switching protection module 200. The power module 100 includes at least two power supply units, each of which is used to supply power to a target device. The power module 100 is electrically connected to the switching protection module 200, and the switching protection module 200 includes at least two switching protection units, each of which is electrically connected to a corresponding power supply unit, and different switching protection units are electrically connected, and at least two switching protection units are used to cut off the power supply to other power supply units when one power supply unit supplies power to a target device.

[0056] The embodiment of the present application is provided with a power supply module of at least two power supply units and a switching protection module of at least two switching protection units, wherein the power supply module is electrically connected to the switching protection module, and each switching protection unit is electrically connected to the corresponding power supply unit. When one power supply unit supplies power to the device, the power supply to other power supply units will be cut off by the corresponding switching protection module. Therefore, the present application utilizes multiple switching protection units to cut off the power supply to other power supply units when multiple power supply units are supplying power at the same time, which can effectively prevent power conflicts, and can also effectively avoid the problem of power backflow that occurs when power is switched in the related art, thereby achieving stable switching when multiple power supplies are supplied at the same time, thereby ensuring the stable operation of the electronic device.

[0057] Reference Figure 2 , an embodiment of the present application provides another structural schematic diagram of a power switching circuit. The switching protection module 200 may specifically include a first switching protection unit 210 and a second switching protection unit 220, and the first switching protection unit 210 is electrically connected to the second switching protection unit 220. Among them, the first switching protection unit 210 may include a first switching switch subunit 211 and a first switching conduction subunit 212, and the first switching switch subunit 211 is electrically connected to the first switching conduction subunit 212. The second switching protection unit 220 may include a second switching switch subunit 221 and a second switching conduction subunit 222, and the second switching switch subunit 221 is electrically connected to the second switching conduction subunit 222.

[0058] In some embodiments, Figure 2As shown, the power supply module 100 may specifically include a first power supply unit 110 and a second power supply unit 120. The first power supply unit 110 is electrically connected to the second power supply unit 120 and the first switching protection unit 210, and the second power supply unit 120 is electrically connected to the second switching protection unit 220. Specifically, the second power supply unit 120 includes a power supply subunit 121 and a switching isolation subunit 122. The power supply subunit 121 is used to supply power to the target device, and the switching isolation subunit 122 is electrically connected to the power supply subunit 121 and the first switching protection unit 210, and is used to cut off the power supply of other power supply units when the power supply subunit 121 supplies power to the target device.

[0059] Reference Figure 3 , an embodiment of the present application provides a specific circuit diagram of a power switching circuit. The first power supply unit 110 includes a first power supply BT1 and a first resistor R1. The positive electrode of the first power supply BT1 is electrically connected to one end of the first resistor R1, the negative electrode of the first power supply BT1 is grounded, and the first power supply BT1 is used to power the target device. The other end of the first resistor R1 is electrically connected to the other end of the fourth resistor R4.

[0060] It should be noted that the first power supply BT1 outputs a voltage through its positive terminal, which can be expressed as VBAT. In order to meet the voltage requirements of the target device, the first power supply BT1 can use a lithium-ion battery as an energy source. Specifically, the first power supply BT1 can generally use 18650 lithium-ion batteries in series or in parallel, and achieve the required voltage output through a specific battery combination (such as series connection). Specifically, a single 18650 lithium-ion battery can provide a voltage range of 2.75 volts (V) to 4.2V. In order to meet the voltage requirements of the target device, four 18650 lithium-ion batteries can be connected in series to increase the total voltage, so that the voltage range output after series connection can be 11V-16.8V, thereby meeting the voltage requirements of the target device. In addition, the first resistor R1 can be a resistor with a resistance of 10 kilo-ohms (kΩ).

[0061] In some embodiments, the power supply unit 121 includes a second power supply J1, a first diode D1, and a second diode D2. The second power supply J1 is used to power the target device. The anode of the first diode D1 is electrically connected to the positive electrode of the second power supply J1, and the cathode of the first diode D1 is electrically connected to the target device. The anode of the second diode D2 is electrically connected to the negative electrode of the second power supply J1, and the cathode of the second diode D2 is electrically connected to the positive electrode of the second power supply J1.

