Power supply circuit and electronic device

Abstract

The present application provides a power supply circuit and an electronic device. The power supply circuit includes a main power connection terminal, a backup power connection terminal, a power supply output terminal, a main power control switch, a main power detection circuit, a main power control circuit, a backup power control switch, a backup power detection circuit, and a backup power control circuit. The main power detection circuit is used to detect the current flowing through the main power control switch and output a first electrical signal; the main power control circuit is used to receive the first electrical signal and control the on / off of the main power control switch according to the first electrical signal; the backup power detection circuit is used to detect the current flowing through the backup power control switch and output a second electrical signal; the backup power control circuit is used to receive the second electrical signal and control the on / off of the backup power control switch according to the second electrical signal and the voltage of the main power supply. By detecting the currents of the main power control switch and the backup power control switch and controlling the on / off of the main power control switch and the backup power control switch, seamless switching between the main power and the backup power is achieved, which is stable and reliable.

Description

Technical Field

[0001] This application relates to the field of electronic technologies, and particularly to a power supply circuit and an electronic device. Background Art

[0002] With the development of technologies and the continuous application of Internet technologies, various electronic devices are capable of maintaining real-time online status or going offline after working for a certain period of time. At the same time, energy management has put forward higher requirements for the power consumption of electronic devices in standby mode. More and more electronic devices use main power and backup power for switched power supply. How to achieve stable switching between main and backup power requires improvement in technology. Summary of the Invention

[0003] This application provides a power supply circuit and an electronic device with stable main-backup power switching.

[0004] This application provides a power supply circuit, including:

[0005] A main power connection terminal for electrically connecting to a main power supply;

[0006] A backup power connection terminal for electrically connecting to a backup power supply;

[0007] A power supply output terminal electrically connected to the main power connection terminal and the backup power connection terminal, and the power supply output terminal is used to output a voltage to supply power to a power receiving system;

[0008] A main power control switch electrically connected between the main power connection terminal and the power supply output terminal;

[0009] A main power detection circuit electrically connected to the main power control switch, and the main power detection circuit is used to detect the current flowing through the main power control switch and output a first electrical signal;

[0010] A main power control circuit electrically connected to the main power control switch and the main power detection circuit, and the main power control circuit is used to receive the first electrical signal and control the on / off of the main power control switch according to the first electrical signal;

[0011] A backup power control switch electrically connected between the backup power connection terminal and the power supply output terminal;

[0012] A backup power detection circuit electrically connected to the backup power control switch, and the backup power detection circuit is used to detect the current flowing through the backup power control switch and output a second electrical signal; and

[0013] A backup power control circuit electrically connected to the backup power control switch, the backup power detection circuit, and the main power connection terminal, and the backup power control circuit is used to receive the second electrical signal and control the on / off of the backup power control switch according to the second electrical signal and the voltage of the main power supply.

[0014] Optionally, the main power control switch includes a main power transistor and a main power body diode connected in parallel with the main power transistor. The conduction direction of the main power body diode is consistent with the direction of the current passing through the main power connection terminal.

[0015] The backup power control switch includes a backup power transistor and a backup power body diode connected in parallel with the backup power transistor. The conduction direction of the backup power body diode is consistent with the direction of the current passing through the backup power connection terminal.

[0016] Optionally, during the power-down process of the main power supply, the main power control circuit is configured to control the main power transistor to turn off when the current flowing through the main power control switch corresponding to the first electrical signal is less than the main power turn-off current threshold, and the backup power control circuit is configured to control the backup power transistor to remain off when the voltage of the main power supply is greater than the first voltage threshold; when the voltage of the main power supply is not greater than the first voltage threshold and the current flowing through the backup power control switch corresponding to the second electrical signal is greater than the backup power turn-on current threshold, control the backup power transistor to turn on, so that the backup power connection terminal supplies power to the power supply output terminal through the backup power transistor.

[0017] Optionally, during the power-up process of the main power supply, the backup power control circuit is configured to control the backup power transistor to turn off when the voltage of the main power supply is greater than the second voltage threshold, and the main power control circuit is configured to control the main power transistor to remain off when the current flowing through the main power control switch corresponding to the first electrical signal is not greater than the main power turn-on current threshold; the main power control circuit is configured to control the main power control switch to turn on when the current flowing through the main power control switch corresponding to the first electrical signal is greater than the main power turn-on current threshold, so that the main power connection terminal supplies power to the power supply output terminal through the main power transistor;

[0018] Wherein, the main power turn-off current threshold is less than the main power turn-on current threshold, and the second voltage threshold is greater than the first voltage threshold.

[0019] Optionally, the main power connection terminal includes a main power high-voltage terminal and a main power low-voltage terminal. The main power detection circuit includes a main power detection resistor. The main power detection resistor is connected in series with the main power control switch to the main power low-voltage terminal, and the main power detection resistor is electrically connected to the main power control circuit.

[0020] Optionally, the backup power connection terminal includes a backup power high-voltage terminal and a backup power low-voltage terminal. The backup power detection circuit includes a backup power detection resistor. The backup power detection resistor is connected in series with the backup power control switch to the backup power low-voltage terminal, and the backup power detection resistor is electrically connected to the backup power control circuit.

[0021] Optionally, the main power connection terminal includes a main power high-voltage terminal and a main power low-voltage terminal. The main power detection circuit includes a main power detection resistor. The main power detection resistor is connected in series with the main power control switch to the main power high-voltage terminal, and the main power detection resistor is electrically connected to the main power control circuit.

[0022] Optionally, the backup power connection terminal includes a backup power high-voltage terminal and a backup power low-voltage terminal. The backup power detection circuit includes a backup power detection resistor. The backup power detection resistor is connected in series with the backup power control switch to the backup power high-voltage terminal, and the backup power detection resistor is electrically connected to the backup power control circuit.

[0023] Optionally, the power supply circuit further includes a voltage detection circuit. The voltage detection circuit is electrically connected to the main power connection terminal and the backup power control circuit. The voltage detection circuit is used to detect the voltage of the main power connection terminal and output a third electrical signal. The backup power control circuit is used to receive the third electrical signal and control the on / off of the backup power control switch according to the second electrical signal and the third electrical signal.

[0024] Optionally, the power supply circuit includes a power supply terminal. The voltage detection circuit includes a first operational amplifier. The first input terminal of the first operational amplifier is electrically connected to the main power connection terminal, and the second input terminal of the first operational amplifier is electrically connected to the power supply terminal. The first operational amplifier is used to detect the voltage of the main power connection terminal and output a third electrical signal.

[0025] Optionally, the voltage detection circuit further includes a first switching tube. The first switching tube is electrically connected between the first operational amplifier and the backup power control circuit. The first switching tube is controlled by the third electrical signal to control the backup power control circuit.

[0026] Optionally, the main power control circuit includes a main power signal conditioning circuit. The main power signal conditioning circuit is electrically connected to the main power detection circuit and the main power control switch, and is used to amplify the first electrical signal.

[0027] Optionally, the main power signal conditioning circuit includes a second operational amplifier. The first input terminal of the second operational amplifier is electrically connected to the main power detection circuit. The second input terminal of the second operational amplifier is electrically connected to the ground terminal and is used to amplify the first electrical signal.

[0028] Optionally, the main power control circuit further includes a main power comparison circuit. The main power comparison circuit is electrically connected between the main power signal conditioning circuit and the main power control switch. The main power comparison circuit includes a circuit for comparing a main power reference signal and the first electrical signal amplified by the main power signal conditioning circuit and outputting a first comparison signal.

[0029] Optionally, the main power control circuit further includes a first reference voltage dividing resistor; the main power comparison circuit includes a first comparator, a first input terminal of the first comparator is electrically connected to the first reference voltage dividing resistor, a second input terminal of the first comparator is electrically connected to an output terminal of the main power signal conditioning circuit, the first reference voltage dividing resistor is used for generating a main power reference signal, and the first comparator is used for comparing the main power reference signal and the first electric signal amplified by the main power signal conditioning circuit, and outputting a first comparison signal.

[0030] Optionally, the main power control circuit further includes a main power driving circuit, the main power driving circuit is electrically connected between the main power comparison circuit and the main power control switch; the main power driving circuit is used for driving the main power control switch to act according to the first comparison signal.

