Power supply circuits and electronic equipment

Abstract

The present application provides a power supply circuit and an electronic device. In the power supply circuit: the voltage conversion circuit is used to convert the voltage of the main AC power supply, output the bus voltage through the bus voltage terminal, and output the main power voltage through the main power supply terminal; the voltage detection circuit is used to detect the bus voltage of the bus voltage terminal and output a first electrical signal; the power supply output terminal is used to output the voltage to supply power to the power receiving system; the main power switch of the main power control circuit is connected in series between the main power supply terminal and the power supply output terminal, and the main power switch control circuit of the main power control circuit is used to receive the first electrical signal and control the on and off of the main power switch according to the first electrical signal; the backup power switch in the backup power control circuit is connected in series between the backup power supply terminal and the power supply output terminal, and the backup power switch control circuit in the backup power control circuit is used to control the on and off of the backup power switch. The solution provided by the present application can prevent current backflow between the main power and the backup power.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a power supply circuit and an electronic device. Background Art

[0002] With the development of technology and the continuous application of Internet technology, various electronic devices have the function of staying online in real time or going offline after working for a certain period of time. At the same time, energy management has put forward higher requirements on the power consumption of electronic devices when they are in standby mode. More and more electronic devices use the main power and backup power switching for power supply. In the related technology, during the switching process of the main power and backup power, there is a risk that the main power will flow back into the backup power, or the backup power will flow back into the main power. Summary of the invention

[0003] The present application provides a power supply circuit and electronic equipment for preventing backflow.

[0004] The present application provides a power supply circuit, comprising:

[0005] A backup power supply terminal, used for electrically connecting a backup power supply;

[0006] A voltage conversion circuit, comprising a power connection terminal, a bus voltage terminal and a main power supply terminal, wherein the power connection terminal is used to electrically connect to a main AC power supply, and the voltage conversion circuit is used to convert the voltage of the main AC power supply, output the bus voltage through the bus voltage terminal, and output the main power voltage through the main power supply terminal;

[0007] A voltage detection circuit, electrically connected to the bus voltage terminal, the voltage detection circuit being used to detect the bus voltage at the bus voltage terminal and output a first electrical signal;

[0008] The power supply output terminal is used to output voltage and supply power to the power receiving system;

[0009] a main power control circuit, electrically connected to the voltage detection circuit and the main power supply end; the main power control circuit comprises a main power switch and a main power switch control circuit, the main power switch is connected in series between the main power supply end and the power supply output end, the main power switch control circuit is electrically connected to the voltage detection circuit and the main power switch, the main power switch control circuit is used to receive the first electrical signal, and control the on and off of the main power switch according to the first electrical signal; and

[0010] The backup power control circuit includes a backup power switch and a backup power switch control circuit. The backup power switch is connected in series between the backup power supply end and the power supply output end. The backup power switch control circuit is electrically connected to the backup power switch for controlling the on and off of the backup power switch.

[0011] Optionally, the power supply circuit further includes a voltage comparison circuit, which is electrically connected to the main power supply end and the backup power supply end; the voltage comparison circuit is used to compare the main power voltage with the backup power voltage of the backup power supply end, and output a second electrical signal;

[0012] The main power switch control circuit is electrically connected to the voltage comparison circuit, and is used to receive the second electrical signal. When the first electrical signal indicates that the bus voltage at the bus voltage end is not lower than the bus voltage threshold, and the second electrical signal indicates that the main power voltage is greater than the backup power voltage, the main power switch is controlled to be turned on so that the main power supply end supplies power to the power receiving system through the main power switch.

[0013] Optionally, the backup power switch control circuit is electrically connected to the main power supply end and the power supply output end; the backup power switch control circuit is used to receive the main power voltage of the main power supply end and the voltage of the power supply output end, and control the on and off of the backup power switch according to the main power voltage and the voltage of the power supply output end; wherein, when the main power voltage is less than the main power voltage threshold and the voltage of the power supply output end is greater than the power supply voltage threshold, the backup power switch is controlled to be turned on so that the backup power supply supplies power to the power receiving system through the backup power switch.

[0014] Optionally, the main power switch includes a main power transistor module, the main power transistor module includes a main power transistor and a main power diode connected in parallel with the main power transistor, the positive pole of the main power diode is electrically connected to the main power supply end, and the negative pole of the main power diode is electrically connected to the power supply output end.

[0015] Optionally, the backup power switch includes a backup power transistor module, the backup power transistor module includes a backup power transistor and a backup power body diode connected in parallel with the backup power transistor, the positive pole of the backup power body diode is electrically connected to the backup power supply end, and the negative pole of the backup power body diode is electrically connected to the power supply output end.

[0016] Optionally, during the power-on process of the main power supply end, when the main power voltage is greater than the main power voltage threshold and the second electrical signal indicates that the main power voltage is less than the backup power voltage, the backup power switch control circuit is used to control the backup power transistor to turn off, and the main power switch control circuit is used to control the main power transistor to turn off.

[0017] Optionally, during power failure at the main power supply end, when the first electrical signal indicates that the bus voltage at the bus voltage end is lower than the bus voltage threshold, and the main power voltage is higher than the main power voltage threshold, the main power switch control circuit is used to control the main power transistor to turn off, and the backup power switch control circuit is used to control the backup power transistor to turn off.

[0018] Optionally, the voltage comparison circuit includes a comparator, a first input terminal of the comparator is electrically connected to the main power supply terminal, a second input terminal of the comparator is electrically connected to the backup power supply terminal, and the comparator voltage is used to compare the main power voltage with the backup power voltage of the backup power supply terminal, and output a second electrical signal.

[0019] Optionally, the voltage comparison circuit further includes a first voltage divider circuit electrically connected between the main power supply terminal and the ground terminal; and the first input terminal of the comparator is electrically connected to a voltage divider node of the first voltage divider circuit.

[0020] Optionally, the voltage comparison circuit further includes a second voltage divider circuit electrically connected between the backup power supply terminal and the ground terminal; and the second input terminal of the comparator is electrically connected to a voltage divider node of the second voltage divider circuit.

[0021] Optionally, the main power switch control circuit includes a first power-controlled switch and a second power-controlled switch electrically connected to the first power-controlled switch, the first power-controlled switch is electrically connected to the voltage detection circuit, the second power-controlled switch is electrically connected to the voltage comparison circuit and to the main power switch, and the first power-controlled switch and the second power-controlled switch are controlled by the first electrical signal and the second electrical signal to control the main power switch.

[0022] Optionally, the backup power switch control circuit includes a third electrically-controlled switch and a fourth electrically-controlled switch electrically connected to the third electrically-controlled switch, the third electrically-controlled switch is electrically connected to the main power supply end, the fourth electrically-controlled switch is electrically connected to the backup power switch and the power supply output end, and the main power supply end is used to provide the main power voltage to control the third electrically-controlled switch, and then control the fourth electrically-controlled switch to control the backup power switch.

[0023] Optionally, the backup power switch control circuit includes a third voltage divider circuit electrically connected between the main power supply terminal and the ground terminal.

[0024] Optionally, the backup power switch control circuit includes a fourth voltage-dividing circuit electrically connected between the power supply output terminal and the ground terminal, and the third electrically-controlled switch and the fourth electrically-controlled switch are electrically connected to a voltage-dividing node of the fourth voltage-dividing circuit.