[0062] It should be noted that Figure 1The VCC_OUT in the circuit can be the output port of the circuit, and the VCC_OUT port is connected to the target device. The second power supply J1 can be connected to various external adapters, so that the second power supply J1 can flexibly receive inputs from various external power supplies. Specifically, the second power supply J1 includes 3 pins, which can be named as the first pin, the second pin and the third pin respectively. Specifically, the first pin of the second power supply J1 is the negative port, the second pin of the second power supply J1 is the ground port, the third pin of the second power supply J1 is the positive port, and the voltage output by the positive port can be expressed as DC. In order to meet the voltage requirements of the target device, the output voltage value can generally be 12V.

[0063] It should be noted that when connecting an external adapter and using the input of the external adapter as the second power supply J1, the operator may be unskilled in installation. For example, there is a risk that the operator will connect the positive and negative poles of the second power supply J1 in reverse, which may cause irreversible damage to the target device. Therefore, the embodiment of the present application sets the anode of the first diode D1 to be electrically connected to the positive pole of the second power supply J1, which can protect the circuit from reverse voltage shock. Specifically, when the voltage connected to the anode of the first diode D1 is a reverse voltage, the first diode D1 is cut off, so the reverse voltage will not be output to the target device at this time, effectively avoiding the occurrence of permanent damage to the target device when the positive and negative poles of the second power supply J1 are reversed. Specifically, the first diode D1 can be selected according to the actual use environment, and is not specifically limited. For example, the first diode D1 can be a Schottky diode.

[0064] It should be noted that in actual use, the second diode D2 can be selected according to the actual use environment, and is not specifically limited. For example, the second diode D2 can be a TVS tube. The TVS tube can absorb voltage spikes, electrostatic discharge (ESD) and power surges in the circuit, thereby protecting the target device. Specifically, when the voltage connected to the cathode of the TVS tube is greater than the preset safety threshold, the TVS tube will be reversely broken down and form a conduction loop, and at the same time can absorb surge power with a power value of up to several kilowatts, and control the voltage at both ends of the TVS tube within a safe voltage range, thereby achieving circuit protection. In addition, the response time of the TVS tube is extremely short, thereby ensuring the stability and safety of the target device. In addition, the second diode D2 can also use other protection devices, such as varistors.

[0065] In some embodiments, the switching isolation subunit 122 includes a third diode D3, a sixth resistor R6, a third triode Q3 and a seventh resistor R7. The anode of the third diode D3 is electrically connected to the positive electrode of the second power supply J1, the cathode of the third diode D3 is electrically connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is electrically connected to the base of the third triode Q3. The collector of the third triode Q3 is electrically connected to the first power supply unit 110, and the emitter of the third triode Q3 is grounded. One end of the seventh resistor R7 is electrically connected to the other end of the sixth resistor R6, and the other end of the seventh resistor R7 is grounded.

[0066] It should be noted that the third diode D3 can be selected according to the actual use environment, and is not specifically limited. For example, the third diode D3 can be a Schottky diode. The sixth resistor R6 and the seventh resistor R7 can both be resistors with a resistance of 4.7kΩ. The sixth resistor R6 can limit the current in the circuit, and the seventh resistor R7 is connected in parallel between the base and the emitter of the third triode Q3, which helps to stabilize the operating point of the third triode Q3 and prevent the third triode Q3 from entering a saturation or cut-off state from the amplification region due to temperature changes or changes in other components in the circuit. The third triode Q3 can be an NPN triode. Specifically, in an NPN triode, when a forward bias voltage is applied between the base and the emitter and the forward bias voltage is greater than 0.7V, the NPN triode is turned on, allowing current to flow from the collector to the emitter, and the voltage output by the collector can be 0.2V.

[0067] In some embodiments, the first switch subunit 211 includes a first transistor MOS1 and a second resistor R2. The gate of the first transistor MOS1 is electrically connected to one end of the second resistor R2, the source of the first transistor MOS1 is electrically connected to the other end of the second resistor R2, and the drain of the first transistor MOS1 is electrically connected to the second switching protection unit 220.

[0068] It should be noted that the first transistor MOS1 can be selected according to the actual use environment, and is not specifically limited. For example, the first transistor MOS1 can be a P-channel enhancement MOS tube. Specifically, for a P-channel MOS tube, when the voltage VGS between the gate and the source is less than or equal to the threshold voltage VGS(th), the channel region of the P-channel MOS tube will accumulate holes to form a conductive channel, allowing current to flow from the drain to the source. The second resistor R2 can be a resistor with a resistance value of 10kΩ. Since the second resistor R2 is connected in parallel between the gate and the source of the first transistor MOS1, it helps to stabilize the operating point of the first transistor MOS1 and prevent the operating point from drifting due to input voltage changes or temperature changes.

