Power switching circuit and electronic device

Abstract

The application belongs to the technical field of electronic circuits and provides a power switching circuit and electronic equipment. The circuit comprises a first switch module, a second switch module, a third switch module, a first diode module and a second diode module. The first switch module is connected with the second switch module, the third switch module, the first diode module, a first end and a second end of the power switching circuit respectively. The second switch module is connected with the first switch module, the first diode module, the second diode module, the third switch module and a load respectively. The third switch module is connected with the second diode module and a third end and a fourth end of the power switching circuit respectively. The application adopts the mode of combining the diode module with the switch module, and the diode module is first turned on and then transits to the switch module to supply power to the load. Meanwhile, the original power is disconnected only after another power is connected, thereby solving the problems of poor stability, high loss and untimely switching of the traditional circuit.

Description

Technical Field

[0001] This application belongs to the field of electronic circuit technology, and in particular relates to a power switching circuit and electronic device. Background Technology

[0002] In electronic devices, dual power inputs are often required to ensure power supply flexibility and reliability. Switching between these two power supplies is typically achieved through a power switching circuit. Current power switching circuits mostly use diodes or switching devices. With diodes, the two power supplies directly power the load through the unidirectional conduction characteristic of the diodes. When the current flowing through the diode is too large, the diode will overheat; continuous overheating not only affects circuit stability but also increases circuit losses. With switching devices, the two power supplies power the load through the mutual exclusion control of the switching devices. However, during switching, if one switching device is conducting while the other has already turned off, the untimely switching will affect the normal power supply to the load. Utility Model Content

[0003] This application provides a power switching circuit and electronic device that can solve the problems of poor stability, high loss, and untimely switching in current power switching circuits.

[0004] In a first aspect, embodiments of this application provide a power switching circuit, including a first switch module, a second switch module, a third switch module, a first diode module, and a second diode module. The first switch module is connected to the second switch module, the third switch module, the first diode module, and a first terminal and a second terminal of the power switching circuit, respectively. The second switch module is connected to the first switch module, the first diode module, the second diode module, the third switch module, and a load, respectively. The third switch module is connected to the second diode module and a third terminal and a fourth terminal of the power switching circuit, respectively. When the third and fourth terminals of the power switching circuit are connected to the first power source, the first power source supplies power to the load through the second diode module. After a first time, the third switch module is turned on, allowing the first power source to supply power to the load through the third switch module. When the first and second terminals of the power switching circuit are connected to the second power source, the second power source supplies power to the load through the first diode module. The third switch module is used to disconnect according to the second power source voltage, and the first switch module is used to turn on according to the second power source voltage and output a first level signal. After a second time, the second switch module is used to turn on according to the first level signal, allowing the second power source to supply power to the load through the second switch module.

[0005] In one possible implementation of the first aspect, the first switching module includes a first resistor, a second resistor, a third resistor, and a first switching transistor. The first end of the first resistor is connected to the first end of the third resistor, the first end of the power switching circuit, the second switching module, the third switching module, and the first diode module. The second end of the first resistor is connected to the first end of the second resistor and the control end of the first switching transistor. The second end of the third resistor is connected to the first conducting end of the first switching transistor and the second switching module. The second end of the second resistor, the second conducting end of the first switching transistor, and the second end of the power switching circuit are all grounded.

[0006] In one possible implementation of the first aspect, the second switching module includes a fourth resistor, a first capacitor, a second switching transistor, and a third switching transistor. The first end of the fourth resistor is connected to the first switching module, and the second end of the fourth resistor is connected to the first end of the first capacitor, the control end of the second switching transistor, and the control end of the third switching transistor. The first conducting end of the second switching transistor is connected to the first conducting end of the third switching transistor. The second conducting end of the second switching transistor is connected to the second end of the first capacitor, the first switching module, the third switching module, the first diode module, and the first end of the power switching circuit. The second conducting end of the third switching transistor is connected to the first diode module, the second diode module, the third switching module, and the load.