[0025] Optionally, the bus voltage at the bus voltage terminal is higher than the main supply voltage at the main power supply terminal; the voltage detection circuit includes an isolation circuit, which is electrically connected between the bus voltage terminal and the main power switch control circuit.

[0026] Optionally, the voltage detection circuit includes a plurality of voltage-dividing resistors and a fifth electrically-controlled switch, the plurality of voltage-dividing resistors are connected in series between the bus voltage terminal and the ground terminal, and the fifth electrically-controlled switch is electrically connected between the plurality of voltage-dividing resistors and the isolation circuit.

[0027] Optionally, the voltage detection circuit includes a sixth electrically controlled switch electrically connected between the isolation circuit and the main electrical switch control circuit.

[0028] Optionally, the isolation circuit includes an isolation optocoupler.

[0029] Optionally, the voltage conversion circuit includes a rectifier circuit, which is electrically connected to the main AC power supply, the power connection terminal, the bus voltage terminal and the main power supply terminal, and the rectifier circuit is used to convert the AC power of the main AC power supply into DC power, and output it through the bus voltage terminal and the main power supply terminal respectively.

[0030] The present application also provides an electronic device, comprising: a power receiving system, a backup power supply and a power supply circuit as described in any one of the above embodiments, wherein the backup power supply is electrically connected to the power supply circuit for providing a backup power voltage, and the power supply circuit is electrically connected to the power receiving system for supplying power to the power receiving system.

[0031] The power supply circuit of the embodiment of the present application uses a voltage detection circuit to detect the bus voltage at the bus voltage end and output a first electrical signal. The main power switch control circuit controls the on and off of the main power switch according to the first electrical signal. The main power supply end outputs the main power voltage for powering the power receiving system. During the switching process between the main AC power supply and the backup power supply, the voltage at the bus voltage end changes more promptly than the main power voltage at the main power supply end, and reflects the voltage change of the main AC power supply earlier. Therefore, the bus voltage can be used to control the switch in advance during the switching process between the main and backup powers, and the other switch can be turned off in advance before one of the main and backup switches is turned on, thereby realizing smooth and seamless switching between the main and backup powers, and preventing the main power and the backup power from being damaged by backflow.

[0032] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0034] Figure 1 Shown is a functional block diagram of an embodiment of an electronic device of the present application.

[0035] Figure 2 Shown Figure 1The circuit diagram of the voltage comparison circuit of the power supply circuit shown.

[0036] Figure 3 Shown Figure 1 Partial circuit diagram of the voltage conversion circuit and voltage detection circuit of the power supply circuit shown.

[0037] Figure 4 Shown Figure 1 The circuit diagram of the main power control circuit of the power supply circuit shown.

[0038] Figure 5 Shown Figure 1 The circuit diagram of the backup power control circuit of the power supply circuit shown. DETAILED DESCRIPTION

[0039] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0040] The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The words "first", "second" and similar words used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantitative limit, but indicate that there is at least one. "Multiple" or "several" means two or more. Unless otherwise specified, words such as "front", "rear", "lower" and / or "upper" are only for the convenience of explanation and are not limited to one position or one spatial orientation. Words such as "include" or "comprise" mean that the elements or objects appearing in front of "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, and can include electrical connections, whether direct or indirect.

[0041] 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 of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items. The explanations of some of the terms involved in the embodiments of this application are as follows:

[0042] Main power: The main power supply for terminal equipment such as controllers during normal operation, which mainly converts AC mains power into DC output and then supplies power to the subsequent systems.

[0043] Backup power: backup power for terminal equipment such as controllers, which supplies power to the subsequent systems when the main power is abnormal. Generally, it is various types of batteries.

[0044] Main and backup power switching: For terminal devices such as controllers, when both main and backup power are present, the main power supply is responsible for supplying power to the subsequent systems. When the main power supply is abnormal, the backup power supply is responsible for supplying power to the subsequent systems. During the switching between the main power supply and the backup power supply, the system must not be damaged by power failure, mutual current backflow, high current impact, etc.

[0045] Bus voltage: Main power supply system, the voltage output of AC mains after passing through the rectifier bridge.

[0046] An embodiment of the present application provides a power supply circuit, including a backup power supply terminal, a voltage conversion circuit, a voltage detection circuit, a power supply output terminal, a main power control circuit and a backup power control circuit. The backup power supply terminal is used to electrically connect to the backup power supply. The voltage conversion circuit includes a power connection terminal, a bus voltage terminal and a main power supply terminal, the power connection terminal is used to electrically connect to the main AC power supply, the voltage conversion circuit is used to convert the voltage of the main AC power supply, output the bus voltage through the bus voltage terminal, and output the main power voltage through the main power supply terminal. The voltage detection circuit is electrically connected to the bus voltage terminal, and the voltage detection circuit is used to detect the bus voltage of the bus voltage terminal and output a first electrical signal. The power supply output terminal is used to output voltage to supply power to the power receiving system. The main power control circuit is electrically connected to the voltage detection circuit and the main power supply end; the main power control circuit includes a main power switch and a main power switch control circuit, the main power switch is connected in series between the main power supply end and the power supply output end, the main power switch control circuit is electrically connected to the voltage detection circuit and the main power switch, the main power switch control circuit is used to receive a first electrical signal, and control the on and off of the main power switch according to the first electrical signal; the backup power control circuit includes a backup power switch and a backup power switch control circuit, the backup power switch is connected in series between the backup power supply end and the power supply output end, the backup power switch control circuit is electrically connected to the backup power switch, and is used to control the on and off of the backup power switch.

[0047] The power supply circuit of the embodiment of the present application uses a voltage detection circuit to detect the bus voltage at the bus voltage end and output a first electrical signal. The main power switch control circuit controls the on and off of the main power switch according to the first electrical signal. The main power supply end outputs the main power voltage for powering the power receiving system. During the switching process between the main AC power supply and the backup power supply, the voltage at the bus voltage end changes more promptly than the main power voltage at the main power supply end, and reflects the voltage change of the main AC power supply earlier. Therefore, the bus voltage can be used to control the switch in advance during the main-backup power switching process, and the other switch is turned off in advance before one of the main power switch and the backup power switch is turned on. During the switching process, after a stage in which the two switches are closed at the same time, and this stage has a certain duration, at any time, the switches on the low voltage side of the main power supply end and the backup power supply end are in a closed state, ensuring that the main power and the backup power will not be backflowed and damaged, thereby achieving smooth and seamless switching of the main and backup powers.

[0048] The power supply circuit and the electronic device of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments and implementations can be combined with each other.

[0049] Figure 1 The electronic device includes a power supply circuit 10, a power receiving system 20 and a backup power supply 30, wherein the backup power supply 30 is electrically connected to the power supply circuit 10 for providing a backup power voltage, and the power supply circuit 10 is electrically connected to the power receiving system 20 for supplying power to the power receiving system 20.

[0050] like Figure 1 As shown, the power supply circuit 10 includes a power supply output terminal 101, which is used to output voltage to supply power to the power receiving system 20. The power supply circuit 10 also includes a backup power supply terminal 102, which is used to electrically connect to the backup power supply 30 to provide a backup power voltage to the power supply output terminal 101. The power supply circuit 10 also includes a voltage conversion circuit 103, a voltage detection circuit 104, a main power control circuit 105 and a backup power control circuit 106.

