Dual-power supply circuit and control method thereof

Abstract

The invention relates to the technical field of electronic circuits, and discloses a dual-power-supply power supply circuit and a control method thereof.The power supply circuit comprises a main power supply, a main power supply circuit, a standby power supply, a standby power supply circuit, a control circuit and electric equipment, and the first input end of the main power supply circuit is connected with the output end of the main power supply; the output end of the main power supply circuit is connected with the input end of the electric equipment; the first input end of the standby power supply circuit is connected with the output end of the standby power supply; the output end of the standby power supply circuit is connected with the output end of the main power supply circuit; the first input end of the control circuit is connected with the output end of the main power supply; the second input end of the control circuit is connected with the output end of the standby power supply; the output end of the control circuit is connected with the second input end of the main power supply circuit; the output end of the control circuit is connected with the second input end of the standby power supply circuit. According to the invention, the circuit power consumption is reduced, the limitation of voltage selection is reduced, and the applicability and safety of the circuit are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a dual power supply circuit and a control method thereof. Background Art

[0002] The use of dual power supply can enable the backup power supply in time when the main power supply cannot supply power to the device for some reason, ensuring the normal use of the device and meeting the user's demand for device power supply reliability. However, in the existing technology, the dual power supply circuit mostly uses a diode circuit, which has two major disadvantages: on the one hand, the forward voltage drop of the diode is usually relatively large, at least several hundred mV, and some can even reach 1V, resulting in large power loss; on the other hand, in the existing design, due to the characteristics of the diode, when the main power supply and the backup power supply are both powered, after circuit screening, the one with a higher voltage will be used to power the electrical equipment, which has requirements for the voltage selection of the main power supply and the backup power supply, and cannot adapt to various situations. Summary of the invention

[0003] The present invention provides a dual-power supply circuit and a control method thereof, which can reduce circuit power consumption, reduce restrictions on voltage selection, and improve the applicability, comprehensiveness and safety of the power supply circuit.

[0004] In order to solve the above technical problems, the present invention provides a dual power supply circuit, including: a main power supply, a main power supply circuit, a backup power supply, a backup power supply circuit, a control circuit and an electric device;

[0005] The first input end of the main power supply circuit is electrically connected to the output end of the main power supply;

[0006] The output end of the main power supply circuit is electrically connected to the input end of the power-consuming device;

[0007] The first input end of the backup power supply circuit is electrically connected to the output end of the backup power supply;

[0008] The output end of the backup power supply circuit is electrically connected to the output end of the main power supply circuit;

[0009] The first input terminal of the control circuit is electrically connected to the output terminal of the main power supply;

[0010] The second input end of the control circuit is electrically connected to the output end of the backup power supply;

[0011] The output end of the control circuit is electrically connected to the second input end of the main power supply circuit;

[0012] The output end of the control circuit is electrically connected to the second input end of the backup power supply circuit.

[0013] Furthermore, the main power supply circuit includes: a first MOS tube, a second MOS tube, a first resistor, a second resistor and a first transistor;

[0014] The current output end of the first MOS tube is electrically connected to the output end of the main power supply;

[0015] The current input end of the first MOS tube is electrically connected to the current input end of the second MOS tube;

[0016] The current output end of the second MOS tube is electrically connected to the input end of the electrical device;

[0017] The control end of the first MOS tube is electrically connected to the control end of the second MOS tube;

[0018] The first end of the first resistor is electrically connected to the current input end of the first MOS tube;

[0019] The second end of the first resistor is electrically connected to the control end of the first MOS tube;

[0020] The first end of the second resistor is electrically connected to the control end of the first MOS tube;

[0021] The second end of the second resistor is electrically connected to the current input end of the first transistor;

[0022] The control end of the first transistor is electrically connected to the output end of the control circuit;

[0023] The current output terminal of the first transistor is grounded.