[0007] In one possible implementation of the first aspect, the third switching module includes a fifth resistor, a sixth resistor, a second capacitor, a fourth switching transistor, and a fifth switching transistor. The first end of the fifth resistor is connected to the first switching module, the second switching module, the first diode module, and the first end of the power switching circuit. The second end of the fifth resistor is connected to the first end of the second capacitor, the first end of the sixth resistor, the control end of the fourth switching transistor, and the control end of the fifth switching transistor. The first conducting end of the fourth switching transistor is connected to the first conducting end of the fifth switching transistor. The second conducting end of the fourth switching transistor is connected to the second end of the second capacitor, the third end of the power switching circuit, and the second diode module. The second conducting end of the fifth switching transistor is connected to the second switching module, the first diode module, the second diode module, and the load. The second end of the sixth resistor and the fourth end of the power switching circuit are both grounded.

[0008] In one possible implementation of the first aspect, the first switch is an NMOS transistor, and the second, third, fourth, and fifth switches are all PMOS transistors.

[0009] In one possible implementation of the first aspect, the first diode module includes a first diode, the anode of the first diode being connected to the first terminal of the first switch module, the second switch module, the third switch module, and the power switching circuit, respectively, and the cathode of the first diode being connected to the second switch module, the third switch module, the second diode module, and the load, respectively.

[0010] In one possible implementation of the first aspect, the second diode module includes a second diode, the anode of which is connected to the third terminal of the third switch module and the third terminal of the power switching circuit, and the cathode of which is connected to the third switch module, the second switch module, the first diode module and the load.

[0011] In one possible implementation of the first aspect, the power switching circuit further includes an overcurrent protection module, which is connected to the first diode module, the second switch module, the third switch module, the second diode module, and the load, respectively. The overcurrent protection module is used to implement overcurrent protection.

[0012] In one possible implementation of the first aspect, the overcurrent protection module includes a fuse, the first end of which is connected to the first diode module, the second switch module, the third switch module, and the second diode module, respectively, and the second end of which is used to connect to the load.

[0013] Secondly, embodiments of this application provide an electronic device including the power switching circuit described in any one of the first aspects.

[0014] The beneficial effects of the embodiments in this application compared with the prior art are: This application provides a power switching circuit, including a first switch module, a second switch module, a third switch module, a first diode module, and a second diode module. The first switch module is connected to the second switch module, the third switch module, the first diode module, and the first and second terminals of the power switching circuit. The second switch module is connected to the first switch module, the first diode module, the second diode module, the third switch module, and a load. The third switch module is connected to the second diode module and the third and fourth terminals of the power switching circuit.

[0015] When the third and fourth terminals of the power switching circuit are connected to the first power supply, the first power supply initially powers the load through the second diode module, forming the initial power supply. However, because the second diode module has a forward conduction voltage, it will generate heat under high current conditions and is not suitable for prolonged conduction. Therefore, after the initial period, the third switch module conducts, allowing the first power supply to power the load through the third switch module. Since the internal resistance of the third switch module is very small after conduction, the load voltage and the first power supply voltage are very close. At this time, the second diode module enters the cutoff state because the voltage across its terminals does not meet the forward conduction condition, thus solving the problem of the second diode module overheating due to high current. This not only reduces the losses of the power switching circuit but also improves the stability of the power switching circuit.

[0016] When the first and second terminals of the power switching circuit are connected to the second power supply, the second power supply first powers the load through the first diode module; simultaneously, the third switching module disconnects according to the second power supply voltage, causing the first power supply to stop supplying power. This ensures that the first power supply has stopped supplying power when the second power supply powers the load, achieving seamless switching between the first and second power supplies and solving the problem of untimely switching caused by the mutual exclusion control of switching devices in traditional power switching circuits. However, because the first diode module has a forward conduction voltage, it will generate heat under high current conditions and is not suitable for prolonged conduction. At the same time, the first switching module also conducts according to the second power supply voltage and outputs a first-level signal; after a second time, the second switching module conducts according to the first-level signal, thus allowing the second power supply to power the load through the second switching module. Since the internal resistance of the second switching module after conduction is very small, the load voltage and the second power supply voltage are very close. At this time, the first diode module enters the cutoff state because the voltage across its terminals does not meet the forward conduction condition, thus solving the problem of the first diode module overheating due to high current. This not only reduces the losses of the power switching circuit but also improves its stability.

[0017] In summary, the power switching circuit provided in this application combines a diode module and a switching module. The diode module conducts first, and then the switching module conducts to supply power to the load. At the same time, it ensures that the original power supply is disconnected only after the other power supply is connected. This effectively solves the problems of poor stability, high loss, and untimely switching that exist in current power switching circuits.