[0031] Optionally, the main power driving circuit includes a first diode, a positive electrode of the first diode is electrically connected to an output terminal of the main power comparison circuit, and a negative electrode of the first diode is electrically connected to the main power control switch.

[0032] Optionally, the main power driving circuit further includes a first discharging circuit, the first discharging circuit is electrically connected between the main power control switch and a grounding terminal; the first discharging circuit includes a first discharging resistor and a first discharging triode, the first discharging resistor is electrically connected between an emitter of the first discharging triode and the main power control switch, a base of the first discharging triode is electrically connected to the positive electrode of the first diode, and a collector of the first discharging triode is electrically connected to the grounding terminal.

[0033] Optionally, the backup power control circuit includes a backup power signal conditioning circuit, the backup power signal conditioning circuit is electrically connected to the backup power detection circuit and the backup power control switch, and is used for amplifying the second electric signal.

[0034] Optionally, the backup power signal conditioning circuit includes a third operational amplifier, a first input terminal of the third operational amplifier is electrically connected to the backup power detection circuit. A second input terminal of the third operational amplifier is electrically connected to the grounding terminal, and is used for amplifying the second electric signal.

[0035] Optionally, the backup power control circuit further includes a backup power comparison circuit, the backup power comparison circuit is electrically connected between the backup power signal conditioning circuit and the backup power control switch; the backup power comparison circuit includes a circuit for comparing a backup power reference signal and the second electric signal amplified by the backup power signal conditioning circuit, and outputting a second comparison signal.

[0036] Optionally, the backup power control circuit further includes a second reference voltage dividing resistor; the backup power comparison circuit includes a second comparator, a first input terminal of the second comparator is electrically connected to the second reference voltage dividing resistor, a second input terminal of the second comparator is electrically connected to an output terminal of the backup power signal conditioning circuit, the second reference voltage dividing resistor is configured to generate a backup power reference signal, and the second comparator is configured to compare the backup power reference signal with the first electrical signal amplified by the backup power signal conditioning circuit and output a first comparison signal.

[0037] Optionally, the backup power control circuit further includes a backup power driving circuit, the backup power driving circuit is electrically connected between the backup power comparison circuit and the backup power control switch; the power supply circuit further includes a voltage detection circuit, the voltage detection circuit is electrically connected to the main power connection terminal and the backup power driving circuit, the voltage detection circuit is configured to detect a voltage of the main power connection terminal and output a third electrical signal; the backup power driving circuit is configured to control on / off of the backup power control switch according to the second comparison signal and the third electrical signal.

[0038] Optionally, the backup power driving circuit includes a second diode, a positive electrode of the second diode is electrically connected to an output terminal of the backup power comparison circuit, and a negative electrode of the second diode is electrically connected to the backup power control switch.

[0039] Optionally, the backup power driving circuit further includes a second discharging circuit, the second discharging circuit is electrically connected between the backup power control switch and a ground terminal; the second discharging circuit includes a second discharging resistor and a second discharging triode, the second discharging resistor is electrically connected between an emitter of the second discharging triode and the backup power control switch, a base of the second discharging triode is electrically connected to a positive electrode of the diode, and a collector of the second discharging triode is electrically connected to the ground terminal.

[0040] The present application further provides an electronic device, including: a power receiving system, a main power supply, a backup power supply, and the power supply circuit according to any one of the above embodiments; the backup power supply is electrically connected to the power supply circuit and configured to provide a backup power voltage; the main power supply is electrically connected to the power supply circuit and configured to provide a main power voltage; the power supply circuit is electrically connected to the power receiving system and configured to supply power to the power receiving system.

[0041] The power supply circuit according to the embodiment of the present application uses a main power detection circuit to detect the current flowing through the main power control switch and outputs a first electrical signal. The main power control circuit controls the on / off of the main power control switch according to the first electrical signal; and uses a backup power detection circuit to detect the current flowing through the backup power control switch and outputs a second electrical signal. The backup power control circuit controls the on / off of the backup power control switch according to the second electrical signal and the voltage of the main power supply. By detecting the currents of the main power control switch and the backup power control switch and controlling the on / off of the main power control switch and the backup power control switch, seamless switching between the main power and the backup power is achieved, which is stable and reliable.

[0042] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. Brief Description of the Drawings

[0043] The drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0044] Figure 1 The principle block diagram of an embodiment of the electronic device according to the present application is shown.

[0045] Figure 2 As shown Figure 1 A partial circuit diagram of the power supply circuit shown.

[0046] Figure 3 As shown Figure 1 A circuit diagram of an embodiment of the main power control circuit of the power supply circuit shown.

[0047] Figure 4 As shown Figure 1 A circuit diagram of an embodiment of the backup power control circuit of the power supply circuit shown. Detailed Description of the Embodiments

[0048] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0049] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. Unless otherwise defined, the technical terms or scientific terms used in this application should have the ordinary meanings understood by those of ordinary skill in the art to which this application pertains. The terms "first", "second" and similar words used in the specification and claims of this application do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "a" or "an" do not denote a limitation of quantity, but mean that there is at least one. "Plurality" or "several" means two or more. Unless otherwise indicated, words such as "front", "rear", "lower" and / or "upper" are for convenience only and are not limited to one position or a spatial orientation. Words such as "comprising" or "including" mean that the elements or items appearing before "comprising" or "including" cover the elements or items listed after "comprising" or "including" and their equivalents, and do not exclude other elements or items. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, and may include electrical connections, whether direct or indirect.

[0050] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms "a", "the" and "said" used in this application and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The explanations of some of the terms involved in the embodiments of this application are as follows:

[0051] Main power: The main power supply for terminal devices such as controllers during normal operation, which mainly supplies power to the subsequent system after converting AC mains power into DC output.

[0052] Standby power: The backup power supply for terminal devices such as controllers, which supplies power to the subsequent system in case of abnormal main power. Generally, it is various types of batteries.

[0053] Main-standby power switching: For terminal devices such as controllers, when both main power and standby power exist, the main power is responsible for supplying power to the subsequent system. When the main power is abnormal, the standby power supplies power to the subsequent system. During the mutual switching process between main power and standby power supply, situations such as system power-off, mutual current backflow, and large current impact that may damage the system shall not occur.

[0054] The present application provides a power supply circuit, which includes a main power connection terminal, a backup power connection terminal, a power supply output terminal, a main power control switch, a main power detection circuit, a main power control circuit, a backup power control switch, a backup power detection circuit, and a backup power control circuit. The main power connection terminal is used for electrically connecting to a main power supply; the backup power connection terminal is used for electrically connecting to a backup power supply; the power supply output terminal is electrically connected to the main power connection terminal and the backup power connection terminal, and the power supply output terminal is used for outputting a voltage to supply power to a power receiving system; the main power control switch is electrically connected between the main power connection terminal and the power supply output terminal; the main power detection circuit is electrically connected to the main power control switch, and the main power detection circuit is used for detecting the current flowing through the main power control switch and outputting a first electrical signal; the main power control circuit is electrically connected to the main power control switch and the main power detection circuit, and the main power control circuit is used for receiving the first electrical signal and controlling the on / off of the main power control switch according to the first electrical signal; the backup power control switch is electrically connected between the backup power connection terminal and the power supply output terminal; the backup power detection circuit is electrically connected to the backup power control switch, and the backup power detection circuit is used for detecting the current flowing through the backup power control switch and outputting a second electrical signal; the backup power control circuit is electrically connected to the backup power control switch, the backup power detection circuit, and the main power connection terminal, and the backup power control circuit is used for receiving the second electrical signal and controlling the on / off of the backup power control switch according to the second electrical signal and the voltage of the main power supply.

[0055] The main power detection circuit is used for detecting the current flowing through the main power control switch and outputting a first electrical signal, and the main power control circuit controls the on / off of the main power control switch according to the first electrical signal; and the backup power detection circuit is used for detecting the current flowing through the backup power control switch and outputting a second electrical signal, and the backup power control circuit controls the on / off of the backup power control switch according to the second electrical signal and the voltage of the main power supply. By detecting the currents of the main power control switch and the backup power control switch and controlling the on / off of the main power control switch and the backup power control switch, seamless switching between the main power and the backup power is achieved, which is stable and reliable.

[0056] The power supply circuit and the electronic device of the present application will be described in detail below with reference to the accompanying drawings. Without conflict, the features in the following embodiments and implementation manners can be combined with each other.