[0051] The voltage conversion circuit 103 includes a power connection terminal 107, a bus voltage terminal 108 and a main power supply terminal 109. The power connection terminal 107 is used to electrically connect the main AC power supply 40. The main AC power supply 40 includes a 220V mains electricity. The voltage conversion circuit 103 is used to convert the voltage of the main AC power supply 40, output the bus voltage through the bus voltage terminal 108, and output the main power voltage through the main power supply terminal 109, which can be provided to the power supply output terminal 101. In some embodiments, the voltage conversion circuit 103 converts the 220V AC power of the main AC power supply 40 into different DC power. The bus voltage and the main power voltage are both DC, and the voltages are different, and the bus voltage is higher than the main power voltage. In some embodiments, the voltage conversion circuit 103 can convert the AC of the main AC power supply 40 to obtain the bus voltage, and then further convert the bus voltage to obtain the main power voltage (for example, 3.3V). In some embodiments, the voltage conversion circuit 103 can also convert other voltages to provide different power supply voltages (for example, 8 to 20V) to different components of the power supply circuit 10. Among them, the bus voltage is greater than the power supply voltage.

[0052] The voltage detection circuit 104 is electrically connected to the bus voltage terminal 108. The voltage detection circuit 104 is used to detect the bus voltage of the bus voltage terminal 108 and output a first electrical signal. By detecting the bus voltage of the bus voltage terminal 108 by the voltage detection circuit 104, it can be determined whether the AC power output by the current main AC power supply 40 is normal. For example, when the bus voltage of the bus voltage terminal 108 is not lower than the bus voltage threshold, it indicates that the AC power output by the main AC power supply 40 is normally supplied. When the bus voltage of the bus voltage terminal 108 is lower than the bus voltage threshold, it indicates that the AC power output by the main AC power supply 40 is powered off, the power supply is abnormal, or the power supply has not reached normal power supply after power-on.

[0053] The main power control circuit 105 is electrically connected to the voltage detection circuit 104 and the main power supply terminal 109. The main power control circuit 105 includes a main power switch 110 and a main power switch control circuit 111. The main power switch 110 is connected in series between the main power supply terminal 109 and the power supply output terminal 101. The main power switch control circuit 111 is electrically connected to the voltage detection circuit 104 and the main power switch 110. The main power switch control circuit 111 is used to receive a first electrical signal and control the on and off of the main power switch 110 according to the first electrical signal. In some embodiments, when the main power switch control circuit 111 receives the first electrical signal indicating that the bus voltage of the bus voltage terminal 108 is not lower than the bus voltage threshold, it indicates that the AC power output by the main AC power supply 40 is normal, and the main power voltage is greater than the backup power voltage. The main power switch control circuit 111 controls the main power switch 110 to turn on and supply power to the power receiving system 20. In some embodiments, when the main power switch control circuit 111 receives the first electrical signal indicating that the bus voltage at the bus voltage terminal 108 is lower than the bus voltage threshold, it indicates that the AC power output by the main AC power supply 40 is powered off and the power supply is abnormal. At this time, the main power switch control circuit 111 controls the main power switch 110 to be turned off. Even if the main power voltage is still greater than the backup power voltage at this time, the main power switch control circuit 111 still controls the main power switch 110 to be turned off, so that the main power switch 110 is turned off in advance when the main AC power supply 40 is powered off.

[0054] During the normal operation of the power supply circuit 10, the power-on and power-off of the main AC power supply 40 will be earlier than the power-on and power-off of the main power supply terminal 109 after the conversion by the voltage conversion circuit 103. Power-on refers to the process of continuous voltage increase. Power-off refers to the process of continuous voltage decrease. The voltage of the bus voltage terminal 108 changes in time when the main AC power supply 40 is powered on and powered off. Just like this, when the bus voltage of the bus voltage terminal 108 is lower than the bus voltage threshold, the main power switch control circuit 111 controls the main power switch 110 to close in advance, which can prevent the voltage of the power supply output terminal 101 from flowing back to the main power supply terminal 109 through the main power switch 110, thereby avoiding damage to the power supply circuit 10.

[0055] The backup power control circuit 106 includes a backup power switch 112 and a backup power switch control circuit 113. The backup power switch 112 is connected in series between the backup power supply terminal 102 and the power supply output terminal 101. The backup power switch control circuit 113 is electrically connected to the backup power switch 112 and is used to control the on and off of the backup power switch 112. When the main power switch control circuit 111 controls the main power switch 110 to be closed and the main power voltage is less than the main power voltage threshold, the backup power switch control circuit 113 can control the backup power switch 112 to be opened to supply power to the power receiving system 20.

[0056] The main and backup power switching can be that when the electronic equipment has both the main and backup power, the main power voltage is responsible for supplying power to the power receiving system 20, and when the main power voltage is abnormal, the backup power voltage supplies power to the power receiving system 20. During the switching between the main power and the backup power supply, the system shall not be damaged by power failure, mutual current backflow, large current impact, etc. The bus voltage can be the voltage output after the AC mains passes through the rectifier bridge.

[0057] During the switching process between the main AC power supply 40 and the backup power supply 30, the voltage of the bus voltage terminal 108 changes more promptly than the main power voltage of the main power supply terminal 109, and reflects the voltage change of the main AC power supply 40 earlier. Therefore, the bus voltage can be used to control the switch in advance during the switching process between the main and backup powers, and the other switch can be turned off in advance before one of the main power switch 110 and the backup power switch 112 is turned on. During the switching process, there is a stage in which the two switches are closed at the same time, and this stage has a certain duration. At any time, the switches on the low voltage side of the main power supply terminal 109 and the backup power supply terminal 102 are in the closed state, ensuring that there is no backflow between the main power and the backup power and damage, thereby achieving smooth and seamless switching of the main and backup powers.

[0058] Figure 2 Shown Figure 1 The voltage conversion circuit 103 and the voltage detection circuit 104 of the power supply circuit 10 are partially shown in FIG. Figure 1 and Figure 2 As shown, the voltage conversion circuit 103 includes a rectifier circuit 125, which is electrically connected to the main AC power supply 40, the power connection terminal 107, the bus voltage terminal 108 and the main power supply terminal 109. The rectifier circuit 125 is used to convert the AC power of the main AC power supply 40 into DC power, and output it through the bus voltage terminal 108 and the main power supply terminal 109 respectively. The rectifier circuit 125 includes a rectifier CB1, and the rectifier circuit 125 converts the AC power of the main AC power supply 40 into DC power. Figure 2 In the embodiment shown, the rectifier circuit 125 converts the AC power into a bus voltage and outputs it through the bus voltage terminal 108. The bus voltage of the bus voltage terminal 108 is higher than the main supply voltage of the main power supply terminal 109. In this way, the voltage of the bus voltage terminal 108 changes in time with the change of the AC power of the main AC power supply 40.