[0018] It is understandable that the beneficial effects of the second aspect mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a power switching circuit provided in an embodiment of this application; Figure 2 This is a circuit connection diagram of a power switching circuit provided in an embodiment of this application; Figure 3 This is a schematic diagram of a power switching circuit provided in another embodiment of this application; Figure 4 This is a circuit connection diagram of a power switching circuit provided in another embodiment of this application.

[0021] In the diagram: 10. Power switching circuit; 11. First switch module; 12. Second switch module; 13. Third switch module; 14. First diode module; 15. Second diode module; 16. Overcurrent protection module; 20. First power supply; 30. Second power supply; 40. Load. Detailed Implementation

[0022] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0023] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0024] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [the described condition or event] is detected," or "in response to detection of [the described condition or event]."

[0025] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0027] Currently, power switching circuits are commonly used to switch between dual power supplies. Traditional power switching circuits often use diodes or switching devices. However, using diodes not only affects circuit stability but also increases circuit losses; while using switching devices can result in untimely switching, thus affecting the normal power supply to the load.

[0028] To address the aforementioned problems, this application provides a power switching circuit 10, including a first switch module 11, a second switch module 12, a third switch module 13, a first diode module 14, and a second diode module 15. The first switch module 11 is connected to the second switch module 12, the third switch module 13, the first diode module 14, and the first and second terminals of the power switching circuit 10. The second switch module 12 is connected to the first switch module 11, the first diode module 14, the second diode module 15, the third switch module 13, and the load 40. The third switch module 13 is connected to the second diode module 15 and the third and fourth terminals of the power switching circuit 10. When the third and fourth terminals of the power switching circuit 10 are connected to a first power supply 20, the first power supply 20 initially supplies power to the load 40 through the second diode module 15, forming an initial power supply. However, since the second diode module 15 has a forward conduction voltage, it will generate heat under high current conditions and is not suitable for prolonged conduction. Therefore, after the initial period, the third switch module 13 conducts, allowing the first power supply 20 to supply power to the load 40 through the third switch module 13. Since the internal resistance of the third switch module 13 is very small after it is turned on, the load voltage and the first power supply voltage are very close. At this time, the second diode module 15 enters the cut-off state because the voltage at both ends does not meet the forward conduction condition, thus solving the problem of the second diode module 15 heating up due to the large current. This not only reduces the loss of the power switching circuit 10, but also improves the stability of the power switching circuit 10.

[0029] When the first and second terminals of the power switching circuit 10 are connected to the second power supply 30, the second power supply 30 first supplies power to the load 40 through the first diode module 14; simultaneously, the third switch module 13 disconnects according to the second power supply voltage, causing the first power supply 20 to stop supplying power. This ensures that the first power supply 20 has stopped supplying power when the second power supply 30 supplies power to the load 40, achieving seamless switching between the first power supply 20 and the second power supply 30, and solving the problem of untimely switching caused by the mutual exclusion control of switching devices when supplying power to the load 40 in traditional power switching circuits. However, because the first diode module 14 has a forward conduction voltage, it will generate heat under high current conditions and is not suitable for prolonged conduction. At the same time, the first switch module 11 also conducts according to the second power supply voltage and outputs a first level signal; after a second time, the second switch module 12 conducts according to the first level signal, thereby causing the second power supply 30 to supply power to the load 40 through the second switch module 12. Since the internal resistance of the second switch module 12 is very small after it is turned on, the load voltage and the second power supply voltage are very close. At this time, the first diode module 14 enters the cut-off state because the voltage at both ends does not meet the forward conduction condition, thus solving the problem of the first diode module 14 heating up due to the large current. This not only reduces the loss of the power switching circuit 10, but also improves the stability of the power switching circuit 10.

[0030] In summary, the power switching circuit 10 provided in this application combines a diode module and a switching module. The diode module is turned on first, and then the switching module is turned on to supply power to the load 40. At the same time, the original power supply is disconnected only after the other power supply is turned on. This effectively solves the problems of poor stability, high loss and untimely switching that exist in current power switching circuits.