[0024] Further, the backup power supply circuit includes: a third MOS tube, a fourth MOS tube, a third resistor, a fourth resistor, a second triode and a third triode;

[0025] The current output end of the third MOS tube is electrically connected to the output end of the backup power supply;

[0026] The current input end of the third MOS tube is electrically connected to the current input end of the fourth MOS tube;

[0027] The current output end of the fourth MOS tube is electrically connected to the output end of the main power supply circuit;

[0028] The control end of the third MOS tube is electrically connected to the control end of the fourth MOS tube;

[0029] The first end of the third resistor is electrically connected to the current input end of the third MOS tube;

[0030] The second end of the third resistor is electrically connected to the control end of the third MOS tube;

[0031] The first end of the fourth resistor is electrically connected to the control end of the third MOS tube;

[0032] The second end of the fourth resistor is electrically connected to the current input end of the second transistor;

[0033] The control end of the second transistor is electrically connected to the current output end of the third MOS tube;

[0034] The current output terminal of the second triode is grounded;

[0035] The current input end of the third triode is electrically connected to the current output end of the third MOS tube;

[0036] The control end of the third transistor is electrically connected to the output end of the control circuit;

[0037] The current output terminal of the third transistor is grounded.

[0038] Further,

[0039] Furthermore, the control circuit includes: a switching circuit and a software control circuit;

[0040] The first input end of the switching circuit is electrically connected to the output end of the main power supply;

[0041] The second input end of the switching circuit is electrically connected to the output end of the backup power supply;

[0042] The first output terminal of the switching circuit is electrically connected to the second input terminal of the main power supply circuit;

[0043] The first output terminal of the switching circuit is electrically connected to the second input terminal of the backup power supply circuit;

[0044] The second output terminal of the switching circuit is electrically connected to the input terminal of the software control circuit;

[0045] The output terminal of the software control circuit is electrically connected to the third input terminal of the switching circuit.

[0046] Further, the switching circuit comprises: a fifth MOS tube, a sixth MOS tube and a fourth triode;

[0047] The current input end of the fifth MOS tube is electrically connected to the output end of the main power supply;

[0048] The current output end of the fifth MOS tube is electrically connected to the second input end of the main power supply circuit;

[0049] The current output end of the fifth MOS tube is electrically connected to the second input end of the backup power supply circuit;

[0050] The control end of the fifth MOS tube is electrically connected to the control end of the sixth MOS tube;

[0051] The current output of the sixth MOS tube is electrically connected to the current output end of the fifth MOS tube;

[0052] The current input end of the sixth MOS tube is electrically connected to the current input end of the fourth triode;

[0053] The control end of the fourth transistor is electrically connected to the output end of the backup power supply;

[0054] The current output terminal of the fourth triode is grounded;

[0055] The current input end of the fourth transistor is electrically connected to the input end of the software control circuit;

[0056] The current input end of the fourth transistor is electrically connected to the output end of the main power supply;

[0057] The current input end of the sixth MOS tube is electrically connected to the output end of the software control circuit.

[0058] Further, the software control circuit comprises: a fifth transistor and a software control output terminal;

[0059] The current input terminal of the fifth triode is electrically connected to the software control output terminal;

[0060] The control end of the fifth transistor is electrically connected to the second output end of the switching circuit;

[0061] The current output terminal of the fifth transistor is electrically connected to the third input terminal of the switching circuit;

[0062] The current output terminal of the fifth transistor is grounded.

[0063] Furthermore, the dual power supply circuit further includes: a short circuit protection circuit;

[0064] The first input end of the short-circuit protection circuit is electrically connected to the output end of the main power supply circuit;

[0065] The second input end of the short circuit protection circuit is electrically connected to the output end of the main power supply;

[0066] The second input end of the short circuit protection circuit is electrically connected to the output end of the backup power supply;

[0067] The first output terminal of the short-circuit protection circuit is electrically connected to the input terminal of the electrical device;

[0068] The second output terminal of the short-circuit protection circuit is electrically connected to the second input terminal of the main power supply circuit;

[0069] The third output terminal of the short circuit protection circuit is electrically connected to the third input terminal of the backup power supply circuit.