[0069] In some embodiments, the first switching conduction subunit 212 includes a first transistor Q1 and a fourth resistor R4. The base of the first transistor Q1 is electrically connected to one end of the fourth resistor R4, the collector of the first transistor Q1 is electrically connected to the gate of the first transistor MOS1, the emitter of the first transistor Q1 is grounded, and the other end of the fourth resistor R4 is electrically connected to the first power supply unit 110.

[0070] It should be noted that the first transistor Q1 can be selected according to the actual use environment, and is not specifically limited. For example, the first transistor Q1 can be an NPN transistor. The fourth resistor R4 can be a resistor with a resistance of 4.7kΩ, which can limit the current in the circuit. Specifically, when the first transistor Q1 is turned on, the collector voltage of the first transistor Q1 can be 0.2V, so that the gate voltage of the first transistor MOS1 is also 0.2V, so the conduction state of the first transistor Q1 can provide a voltage difference between the gate and source of the first transistor MOS1, thereby controlling the conduction of the first transistor MOS1.

[0071] In some embodiments, the second switch subunit 221 includes a second transistor MOS2 and a third resistor R3. The gate of the second transistor MOS2 is electrically connected to one end of the third resistor R3, the source of the second transistor MOS2 is electrically connected to the other end of the third resistor R3, and the drain of the second transistor MOS2 is electrically connected to the drain of the first transistor MOS1.

[0072] It should be noted that the second transistor MOS2 can be selected according to the actual use environment, and is not specifically limited. For example, the second transistor MOS2 can be a P-channel enhancement MOS tube. The third resistor R3 can be a resistor with a resistance value of 10kΩ, which can limit the current in the circuit. Because the third resistor R3 is connected in parallel between the gate and the source of the second transistor MOS2, it also helps to stabilize the operating point of the second transistor MOS2 and prevent the operating point from drifting due to input voltage changes or temperature changes.

[0073] In some embodiments, the second switching conduction subunit 222 includes a second triode Q2 and a fifth resistor R5, wherein the base of the second triode Q2 is electrically connected to one end of the fifth resistor R5, the collector of the second triode Q2 is electrically connected to the gate of the second transistor MOS2, the emitter of the second triode Q2 is grounded, and the other end of the fifth resistor R5 is electrically connected to the other end of the fourth resistor R4.

[0074] It should be noted that the second transistor Q2 can be selected according to the actual use environment, and is not specifically limited. For example, the second transistor Q2 can be an NPN transistor. The fifth resistor R5 can be a resistor with a resistance of 4.7kΩ, which can limit the current in the circuit. Specifically, when the second transistor Q2 is turned on, the collector voltage of the second transistor Q2 can be 0.2V, so that the gate voltage of the second transistor MOS2 is also 0.2V, so the conduction state of the second transistor Q2 can provide a voltage difference between the gate and the source of the second transistor MOS2, thereby controlling the conduction of the second transistor MOS2.

[0075] Reference Figure 4 The embodiment of the present application provides a specific circuit diagram of a first working state of the power switching circuit. The first working state may be a working state of the circuit when only the second power supply J1 supplies power to the circuit.

[0076] Specifically, when only the second power supply J1 supplies power, the voltage outputted by the positive electrode of the second power supply J1 is outputted to the output port VCC_OUT through the first diode D1. The voltage DC outputted by the positive electrode of the second power supply J1 reaches the gate of the second transistor MOS2 through the third resistor R3. Since the voltages at both ends of the third resistor R3 are 12V (the voltage drop generated by the voltage passing through the third resistor R3 is ignored at this time), the voltage at the gate of the second transistor MOS2 is also 12V. Since the source of the second transistor MOS2 is directly electrically connected to the cathode of the first diode D1, the voltage at the source of the second transistor MOS2 is also 12V. Therefore, the second transistor MOS2 is cut off, which can block the voltage DC outputted by the positive electrode of the second power supply J1 from being fed back to the first power supply BT1. In other words, when only the second power supply J1 supplies power, the voltage DC 12V outputted by the positive electrode of the second power supply J1 outputs the voltage to the output port VCC_OUT through the first diode D1. The gate and source voltages of the second transistor MOS2 are both DC12V, that is, the second transistor MOS2 is cut off, and can block the DC 12V from flowing back to the first power supply BT1.