[0031] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0032] Figure 1 A schematic diagram of a power switching circuit 10 provided in an embodiment of this application is shown, as follows: Figure 1 As shown, the power switching circuit 10 includes a first switch module 11, a second switch module 12, a third switch module 13, a first diode module 14, and a second diode module 15. The first switch module 11 is connected to the second switch module 12, the third switch module 13, the first diode module 14, and the first and second terminals of the power switching circuit 10, respectively. The second switch module 12 is connected to the first switch module 11, the first diode module 14, the second diode module 15, the third switch module 13, and the load 40, respectively. The third switch module 13 is connected to the second diode module 15, and the third and fourth terminals of the power switching circuit 10, respectively.

[0033] Specifically, when the third and fourth terminals of the power switching circuit 10 are connected to the first power supply 20, the first power supply 20 first supplies power to the load 40 through the second diode module 15, forming an initial power supply. However, since the second diode module 15 has a forward conduction voltage, it will generate heat under high current conditions and is not suitable for long-term conduction. Therefore, after the first time (i.e., a certain delay time), the third switch module 13 is turned on, allowing the first power supply 20 to supply power to the load 40 through the third switch module 13. Since the internal resistance of the third switch module 13 is very small after it is turned on, the load voltage and the first power supply voltage are very close. At this time, the second diode module 15 enters the cutoff state because the voltage at both ends does not meet the forward conduction condition, thus solving the problem of the second diode module overheating caused by high current. This not only reduces the loss of the power switching circuit 10 but also improves the stability of the power switching circuit 10.

[0034] When the first and second terminals of the power switching circuit 10 are connected to the second power supply 30, the second power supply 30 first supplies power to the load 40 through the first diode module 14; simultaneously, the third switch module 13 disconnects according to the second power supply voltage, causing the first power supply 20 to stop supplying power. This ensures that the first power supply 20 has stopped supplying power when the second power supply 30 supplies power to the load 40, achieving seamless switching between the first power supply 20 and the second power supply 30 (i.e., ensuring the continuity of power supply to the load 40), and solving the problem of untimely switching caused by the mutual exclusion control of switching devices in traditional power switching circuits when supplying power to the load 40. However, because the first diode module 14 has a forward conduction voltage, it will generate heat under high current conditions and is not suitable for prolonged conduction. At the same time, the first switch module 11 also conducts according to the second power supply voltage and outputs a first level signal; in this embodiment, the first level signal is low. After a second time (i.e., a certain delay time), the second switch module 12 conducts according to the first level signal, thereby enabling the second power supply 30 to supply power to the load through the second switch module 12. Since the internal resistance of the second switch module 12 is very small after it is turned on, the load voltage and the second power supply voltage are very close. At this time, the first diode module 14 enters the cut-off state because the voltage at both ends does not meet the forward conduction condition, thus solving the problem of the first diode module 14 heating up due to the large current. This not only reduces the loss of the power switching circuit 10, but also improves the stability of the power switching circuit 10.

[0035] In one embodiment of this application, such as Figure 2 As shown, the first switching module 11 includes a first resistor R1, a second resistor R2, a third resistor R3, and a first switching transistor Q1. The first end of the first resistor R1 is connected to the first end of the third resistor R3, the first end of the power switching circuit 10, the second switching module 12, the third switching module 13, and the first diode module 14. The second end of the first resistor R1 is connected to the first end of the second resistor R2 and the control terminal of the first switching transistor Q1. The second end of the third resistor R3 is connected to the first conducting terminal of the first switching transistor Q1 and the second switching module 12. The second end of the second resistor R2, the second conducting terminal of the first switching transistor Q1, and the second end of the power switching circuit 10 are all grounded. In this embodiment, the first switching transistor Q1 is an NMOS (N-channel Metal-Oxide-Semiconductor Field-Effect Transistor). The control terminal of the first switching transistor Q1 is the gate of the NMOS transistor, the first conducting terminal of the first switching transistor Q1 is the drain of the NMOS transistor, and the second conducting terminal of the first switching transistor Q1 is the source of the NMOS transistor.

[0036] Specifically, when the first and second terminals of the power switching circuit 10 are not connected to the second power supply 30, the first switching transistor Q1 is in the off state. When the first and second terminals of the power switching circuit 10 are connected to the second power supply 30, the second power supply 30 pulls up the voltage at the control terminal of the first switching transistor Q1, thereby controlling the first switching transistor Q1 to conduct; after the first switching transistor Q1 conducts, its first conducting terminal is at a low level (i.e., a first level signal). The first resistor R1 and the second resistor R2 serve as voltage divider resistors, and the third resistor R3 serves as a current-limiting resistor.