[0070] Furthermore, the short-circuit protection circuit includes: a current sampling resistor, a first transistor output optocoupler, a second transistor output optocoupler, a third transistor output optocoupler, a seventh MOS tube and an eighth MOS tube;

[0071] The first end of the current sampling resistor is electrically connected to the output end of the main power supply circuit;

[0072] The second end of the current sampling resistor is electrically connected to the input end of the electrical device;

[0073] The input anode of the first transistor output optocoupler is electrically connected to the first end of the current sampling resistor;

[0074] The cathode of the input end of the first transistor output optocoupler is electrically connected to the second end of the current sampling resistor;

[0075] The output collector of the first transistor output optocoupler is electrically connected to the output collector of the second transistor output optocoupler;

[0076] The emitter of the output terminal of the first transistor output optocoupler is electrically connected to the anode of the input terminal of the second transistor output optocoupler;

[0077] The cathode of the input terminal of the second transistor output optocoupler is electrically connected to the anode of the input terminal of the third transistor output optocoupler;

[0078] The output end emitter of the second transistor output optocoupler is electrically connected to the output end emitter of the first transistor output optocoupler;

[0079] The cathode of the input end of the third transistor output optical coupler is electrically connected to the control end of the seventh MOS transistor;

[0080] The collector of the output end of the third transistor output optocoupler is electrically connected to the current input end of the seventh MOS tube;

[0081] The output end emitter of the third transistor output optocoupler is grounded;

[0082] The current input end of the seventh MOS tube is electrically connected to the current input end of the eighth MOS tube;

[0083] The control end of the seventh MOS tube is electrically connected to the control end of the eighth MOS tube;

[0084] The current output end of the seventh MOS tube is electrically connected to the second input end of the main power supply circuit;

[0085] The current output end of the eighth MOS tube is electrically connected to the third input end of the backup power supply circuit;

[0086] The collector of the output end of the first transistor output optocoupler is electrically connected to the output end of the main power supply;

[0087] The collector of the output end of the first transistor output optocoupler is electrically connected to the output end of the backup power supply.

[0088] Further, the current output end of the eighth MOS tube is electrically connected to the third input end of the backup power supply circuit, specifically:

[0089] The current output end of the eighth MOS tube is electrically connected to the control end of the second transistor.

[0090] Accordingly, the present invention provides a dual power supply circuit control method for controlling the dual power supply circuit described above, comprising:

[0091] Utilizing a main power supply circuit to receive a first voltage signal emitted by a main power supply;

[0092] Utilizing the backup power supply circuit to receive a second voltage signal sent by the backup power supply;

[0093] receiving a software control signal using a control circuit;

[0094] determining a power supply by combining the first voltage signal, the second voltage signal and the software control signal;

[0095] Controlling the power supply to supply power to the electrical equipment;

[0096] Wherein, the power supply includes a main power supply and a backup power supply.

[0097] The present invention provides a dual-power supply circuit and a control method thereof. The power supply circuit comprises a main power supply, a main power supply circuit, a backup power supply, a backup power supply circuit, a control circuit and an electric device. A dual-power supply function is completed by using a triode and a MOS tube. The characteristic of low on-resistance when the MOS tube is turned on is utilized to greatly reduce power consumption. Regardless of the voltages of the main power supply and the backup power supply, the main power supply is used for power supply by default, thereby reducing restrictions on voltage selection. The power supply can be independently selected through software, thereby improving the comprehensive applicability of the power supply circuit. A short-circuit protection circuit is utilized to protect the power supply circuit, thereby improving the safety of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Figure 1A circuit diagram of an embodiment of a dual power supply circuit provided by the present invention;

[0099] Figure 2 A circuit diagram of an embodiment of a main power supply circuit provided by the present invention;

[0100] Figure 3 A circuit diagram of an embodiment of a backup power supply circuit provided by the present invention;