[0077] Because the voltage DC passes through the third diode D3 to make the voltage between the base and the emitter of the third transistor Q3 greater than its conduction voltage drop (such as 0.7V), the third transistor Q3 is turned on. However, at this time, the first power supply BT1 is not supplying power, so there is no voltage input to the collector of the third transistor Q3, so there is no voltage input to the base of the first transistor Q1 and the second transistor Q2, so the first transistor Q1 and the second transistor Q2 are turned off. Since there is no voltage difference between the gate and the source of the first transistor MOS1, the first transistor MOS1 is turned off. It can be seen that in the first working state, the conduction conditions of each switch device in the circuit are: the third transistor Q3 is turned on, the first transistor Q1 is turned off, the second transistor Q2 is turned off, the first transistor MOS1 is turned off, and the second transistor MOS2 is turned off.

[0078] Reference Figure 5 The embodiment of the present application provides a specific circuit diagram of the second working state of the power switching circuit. The second working state can be a working state in which the first power supply BT1 starts to intervene in the power supply when the second power supply J1 in the circuit is supplying power.

[0079] Specifically, the voltage DC outputted by the positive electrode of the second power supply J1 is outputted to the output port VCC_OUT through the first diode D1. DC passes through the third diode D3 to make the voltage between the base and the emitter of the third triode Q3 greater than its conduction voltage drop (such as 0.7V), so the third triode Q3 is turned on, and the voltage of the collector of the third triode Q3 can be 0.2V. Because the base of the first triode Q1 is electrically connected to the collector of the third triode Q3, that is, the base voltage of the first triode Q1 is less than its conduction voltage drop, the first triode Q1 is turned off. Similarly, it can be known that the second triode Q2 is also turned off.

[0080] Because the voltage VBAT outputted from the positive electrode of the first power supply BT1 flows directly into the source of the first transistor MOS1, that is, the source voltage of the first transistor MOS1 is VBAT. And because the voltage VBAT outputted from the positive electrode of the first power supply BT1 flows into the gate of the first transistor MOS1 through the second resistor R2 (ignoring the voltage drop generated by the voltage VBAT passing through the second resistor R2 at this time), that is, the gate voltage of the first transistor MOS1 is also VBAT, the first transistor MOS1 is cut off, blocking the first power supply BT1 from supplying power to the target device, thereby realizing that the power supply priority of the second power supply J1 is higher than the power supply priority of the first power supply BT1. Similarly, it can be known that the gate and source of the second transistor MOS2 are both voltage DC, and the second transistor MOS2 is cut off, thereby preventing the voltage DC outputted from the positive electrode of the second power supply J1 from flowing back to the first power supply BT1.

[0081] In other words, when the second power supply J1 is supplying power, the first power supply BT1 is connected, and the voltage DC 12V output by the positive electrode of the second power supply J1 is output to the output port VCC_OUT through the first diode D1. The voltage DC 12V output by the positive electrode of the second power supply J1 turns on the third transistor Q3 through the third diode D3. At this time, the collector voltage of the third transistor Q3 is 0.2V, so that the first transistor Q1 is turned off. Because the gate and source of the first transistor MOS1 are both voltage VBAT, that is, the first transistor MOS1 is turned off, the power supply of the first power supply BT1 can be blocked, ensuring that the power supply priority of the second power supply J1 (external adapter) is higher than the power supply priority of the first power supply BT1 (lithium-ion battery). Because the gate and source of the second transistor MOS2 are both voltage DC 12V, the second transistor MOS2 is turned off to prevent the voltage DC 12V output by the positive electrode of the second power supply J1 from flowing back to the first power supply BT1.

[0082] It can be seen that in the second working state, the conduction conditions of the switch devices in the circuit are: the third transistor Q3 is turned on, the first transistor Q1 is turned off, the second transistor Q2 is turned off, the first transistor MOS1 is turned off, and the second transistor MOS2 is turned off.

[0083] Reference Figure 6 , the embodiment of the present application provides a specific circuit diagram of the third working state of the power switching circuit. The third working state can be the working state of the circuit when only the first power supply BT1 supplies power in the circuit.