[0059] In this embodiment, the voltage detection circuit 104 includes an isolation circuit 114, which is electrically connected between the bus voltage terminal 108 and the main power switch control circuit 111. Figure 2 The AC_check terminal of the medium voltage detection circuit 104 is connected to the main power switch control circuit 111 to output a first electrical signal. Figure 2In the embodiment shown, the isolation circuit 114 may include an isolation optocoupler OP1. VCC is a DC power converted from an AC power, and its voltage is low voltage, generally around 8-20V. The bus voltage is high voltage, and the main power voltage is low voltage. The isolation circuit 114 isolates the high voltage bus voltage and the main power switch control circuit 111 to ensure safety. In this embodiment, the voltage detection circuit 104 also includes a resistor R15, which is electrically connected between the output end of the isolation optocoupler OP1 and the ground terminal GND.

[0060] In some embodiments, the voltage detection circuit 104 includes a plurality of voltage-dividing resistors 115 and a fifth electrically controlled switch Q2, wherein the plurality of voltage-dividing resistors 115 are connected in series between the bus voltage terminal 108 and the ground terminal PGND, and the fifth electrically controlled switch Q2 is electrically connected between the plurality of voltage-dividing resistors 115 and the isolation circuit 114. The voltage divided by the plurality of voltage-dividing resistors 115 is used to control the fifth electrically controlled switch Q2. The bus voltage is relatively high, and the voltage divided can meet the control voltage requirement of the fifth electrically controlled switch Q2. In this embodiment, the plurality of voltage-dividing resistors 115 include resistors R1, R3, R7, R10, R13, R14, and R17. The voltage-dividing ratio can be adjusted by setting the resistance values ​​of the resistors R1, R3, R7, R10, R13, R14, and R17. The bus voltage is high voltage, and multiple resistors R1, R3, R7, R10, R13, and R14 are connected in series. The withstand voltage and packaging power of the resistors can meet the normal working requirements of the full input voltage range of the AC power of the main AC power supply 40. The fifth electronically controlled switch Q2 can be a triode. The voltage terminal VCC, the resistor R2, the resistor R4, and the fifth electronically controlled switch Q2 can be used to drive the isolation optocoupler OP1 to turn on or off. When the bus voltage is greater than the bus voltage threshold, the fifth electronically controlled switch Q2 is turned on and the isolation optocoupler OP1 is turned on. When the bus voltage is not greater than the bus voltage threshold, the fifth electronically controlled switch Q2 is turned off and the isolation optocoupler OP1 is disconnected. A current-limiting resistor R16 is connected in series between the fifth electronically controlled switch Q2 and the voltage-dividing resistor 115.

[0061] In some embodiments, the voltage detection circuit 104 includes a sixth electrically controlled switch Q1, which is electrically connected between the isolation circuit 114 and the main power switch control circuit 111. In this embodiment, the sixth electrically controlled switch Q1 can be a triode. When the bus voltage is greater than the bus voltage threshold, the isolation optocoupler OP1 is turned on. At this time, the sixth electrically controlled switch Q1 is turned off, and the first electrical signal output from the AC_Check terminal is at a low level, indicating that the main AC power supply 40 is normally powered. When the bus voltage is not greater than the bus voltage threshold, the isolation optocoupler OP1 is disconnected. At this time, the sixth electrically controlled switch Q1 is turned on, and the first electrical signal output from the AC_Check terminal is at a high level, indicating that the main AC power supply 40 is abnormally powered. The bus voltage threshold is the lower limit of the DC voltage after rectification of the AC voltage of the main AC power supply 40 required by the product to enable the system to work normally. When it is greater than the bus voltage threshold, it means that the AC voltage of the main AC power supply 40 meets the product power supply requirements and the power supply is normal. In this way, the condition of the AC voltage can be determined by detecting the bus voltage. Figure 2 In the illustrated embodiment, the voltage detection circuit 104 further includes a resistor R11 electrically connected between the base and the emitter of the sixth electronically controlled switch Q1. The voltage detection circuit 104 further includes a capacitor C2 electrically connected between the base and the emitter of the sixth electronically controlled switch Q1.

[0062] Figure 3 Shown Figure 1 FIG. 1 is a circuit diagram of a voltage comparison circuit 116 of a power supply circuit 10. Figures 1 to 3 As shown, the power supply circuit 10 also includes a voltage comparison circuit 116, which is electrically connected to the main power supply terminal 109 and the backup power supply terminal 102. The voltage comparison circuit 116 is used to compare the main power voltage and the backup power voltage of the backup power supply terminal 102, and output a second electrical signal Compare_OUT. The main power switch control circuit 111 is electrically connected to the voltage comparison circuit 116, and is used to receive the second electrical signal Compare_OUT. When the first electrical signal AC_Check indicates that the bus voltage of the bus voltage terminal 108 is not lower than the bus voltage threshold, it means that the AC power output by the main AC power supply 40 is normal. And when the second electrical signal Compare_OUT indicates that the main power voltage is greater than the backup power voltage, the main power switch control circuit 111 controls the main power switch 110 to turn on, so that the main power supply terminal 109 supplies power to the power receiving system 20 through the main power switch 110. In this way, when the main power voltage and the backup power voltage exist at the same time, the main power supply terminal 109 supplies power to the power receiving system 20 through the main power switch 110. When either the first electrical signal AC_Check or the second electrical signal Compare_OUT does not satisfy the above conditions, the main power switch control circuit 111 controls the main power switch 110 to be turned off.

[0063] The voltage comparison circuit 116 includes a comparator U2A and at least one of a first voltage divider circuit 117 and a second voltage divider circuit 118. Figure 3 In the illustrated embodiment, the voltage comparison circuit 116 includes a comparator U2A, a first voltage divider circuit 117, and a second voltage divider circuit 118. The first input terminal of the comparator U2A is electrically connected to the main power supply terminal 109, and the second input terminal of the comparator U2A is electrically connected to the backup power supply terminal 102. In this embodiment, the first input terminal of the comparator U2A is a positive input terminal. The second input terminal of the comparator U2A can be an inverting input terminal. The first voltage divider circuit 117 is electrically connected between the main power supply terminal 109 and the ground terminal GND, and the first input terminal of the comparator U2A is electrically connected to the voltage dividing node of the first voltage divider circuit 117. The second voltage divider circuit 118 is electrically connected between the backup power supply terminal 102 and the ground terminal GND, and the inverting input terminal of the comparator U2A is electrically connected to the voltage dividing node of the second voltage divider circuit 118. In this embodiment, the comparator U2A adopts an operational amplifier comparator. The first voltage divider circuit 117 includes a resistor R29 and a resistor R40, and is electrically connected to the positive input terminal of the comparator U2A through a resistor R38. The second voltage divider circuit 118 includes a resistor R31 and a resistor R39, and is electrically connected to the negative input terminal of the comparator U2A through a resistor R37. When the main power voltage output by the main power supply terminal 109 is greater than the backup power voltage of the backup power supply terminal 102, after the voltage is divided by the first voltage divider circuit 117 and the second voltage divider circuit 118, the voltage at the positive input terminal of the comparator U2A is greater than the voltage at the negative input terminal of the comparator U2A. At this time, the second electrical signal Compare_OUT output by the comparator U2A is a high level. Therefore, when the second electrical signal Compare_OUT output by the comparator U2A is at a high level, it indicates that the main power voltage is greater than the backup power voltage. On the contrary, when the second electrical signal Compare_OUT output by the comparator U2A is at a low level, it indicates that the main power voltage is less than the backup power voltage. Of course, in some other embodiments, the connection modes of the positive phase and the negative phase of the comparator U2A can be interchanged, and the high and low levels of the second electrical signal Compare_OUT are also opposite to those in the above embodiment.