[0101] Figure 4 A circuit diagram of another embodiment of the dual power supply circuit provided by the present invention;

[0102] Figure 5 A circuit diagram of an embodiment of a switching circuit provided by the present invention;

[0103] Figure 6 A circuit diagram of an embodiment of a software control circuit provided by the present invention;

[0104] Figure 7 A circuit diagram of another embodiment of the dual power supply circuit provided by the present invention;

[0105] Figure 8 A circuit diagram of an embodiment of a short-circuit protection circuit provided by the present invention;

[0106] Fig. 9 A schematic flow chart of an embodiment of a dual power supply circuit control method provided by the present invention. DETAILED DESCRIPTION

[0107] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0108] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0109] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0110] like Figure 1, which is a circuit diagram of an embodiment of a dual power supply circuit provided by the present invention, the circuit includes a main power supply, a main power supply circuit, a backup power supply, a backup power supply circuit, a control circuit and an electric device;

[0111] The first input end of the main power supply circuit is electrically connected to the output end of the main power supply;

[0112] The output end of the main power supply circuit is electrically connected to the input end of the power-consuming device;

[0113] The first input end of the backup power supply circuit is electrically connected to the output end of the backup power supply;

[0114] The output end of the backup power supply circuit is electrically connected to the output end of the main power supply circuit;

[0115] The first input terminal of the control circuit is electrically connected to the output terminal of the main power supply;

[0116] The second input end of the control circuit is electrically connected to the output end of the backup power supply;

[0117] The output end of the control circuit is electrically connected to the second input end of the main power supply circuit;

[0118] The output end of the control circuit is electrically connected to the second input end of the backup power supply circuit.

[0119] Further, in an embodiment of the present invention, the main power supply circuit includes: a first MOS tube, a second MOS tube, a first resistor, a second resistor and a first triode;

[0120] The current output end of the first MOS tube is electrically connected to the output end of the main power supply;

[0121] The current input end of the first MOS tube is electrically connected to the current input end of the second MOS tube;

[0122] The current output end of the second MOS tube is electrically connected to the input end of the electrical device;

[0123] The control end of the first MOS tube is electrically connected to the control end of the second MOS tube;

[0124] The first end of the first resistor is electrically connected to the current input end of the first MOS tube;

[0125] The second end of the first resistor is electrically connected to the control end of the first MOS tube;

[0126] The first end of the second resistor is electrically connected to the control end of the first MOS tube;

[0127] The second end of the second resistor is electrically connected to the current input end of the first transistor;

[0128] The control end of the first transistor is electrically connected to the output end of the control circuit;

[0129] The current output terminal of the first transistor is grounded.

[0130] As an example of an embodiment of the present invention, see Figure 2 , is a circuit diagram of an embodiment of a main power supply circuit provided by the present invention. Figure 2 Output 1 in is connected to the electrical equipment, and signal 1 comes from the output end of the control circuit.

[0131] Component 1 is the first MOS tube, and component 2 is the second MOS tube. Both the first MOS tube and the second MOS tube are PMOS tubes, the source of the PMOS tube is the current input terminal, the drain is the current output terminal, and the gate is the control terminal. The characteristics of the PMOS tube are: when the voltage of the gate of the PMOS tube is less than the source voltage of the PMOS tube and the difference is greater than or equal to the threshold voltage, the source of the PMOS tube and the drain of the PMOS tube are turned on; when the gate voltage of the PMOS tube is greater than or equal to the source voltage of the PMOS tube or the gate voltage of the PMOS tube is less than the source voltage of the PMOS tube but the difference between the two is less than the threshold voltage, the source of the PMOS tube and the drain of the PMOS tube are not turned on. Among them, PMOS tubes of different brands and specifications correspond to different threshold voltages.