[0057] Figure 1 The principle block diagram of an embodiment of the electronic device of the present application is shown. The electronic device includes a power supply circuit 10, a main power supply 20, a backup power supply 30, and a power receiving system 40. Among them, the backup power supply 30 is electrically connected to the power supply circuit 10 and is used for providing a backup power voltage. The main power supply 20 is electrically connected to the power supply circuit 10 and is used for providing a main power voltage. The power supply circuit 10 is electrically connected to the power receiving system 40 and is used for supplying power to the power receiving system 40.

[0058] As Figure 1As shown, the power supply circuit 10 includes a main power connection terminal 101, a backup power connection terminal 102, and a power supply output terminal 103. The main power connection terminal 101 is used for electrically connecting to the main power supply 20. The main power supply 20 can supply a main power voltage to the main power connection terminal 101. The backup power connection terminal 102 is used for electrically connecting to the backup power supply 30. The backup power supply 30 can supply a backup power voltage to the backup power connection terminal 102. The power supply output terminal 103 is electrically connected to the main power connection terminal 101 and the backup power connection terminal 102. The power supply output terminal 103 is used for outputting a voltage to supply power to the power receiving system 40. The main power supply 20 can supply power to the power receiving system 40 through the main power connection terminal 101. The backup power supply 30 can supply power to the power receiving system 40 through the backup power connection terminal 102.

[0059] In Figure 1 In the illustrated embodiment, the power supply circuit 10 includes a main power control switch 104, a main power detection circuit 105, and a main power control circuit 106. The main power control switch 104 is electrically connected between the main power connection terminal 101 and the power supply output terminal 103. The main power control switch 104 is used for controlling the on / off between the main power connection terminal 101 and the power supply output terminal 103. The main power detection circuit 105 is electrically connected to the main power control switch 104. The main power detection circuit 105 and the main power control switch 104 are connected in series between the main power connection terminal 101 and the power supply output terminal 103. The main power detection circuit 105 is used for detecting the current flowing through the main power control switch 104 and outputting a first electrical signal. The first electrical signal can be a voltage signal, reflecting the current flowing through the main power control switch 104. The main power control circuit 106 is electrically connected to the main power control switch 104 and the main power detection circuit 105. The main power control circuit 106 is electrically connected between the main power detection circuit 105 and the main power control switch 104. The main power control circuit 106 is used for receiving the first electrical signal and controlling the on / off of the main power control switch 104 according to the first electrical signal. When the first electrical signal indicates that the current flowing through the main power control switch 104 reaches a certain value, the main power control circuit 106 controls the main power control switch 104 to open, so that the main power supply 20 supplies the main power voltage to the power supply output terminal 103 through the main power connection terminal 101 to supply power to the power receiving system 40. Conversely, the main power control circuit 106 controls the main power control switch 104 to close.

[0060] In Figure 1In the illustrated embodiment, the power supply circuit 10 includes a backup power control switch 107, a backup power detection circuit 108, and a backup power control circuit 109. The backup power control switch 107 is electrically connected between the backup power connection terminal 102 and the power supply output terminal 103. The backup power control switch 107 is used to control the on / off between the backup power connection terminal 102 and the power supply output terminal 103. The backup power detection circuit 108 is electrically connected to the backup power control switch 107. The backup power detection circuit 108 and the backup power control switch 107 are connected in series between the backup power connection terminal 102 and the power supply output terminal 103. The backup power detection circuit 108 is used to detect the current flowing through the backup power control switch 107 and output a second electrical signal. The second electrical signal can be a voltage signal, reflecting the current flowing through the backup power control switch 107. The backup power control circuit 109 is electrically connected to the backup power control switch 107, the backup power detection circuit 108, and the main power connection terminal 101. The backup power control circuit 109 is electrically connected between the backup power detection circuit 108 and the backup power control switch 107 and is electrically connected to the main power connection terminal 101. The backup power control circuit 109 is used to receive the second electrical signal and control the on / off of the backup power control switch 107 according to the second electrical signal and the voltage of the main power supply 20. When the main power voltage is less than the backup power voltage and when the second electrical signal indicates that the current flowing through the backup power control switch 107 reaches a certain value, the backup power control circuit 109 controls the backup power control switch 107 to turn on, so that the backup power supply 30 supplies the backup power voltage to the power supply output terminal 103 through the backup power connection terminal 102 to supply power to the power receiving system 40. Conversely, when the main power voltage is greater than the backup power voltage, or when the second electrical signal indicates that the current flowing through the backup power control switch 107 does not reach a certain value, the backup power control circuit 109 controls the backup power control switch 107 to turn off.

[0061] In this way, the main power detection circuit 105 is used to detect the current flowing through the main power control switch 104 and output a first electrical signal, and the main power control circuit 106 controls the on / off of the main power control switch 104 according to the first electrical signal. And the backup power detection circuit 108 is used to detect the current flowing through the backup power control switch 107 and output a second electrical signal, and the backup power control circuit 109 controls the on / off of the backup power control switch 107 according to the second electrical signal and the voltage of the main power supply 20. By detecting the currents of the main power control switch and the backup power control switch and controlling the on / off of the main power control switch and the backup power control switch, seamless switching between the main power and the backup power is achieved, which is stable and reliable.

[0062] Figure 2 As shown Figure 1 The partial circuit diagram of the illustrated power supply circuit 10. Figure 3 As shown Figure 1 The circuit diagram of an embodiment of the main power control circuit 106 of the illustrated power supply circuit 10. Figure 4 As shown Figure 1 The circuit diagram of an embodiment of the backup power control circuit 109 of the illustrated power supply circuit 10.

[0063] In Figures 1 to 4 the illustrated embodiment, the main power control switch 104 includes a main power transistor 110 and a main power body diode 111 connected in parallel with the main power transistor 110. The conduction direction of the main power body diode 111 is the same as the current direction through the main power connection terminal 101. When the main power control circuit 106 controls the main power control switch 104 to conduct, it means controlling the main power transistor 110 to conduct. At this time, the main power supply 20 supplies the main power voltage to the power supply output terminal 103 through the main power transistor 110. When the main power control circuit 106 controls the main power control switch 104 to turn off, it means controlling the main power transistor 110 to turn off. At this time, the main power supply 20 supplies power to the power supply output terminal 103 through the main power body diode 111, or does not supply power. During this process, the conduction direction of the main power body diode 111 is the same as the current direction through the main power connection terminal 101. The current at the main power connection terminal 101 can flow through the main power body diode 111 and be supplied to the power supply output terminal 103. The current at the power supply output terminal 103 will not flow back to the main power connection terminal 101, which can avoid current backflow and is safe and reliable.

[0064] In Figures 1 to 4 the illustrated embodiment, the backup power control switch 107 includes a backup power transistor 112 and a backup power body diode 113 connected in parallel with the backup power transistor 112. The conduction direction of the backup power body diode 113 is the same as the current direction through the backup power connection terminal 102. When the backup power control circuit 109 controls the backup power control switch 107 to conduct, it means controlling the backup power transistor 112 to conduct. At this time, the backup power supply 30 supplies the backup power voltage to the power supply output terminal 103 through the backup power transistor 112. When the backup power control circuit 109 controls the backup power control switch 107 to turn off, it means controlling the backup power transistor 112 to turn off. At this time, the backup power supply 30 supplies power to the power supply output terminal 103 through the backup power body diode 113, or does not supply power. During this process, the conduction direction of the backup power body diode 113 is the same as the current direction through the backup power connection terminal 102. The current at the backup power connection terminal 102 can flow through the backup power body diode 113 and be supplied to the power supply output terminal 103. The current at the power supply output terminal 103 will not flow back to the backup power connection terminal 102, which can avoid current backflow and is safe and reliable.

[0065] When the main power supply voltage at the main power connection terminal 101 and the backup power supply voltage at the backup power connection terminal 102 exist simultaneously, the main power supply voltage at the main power connection terminal 101 takes precedence over the backup power supply voltage at the backup power connection terminal 102 to supply power to the power receiving system 40. When the main power supply voltage at the main power connection terminal 101 is insufficient to supply power to the power receiving system 40, it can be switched to the backup power supply current at the backup power connection terminal 102 to supply power to the power receiving system 40. During a stage (referred to as the intermediate stage or dead zone stage) in the process of switching between the main power supply and the backup power supply, both the main power control switch 104 and the backup power control switch 107 are in the closed state. In this case, the main power transistor 110 and the backup power transistor 112 are in the off state, while the main power body diode 111 and the backup power body diode 113 are in the opposite state, and the higher one of the main power supply voltage and the backup power supply voltage supplies power to the power receiving system 40.