[0064] exist Figure 3 In the embodiment shown, considering the main power voltage fluctuation caused by the load and the deviation after voltage division caused by the resistor accuracy deviation, when the main power is normal, the main power voltage is greater than the maximum backup power voltage by a certain value, and at the same time, resistors R31, R39, R29, and R40 are high-precision resistors with an accuracy of more than 0.1%. Ensure that when the main power is normal, the main power voltage after resistor voltage division is greater than the maximum backup power voltage after resistor voltage division, thereby ensuring that the main power voltage can supply power to the power receiving system. Figure 3In the illustrated embodiment, the voltage comparison circuit 116 further includes a resistor R28, electrically connected between the power supply terminal of the comparator U2A and the DC voltage terminal VCC_3.3V. The voltage comparison circuit 116 further includes a capacitor C14, electrically connected between the power supply terminal of the comparator U2A and the ground terminal GND. The voltage comparison circuit 116 further includes a resistor R22, electrically connected between the non-inverting input terminal of the comparator U2A and the output terminal of the comparator U2A. The voltage comparison circuit 116 further includes a capacitor C12, electrically connected between the non-inverting input terminal of the comparator U2A and the output terminal of the comparator U2A.

[0065] Figure 4 Shown Figure 1 The circuit diagram of the main power control circuit 105 of the power supply circuit 10 is shown in FIG. Figures 1 to 4 In the illustrated embodiment, the main power switch 110 includes a main power transistor module. The main power transistor module includes a main power transistor 119 and a main power diode 120 connected in parallel with the main power transistor 119, the positive electrode of the main power diode 120 is electrically connected to the main power supply terminal 109, and the negative electrode of the main power diode 120 is electrically connected to the power supply output terminal 101. When the first electrical signal AC_Check indicates that the bus voltage of the bus voltage terminal 108 is not lower than the bus voltage threshold, it means that the AC power output by the main AC power supply 40 is normal. And when the second electrical signal Compare_OUT indicates that the main power voltage is greater than the backup power voltage, the main power voltage is better than the backup power voltage. The main power switch control circuit 111 controls the main power transistor 119 to turn on, so that the main power supply terminal 109 supplies power to the power receiving system 20 through the main power transistor 119. When the first electrical signal AC_Check indicates that the bus voltage at the bus voltage terminal 108 is lower than the bus voltage threshold, it means that the AC power output by the main AC power supply 40 is abnormal, and the main power switch control circuit 111 controls the main power transistor 119 to be turned off. During the power-off process of the main AC power supply 40, when the first electrical signal AC_Check indicates that the bus voltage at the bus voltage terminal 108 is lower than the bus voltage threshold, and the second electrical signal Compare_OUT indicates that the main power voltage is greater than the backup power voltage, the main power switch control circuit 111 controls the main power transistor 119 to be turned off, and the main power supply terminal 109 supplies power to the power receiving system 20 through the main power diode 120. At this time, the AC power of the main AC power supply 40 is powered off, the bus voltage drops, but the main power voltage is still relatively high, and the main power voltage can supply power to the power receiving system 20 through the main power diode 120. At this time, the main power supply terminal 109 can supply power to the power output terminal 101. When the main power voltage drops below the main power voltage threshold, the backup power switch is turned on, the backup power voltage is supplied, and the main power body diode 120 can prevent the power output terminal 101 from backflowing to the main power supply terminal 109, which is safe and reliable.

[0066] exist Figure 4In the illustrated embodiment, the main power switch control circuit 111 includes a first power-controlled switch Q6 and a second power-controlled switch Q5 electrically connected to the first power-controlled switch Q6. The first power-controlled switch Q6 is electrically connected to the voltage detection circuit 104, and the second power-controlled switch Q5 is electrically connected to the voltage comparison circuit 116 and the main power switch 110. The first power-controlled switch Q6 and the second power-controlled switch Q5 are controlled by the first electrical signal AC_Check and the second electrical signal Compare_OUT to control the main power switch 110. When the first electrical signal AC_Check indicates that the bus voltage at the bus voltage terminal 108 is not lower than the bus voltage threshold and outputs a low level, it indicates that the AC power output by the main AC power supply 40 is normal. At this time, the base of the first power-controlled switch Q6 is at a low level and is not conducting. At the same time, when the second electrical signal Compare_OUT indicates that the main power voltage is greater than the backup power voltage, a high level is output to drive the second electrical control switch Q5 to turn on, so as to drive the main power switch 110. At this time, the main power switch control circuit 111 controls the main power transistor 119 to turn on, so that the main power supply terminal 109 supplies power to the power receiving system 20 through the main power transistor 119.

[0067] In this embodiment, the main power transistor 119 includes a P-channel MOS transistor, whose drain is electrically connected to the main power supply terminal 109, and whose source is electrically connected to the power supply output terminal 101. When the main power transistor 119 is turned off, in some cases, the main power voltage can supply power to the power receiving system 20 through the main power body diode 120, and there is a voltage difference of the main power body diode 120 between the main power supply terminal 109 and the power supply output terminal 101. When the main power transistor 119 is turned on, the main power body diode 120 is bypassed, and the main power supply terminal 109 supplies power to the power supply output terminal 101 through the internal resistance of the main power transistor 119 itself, and the voltage of the main power supply terminal 109 is substantially equal to that of the power supply output terminal 101. The first electrical signal AC_Check and the second electrical signal Compare_OUT act together on the main power switch control circuit 111 to control the on and off of the main power switch 110. The two are in an AND relationship, and the main power transistor 119 will be turned on only when the second electrical signal Compare_OUT is at a high level and the first electrical signal AC_Check is at a low level, otherwise the power is supplied through the main power diode 120. In other words, the main power transistor 119 will be turned on when the main power voltage is greater than the backup power voltage and the bus voltage is greater than the bus voltage threshold.

[0068] exist Figure 4In the embodiment shown, the main power switch control circuit 111 also includes a resistor R27, which is electrically connected between the output end of the voltage conversion circuit 103 and the base of the first power-controlled switch Q6, and plays a role in current limiting. The main power switch control circuit 111 also includes a resistor R32, which is electrically connected between the base and the emitter of the first power-controlled switch Q6. The main power switch control circuit 111 also includes a capacitor C15, which is electrically connected between the base and the emitter of the first power-controlled switch Q6. The main power switch control circuit 111 also includes a resistor R23, which is electrically connected between the output end of the voltage comparison circuit 116 and the collector of the first power-controlled switch Q6. And the resistor R23 is electrically connected between the output end of the voltage comparison circuit 116 and the base of the second power-controlled switch Q5, and plays a role in current limiting. The main power switch control circuit 111 also includes a resistor R33, which is electrically connected between the base and the emitter of the second power-controlled switch Q5. The main power switch control circuit 111 also includes a capacitor C16, which is electrically connected between the base and the emitter of the second power-controlled switch Q5. The main power switch control circuit 111 further includes a resistor R20 electrically connected between the collector of the second power-controlled switch Q5 and the gate of the main power switch 110. The main power switch control circuit 111 further includes a resistor R19 electrically connected between the gate and the source of the main power transistor 119. The main power switch control circuit 111 further includes a capacitor C9 electrically connected between the gate and the source of the main power transistor 119. The main power switch control circuit 111 further includes a voltage-stabilizing diode D1, the positive electrode of the voltage-stabilizing diode D1 is electrically connected to the gate of the main power transistor 119, and the negative electrode of the voltage-stabilizing diode D1 is electrically connected to the source of the main power transistor 119. The main power switch control circuit 111 further includes a capacitor C8 electrically connected between the main power supply terminal 109 and the ground terminal GND.