[0132] Due to the characteristics of the PMOS tube, when the PMOS tube is not conducting, it is equivalent to a diode that conducts unidirectionally from the drain of the PMOS tube to the source of the PMOS tube between the drain and the source of the PMOS tube. Therefore, when the drain voltage of the PMOS tube is greater than the source voltage of the PMOS tube, due to the existence of the equivalent diode, the source voltage of the PMOS tube will be pulled up to the same voltage as the drain voltage of the PMOS tube; when the drain voltage of the PMOS tube is less than the source voltage of the PMOS tube, the source voltage of the PMOS tube cannot pull up the drain voltage of the PMOS tube.

[0133] Component 3 is a first resistor, and component 4 is a second resistor. The first resistor and the second resistor are voltage-dividing resistors, and the voltage-dividing magnitude of node 2 can be determined by adjusting the resistance values ​​of the first resistor and the second resistor.

[0134] Component 5 is the first transistor, which is an NPN transistor. The collector of the NPN transistor is the current input terminal, the emitter is the current output terminal, and the base is the control terminal. The characteristic of the NPN transistor is that when the base voltage of the NPN transistor is higher than the emitter voltage of the NPN transistor and the difference is greater than the threshold voltage, the collector of the NPN transistor and the emitter of the NPN transistor are turned on.

[0135] Component 6 is a current limiting resistor, which is used to limit the current of the main power supply circuit; component 7 is a pull-down resistor, which is used to give the base of the first transistor of component 5 a low level initial state, so that it can be cut off more reliably and prevent mis-conduction.

[0136] Therefore, based on the characteristics of the MOS tube with an equivalent diode, when the main power supply is powered, Figure 2 The voltage of the middle node 1 will be pulled up by the main power supply. When the first MOS tube and the second MOS tube are turned on, the source and the drain are connected, and a path is formed between the main power supply and "output 1", and the main power supply supplies power to the power-consuming device. The high and low levels of signal 1 are used to control the on and off of the path between the main power supply and the power-consuming device.

[0137] Further, in an embodiment of the present invention, the backup power supply circuit includes: a third MOS transistor, a fourth MOS transistor, a third resistor, a fourth resistor, a second triode and a third triode;

[0138] The current output end of the third MOS tube is electrically connected to the output end of the backup power supply;

[0139] The current input end of the third MOS tube is electrically connected to the current input end of the fourth MOS tube;

[0140] The current output end of the fourth MOS tube is electrically connected to the output end of the main power supply circuit;

[0141] The control end of the third MOS tube is electrically connected to the control end of the fourth MOS tube;

[0142] The first end of the third resistor is electrically connected to the current input end of the third MOS tube;

[0143] The second end of the third resistor is electrically connected to the control end of the third MOS tube;

[0144] The first end of the fourth resistor is electrically connected to the control end of the third MOS tube;

[0145] The second end of the fourth resistor is electrically connected to the current input end of the second transistor;

[0146] The control end of the second transistor is electrically connected to the current output end of the third MOS tube;

[0147] The current output terminal of the second triode is grounded;

[0148] The current input end of the third triode is electrically connected to the current output end of the third MOS tube;

[0149] The control end of the third transistor is electrically connected to the output end of the control circuit;

[0150] The current output terminal of the third transistor is grounded.

[0151] As an example of an embodiment of the present invention, see Figure 3 , is a circuit diagram of an embodiment of a backup power supply circuit provided by the present invention. Figure 3 Output 1 is connected to the electrical equipment, and signal 1 comes from the output end of the control circuit.

[0152] Component 8 is a third MOS tube, and component 9 is a fourth MOS tube. Both the third MOS tube and the fourth MOS tube are PMOS tubes.

[0153] Component 11 is a third resistor, and component 12 is a fourth resistor. The third resistor and the fourth resistor are voltage-dividing resistors, and the voltage-dividing magnitude of the node 4 can be determined by adjusting the resistance values ​​of the first resistor and the second resistor.

[0154] Component 15 is a second triode, and component 16 is a third triode. Both the second triode and the third triode are NPN triodes.

[0155] Component 10 is a pull-up resistor, which provides a high level for the control terminal of the second transistor. Component 13 is a current limiting resistor.