[0066] When the main power supply voltage at the main power connection terminal 101 and the backup power supply voltage at the backup power connection terminal 102 exist simultaneously, only one of them supplies power to the power supply output terminal 103. For example, when the main power supply voltage at the main power connection terminal 101 supplies power to the power receiving system 40, the backup power control switch 107 is in the closed state. In this case, the backup power transistor 112 is in the off state, and due to the backup power body diode 113, the current at the power supply output terminal 103 cannot flow back to the backup power connection terminal 102, thus avoiding current backflow. Similarly, when the backup power supply current at the backup power connection terminal 102 supplies power to the power receiving system 40, the main power control switch 104 is in the closed state. In this case, due to the main power body diode 111, the current at the power supply output terminal 103 cannot flow back to the main power connection terminal 101.

[0067] With such a setting, it is applicable not only in the case of small current but also in the case of large current, and can avoid current backflow, is safe and reliable, and has a wide range of applications.

[0068] In Figures 1 to 4 In the illustrated embodiment, during the process of powering down the main power supply 20, it is switched from the main power connection terminal 101 to the backup power connection terminal 102. During the process of powering up the main power supply 20, it is switched from the backup power connection terminal 102 to the main power connection terminal 101.

[0069] In some embodiments, during the power-down process of the main power supply 20, the main power voltage output by the main power supply 20 decreases. At this time, the backup power supply 30 is normally powered. During the decrease of the main power voltage, the main power control circuit 106 is configured to control the main power transistor 110 to turn off when the current flowing through the main power control switch 104 corresponding to the first electrical signal is less than the main power-off current threshold ISET_L1, and the backup power control circuit 109 is configured to control the backup power transistor 112 to remain off when the voltage of the main power supply 20 is greater than the first voltage threshold VSET_L. At this time, the two body diodes are in an opposite state. It may be that the main power connection terminal 101 supplies power to the power-receiving system 40 through the main power body diode 111, or it may be that the backup power connection terminal 102 supplies power to the power-receiving system 40 through the backup power body diode 113. It depends on which voltage is higher. During this process, the main power voltage is still greater than the backup power voltage, and the main power voltage supplies power to the power-receiving system 40 through the main power body diode 111. During this process, since the main power transistor 110 is turned off, the main power body diode 111 conducts unidirectionally, and the backup power current cannot flow back to the main power control circuit 106. Since the backup power transistor 112 is turned off, the backup power body diode 113 conducts unidirectionally, and the main power current cannot flow back to the backup power supply 30, thus preventing current backflow.

[0070] The main power voltage continues to decrease. At this time, since the voltage of the main power supply 20 is greater than the first voltage threshold VSET_L, the backup power transistor 112 still remains off, and the two body diodes are still in an opposite state. The main power voltage drops below the backup power voltage. The current flowing through the backup power control switch 107 corresponding to the second electrical signal is not greater than the backup power conduction current threshold ISET_H2, and the backup power voltage supplies power to the power-receiving system 40 through the backup power body diode 113. The main power voltage continues to decrease. When the voltage of the main power supply 20 is not greater than the first voltage threshold VSET_L and the current flowing through the backup power control switch 107 corresponding to the second electrical signal is greater than the backup power conduction current threshold ISET_H2, the backup power transistor 112 is controlled to conduct, so that the backup power connection terminal 102 supplies power to the power supply output terminal 103 through the backup power transistor 112, thus completing the process of switching from main power supply to backup power supply.

[0071] In some embodiments, during the power-on process of the main power supply 20, the main power voltage output by the main power supply 20 rises. At this time, the backup power supply 30 supplies power normally. During the rise of the main power voltage, the backup power control circuit 109 is used to control the backup power transistor 112 to turn off when the voltage of the main power supply 20 is greater than the second voltage threshold VSET_H, and the main power control circuit 106 is used to control the main power transistor 110 to remain off when the current flowing through the main power control switch 104 corresponding to the first electrical signal is not greater than the main power conduction current threshold ISET_H1. During this process, the voltage of the main power supply 20 rises to a certain value (the second voltage threshold VSET_H), but the current of the main power supply 20 is not yet large enough. The backup power transistor 112 turns off, and the main power transistor 110 remains off. The two body diodes are in an opposing state. It is possible that the main power connection terminal 101 supplies power to the power receiving system 40 through the main power body diode 111, or it is also possible that the backup power connection terminal 102 supplies power to the power receiving system 40 through the backup power body diode 113. It depends on which voltage is higher. And during this process, when the voltage of the backup power supply 30 is higher than the voltage of the main power supply 20, the backup power supply 30 supplies power through the backup power body diode 113. The main power turn-off current threshold ISET_L1 is less than the main power conduction current threshold ISET_H1.

[0072] After that, the main power voltage continues to rise. When it is close to the voltage of the backup power supply 30 minus the voltage drop of the backup power body diode 113, the main power supply 20 supplies power through the main power body diode 111. The backup power current flowing through the backup power transistor 112 gradually decreases, while the main power current flowing through the main power transistor 110 begins to gradually increase. The main power control circuit 106 is used to control the main power control switch 104 to conduct when the current flowing through the main power control switch 104 corresponding to the first electrical signal is greater than the main power conduction current threshold ISET_H1, so that the main power connection terminal 101 supplies power to the power supply output terminal 103 through the main power transistor 110; wherein, the second voltage threshold VSET_H is greater than the first voltage threshold VSET_L. During this process, the main power current continues to rise. When it is greater than the main power conduction current threshold ISET_H1, the main power control circuit 106 controls the main power control switch 104 to conduct and supplies power to the power receiving system 40 through the main power transistor 110. In this way, the process of switching from backup power supply to main power supply is completed.

[0073] When the current flowing through the main power control switch 104 is greater than the main power conduction current threshold ISET_H1, the main power transistor 110 of the main power control switch 104 conducts, and the current no longer flows through the main power body diode 111, thereby reducing the loss of the main power transistor 110 under high power conditions. When the current flowing through the main power control switch 104 is less than the main power turn-off current threshold ISET_L1, the main power transistor 110 of the main power control switch 104 turns off, and the current continues to flow through the main power body diode 111, thereby avoiding the reverse flow of the current at the backup power connection terminal 102 to the main power connection terminal 101.

[0074] Regarding the control logic of the main power control switch 104, the on and off logic of the backup power control switch 107 adds the factor of the main power voltage of the main power supply 20.

[0075] If the main power voltage of the main power supply 20 is greater than the second voltage threshold VSET_H, the main power voltage of the main power supply 20 supplies power to the power receiving system 40 prior to the backup power voltage of the backup power supply 30. In this case, the backup power transistor 112 of the backup power control switch 107 is unconditionally turned off regardless of the magnitude of the current flowing through the backup power control switch 107, thereby ensuring the priority of the main power voltage to supply power to the power receiving system 40. If the main power voltage of the main power supply 20 is less than the first voltage threshold VSET_L, when the current flowing through the backup power control switch 107 is greater than the backup power conduction current threshold ISET_H2, the backup power transistor 112 of the backup power control switch 107 conducts, and the current no longer flows through the backup power body diode 113, thereby reducing the loss of the backup power transistor 112 under high power conditions. When the current flowing through the backup power control switch 107 is less than the backup power turn-off current threshold ISET_L2, the backup power transistor 112 of the backup power control switch 107 turns off, and the current continues to flow through the backup power body diode 113, thereby avoiding the reverse flow of the main power current at the main power connection terminal 101 to the backup power connection terminal 102. The backup power turn-off current threshold ISET_L2 is less than the backup power conduction current threshold ISET_H2.

[0076] It should be noted that in the above solution, when the main power voltage of the main power supply 20 supplies power normally, its main power voltage must be greater than the difference between the voltage of the backup power supply 30 and the voltage drop of the backup power body diode 113 of the backup power control switch 107. Such a setting ensures that when the main power voltage of the main power supply 20 supplies power normally, it supplies power prior to the backup power voltage of the backup power supply 30.