[0084] Specifically, when only the first power supply BT1 supplies power, the voltage VBAT outputted from the positive electrode of the first power supply BT1 makes the voltage between the base and the emitter of the first transistor Q1 greater than its conduction voltage drop (such as 0.7V) through the first resistor R1 and the fourth resistor R4, then the first transistor Q1 is turned on, and the voltage of the collector of the first transistor Q1 can be 0.2V. Because the source voltage of the first transistor MOS1 is VBAT and the gate voltage of the first transistor MOS1 is 0.2V, the difference between the source and gate voltages of the first transistor MOS1 VGS<VGS(th), that is, the first transistor MOS1 is turned on. When the first transistor MOS1 is turned on, the current direction of the first transistor MOS1 can be rightward. At this time, ignoring the conduction voltage drop of the first transistor MOS1, the drain voltage of the second transistor MOS2 is the voltage VBAT. The drain voltage of the second transistor MOS2 reaches the source of the second transistor MOS2 through its internal body diode, so the voltage of the source of the second transistor MOS2 is lower than the voltage VBAT.

[0085] The voltage VBAT outputted from the positive electrode of the first power supply BT1 passes through the first resistor R1 so that the voltage between the base and the emitter of the second transistor Q2 is greater than its conduction voltage drop (such as 0.7V), then the second transistor Q2 is turned on, and the voltage of the collector of the second transistor Q2 can be 0.2V. Because the voltage of the source of the second transistor MOS2 is lower than the voltage VBAT, the voltage of the gate of the second transistor MOS2 is 0.2V, and the difference between the source and gate voltages of the second transistor MOS2 is VGS<VGS(th), that is, the second transistor MOS2 is turned on, and the current direction of the second transistor MOS2 can be rightward. At this time, the first transistor MOS1 and the second transistor MOS2 are both turned on, ignoring the tube voltage drop of the first transistor MOS1 and the second transistor MOS2, then the source voltage of the second transistor MOS2 is also VBAT, and finally output to the output port VCC_OUT. The first diode D1 can prevent the first power supply BT1 from backflowing to the second power supply J1. Because the second power supply J1 is not supplying power at this time, the third transistor Q3 is turned off.

[0086] In other words, when only the first power supply BT1 supplies power, there is no DC12V output because there is no second power supply J1, so the third transistor Q3 is turned off. The voltage VBAT output from the positive electrode of the first power supply BT1 turns on the first transistor Q1 through the first resistor R1 and the fourth resistor R4. After the conduction, the voltage of the collector of the first transistor Q1 is 0.2V. Because the source voltage of the first transistor MOS1 is VBAT, the voltage difference between the source and the gate of the first transistor MOS1 is VGS<VGS(th), that is, the first transistor MOS1 is turned on. Similarly, the second transistor Q2 is turned on, and the voltage of the collector of the second transistor Q2 is 0.2V. The voltage of the drain of the second transistor MOS2 pulls the voltage of the source of the second transistor MOS2 to VBAT through its internal body diode. The voltage difference between the source and the gate of MOS2 is VGS<VGS(th), so the second transistor MOS2 is turned on, and the voltage VBAT is output to the output port VCC_OUT. At this time, the first diode D1 is in a reverse cut-off state, which can prevent the voltage VBAT from flowing back to the second power supply J1.

[0087] It can be seen that in the third working state, the conduction conditions of the switch devices in the circuit are: the third transistor Q3 is turned off, the first transistor Q1 is turned on, the second transistor Q2 is turned on, the first transistor MOS1 is turned on, and the second transistor MOS2 is turned on.

[0088] Reference Figure 7 The embodiment of the present application provides a specific circuit diagram of the fourth working state of the power switching circuit. The fourth working state may be a working state in which the second power supply J1 starts to intervene in the power supply when the first power supply BT1 in the circuit is supplying power.

[0089] Specifically, the voltage outputted by the positive electrode of the second power supply J1 is outputted to the output port VCC_OUT through the first diode D1. The DC passes through the third diode D3 to make the voltage between the base and the emitter of the third triode Q3 greater than its conduction voltage drop (such as 0.7V), then the third triode Q3 is turned on, and the voltage of the collector of the third triode Q3 can be 0.2V. Because the base of the first triode Q1 is electrically connected to the collector of the third triode Q3, that is, the base voltage of the first triode Q1 is less than its conduction voltage drop, the first triode Q1 is turned off. Similarly, it can be known that the second triode Q2 is also turned off.