[0037] In one embodiment of this application, such as Figure 2 As shown, the second switching module 12 includes a fourth resistor R4, a first capacitor C1, a second switching transistor Q2, and a third switching transistor Q3. The first end of the fourth resistor R4 is connected to the first switching module 11. The second end of the fourth resistor R4 is connected to the first end of the first capacitor C1, the control end of the second switching transistor Q2, and the control end of the third switching transistor Q3. The first conducting end of the second switching transistor Q2 is connected to the first conducting end of the third switching transistor Q3. The second conducting end of the second switching transistor Q2 is connected to the second end of the first capacitor C1, the first switching module 11, the third switching module 13, the first diode module 14, and the first end of the power switching circuit 10. The second conducting end of the third switching transistor Q3 is connected to the first diode module 14, the second diode module 15, the third switching module 13, and the load 40. In this embodiment, both the second switch Q2 and the third switch Q3 are PMOS (P-channel Metal-Oxide-Semiconductor Field-Effect Transistor) transistors. The control terminals of the second switch Q2 and the third switch Q3 are the gates of the PMOS transistors, the first conducting terminals of the second switch Q2 and the third switch Q3 are the drains of the PMOS transistors, and the second conducting terminals of the second switch Q2 and the third switch Q3 are the sources of the PMOS transistors.

[0038] Specifically, when the first and second terminals of the power switching circuit 10 are not connected to the second power supply 30, the first switch Q1 is in the off state, and consequently the second and third switches Q2 and Q3 are also in the off state. When the first and second terminals of the power switching circuit 10 are connected to the second power supply 30, the first switch Q1 is turned on; after the first switch Q1 is turned on, its first conducting terminal is at a low level (i.e., a first level signal). After a certain delay, the second and third switches Q2 and Q3 are turned on under the control of the low level. The first capacitor C1 is used to pull up the voltage of the control terminals of the second and third switches Q2 and Q3 at the moment the second power supply 30 is powered on, taking advantage of the characteristic that the voltage across the capacitor cannot change abruptly, so that the second and third switches Q2 and Q3 are in the off state. After a certain delay, the second and third switches Q2 and Q3 will turn on according to the first level signal, thus ensuring that the first diode module 14 turns on first, and then the second and third switches Q2 and Q3 turn on. The fourth resistor R4 is used as a current-limiting resistor.

[0039] It should be noted that the second switching module 12 uses two switching transistors connected in series, and the body diodes of the two transistors are in opposite directions to prevent reverse current flow. It should also be noted that switching transistors Q2 and Q3, in order to adapt to high current conditions, employ... Figure 2 The structure shown has multiple sources and multiple drains.

[0040] In one embodiment of this application, such as Figure 2 As shown, the third switch module 13 includes a fifth resistor R5, a sixth resistor R6, a second capacitor C2, a fourth switch Q4, and a fifth switch Q5. The first end of the fifth resistor R5 is connected to the first switch module 11, the second switch module 12, the first diode module 14, and the first end of the power switching circuit 10. The second end of the fifth resistor R5 is connected to the first end of the second capacitor C2, the first end of the sixth resistor R6, the control end of the fourth switch Q4, and the control end of the fifth switch Q5. The first conducting end of the fourth switch Q4 is connected to the first conducting end of the fifth switch Q5. The second conducting end of the fourth switch Q4 is connected to the second end of the second capacitor C2, the third end of the power switching circuit 10, and the second diode module 15. The second conducting end of the fifth switch Q5 is connected to the second switch module 12, the first diode module 14, the second diode module 15, and the load 40. The second end of the sixth resistor R6 and the fourth end of the power switching circuit 10 are both grounded. In this embodiment, both the fourth switch Q4 and the fifth switch Q5 are PMOS transistors. The control terminals of the fourth switch Q4 and the fifth switch Q5 are the gates of the PMOS transistors, the first conducting terminals of the fourth switch Q4 and the fifth switch Q5 are the drains of the PMOS transistors, and the second conducting terminals of the fourth switch Q4 and the fifth switch Q5 are the sources of the PMOS transistors.