[0077] It should be noted that the main power conduction current threshold ISET_H1 and the backup power conduction current threshold ISET_H2 may be the same or different. The main power turn-off current threshold ISET_L1 and the backup power turn-off current threshold ISET_L2 may be the same or different. The above data can all be set through the circuit and are not limited in this application.

[0078] In Figure 2 In the illustrated embodiment, the main power connection terminal 101 includes a main power high-voltage terminal 1011 and a main power low-voltage terminal 1012. The main power control switch 104 is connected to the main power low-voltage terminal 1012. The negative electrode of the main power body diode 111 is connected to the main power low-voltage terminal 1012. The main power detection circuit 105 is connected to the main power low-voltage terminal 1012. The main power detection circuit 105 includes a main power detection resistor R3. The main power detection resistor R3 is connected in series with the main power control switch 104 to the main power low-voltage terminal 1012, and the main power detection resistor R3 is electrically connected to the main power control circuit 106. The main power detection resistor R3 is used to convert a current signal into a voltage signal, and the current is detected by detecting the voltage, and the circuit is simple. Since the main power detection resistor R3 is connected in series with the main power control switch 104 to the main power low-voltage terminal 1012, the voltage of the main power detection resistor R3 detected is negative. When the voltage on the main power detection resistor R3 decreases, the detected negative voltage value increases instead. Similarly, when the voltage on the main power detection resistor R3 increases, the detected negative voltage value decreases instead. In some other embodiments, the main power detection resistor R3 is connected in series with the main power control switch 104 to the main power high-voltage terminal 1011, and the main power detection resistor R3 is electrically connected to the main power control circuit 106. This is not limited in the present application.

[0079] In Figure 2 In the illustrated embodiment, the main power control switch 104 may be an N-type MOS transistor. The power supply circuit 10 further includes a zener diode D2, which is electrically connected between the gate and the source of the main power control switch 104, and is used to protect the voltages of the gate and the source of the main power control switch 104 from exceeding the device specifications, which is safe and reliable. The power supply circuit 10 further includes a resistor R11, which is connected in parallel with the zener diode D2 and electrically connected between the gate and the source of the main power control switch 104. The resistor R11 can provide a bias voltage for the main power control switch 104 and play a role in discharging to protect the gate and the source of the main power control switch 104.

[0080] In Figure 2In the illustrated embodiment, the backup power connection terminal 102 includes a backup power high-voltage terminal 1021 and a backup power low-voltage terminal 1022. The backup power control switch 107 is connected to the backup power low-voltage terminal 1022. The negative electrode of the backup power body diode 113 is connected to the backup power low-voltage terminal 1022. The backup power detection circuit 108 is connected to the backup power low-voltage terminal 1022. The backup power detection circuit 108 includes a backup power detection resistor R4. The backup power detection resistor R4 and the backup power control switch 107 are connected in series to the backup power low-voltage terminal 1022, and the backup power detection resistor R4 is electrically connected to the backup power control circuit 109. The backup power detection resistor R4 is used to convert the current signal into a voltage signal and detect the current by detecting the voltage, and the circuit is simple. Since the backup power detection resistor R4 and the backup power control switch 107 are connected in series to the backup power low-voltage terminal 1022, the detected voltage of the backup power detection resistor R4 is negative. When the voltage on the backup power detection resistor R4 decreases, the detected negative voltage value increases instead. Similarly, when the voltage on the backup power detection resistor R4 increases, the detected negative voltage value decreases instead. In some other embodiments, the backup power detection resistor R4 and the backup power control switch 107 are connected in series to the backup power high-voltage terminal 1021, and the backup power detection resistor R4 is electrically connected to the backup power control circuit 109. This is not limited in the present application.

[0081] In Figure 1 and Figure 2 the illustrated embodiment, the backup power control switch 107 can be an N-type MOS transistor. The power supply circuit 10 further includes a zener diode D3, which is electrically connected between the gate and the source of the backup power control switch 107 and is used to protect the voltages of the gate and the source of the backup power control switch 107 from exceeding the device specifications, which is safe and reliable. In Figure 2 the illustrated embodiment, the power supply circuit 10 further includes a resistor R12, which is connected in parallel with the zener diode D3 and electrically connected between the gate and the source of the backup power control switch 107. The resistor R12 can provide a bias voltage for the backup power control switch 107 and play a role in discharging to protect the gate and the source of the backup power control switch 107.

[0082] In Figures 1 to 3In the illustrated embodiment, the main power control circuit 106 includes a main power signal conditioning circuit 114. The main power signal conditioning circuit 114 is electrically connected to the main power detection circuit 105 and the main power control switch 104, and is used to amplify the first electrical signal CUR_M. The main power signal conditioning circuit 114 includes a second operational amplifier U23A. The first input terminal of the second operational amplifier U23A is electrically connected to the main power detection circuit 105. The second input terminal of the second operational amplifier U23A is electrically connected to the ground terminal GND. In this embodiment, the first input terminal of the second operational amplifier U23A may be the non-inverting input terminal. The second input terminal of the second operational amplifier U23A may be the inverting input terminal. The second operational amplifier U23A is used to amplify and bias the first electrical signal CUR_M. The power supply terminal of the second operational amplifier U23A is electrically connected to VCC_3.3V. The non-inverting input terminal of the second operational amplifier U23A is electrically connected to the main power detection circuit 105 through a resistor R61. The inverting input terminal of the second operational amplifier U23A is electrically connected to the ground terminal through a resistor R55. The main power signal conditioning circuit 114 further includes a resistor R66, which is electrically connected between the inverting input terminal and the output terminal of the second operational amplifier U23A. The main power signal conditioning circuit 114 further includes a resistor R41 and a resistor R45, which are serially connected between the power supply terminal of the second operational amplifier U23A and the non-inverting input terminal of the second operational amplifier U23A, and the resistor R45 is closer to the non-inverting input terminal of the second operational amplifier U23A than the resistor R41. The main power signal conditioning circuit 114 further includes a resistor R44, which is electrically connected between the resistor R45 and the ground terminal GND. The main power signal conditioning circuit 114 further includes a capacitor C48, and the capacitor C48 is connected in parallel with the resistor R44 between the resistor R45 and the ground terminal GND. The main power signal conditioning circuit 114 further includes a capacitor C50, which is electrically connected between the power supply terminal of the second operational amplifier U23A and the ground terminal GND.

[0083] When the first electrical signal CUR_M is at a low level, the output of the non-inverting input terminal of the second operational amplifier U23A is a bias voltage. Since the resistance values of the resistors R41 and R44 are much smaller than the resistance values of the resistors R61 and R45, this bias voltage may be the voltage division of the resistors R61 and R45. When the first electrical signal CUR_M is at a high level, the output of the non-inverting input terminal of the second operational amplifier U23A is an amplified voltage, and its amplification ratio is the ratio of the resistance values of the resistors R45 and R66. With such a setting, regardless of whether the first electrical signal CUR_M is at a low level or a high level, there will be an output voltage at the output terminal of the second operational amplifier U23A.

[0084] In Figures 1 to 3In the illustrated embodiment, the main power control circuit 106 further includes a main power comparison circuit 115, and the main power comparison circuit 115 is electrically connected between the main power signal conditioning circuit 114 and the main power control switch 104. The main power comparison circuit 115 includes a component for comparing a main power reference signal and a first electrical signal CUR_M amplified by the main power signal conditioning circuit 114, and outputting a first comparison signal. The main power comparison circuit 115 includes a first comparator U21A. The first input terminal of the first comparator U21A is electrically connected to a first reference voltage dividing resistor (resistor R47 and a first discharge resistor R62), and the second input terminal of the first comparator U21A is electrically connected to the output terminal of the main power signal conditioning circuit 114. In this embodiment, the first input terminal of the first comparator U21A may be the non-inverting input terminal, and the second input terminal of the first comparator U21A may be the inverting input terminal. The first reference voltage dividing resistor (resistor R47 and the first discharge resistor R62) is used to generate the main power reference signal, and the first comparator U21A is used to compare the main power reference signal and the first electrical signal CUR_M amplified by the main power signal conditioning circuit 114, and output a first comparison signal. The power supply terminal of the first comparator U21A is electrically connected to the power supply terminal VCC_12V. The non-inverting input terminal of the second operational amplifier U23A is electrically connected through a voltage dividing node of the resistor R58, the first reference voltage dividing resistor R47 and the first discharge resistor R62. The first reference voltage dividing resistor R47 and the first discharge resistor R62 are electrically connected between the power supply terminal VCC_12V and the ground terminal GND. The inverting input terminal of the second operational amplifier U23A is electrically connected to the output terminal of the main power signal conditioning circuit 114 through the resistor R59. The main power control circuit 106 further includes a resistor R43, which is electrically connected between the non-inverting input terminal and the output terminal of the second operational amplifier U23A. The main power control circuit 106 further includes a capacitor C51, which is connected in parallel with the first discharge resistor R62. Among them, the signal after voltage division by the first reference voltage dividing resistor R47 and the first discharge resistor R62 is used as the main power reference signal.