[0090] Because the voltage VBAT outputted from the positive electrode of the first power supply BT1 flows directly into the source of the first transistor MOS1, that is, the source voltage of the first transistor MOS1 is VBAT. And because the voltage VBAT outputted from the positive electrode of the first power supply BT1 flows into the gate of the first transistor MOS1 through the second resistor R2 (ignoring the voltage drop generated by the voltage VBAT passing through the second resistor R2 at this time), that is, the gate voltage of the first transistor MOS1 is also VBAT, the first transistor MOS1 is cut off, blocking the first power supply BT1 from supplying power to the target device, thereby realizing that the power supply priority of the second power supply J1 is higher than the power supply priority of the first power supply BT1. Similarly, it can be known that the gate and source of the second transistor MOS2 are both voltage DC, then the second transistor MOS2 is cut off, thereby preventing the voltage DC outputted from the positive electrode of the second power supply J1 from being fed back to the first power supply BT1. The output in the fourth working state is not affected by the VBAT voltage fluctuation outputted by the first power supply BT1. When the VBAT voltage is in the range of 11V to 16.8V, the effect of giving priority to the second power supply J1 and preventing the second power supply J1 from being fed back to the first power supply BT1 can be achieved.

[0091] In other words, when the first power supply BT1 (lithium-ion battery) supplies power, the second power supply J1 (external adapter) is connected. At this time, DC 12V turns on the third transistor Q3 through the third diode D3, and the voltage of the collector of the third transistor Q3 is 0.2V, so the first transistor Q1 is turned off. Because the gate and source voltages of the first transistor MOS1 are both voltage VBAT, that is, the first transistor MOS1 is turned off, the first power supply BT1 can be blocked from supplying power. Similarly, the second transistor Q2 is turned off. DC 12V is output to the output port VCC_OUT through the first diode D1, so that the power supply priority of the external adapter is higher than the power supply priority of the lithium-ion battery. Because the gate and source of the second transistor MOS2 are both DC 12V, that is, the second transistor MOS2 is turned off, the DC 12V can be blocked from backflowing to the first power supply BT1. This working state is not affected by the VBAT voltage fluctuation output by the lithium-ion battery, that is, the VBAT voltage can achieve the function of giving priority to the external adapter and preventing power backflow when it is 11-16.8V.

[0092] It can be seen that in the fourth working state, the conduction conditions of the switch devices in the circuit are: the third transistor Q3 is turned on, the first transistor Q1 is turned off, the second transistor Q2 is turned off, the first transistor MOS1 is turned off, and the second transistor MOS2 is turned off.

[0093] Reference Figures 4 to 7 , Figures 4 to 7 The red arrow in the middle represents the direction of the current in the circuit, and "X" represents that the circuit here is in an open circuit state. In summary, in the four working states, the on and off states of the first transistor Q1 and the first transistor MOS1 are consistent, the on and off states of the second transistor Q2 and the second transistor MOS2 are consistent, and the on and off states of the first transistor Q1, the second transistor Q2, the first transistor MOS1 and the second transistor MOS2 are consistent, so the priority switching when multiple power supplies are supplied simultaneously in the power switching circuit can be realized, and the situation of multiple power supplies backflowing each other can also be prevented. The first transistor Q1, the second transistor Q2, the first transistor MOS1 and the second transistor MOS2 are regarded as a whole, and the conduction state of the third transistor Q3 is opposite to that of this whole, so the third transistor Q3 can control the conduction or cutoff of the first transistor Q1, the second transistor Q2, the first transistor MOS1 and the second transistor MOS2 to a certain extent, thereby ensuring that the power supply priority of the second power supply J1 is higher than the power supply priority of the first power supply BT1.

[0094] In addition, the embodiment of the utility model also discloses a power switching system, which includes the power switching circuit as described above. The power switching system includes the power switching circuit as described above, which can effectively avoid the problem of power backflow during power switching, thereby achieving stable switching when multiple power supplies are supplied at the same time, thereby ensuring the stable operation of the electronic device.

[0095] Finally, the embodiment of the utility model also discloses a multi-way power supply device, and the multi-way power supply device includes the power switching system as described above. The multi-way power supply device includes the power switching system described above, which can effectively avoid the problem of power backflow during power switching, thereby achieving stable switching when multiple power supplies are supplied at the same time, thereby ensuring the stable operation of the multi-way power supply device. It should be noted that the multi-way power supply device can be a common handheld portable electronic device (such as in the fields of broadcasting and television systems, handheld medical treatment, industrial detection, etc.), and is not specifically limited. For example, in a broadcasting and television system, the multi-way power supply device can be a camera, a microphone, a lighting device, and the like.