[0069] Figure 5 Shown Figure 1 FIG. 1 is a circuit diagram of a backup power control circuit 106 of a power supply circuit 10 shown in FIG. Figures 1 to 4 In the illustrated embodiment, the backup power switch control circuit 113 is electrically connected to the main power supply terminal 109 and the power supply output terminal 101. The backup power switch control circuit 113 is used to receive the main power voltage of the main power supply terminal 109 and the voltage of the power supply output terminal 101, and control the on and off of the backup power switch 112 according to the main power voltage and the voltage of the power supply output terminal 101. When the main power voltage is less than the main power voltage threshold, and the voltage of the power supply output terminal 101 is greater than the power supply voltage threshold, the backup power switch 112 is controlled to be turned on, so that the backup power supply 30 supplies power to the power receiving system 20 through the backup power switch 112. Among them, the main power voltage threshold is less than the power supply voltage threshold. In this way, when the main power voltage is insufficient to supply power to the power receiving system 20, it is switched to the backup power supply 30 in time, and the power receiving system 20 is supplied with power through the backup power switch 112, so that the seamless switching of the main and backup power can be realized, and the output voltage of the power supply output terminal 101 is ensured to be stable and reliable.

[0070] In some embodiments, the backup power switch 112 includes a backup power transistor module. The backup power transistor module includes a backup power transistor 121 and a backup power body diode 122 connected in parallel with the backup power transistor 121. The anode of the backup power body diode 122 is electrically connected to the backup power supply terminal 102, and the cathode of the backup power body diode 122 is electrically connected to the power supply output terminal 101. When the main power voltage is less than the main power voltage threshold, and the voltage of the power supply output terminal 101 is greater than the power supply voltage threshold, the backup power transistor 121 is controlled to be turned on, so that the backup power supply 30 supplies power to the power receiving system 20 through the backup power transistor 121. When the main power voltage is greater than the main power voltage threshold, or the voltage of the power supply output terminal 101 is less than the power supply voltage threshold, the backup power transistor 121 is controlled to be turned off.

[0071] exist Figure 5 In the illustrated embodiment, the backup power switch control circuit 113 includes a third power-controlled switch Q7 and a fourth power-controlled switch Q8 electrically connected to the third power-controlled switch Q7, the third power-controlled switch Q7 is electrically connected to the main power supply terminal 109, the fourth power-controlled switch Q8 is electrically connected to the backup power switch 112 and the power supply output terminal 101, and the main power supply terminal 109 is used to provide a main power voltage to control the third power-controlled switch Q7, and then control the fourth power-controlled switch Q8 to control the backup power switch 112. In this embodiment, the third power-controlled switch Q7 and the fourth power-controlled switch Q8 can both be triodes. The voltages of the main power supply terminal 109 and the power supply output terminal 101 drive different triodes to jointly control the on and off of the backup power switch 112. In this embodiment, the backup power transistor 121 adopts a P-channel MOS tube, whose drain is electrically connected to the backup power supply terminal 102, and the source is electrically connected to the power supply output terminal 101. When the backup power transistor 121 is turned off, in some cases the backup power source 30 supplies power to the power receiving system 20 through the backup power body diode 122, and there is a voltage difference of the backup power body diode 122 between the backup power supply terminal 102 and the power supply output terminal 101. When the backup power transistor 121 is turned on, the backup power body diode 122 is bypassed, and the backup power supply terminal 102 supplies power to the power supply output terminal 101 through the internal resistance of the backup power transistor 121, and the voltage of the backup power supply terminal 102 is substantially equal to that of the power supply output terminal 101.

[0072] exist Figure 5In the illustrated embodiment, the backup power switch control circuit 113 includes a third voltage divider circuit 123 and a fourth voltage divider circuit 124. The third voltage divider circuit 123 is electrically connected between the main power supply terminal 109 and the ground terminal GND. The fourth voltage divider circuit 124 is electrically connected between the power supply output terminal 101 and the ground terminal GND, and the third electric control switch Q7 and the fourth electric control switch Q8 are electrically connected to the voltage dividing node of the fourth voltage divider circuit 124. In this embodiment, the third voltage divider circuit 123 includes a resistor R24, a resistor R30 and a resistor R38. The fourth voltage divider circuit 124 includes a resistor R25 and a resistor R41. The voltages of the main power supply terminal 109 and the power supply output terminal 101 are set to be different when the third electric control switch Q7 and the fourth electric control switch Q8 are turned on by the voltage division of the resistor R24, the resistor R30 and the resistor R38, and the voltage division of the resistor R25 and the resistor R41. The voltage of the main power supply terminal 109 when the third power switch Q7 needs to be turned on is set to be smaller than the voltage of the power supply output terminal 101 when the fourth power switch Q8 needs to be turned on. The third power switch Q7 and the fourth power switch Q8 are driven by the backup power switch 112 together.

[0073] exist Figure 5 In the illustrated embodiment, the backup power switch control circuit 113 further includes a resistor R35, electrically connected between the voltage-dividing node of the resistor R24, the resistor R30 and the resistor R38 (between the resistor R30 and the resistor R38) and the base of the third electric-controlled switch Q7. The backup power switch control circuit 113 further includes a capacitor C17, electrically connected between the base and the emitter of the third electric-controlled switch Q7. The backup power switch control circuit 113 further includes a resistor R34, electrically connected between the voltage-dividing node of the resistor R25 and the resistor R41 (between the resistor R25 and the resistor R41) and the base of the fourth electric-controlled switch Q8. The backup power switch control circuit 113 further includes a capacitor C18, electrically connected between the base and the emitter of the fourth electric-controlled switch Q8. The backup power switch control circuit 113 further includes a resistor R34, electrically connected between the collector of the fourth electric-controlled switch Q8 and the gate of the backup power transistor 121. The backup power switch control circuit 113 further includes a resistor R21, electrically connected between the gate and source of the backup power transistor 121. The backup power switch control circuit 113 further includes a capacitor C13, electrically connected between the gate and source of the backup power transistor 121. The backup power switch control circuit 113 further includes a Zener diode D2, wherein the positive electrode of the Zener diode D2 is electrically connected to the gate of the backup power transistor 121, and the negative electrode of the Zener diode D1 is electrically connected to the source of the backup power transistor 121.