[0085] In some embodiments, the second operational amplifier U23A may be a hysteresis comparator. The hysteresis comparator can not only compare the main power reference signal and the first electrical signal CUR_M amplified by the main power signal conditioning circuit 114, but also set an upper voltage threshold and a lower voltage threshold through components electrically connected to the second operational amplifier U23A, so as to set a main power conduction current threshold ISET_H1 and a main power turn-off current threshold ISET_L1.

[0086] In this embodiment, if the amplified first electrical signal CUR_M is greater than the main power reference signal, the output of the main power control circuit 106 is at a low level. If the amplified first electrical signal CUR_M is less than the main power reference signal, the output of the main power control circuit 106 is at a high level. In this way, the first comparison signal can be determined.

[0087] In Figures 1 to 3 In the illustrated embodiment, the main power control circuit 106 further includes a main power driving circuit 116. The main power driving circuit 116 is electrically connected between the main power comparison circuit 115 and the main power control switch 104. The main power driving circuit 116 is configured to drive the main power control switch 104 to act according to the first comparison signal. The main power driving circuit 116 includes a first diode D7. The positive electrode of the first diode D7 is electrically connected to the output terminal of the main power comparison circuit 115, and the negative electrode of the first diode D7 is electrically connected to the main power control switch 104. The main power driving circuit 116 further includes a resistor R51, which is electrically connected between the positive electrode of the first diode D7 and the power supply terminal VCC_12V. The main power driving circuit 116 further includes a first discharging circuit. The first discharging circuit includes a first discharging resistor R62 and a first discharging triode Q5. The first discharging resistor R62 is electrically connected between the emitter of the first discharging triode Q5 and the main power control switch 104. The base of the first discharging triode Q5 is electrically connected to the positive electrode of the first diode D7, and the collector of the first discharging triode Q5 is electrically connected to the ground terminal GND. When the first comparison signal is at a high level, the main power control switch 104 can be driven to conduct. When the first comparison signal is at a low level, the main power control switch 104 can be driven to turn off. Since the load driving capacity of the first comparator U21A is relatively limited, directly driving the main power control switch 104 will cause the main power control switch 104 to fail to turn off in time, resulting in current backflow. Therefore, a driving circuit based on the first discharging triode Q5 is added. When U21A outputs a low level, the first discharging triode Q5 conducts, and the voltage on the gate and source of the main power control switch 104 is quickly discharged through the first discharging resistor R62, thereby accelerating the turn-off.

[0088] In Figures 1 to 2 and Figure 4 In the illustrated embodiment, the backup power control circuit 109 includes a backup power signal conditioning circuit 118. The backup power signal conditioning circuit 118 is electrically connected to the backup power detection circuit 108 and the backup power control switch 107, and is configured to amplify the second electrical signal CUR_B. The backup power signal conditioning circuit 118 includes a third operational amplifier U23B. The first input terminal of the third operational amplifier U23B is electrically connected to the backup power detection circuit 108. The second input terminal of the third operational amplifier U23B is electrically connected to the ground terminal GND. In this embodiment, the first input terminal of the third operational amplifier U23B may be the non-inverting input terminal, and the second input terminal of the third operational amplifier U23B may be the inverting input terminal. The third operational amplifier U23B is configured to amplify and bias the second electrical signal CUR_B. The power supply terminal of the third operational amplifier U23B is electrically connected to VCC_3.3V.

[0089] The non-inverting input terminal of the third operational amplifier U23B is electrically connected to the backup power detection circuit 108 through a resistor R56.

[0090] The inverting input terminal of the third operational amplifier U23B is electrically connected to the ground terminal GND through a resistor R60. The backup power signal conditioning circuit 118 further includes a resistor R67, which is electrically connected between the inverting input terminal and the output terminal of the third operational amplifier U23B. The backup power signal conditioning circuit 118 further includes a resistor R49 and a resistor R42, which are serially connected between the power supply terminal of the third operational amplifier U23B and the non-inverting input terminal of the third operational amplifier U23B, and the resistor R49 is closer to the non-inverting input terminal of the third operational amplifier U23B than the resistor R42. The backup power signal conditioning circuit 118 further includes a resistor R48, which is electrically connected between the resistor R49 and the ground terminal GND. The backup power signal conditioning circuit 118 further includes a capacitor C49, and the capacitor C49 is connected in parallel with the resistor R48 between the resistor R49 and the ground terminal GND.

[0091] When the second electrical signal CUR_B is at a low level, the output of the non-inverting input terminal of the third operational amplifier U23B is a bias voltage. Since the resistance values of the resistors R42 and R48 are much smaller than the resistance values of the resistors R56 and R49, this bias voltage can be the voltage division of the resistors R56 and R49. When the second electrical signal CUR_B is at a high level, the output of the non-inverting input terminal of the third operational amplifier U23B is an amplified voltage, and its amplification ratio is the ratio of the resistance values of the resistor R49 and the resistor R67. With such a setting, regardless of whether the second electrical signal CUR_B is at a low level or a high level, there will be an output voltage at the output terminal of the second operational amplifier U23A.

[0092] In some embodiments, the backup power control circuit 109 further includes a backup power comparison circuit 119, which is electrically connected between the backup power signal conditioning circuit 118 and the backup power control switch 107. The backup power comparison circuit 119 includes a component for comparing a backup power reference signal and a second electrical signal amplified by the backup power signal conditioning circuit 118, and outputting a second comparison signal CUR_B. The backup power comparison circuit 119 includes a second comparator U21B. The first input terminal of the second comparator U21B is electrically connected to a second reference voltage dividing resistor (resistors R50 and R65). The second input terminal of the second comparator U21B is electrically connected to the output terminal of the backup power signal conditioning circuit 118. In this embodiment, the first input terminal of the second comparator U21B can be the non-inverting input terminal, and the inverting input terminal of the second comparator U21B. The second reference voltage dividing resistor (resistors R50 and R65) is used to generate the backup power reference signal. The second comparator U21B is used to compare the backup power reference signal and the second electrical signal CUR_B amplified by the backup power signal conditioning circuit 118, and output a second comparison signal. The power supply terminal of the second comparator U21B is electrically connected to the power supply terminal VCC_12V. The non-inverting input terminal of the third operational amplifier U23B is electrically connected through a resistor R54 to the voltage dividing node of the second reference voltage dividing resistor R50 and resistor R65. The voltage dividing resistors R50 and R652 are electrically connected between the power supply terminal VCC_12V and the ground terminal GND. The inverting input terminal of the third operational amplifier U23B is electrically connected through a resistor R57 to the output terminal of the backup power signal conditioning circuit 118. The backup power control circuit 109 further includes a resistor R52, which is electrically connected between the non-inverting input terminal and the output terminal of the third operational amplifier U23B. The backup power control circuit 109 further includes a capacitor C52, which is connected in parallel with the resistor R65. Among them, the signal after voltage division by the voltage dividing resistors R50 and R65 serves as the backup power reference signal.

[0093] In some embodiments, the third operational amplifier U23B can be a hysteresis comparator. The hysteresis comparator can not only compare the backup power reference signal and the second electrical signal CUR_B amplified by the backup power signal conditioning circuit 118, but also set an upper voltage threshold and a lower voltage threshold through components electrically connected to the third operational amplifier U23B, so as to set a backup power conduction current threshold ISET_H2 and a backup power turn-off current threshold ISET_L2.