[0041] Specifically, when the first power supply 20 is connected to the third terminal of the power switching circuit 10, and the second and third terminals of the power switching circuit 10 are not connected to the second power supply 30, the fourth switch Q4 and the fifth switch Q5 will conduct after a certain delay. When the second power supply 30 is connected to the first and second terminals of the power switching circuit 10, the second power supply 30 will pull up the voltage at the control terminals of the fourth switch Q4 and the fifth switch Q5, controlling the fourth switch Q4 and the fifth switch Q5 to turn off. The second capacitor C2 is used to pull up the voltage at the control terminals of the fourth switch Q4 and the fifth switch Q5 at the instant the first power supply 20 is powered on, utilizing the characteristic that the voltage across a capacitor cannot change abruptly, thus putting the fourth switch Q4 and the fifth switch Q5 in an off state. After a certain delay, the fourth switch Q4 and the fifth switch Q5 will conduct, thus ensuring that the second diode module 15 conducts first, followed by the second switch Q2 and the third switch Q3.

[0042] It should be noted that the third switching module 13 uses two switching transistors connected in series, and the body diodes of the two transistors are in opposite directions to prevent reverse current flow. It should also be noted that the fourth switching transistor Q4 and the fifth switching transistor Q5 employ [a specific design / mechanism] to accommodate high current conditions. Figure 2 The structure shown has multiple sources and multiple drains.

[0043] In one embodiment of this application, such as Figure 2 As shown, the first diode module 14 includes a first diode D1. The anode of the first diode D1 is connected to the first terminal of the first switch module 11, the second switch module 12, the third switch module 13, and the power switching circuit 10, respectively. The cathode of the first diode D1 is connected to the second switch module 12, the third switch module 13, the second diode module 15, and the load 40, respectively. For example, the first diode D1 is a Schottky diode.

[0044] Specifically, when the second power supply 30 is connected to the first and second terminals of the power switching circuit 10, the second power supply 30 first supplies power to the load 40 through the first diode D1. However, since the first diode D1 has a forward conduction voltage, it will generate heat under high current conditions and is not suitable for long-term conduction. After a second period, the second switch Q2 and the third switch Q3 conduct, allowing the second power supply 30 to supply power to the load 40 through the second switch Q2 and the third switch Q3. Since the internal resistance of the second switch Q2 and the third switch Q3 is very small after conduction, the load voltage and the second power supply voltage are very close. At this time, the first diode D1 enters the cutoff state because the voltage across its terminals does not meet the forward conduction condition, thus solving the problem of heat generation caused by high current flowing through the first diode D1. This not only reduces the losses of the power switching circuit 10 but also improves the stability of the power switching circuit 10.

[0045] In one embodiment of this application, such as Figure 2 As shown, the second diode module 15 includes a second diode D2. The positive terminal of the second diode D2 is connected to the third terminal of the third switch module 13 and the power switching circuit 10, respectively. The negative terminal of the second diode D2 is connected to the third switch module 13, the second switch module 12, the first diode module 14, and the load 40, respectively. For example, the second diode D2 is a Schottky diode.

[0046] Specifically, when the first power supply 20 is connected to the third and fourth terminals of the power switching circuit 10, the first power supply 20 first supplies power to the load through the second diode D2. However, since the second diode D2 has a forward conduction voltage, it will generate heat under high current conditions and is not suitable for long-term conduction. After the first time, the fourth switch Q4 and the fifth switch Q5 turn on, allowing the first power supply 20 to supply power to the load 40 through the fourth switch Q4 and the fifth switch Q5. Since the internal resistance of the fourth switch Q4 and the fifth switch Q5 is very small after conduction, the load voltage and the first power supply voltage are very close. At this time, the second diode D2 enters the cutoff state because the voltage across its terminals does not meet the forward conduction condition, thus solving the problem of heat generation caused by the large current flowing through the second diode D2. This not only reduces the losses of the power switching circuit 10 but also improves the stability of the power switching circuit 10.

[0047] In one embodiment of this application, such as Figure 3 As shown, the power switching circuit 10 also includes an overcurrent protection module 16, which is connected to the first diode module 14, the second switch module 12, the third switch module 13, the second diode module 15, and the load 40. Specifically, the overcurrent protection module 16 is used to implement overcurrent protection.