[0074] Combination Figures 2 to 5In the illustrated embodiment, when the main AC power supply 40 is not connected, the backup power transistor 121 is turned on, the main power transistor 119 is turned off, and the backup power supply 30 supplies power. When both the main AC power supply 40 and the backup power supply 30 are present, during the power-on process of the main power supply terminal 109, when the main power voltage is greater than the main power voltage threshold and the second electrical signal Compare_OUT indicates that the main power voltage is less than the backup power voltage, the backup power switch control circuit 113 is used to control the backup power transistor 121 to turn off, and the main power switch control circuit 111 is used to control the main power transistor 119 to remain turned off. At this time, the main power body diode 120 and the backup power body diode 122 are in a top-to-top state, and the backup power supply terminal 102 and the main power supply terminal 109 compete for power supply through the main power body diode 120 and the backup power body diode 122. The main power body diode 120 and the backup power body diode 122 are top-to-top, ensuring that there is no backflow between the main power and the backup power, which is safe and reliable. The main power voltage rises and reaches a certain value (main power voltage threshold) but does not exceed the backup power voltage. The backup power transistor 121 is turned off in time, and the two body diodes are in a state of facing each other, that is, the intermediate state or dead zone state is entered. The backup power switch is turned off early so that the intermediate state has a certain duration to ensure smooth and seamless switching. In the embodiment shown in the figure, the second electrical signal Compare_OUT is at a low level, the second electrical control switch Q5 is turned off, and the main power transistor 119 is turned off. The main power voltage is greater than the main power voltage threshold, so that the third electrical control switch Q7 is turned on, the fourth electrical control switch Q8 is turned off, and the backup power transistor 121 is turned off.

[0075] The main power voltage continues to rise. When the second electrical signal Compare_OUT indicates that the main power voltage is greater than the backup power voltage, the output is high, and the bus voltage is greater than the bus voltage threshold, and the first electrical signal AC_Check is low. Under the action of the first electrical signal AC_Check and the second electrical signal Compare_OUT, at this time, the first electric control switch Q6 is turned off, the second electric control switch Q5 is turned on, and the main power transistor 119 is turned on. The main power supply terminal 109 provides the main power voltage to the power supply output terminal 101 through the main power transistor 119 to supply power to the power receiving system 20. The main power voltage threshold is greater than the backup power voltage. The backup power body diode 122 can prevent the power supply output terminal 101 from backflowing to the backup power supply terminal 102. At this time, the power receiving system 20 switches to the main power voltage supply, thereby completing the switch from the backup power supply to the main power supply.

[0076] exist Figures 2 to 5In the illustrated embodiment, during the power-off process of the main power supply terminal 109, when the first electrical signal AC_Check indicates that the bus voltage of the bus voltage terminal 108 is lower than the bus voltage threshold, and the second electrical signal Compare_OUT indicates that the main power voltage is higher than the backup power voltage, the main power switch control circuit 111 is used to control the main power transistor 119 to be turned off, and the backup power switch control circuit 113 is used to control the backup power transistor 121 to be turned off. When the first electrical signal AC_Check indicates that the bus voltage of the bus voltage terminal 108 is lower than the bus voltage threshold, it is a high level. When the second electrical signal Compare_OUT indicates that the main power voltage is higher than the backup power voltage, it is a high level. Under the combined action of the first electrical signal AC_Check and the second electrical signal Compare_OUT, at this time, the first electrical control switch Q6 is turned on, the second electrical control switch Q5 is turned off, and the main power transistor 119 is turned off. Although the main AC power supply 40 has begun to lose power, during this process, the main power voltage of the main power supply terminal 109 still exists, and the main power voltage is still higher than the backup power voltage, and the main power supply terminal 109 is powered through the main power body diode 120. At this time, the backup power switch control circuit 113 still controls the backup power transistor 121 to be turned off. In this way, during the process of the main power voltage being powered off, the main and backup powers are in a top-to-top state through the corresponding main power body diode 120 and the backup power body diode 122, so as to compete for power to the power receiving system 20 according to the voltage size, thus ensuring smooth and seamless switching between the main power and the backup power, and maintaining continuous power supply to the power receiving system 20.

[0077] As the main AC power source 40 continues to lose power, the main power voltage will also drop. When the second electrical signal Compare_OUT indicates that the main power voltage is less than the backup power voltage, it is at a low level, the second electrical control switch Q5 is turned off, and the main power transistor 119 remains turned off. When the main power voltage drops to less than the main power voltage threshold, in the backup power control circuit 106, since the main power voltage is less than the main power voltage threshold, the third electrical control switch Q7 is turned off. When the voltage at the power output terminal 101 is greater than the power supply voltage threshold, the fourth electrical control switch Q8 is turned on, and the backup power transistor 121 is turned on. At this time, the power receiving system 20 switches to the backup power voltage supply, thereby completing the switch from the main power supply to the backup power supply.

[0078] In addition, when both the main AC power supply 40 and the backup power supply 30 exist, and the main AC power supply 40 is normal, the power supply circuit 10 uses the main power voltage to supply power to the power receiving system 20. If the backup power voltage is powered off at this time, the power receiving system 20 will continue to be powered by the main power voltage without switching. Among them, when both the main AC power supply 40 and the backup power supply 30 do not exist, the main power body diode 120 and the backup power body diode 122 are connected to the top. The same pole (positive pole or negative pole) of the main power body diode 120 and the backup power body diode 122 is electrically connected to the power supply output terminal 101. In this embodiment, the negative poles of the main power body diode 120 and the backup power body diode 122 are both electrically connected to the power supply output terminal 101.

[0079] In the actual circuit application process, it is necessary to reasonably select the package of the PMOS tube and perform reasonable heat dissipation during the layout of the printed circuit board to ensure that if the system is loaded with rated load during the switching process, the heat loss of the MOS tube can meet the use requirements and the device will not be damaged. At the same time, in the application process, through the reasonable design of the main and standby power load resistance circuit, the time for the double diodes to face each other during the switching process can be accelerated, thereby reducing the heating of the MOS tube itself during the switching process.

[0080] In the above scheme, a bus voltage judgment mechanism is introduced. During the main and standby power switching process, the main power transistor 119 is turned off in advance, and power is supplied through the main power diode 120, thereby realizing smooth and seamless switching of the main and standby power supply. At the same time, during the switching process, the main power transistor 119 and the standby power transistor 121 are always turned off at the same time, and the main power diode 120 and the standby power diode 122 are in a state of facing each other. At any time, the transistor on the low voltage side is turned off to ensure that there is no mutual backflow and damage between the main power and the standby power. In addition, the circuit is simple to implement, without the participation of software, and pure hardware autonomous switching is realized, reducing the development cycle and development cost. The switching logic is strict, and the load is powered by the internal resistance of the MOS tube after the switching is completed, with low loss and high efficiency. The application has a high degree of freedom, and only needs to reasonably select the MOS tube for the main and standby power switching, which can be applied to the main and standby power switching scenarios of different voltage levels and load current levels. In the application of high-power circuit systems, it has cost advantages. In addition, the transistor module (main power transistor module and standby power transistor module) described in this article can be a transistor device, which can be a MOS tube. The body diode is a parasitic diode of a MOS tube device. By using the body diode of the transistor module itself, a one-way conduction can be achieved when the transistor is turned off, so that the output does not lose power, and the functions of seamless power supply and backflow prevention can be achieved. In some other embodiments, the transistor module can also be a combination of a transistor device and a diode device, which is not limited in this application.

[0081] 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.