[0094] In this embodiment, if the amplified second electrical signal CUR_B is greater than the backup power reference signal, the output of the backup power control circuit 109 is at a low level. If the amplified second electrical signal CUR_B is less than the backup power reference signal, the output of the backup power control circuit 109 is at a high level. In this way, the second comparison signal can be determined.

[0095] In some embodiments, the backup power control circuit 109 further includes a backup power driving circuit 120, and the backup power driving circuit 120 is electrically connected between the backup power comparison circuit 119 and the backup power control switch 107. The backup power driving circuit 120 is configured to control the on / off of the backup power control switch 107 according to the second comparison signal and the third electrical signal. The backup power driving circuit 120 includes a second diode D6, the positive electrode of the second diode D6 is electrically connected to the output terminal of the backup power comparison circuit 119, and the negative electrode of the second diode D6 is electrically connected to the backup power control switch 107. The backup power driving circuit 120 further includes a resistor R53, which is electrically connected between the positive electrode of the second diode D6 and the power supply terminal VCC_12V. The backup power driving circuit 120 further includes a second discharging circuit. The second discharging resistor includes a second discharging resistor R63 and a second discharging triode Q6. The second discharging resistor R63 is electrically connected between the emitter of the second discharging triode Q6 and the backup power control switch 107. The base of the second discharging triode Q6 is electrically connected to the positive electrode of the second diode D6, and the collector of the second discharging triode Q6 is electrically connected to the ground terminal GND. When the second comparison signal is at a high level, the backup power control switch 107 can be driven to conduct. When the second comparison signal is at a low level, the backup power control switch 107 can be driven to turn off. Since the load driving capacity of the first comparator U21A is relatively limited, directly driving the backup power control switch 107 will cause the backup power control switch 107 to fail to turn off in time, resulting in current backflow. Therefore, a driving circuit based on the second discharging triode Q6 is added. When U21A outputs a low level, the second discharging triode Q6 conducts, and the voltage on the gate and source of the backup power control switch 107 is quickly discharged through the second discharging resistor R63, thereby accelerating the turn-off.

[0096] The circuit structures of the backup power control circuit 109 and the main power control circuit 106 are similar. The difference is that the power supply circuit 10 further includes a voltage detection circuit 117. The voltage detection circuit 117 is configured to detect the main power voltage and jointly determine the on / off of the backup power control switch 107 in combination with the second electrical signal output by the backup power detection circuit 108.

[0097] In Figures 1 to 2 and Figure 4In the illustrated embodiment, the voltage detection circuit 117 is electrically connected to the main power connection terminal 101 and the backup power control circuit 109. The voltage detection circuit 117 is configured to detect the voltage of the main power connection terminal 101 and output a third electrical signal. The backup power control circuit 109 is configured to receive the third electrical signal and control the on / off state of the backup power control switch 107 according to the second electrical signal and the third electrical signal. The voltage detection circuit 117 includes a first operational amplifier U18A. The first input terminal of the first operational amplifier U18A is electrically connected to the main power connection terminal 101, and the second input terminal of the first operational amplifier U18A is electrically connected to the power supply terminal VCC_3.3V. The first operational amplifier U18A is configured to receive the voltage of the main power connection terminal 101 and output a third electrical signal. In this embodiment, the first input terminal of the first operational amplifier U18A may be the non-inverting input terminal, and the second input terminal of the first operational amplifier U18A may be the inverting input terminal. The power supply terminal of the first operational amplifier U18A is electrically connected to the power supply terminal VCC_3.3V. The non-inverting input terminal of the first operational amplifier U18A is electrically connected to the main power connection terminal 101 through a resistor R73. The inverting input terminal of the first operational amplifier U18A is electrically connected to the power supply terminal VCC_3.3V through a resistor R73 and a resistor R71. The voltage detection circuit 117 further includes a resistor R79, which is electrically connected between the resistor 74 and the ground terminal GND. The voltage detection circuit 117 further includes a capacitor C59, which is connected in parallel with the resistor R79 and electrically connected between the resistor 74 and the ground terminal GND. The voltage detection circuit 117 further includes a resistor R72, which is electrically connected between the non-inverting input terminal and the output terminal of the first operational amplifier U18A. The voltage detection circuit 117 further includes a first switching transistor. The first switching transistor is electrically connected between the first operational amplifier and the backup power control circuit, and the first switching transistor is controlled by the third electrical signal to control the backup power control circuit. In this embodiment, the first switching transistor is a triode Q8, and the base of the triode Q8 is connected to the output terminal of the first operational amplifier U18A through a resistor R75. The emitter of the triode Q8 is electrically connected to the ground terminal GND. The collector of the triode Q8 is electrically connected to the positive electrode of the second diode D6. The voltage detection circuit 117 further includes a resistor R78, which is electrically connected between the base and the emitter of the triode Q8. The voltage detection circuit 117 is configured to detect the main power voltage and output a third electrical signal. When the main power voltage is higher than the main power voltage threshold, the third electrical signal output by the first operational amplifier U18A is at a high level, driving the triode Q8 to conduct, and the second discharge triode Q6 to conduct. At this time, the backup power control switch 107 remains in the off state continuously.

[0098] In the above scheme, discrete devices can be used, and the application freedom is higher. Only by reasonably selecting MOS tubes, it can be applied to DC application scenarios of all voltage levels and current levels. Different devices are highly replaceable and less affected by the supply chain. Compared with relays, N-type MOS tubes are used as power devices for main and standby power switching to avoid noise during the switching process. When a small current is used, the main power diode 111 and the standby power diode 113 are switched to the top, and the large current main power transistor 110 or the standby power transistor 112 is turned on to achieve seamless main and standby power switching. There is no voltage drop during switching, and the heat loss is low in high current application scenarios. And the peripheral circuit is relatively simple, the device requirements are low, and the cost is low. The main and standby power switching is achieved by detecting the current using the main power detection circuit 105 and the standby power detection circuit 108. Compared with the main and standby power switching achieved by voltage detection, there will be no current backflow during the switching process, and it will not cause the problem of switching back and forth due to backflow.

[0099] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0100] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A power supply circuit, characterized in that, Comprising: A main power connection terminal for electrically connecting to a main power supply; A backup power connection terminal for electrically connecting to a backup power supply; A power supply output terminal electrically connected to the main power connection terminal and the backup power connection terminal, the power supply output terminal being used to output a voltage to supply power to a power receiving system; A main power control switch electrically connected between the main power connection terminal and the power supply output terminal; A main power detection circuit electrically connected to the main power control switch, the main power detection circuit being used to detect the current flowing through the main power control switch and output a first electrical signal; A main power control circuit electrically connected to the main power control switch and the main power detection circuit, the main power control circuit being used to receive the first electrical signal and control the on / off of the main power control switch according to the first electrical signal; A backup power control switch electrically connected between the backup power connection terminal and the power supply output terminal; A backup power detection circuit electrically connected to the backup power control switch, the backup power detection circuit being used to detect the current flowing through the backup power control switch and output a second electrical signal; And A backup power control circuit electrically connected to the backup power control switch, the backup power detection circuit, and the main power connection terminal, the backup power control circuit being used to receive the second electrical signal and control the on / off of the backup power control switch according to the second electrical signal and the voltage of the main power supply; Wherein, the main power control switch includes a main power transistor and a main power body diode connected in parallel with the main power transistor; the backup power control switch includes a backup power transistor and a backup power body diode connected in parallel with the backup power transistor; During the process of the main power supply losing power, the main power control circuit is used to control the main power transistor to turn off when the current flowing through the main power control switch corresponding to the first electrical signal is less than the main power turn-off current threshold, and the backup power control circuit is used to control the backup power transistor to remain off when the voltage of the main power supply is greater than the first voltage threshold; when the voltage of the main power supply is not greater than the first voltage threshold and the current flowing through the backup power control switch corresponding to the second electrical signal is greater than the backup power turn-on current threshold, control the backup power transistor to turn on, so that the backup power connection terminal supplies power to the power supply output terminal through the backup power transistor.

2. The power supply circuit according to claim 1, characterized in that The conduction direction of the main power body diode is consistent with the direction of the current passing through the main power connection terminal; The conduction direction of the backup power body diode is consistent with the direction of the current passing through the backup power connection terminal.