[0156] Components 14 and 17 are pull-down resistors, which enable the control terminals of the second transistor and the third transistor to be pulled down to the ground signal when there is no high-level input, so as to prevent mis-conduction.

[0157] When the backup power supply is powered, node 3 is pulled up to the level of the backup power supply through the third MOS tube. If the third MOS tube and the fourth MOS tube are turned on, a path is formed between the backup power supply and "output 1", and the backup power supply supplies power to the power-consuming device. The on and off of the path between the backup power supply and the power-consuming device is controlled by the high and low levels of signal 1. Figure 3 Signal 2 in FIG. 1 is a signal related to the short-circuit protection circuit, which will be described in the subsequent short-circuit protection circuit.

[0158] Further, in an embodiment of the present invention, the control circuit includes: a switching circuit and a software control circuit;

[0159] The first input end of the switching circuit is electrically connected to the output end of the main power supply;

[0160] The second input end of the switching circuit is electrically connected to the output end of the backup power supply;

[0161] The first output terminal of the switching circuit is electrically connected to the second input terminal of the main power supply circuit;

[0162] The first output terminal of the switching circuit is electrically connected to the second input terminal of the backup power supply circuit;

[0163] The second output terminal of the switching circuit is electrically connected to the input terminal of the software control circuit;

[0164] The output terminal of the software control circuit is electrically connected to the third input terminal of the switching circuit.

[0165] See also Figure 4 , is a circuit diagram of another embodiment of the dual power supply circuit provided by the present invention, the control circuit includes a switching circuit and a software control circuit, the switching circuit is connected to the main power supply and the backup power supply, and switches the power supply of the electrical equipment by receiving signals from the main power supply and the backup power supply; the software control circuit is connected to the switching power supply, and transmits the software control signal to the switching power supply by receiving the software control signal, so that the switching power supply switches the power supply of the electrical equipment.

[0166] Further, in an embodiment of the present invention, the switching circuit includes: a fifth MOS transistor, a sixth MOS transistor and a fourth triode;

[0167] The current input end of the fifth MOS tube is electrically connected to the output end of the main power supply;

[0168] The current output end of the fifth MOS tube is electrically connected to the second input end of the main power supply circuit;

[0169] The current output end of the fifth MOS tube is electrically connected to the second input end of the backup power supply circuit;

[0170] The control end of the fifth MOS tube is electrically connected to the control end of the sixth MOS tube;

[0171] The current output end of the sixth MOS tube is electrically connected to the current output end of the fifth MOS tube;

[0172] The current input end of the sixth MOS tube is electrically connected to the current input end of the fourth triode;

[0173] The control end of the fourth transistor is electrically connected to the output end of the backup power supply;

[0174] The current output terminal of the fourth triode is grounded;

[0175] The current input end of the fourth transistor is electrically connected to the input end of the software control circuit;

[0176] The current input end of the fourth transistor is electrically connected to the output end of the main power supply;

[0177] The current input end of the sixth MOS tube is electrically connected to the output end of the software control circuit.

[0178] As an example of an embodiment of the present invention, see Figure 5, is a circuit diagram of an embodiment of a switching circuit provided by the present invention. Figure 5 Signal 1 of the switching circuit is output to the main power supply circuit and the backup power supply circuit, signal 3 is output to the software control circuit, and signal 4 comes from the software control circuit.

[0179] Component 25 is the fifth MOS tube, which is a PMOS tube. Component 26 is the sixth MOS tube, which is an NMOS tube, the drain of which is a current input terminal, the source of which is a current output terminal, and the gate of which is a control terminal. The characteristics of the NMOS tube are: when the gate voltage of the NMOS tube is greater than the source voltage of the NMOS tube and the difference is greater than or equal to the threshold voltage, the source of the NMOS tube and the drain of the NMOS tube are connected; when the gate voltage of the NMOS tube is less than or equal to the source voltage of the NMOS tube or the gate voltage of the NMOS tube is greater than the source voltage of the NMOS tube but the difference between the two is less than the threshold voltage, the source of the NMOS tube and the drain of the NMOS tube are not connected. Among them, NMOS tubes of different brands and specifications correspond to different threshold voltages.