[0082] 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: include: A backup power supply terminal, used for electrically connecting a backup power supply; A voltage conversion circuit, comprising a power connection terminal, a bus voltage terminal and a main power supply terminal, wherein the power connection terminal is used to electrically connect to a main AC power supply, and the voltage conversion circuit is used to convert the voltage of the main AC power supply, output the bus voltage through the bus voltage terminal, and output the main power voltage through the main power supply terminal; A voltage detection circuit, electrically connected to the bus voltage terminal, the voltage detection circuit being used to detect the bus voltage at the bus voltage terminal and output a first electrical signal; The power supply output terminal is used to output voltage and supply power to the power receiving system; a main power control circuit, electrically connected to the voltage detection circuit and the main power supply end; the main power control circuit comprises a main power switch and a main power switch control circuit, the main power switch is connected in series between the main power supply end and the power supply output end, the main power switch control circuit is electrically connected to the voltage detection circuit and the main power switch, and the main power switch control circuit is used to receive the first electrical signal and control the on and off of the main power switch according to the first electrical signal; and The backup power control circuit includes a backup power switch and a backup power switch control circuit. The backup power switch is connected in series between the backup power supply end and the power supply output end. The backup power switch control circuit is electrically connected to the backup power switch for controlling the on and off of the backup power switch.

2. The power supply circuit according to claim 1, characterized in that: The power supply circuit further includes a voltage comparison circuit, which is electrically connected to the main power supply end and the backup power supply end; the voltage comparison circuit is used to compare the main power voltage with the backup power voltage of the backup power supply end, and output a second electrical signal; The main power switch control circuit is electrically connected to the voltage comparison circuit, and is used to receive the second electrical signal. When the first electrical signal indicates that the bus voltage at the bus voltage end is not lower than the bus voltage threshold, and the second electrical signal indicates that the main power voltage is greater than the backup power voltage, the main power switch is controlled to be turned on so that the main power supply end supplies power to the power receiving system through the main power switch.

3. The power supply circuit according to claim 2, characterized in that: The backup power switch control circuit is electrically connected to the main power supply end and the power supply output end; the backup power switch control circuit is used to receive the main power voltage of the main power supply end and the voltage of the power supply output end, and control the on and off of the backup power switch according to the main power voltage and the voltage of the power supply output end; wherein, when the main power voltage is less than the main power voltage threshold and the voltage of the power supply output end is greater than the power supply voltage threshold, the backup power switch is controlled to be turned on so that the backup power supply supplies power to the power receiving system through the backup power switch.

4. The power supply circuit according to claim 3, characterized in that: The main power switch includes a main power transistor module, which includes a main power transistor and a main power diode connected in parallel with the main power transistor, the positive electrode of the main power diode is electrically connected to the main power supply end, and the negative electrode of the main power diode is electrically connected to the power supply output end.

5. The power supply circuit according to claim 4, characterized in that: The backup power switch includes a backup power transistor module, which includes a backup power transistor and a backup power body diode connected in parallel with the backup power transistor, wherein the anode of the backup power body diode is electrically connected to the backup power supply end, and the cathode of the backup power body diode is electrically connected to the power supply output end.

6. The power supply circuit according to claim 5, characterized in that: During the power-on process of the main power supply end, when the main power voltage is greater than the main power voltage threshold and the second electrical signal indicates that the main power voltage is less than the backup power voltage, the backup power switch control circuit is used to control the backup power transistor to be turned off, and the main power switch control circuit is used to control the main power transistor to be turned off; and / or During power failure at the main power supply end, when the first electrical signal indicates that the bus voltage at the bus voltage end is lower than the bus voltage threshold, and the main power voltage is higher than the main power voltage threshold, the main power switch control circuit is used to control the main power transistor to be turned off, and the backup power switch control circuit is used to control the backup power transistor to be turned off.

7. The power supply circuit according to claim 2, characterized in that: The voltage comparison circuit includes a comparator, a first input terminal of the comparator is electrically connected to the main power supply terminal, a second input terminal of the comparator is electrically connected to the backup power supply terminal, and the comparator voltage is used to compare the main power voltage with the backup power voltage of the backup power supply terminal and output a second electrical signal.

8. The power supply circuit according to claim 7, characterized in that: The voltage comparison circuit further includes a first voltage divider circuit electrically connected between the main power supply terminal and the ground terminal; the first input terminal of the comparator is electrically connected to a voltage dividing node of the first voltage divider circuit; and / or The voltage comparison circuit also includes a second voltage divider circuit electrically connected between the backup power supply terminal and the ground terminal; the second input terminal of the comparator is electrically connected to a voltage dividing node of the second voltage divider circuit.

9. The power supply circuit according to claim 2, characterized in that: The main electric switch control circuit includes a first electric controlled switch and a second electric controlled switch electrically connected to the first electric controlled switch, the first electric controlled switch is electrically connected to the voltage detection circuit, the second electric controlled switch is electrically connected to the voltage comparison circuit and to the main electric switch, the first electric controlled switch and the second electric controlled switch are controlled by the first electric signal and the second electric signal to control the main electric switch.

10. The power supply circuit according to claim 2, characterized in that: The backup power switch control circuit includes a third electrically-controlled switch and a fourth electrically-controlled switch electrically connected to the third electrically-controlled switch, the third electrically-controlled switch is electrically connected to the main power supply end, the fourth electrically-controlled switch is electrically connected to the backup power switch and the power supply output end, the main power supply end is used to provide the main power voltage to control the third electrically-controlled switch, and then control the fourth electrically-controlled switch to control the backup power switch.

11. The power supply circuit according to claim 10, characterized in that: The backup power switch control circuit includes a third voltage divider circuit electrically connected between the main power supply terminal and the ground terminal; and / or The backup power switch control circuit includes a fourth voltage-dividing circuit electrically connected between the power supply output terminal and the ground terminal, and the third electrically-controlled switch and the fourth electrically-controlled switch are electrically connected to a voltage-dividing node of the fourth voltage-dividing circuit.

12. The power supply circuit according to claim 1, characterized in that: The bus voltage at the bus voltage end is higher than the main supply voltage at the main power supply end; the voltage detection circuit includes an isolation circuit, which is electrically connected between the bus voltage end and the main power switch control circuit.

13. The power supply circuit according to claim 12, characterized in that: The voltage detection circuit comprises a plurality of voltage-dividing resistors and a fifth electrically-controlled switch, wherein the plurality of voltage-dividing resistors are connected in series between the bus voltage terminal and the ground terminal, and the fifth electrically-controlled switch is electrically connected between the plurality of voltage-dividing resistors and the isolation circuit; and / or The voltage detection circuit comprises a sixth electric control switch electrically connected between the isolation circuit and the main electric switch control circuit; and / or The isolation circuit includes an isolation optocoupler.

14. The power supply circuit according to claim 1, characterized in that: The voltage conversion circuit includes a rectifier circuit, which is electrically connected to the main AC power supply, the power connection terminal, the bus voltage terminal and the main power supply terminal. The rectifier circuit is used to convert the AC power of the main AC power supply into DC power, and output it through the bus voltage terminal and the main power supply terminal respectively.

15. An electronic device, characterized in that: include: A power receiving system, a backup power supply and a power supply circuit as claimed in any one of claims 1 to 14, wherein the backup power supply is electrically connected to the power supply circuit for providing a backup power voltage, and the power supply circuit is electrically connected to the power receiving system for supplying power to the power receiving system.

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