[0048] In one embodiment of this application, such as Figure 4As shown, the overcurrent protection module 16 includes a fuse. The first end of the fuse is connected to the first diode module 14, the second switch module 12, the third switch module 13, and the second diode module 15, respectively. The second end of the fuse is used to connect to the load 40. Specifically, the fuse is used to implement overcurrent protection. When the current in the circuit exceeds the rated current of the fuse due to a short circuit in the load 40 or other reasons, the fuse will quickly melt, thereby cutting off the connection between the load 40 and the preceding circuit (i.e., the diode module and the switch module), preventing a large current from continuously flowing through the preceding circuit and the load 40, and preventing the devices from burning out or being damaged due to overheating.

[0049] The following is based on Figure 4 Explanation of how this application works: When the third and fourth terminals of the power switching circuit 10 are connected to the first power supply 20, the second diode D2 conducts first, and the first power supply 20 supplies power to the load 40 through the second diode D2, forming the initial power supply. However, since the second diode D2 has a forward conduction voltage, it will generate heat under high current conditions and is not suitable for long-term conduction. Since the first and second terminals of the power switching circuit 10 are not connected to the second power supply 30, after a certain delay, the fourth switch Q4 and the fifth switch Q5 conduct, allowing the first power supply 20 to supply power to the load 40 through the fourth switch Q4 and the fifth switch Q5. Since the internal resistance of the fourth switch Q4 and the fifth switch Q5 is very small after conduction, the load voltage and the first power supply voltage are very close. At this time, the second diode D2 enters the cutoff state because the voltage across its terminals does not meet the forward conduction condition, thus solving the problem of heat generation caused by high current flowing through the second diode D2. This not only reduces the losses of the power switching circuit 10 but also improves its stability.

[0050] When the first and second terminals of the power switching circuit 10 are connected to the second power supply 30, the first diode D1 conducts first, and the second power supply 30 supplies power to the load 40 through the first diode D1. However, since the first diode D1 has a forward conduction voltage, it will generate heat under high current conditions and is not suitable for long-term conduction.

[0051] Simultaneously, the second power supply 30 pulls up the voltage at the control terminals of the fourth and fifth switching transistors Q4 and Q5 through the fifth resistor R5, thus disconnecting the fourth and fifth switching transistors Q4 and Q5, and stopping the first power supply 20 from supplying power. This ensures that the first power supply 20 has stopped supplying power when the second power supply 30 supplies power to the load 40, achieving seamless switching between the first and second power supplies 20. This solves the problem of untimely switching caused by the use of mutual exclusion control of switching devices to supply power to the load in traditional power switching circuits.

[0052] Meanwhile, the second power supply 30 pulls up the voltage at the control terminal of the first switching transistor Q1 through the first resistor R1, controlling the first switching transistor Q1 to conduct and output a low level. After a certain delay, the second switching transistor Q2 and the third switching transistor Q3 conduct under the control of the low level, so that the second power supply 30 supplies power to the load 40 through the second switching transistor Q2 and the third switching transistor Q3. Since the internal resistance of the second switching transistor Q2 and the third switching transistor Q3 is very small after conduction, the load voltage and the second power supply voltage are very close. At this time, the first diode D1 enters the cutoff state because the voltage across its two ends does not meet the forward conduction condition, thus solving the problem of heat generation caused by large current flowing through the first diode D1. This not only reduces the loss of the power switching circuit 10, but also improves the stability of the power switching circuit 10.

[0053] In summary, the power switching circuit 10 provided in this application uses a combination of diodes and switching transistors to supply power to the load 40 by first turning on the diodes and then transitioning to turning on the switching transistors. At the same time, it ensures that the original power supply is disconnected only after the other power supply is turned on, which effectively solves the problems of poor stability, high loss and untimely switching in current power switching circuits. Furthermore, the overall circuit structure of this application is simple and does not require the use of mechanical switches.

[0054] This application also provides an electronic device including the power switching circuit described above. Since the electronic device provided in this application adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated upon here. The electronic device provided in this application can be any electronic device including the power switching circuit described above.