[0180] Due to the characteristics of the NMOS tube, when the NMOS tube is not conducting, it is equivalent to a diode that conducts unidirectionally from the source of the NMOS tube to the drain of the NMOS tube between the drain of the NMOS tube and the source of the NMOS tube. Therefore, when the source voltage of the NMOS tube is greater than the drain voltage of the NMOS tube, due to the existence of the equivalent diode, the drain voltage of the NMOS tube will be pulled up to the same voltage as the source voltage of the NMOS tube; when the source voltage of the NMOS tube is less than the drain voltage of the NMOS tube, the drain voltage of the NMOS tube cannot pull up the source voltage of the NMOS tube.

[0181] Component 22 is a fourth transistor, and the fourth transistor is an NPN transistor. Components 18, 19, 20, 21, 23, 24, 27, 28, and 29 are resistors, and the resistance values ​​can be set according to actual application scenarios.

[0182] Further, in an embodiment of the present invention, the software control circuit includes: a fifth triode and a software control output terminal;

[0183] The current input terminal of the fifth triode is electrically connected to the software control output terminal;

[0184] The control end of the fifth transistor is electrically connected to the second output end of the switching circuit;

[0185] The current output terminal of the fifth transistor is electrically connected to the third input terminal of the switching circuit;

[0186] The current output terminal of the fifth transistor is grounded.

[0187] As an example of an embodiment of the present invention, see Figure 6 , is a circuit diagram of an embodiment of the software control circuit provided by the present invention. Figure 6 The signal 3 of the software control circuit comes from the switching circuit, and the signal 4 is output to the switching circuit.

[0188] Component 33 is a fifth transistor, and the fifth transistor is an NPN transistor. Components 30, 31, 32, and 34 are resistors, and the resistance values ​​can be set according to actual application scenarios.

[0189] Figure 6 The "control signal" here refers to the signal connected from the power-consuming device. The purpose of controlling the switching of the power supply can be achieved by outputting high and low level signals from the power-consuming device.

[0190] Furthermore, in the embodiment of the present invention, the dual power supply circuit further includes: a short circuit protection circuit;

[0191] The first input end of the short-circuit protection circuit is electrically connected to the output end of the main power supply circuit;

[0192] The second input end of the short circuit protection circuit is electrically connected to the output end of the main power supply;

[0193] The second input end of the short circuit protection circuit is electrically connected to the output end of the backup power supply;

[0194] The first output terminal of the short-circuit protection circuit is electrically connected to the input terminal of the electrical device;

[0195] The second output terminal of the short-circuit protection circuit is electrically connected to the second input terminal of the main power supply circuit;

[0196] The third output terminal of the short circuit protection circuit is electrically connected to the third input terminal of the backup power supply circuit.

[0197] See also Figure 7 , is a circuit diagram of another embodiment of the dual power supply circuit provided by the present invention, wherein the first input end of the short-circuit protection circuit receives a signal from the main power supply circuit, the second input end receives a signal from the main power supply and the backup power supply, the first output end is connected to the power-consuming device, the second output end outputs a signal to the main power supply circuit, and the third output end outputs a signal to the backup power supply circuit. The short-circuit protection circuit is used to protect the power supply circuit. When a short-circuit fault occurs in the power-consuming device, the path between the main power supply and the power-consuming device, as well as the path between the backup power supply and the power-consuming device are disconnected, so that neither the main power supply nor the backup power supply can supply power to the power-consuming device, and the power supply is continuously cut off, requiring manual intervention to restore power supply, thereby preventing the power supply from automatically restoring power supply when the short-circuit fault of the power-consuming device has not been resolved, causing the device to burn out.