[0096] The embodiments of the utility model are described in detail above in conjunction with the accompanying drawings, but the utility model is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the utility model. In addition, the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

Claims

1. A power switching circuit, characterized in that: include: A power supply module, the power supply module comprising at least two power supply units, each of the power supply units being used to supply power to the target device; A switching protection module, wherein the power supply module is electrically connected to the switching protection module, and the switching protection module includes at least two switching protection units, each of which is electrically connected to the corresponding power supply unit, and different switching protection units are electrically connected, and the at least two switching protection units are used to cut off the power supply of other power supply units when one power supply unit supplies power to the target device.

2. The power switching circuit according to claim 1, characterized in that: The at least two switching protection units include a first switching protection unit and a second switching protection unit, and the first switching protection unit is electrically connected to the second switching protection unit; The at least two power supply units include a first power supply unit and a second power supply unit, the first power supply unit is electrically connected to the second power supply unit and the first switching protection unit, and the second power supply unit is electrically connected to the second switching protection unit.

3. The power switching circuit according to claim 2, characterized in that: The first switching protection unit includes: a first switching switch subunit, the first switching switch subunit comprising a first transistor and a second resistor, a gate of the first transistor being electrically connected to one end of the second resistor, a source of the first transistor being electrically connected to the other end of the second resistor, and a drain of the first transistor being electrically connected to the second switching protection unit; A first switching conduction subunit, the first switching conduction subunit includes a first transistor and a fourth resistor, the base of the first transistor is electrically connected to one end of the fourth resistor, the collector of the first transistor is electrically connected to the gate of the first transistor, the emitter of the first transistor is grounded, and the other end of the fourth resistor is electrically connected to the first power supply unit.

4. The power switching circuit according to claim 3, characterized in that: The second switching protection unit includes: a second switching subunit, the second switching subunit comprising a second transistor and a third resistor, the gate of the second transistor being electrically connected to one end of the third resistor, the source of the second transistor being electrically connected to the other end of the third resistor, and the drain of the second transistor being electrically connected to the drain of the first transistor; A second switching conduction subunit, the second switching conduction subunit includes a second transistor and a fifth resistor, the base of the second transistor is electrically connected to one end of the fifth resistor, the collector of the second transistor is electrically connected to the gate of the second transistor, the emitter of the second transistor is grounded, and the other end of the fifth resistor is electrically connected to the other end of the fourth resistor.

5. The power switching circuit according to claim 2, characterized in that: The first power supply unit comprises: A first power supply, wherein a positive electrode of the first power supply is electrically connected to one end of a first resistor, a negative electrode of the first power supply is grounded, and the first power supply is used to supply power to the target device; A first resistor, wherein the other end of the first resistor is electrically connected to the other end of the fourth resistor.

6. The power switching circuit according to claim 2, characterized in that: The second power supply unit includes: a power supply subunit, the power supply subunit being used to supply power to the target device; A switching and isolating subunit, the switching and isolating subunit is electrically connected to the power supply subunit and the first switching protection unit, and is used to cut off the power supply of other power supply units when the power supply subunit supplies power to the target device.

7. The power switching circuit according to claim 6, characterized in that: The sub-supply unit comprises: A second power supply, wherein the second power supply is used to supply power to the target device; a first diode, wherein an anode of the first diode is electrically connected to a positive electrode of the second power supply, and a cathode of the first diode is electrically connected to the target device; A second diode, wherein an anode of the second diode is electrically connected to a negative electrode of the second power supply, and a cathode of the second diode is electrically connected to a positive electrode of the second power supply.

8. The power switching circuit according to claim 7, characterized in that: The switching and isolating subunit comprises: a third diode, wherein an anode of the third diode is electrically connected to the positive electrode of the second power supply, and a cathode of the third diode is electrically connected to one end of a sixth resistor; a sixth resistor, the other end of which is electrically connected to the base of the third transistor; a third triode, wherein the collector of the third triode is electrically connected to the first power supply unit, and the emitter of the third triode is grounded; a seventh resistor, one end of the seventh resistor is electrically connected to the other end of the sixth resistor, and the other end of the seventh resistor is grounded.

9. A power switching system, characterized in that: The power switching system comprises a power switching circuit as described in any one of claims 1-8.

10. A multi-channel power supply device, characterized in that: The multi-way power supply device comprises the power switching system as claimed in claim 9.

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