[0055] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A power switching circuit, characterized in that, It includes a first switch module, a second switch module, a third switch module, a first diode module, and a second diode module. The first switch module is connected to the second switch module, the third switch module, the first diode module, and the first and second terminals of the power switching circuit. The second switch module is connected to the first switch module, the first diode module, the second diode module, the third switch module, and the load. The third switch module is connected to the second diode module and the third and fourth terminals of the power switching circuit. When the third and fourth terminals of the power switching circuit are connected to the first power source, the first power source supplies power to the load through the second diode module. After a first time, the third switch module is turned on, allowing the first power source to supply power to the load through the third switch module. When the first and second terminals of the power switching circuit are connected to the second power source, the second power source supplies power to the load through the first diode module. The third switch module is used to disconnect according to the second power source voltage, and the first switch module is used to turn on according to the second power source voltage and output a first level signal. After a second time, the second switch module is used to turn on according to the first level signal, allowing the second power source to supply power to the load through the second switch module.

2. The power switching circuit according to claim 1, characterized in that, The first switching module includes a first resistor, a second resistor, a third resistor, and a first switching transistor. The first end of the first resistor is connected to the first end of the third resistor, the first end of the power switching circuit, the second switching module, the third switching module, and the first diode module. The second end of the first resistor is connected to the first end of the second resistor and the control end of the first switching transistor. The second end of the third resistor is connected to the first conducting end of the first switching transistor and the second switching module. The second end of the second resistor, the second conducting end of the first switching transistor, and the second end of the power switching circuit are all grounded.

3. The power switching circuit according to claim 2, characterized in that, The second switching module includes a fourth resistor, a first capacitor, a second switching transistor, and a third switching transistor. The first end of the fourth resistor is connected to the first switching module. The second end of the fourth resistor is connected to the first end of the first capacitor, the control end of the second switching transistor, and the control end of the third switching transistor. The first conducting end of the second switching transistor is connected to the first conducting end of the third switching transistor. The second conducting end of the second switching transistor is connected to the second end of the first capacitor, the first switching module, the third switching module, the first diode module, and the first end of the power switching circuit. The second conducting end of the third switching transistor is connected to the first diode module, the second diode module, the third switching module, and the load.

4. The power switching circuit according to claim 3, characterized in that, The third switching module includes a fifth resistor, a sixth resistor, a second capacitor, a fourth switching transistor, and a fifth switching transistor. The first end of the fifth resistor is connected to the first switching module, the second switching module, the first diode module, and the first end of the power switching circuit. The second end of the fifth resistor is connected to the first end of the second capacitor, the first end of the sixth resistor, the control end of the fourth switching transistor, and the control end of the fifth switching transistor. The first conducting end of the fourth switching transistor is connected to the first conducting end of the fifth switching transistor. The second conducting end of the fourth switching transistor is connected to the second end of the second capacitor, the third end of the power switching circuit, and the second diode module. The second conducting end of the fifth switching transistor is connected to the second switching module, the first diode module, the second diode module, and the load. The second end of the sixth resistor and the fourth end of the power switching circuit are both grounded.

5. The power switching circuit according to claim 4, characterized in that, The first switch is an NMOS transistor, while the second, third, fourth, and fifth switches are all PMOS transistors.

6. The power switching circuit according to claim 1, characterized in that, The first diode module includes a first diode, the anode of which is connected to the first terminal of the first switch module, the second switch module, the third switch module and the power switching circuit, respectively, and the cathode of which is connected to the second switch module, the third switch module, the second diode module and the load, respectively.

7. The power switching circuit according to claim 1, characterized in that, The second diode module includes a second diode, the positive terminal of which is connected to the third terminal of the third switch module and the third terminal of the power switching circuit, and the negative terminal of which is connected to the third switch module, the second switch module, the first diode module and the load.

8. The power switching circuit according to any one of claims 1-7, characterized in that, The power switching circuit further includes an overcurrent protection module, which is connected to the first diode module, the second switch module, the third switch module, the second diode module, and the load, respectively. The overcurrent protection module is used to implement overcurrent protection.

9. The power switching circuit according to claim 8, characterized in that, The overcurrent protection module includes a fuse, the first end of which is connected to the first diode module, the second switch module, the third switch module, and the second diode module, respectively, and the second end of which is connected to the load.

10. An electronic device, characterized in that, Includes the power switching circuit as described in any one of claims 1-9.

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