3. The power supply circuit according to claim 2, wherein During the process of the main power supply powering on, the backup power control circuit is used to control the backup power transistor to turn off when the voltage of the main power supply is greater than the second voltage threshold, and the main power control circuit is used to control the main power transistor to remain off when the current flowing through the main power control switch corresponding to the first electrical signal is not greater than the main power turn-on current threshold; the main power control circuit is used to control the main power control switch to turn on when the current flowing through the main power control switch corresponding to the first electrical signal is greater than the main power turn-on current threshold, so that the main power connection terminal supplies power to the power supply output terminal through the main power transistor; Among them, the main power-off current threshold is less than the main power-on current threshold, and the second voltage threshold is greater than the first voltage threshold.

4. The power supply circuit according to claim 1, wherein The main power connection terminal includes a main power high-voltage terminal and a main power low-voltage terminal. The main power detection circuit includes a main power detection resistor. The main power detection resistor is connected in series with the main power control switch to the main power low-voltage terminal, and the main power detection resistor is electrically connected to the main power control circuit; and / or The backup power connection terminal includes a backup power high-voltage terminal and a backup power low-voltage terminal. The backup power detection circuit includes a backup power detection resistor. The backup power detection resistor is connected in series with the backup power control switch to the backup power low-voltage terminal, and the backup power detection resistor is electrically connected to the backup power control circuit.

5. The power supply circuit according to claim 1, wherein The main power connection terminal includes a main power high-voltage terminal and a main power low-voltage terminal. The main power detection circuit includes a main power detection resistor. The main power detection resistor is connected in series with the main power control switch to the main power high-voltage terminal, and the main power detection resistor is electrically connected to the main power control circuit; and / or The backup power connection terminal includes a backup power high-voltage terminal and a backup power low-voltage terminal. The backup power detection circuit includes a backup power detection resistor. The backup power detection resistor is connected in series with the backup power control switch to the backup power high-voltage terminal, and the backup power detection resistor is electrically connected to the backup power control circuit.

6. The power supply circuit according to claim 1, wherein The power supply circuit further includes a voltage detection circuit. The voltage detection circuit is electrically connected to the main power connection terminal and the backup power control circuit. The voltage detection circuit is used to detect the voltage of the main power connection terminal and output a third electrical signal; The backup power control circuit is used to receive the third electrical signal and control the on / off of the backup power control switch according to the second electrical signal and the third electrical signal.

7. The power supply circuit according to claim 6, wherein The power supply circuit includes a power supply terminal. The voltage detection circuit includes a first operational amplifier. The first input terminal of the first operational amplifier is electrically connected to the main power connection terminal, and the second input terminal of the first operational amplifier is electrically connected to the power supply terminal. The first operational amplifier is used to receive the voltage of the main power connection terminal and output a third electrical signal.

8. The power supply circuit according to claim 7, wherein The voltage detection circuit further includes a first switching tube. The first switching tube is electrically connected between the first operational amplifier and the backup power control circuit. The first switching tube is controlled by the third electrical signal to control the backup power control circuit.

9. The power supply circuit according to claim 1, wherein The main power control circuit includes a main power signal conditioning circuit. The main power signal conditioning circuit is electrically connected to the main power detection circuit and the main power control switch and is used to amplify the first electrical signal.

10. The power supply circuit according to claim 9, wherein The main power signal conditioning circuit includes a second operational amplifier. The first input terminal of the second operational amplifier is electrically connected to the main power detection circuit, and the second input terminal of the second operational amplifier is electrically connected to the ground terminal and is used to amplify the first electrical signal.

11. The power supply circuit according to claim 9, wherein The main power control circuit further includes a main power comparison circuit. The main power comparison circuit is electrically connected between the main power signal conditioning circuit and the main power control switch; the main power comparison circuit includes comparing a main power reference signal and the first electrical signal amplified by the main power signal conditioning circuit and outputting a first comparison signal.

12. The power supply circuit according to claim 11, wherein The main power control circuit further includes a first reference voltage dividing resistor; the main power comparison circuit includes a first comparator, a first input terminal of the first comparator is electrically connected to the first reference voltage dividing resistor, a second input terminal of the first comparator is electrically connected to an output terminal of the main power signal conditioning circuit, the first reference voltage dividing resistor is used to generate a main power reference signal, and the first comparator is used to compare the main power reference signal and the first electrical signal amplified by the main power signal conditioning circuit, and output a first comparison signal.

13. The power supply circuit according to claim 12, characterized in that, The main power control circuit further includes a main power driving circuit, the main power driving circuit is electrically connected between the main power comparison circuit and the main power control switch; the main power driving circuit is used to drive the main power control switch to act according to the first comparison signal.

14. The power supply circuit according to claim 13, characterized in that, The main power driving circuit includes a first diode, a positive electrode of the first diode is electrically connected to the output terminal of the main power comparison circuit, and a negative electrode of the first diode is electrically connected to the main power control switch.

15. The power supply circuit according to claim 14, wherein The main power driving circuit further includes a first discharging circuit, the first discharging circuit is electrically connected between the main power control switch and the ground terminal; the first discharging circuit includes a first discharging resistor and a first discharging triode, the first discharging resistor is electrically connected between an emitter of the first discharging triode and the main power control switch, a base of the first discharging triode is electrically connected to the positive electrode of the first diode, and a collector of the first discharging triode is electrically connected to the ground terminal.

16. The power supply circuit according to claim 1, characterized in that, The backup power control circuit includes a backup power signal conditioning circuit, the backup power signal conditioning circuit is electrically connected to the backup power detection circuit and the backup power control switch, and is used to amplify the second electrical signal.

17. The power supply circuit according to claim 16, wherein The backup power signal conditioning circuit includes a third operational amplifier, a first input terminal of the third operational amplifier is electrically connected to the backup power detection circuit, a second input terminal of the third operational amplifier is electrically connected to the ground terminal, and is used to amplify the second electrical signal.

18. The power supply circuit according to claim 16, wherein The backup power control circuit further includes a backup power comparison circuit, the backup power comparison circuit is electrically connected between the backup power signal conditioning circuit and the backup power control switch; the backup power comparison circuit includes a circuit for comparing a backup power reference signal and the second electrical signal amplified by the backup power signal conditioning circuit, and outputting a second comparison signal.

19. The power supply circuit according to claim 18, characterized in that, The backup power control circuit further includes a second reference voltage dividing resistor; the backup power comparison circuit includes a second comparator, a first input terminal of the second comparator is electrically connected to the second reference voltage dividing resistor, a second input terminal of the second comparator is electrically connected to the output terminal of the backup power signal conditioning circuit, the second reference voltage dividing resistor is used to generate a backup power reference signal, and the second comparator is used to compare the backup power reference signal and the first electrical signal amplified by the backup power signal conditioning circuit, and output a first comparison signal.

20. The power supply circuit according to claim 18, wherein The backup power control circuit further includes a backup power driving circuit, which is electrically connected between the backup power comparison circuit and the backup power control switch; the power supply circuit further includes a voltage detection circuit, which is electrically connected to the main power connection terminal and the backup power driving circuit, and the voltage detection circuit is used to detect the voltage of the main power connection terminal and output a third electrical signal; The backup power driving circuit is used to control the on / off of the backup power control switch according to the second comparison signal and the third electrical signal.

21. The power supply circuit according to claim 20, characterized in that, The backup power driving circuit includes a second diode, the positive electrode of the second diode is electrically connected to the output terminal of the backup power comparison circuit, and the negative electrode of the second diode is electrically connected to the backup power control switch.

22. The power supply circuit according to claim 21, wherein The backup power driving circuit further includes a second discharge circuit, which is electrically connected between the backup power control switch and the ground terminal; the second discharge circuit includes a second discharge resistor and a second discharge triode, the second discharge resistor is electrically connected between the emitter of the second discharge triode and the backup power control switch, the base of the second discharge triode is electrically connected to the positive electrode of the diode, and the collector of the second discharge triode is electrically connected to the ground terminal.

23. An electronic device, characterized in that, Including: A power receiving system, a main power supply, a backup power supply, and the power supply circuit according to any one of claims 1 to 22; The backup power supply is electrically connected to the power supply circuit for providing a backup power voltage; the main power supply is electrically connected to the power supply circuit for providing a main power voltage; the power supply circuit is electrically connected to the power receiving system for supplying power to the power receiving system.

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