[0198] Further, in an embodiment of the present invention, the short-circuit protection circuit includes: a current sampling resistor, a first transistor output optocoupler, a second transistor output optocoupler, a third transistor output optocoupler, a seventh MOS tube and an eighth MOS tube;

[0199] The first end of the current sampling resistor is electrically connected to the output end of the main power supply circuit;

[0200] The second end of the current sampling resistor is electrically connected to the input end of the electrical device;

[0201] The input anode of the first transistor output optocoupler is electrically connected to the first end of the current sampling resistor;

[0202] The cathode of the input end of the first transistor output optocoupler is electrically connected to the second end of the current sampling resistor;

[0203] The output collector of the first transistor output optocoupler is electrically connected to the output collector of the second transistor output optocoupler;

[0204] The emitter of the output terminal of the first transistor output optocoupler is electrically connected to the anode of the input terminal of the second transistor output optocoupler;

[0205] The cathode of the input terminal of the second transistor output optocoupler is electrically connected to the anode of the input terminal of the third transistor output optocoupler;

[0206] The output end emitter of the second transistor output optocoupler is electrically connected to the output end emitter of the first transistor output optocoupler;

[0207] The cathode of the input end of the third transistor output optical coupler is electrically connected to the control end of the seventh MOS transistor;

[0208] The collector of the output end of the third transistor output optocoupler is electrically connected to the current input end of the seventh MOS tube;

[0209] The output end emitter of the third transistor output optocoupler is grounded;

[0210] The current input end of the seventh MOS tube is electrically connected to the current input end of the eighth MOS tube;

[0211] The control end of the seventh MOS tube is electrically connected to the control end of the eighth MOS tube;

[0212] The current output end of the seventh MOS tube is electrically connected to the second input end of the main power supply circuit;

[0213] The current output end of the eighth MOS tube is electrically connected to the third input end of the backup power supply circuit;

[0214] The collector of the output end of the first transistor output optocoupler is electrically connected to the output end of the main power supply;

[0215] The collector of the output end of the first transistor output optocoupler is electrically connected to the output end of the backup power supply.

[0216] Further, in the embodiment of the present invention, the current output end of the eighth MOS tube is electrically connected to the third input end of the backup power supply circuit, specifically:

[0217] The current output end of the eighth MOS tube is electrically connected to the control end of the second transistor.

[0218] As an example of an embodiment of the present invention, see Figure 8 , is a circuit diagram of an embodiment of a short-circuit protection circuit provided by the present invention. Figure 8 Output 1 is connected to the electrical equipment; signal 1 is output to the main power supply circuit; signal 2 is output to the backup power supply circuit, specifically connected to the control end of the second transistor in the backup power supply circuit; signal 6 comes from the main power supply and the backup power supply, and the connection between the main power supply and the backup power supply and the short-circuit protection circuit is that the main power supply and the backup power supply are connected to the short-circuit protection circuit through a diode respectively. Since the function of the connection between the main power supply and the backup power supply and the short-circuit protection circuit is only to provide a high level, and not to power any working equipment, the voltage drop and power consumption of the diodes between them can be ignored.

[0219] Component 35 is a current sampling resistor, and its resistance value is usually very small, and the voltage drop in the circuit is very small. Only when a short circuit occurs in the electrical equipment, the current in the circuit suddenly increases, which will cause the voltage difference across the component 35 to increase.

[0220] Component 37 is the first transistor output optocoupler, component 38 is the second transistor output optocoupler, and component 39 is the third transistor output optocoupler. The transistor output optocoupler is divided into a left input port and a right output port. The left end is equivalent to an infrared diode, and the right end is equivalent to an NPN transistor without a B pole. When the required voltage is applied to the anode input and cathode input at the left end, the diode emits infrared light, which becomes the excitation of the output end. At this time, the collector of the output end and the emitter of the output end are turned on. When there is no input at the left end, the collector of the output end and the emitter of the output end are not turned on.

[0221] Component 36 , component 40 , component 41 , component 42 , and component 43 are resistors, and the resistance values ​​can be set according to actual application scenarios.

[0222] Component 44 is the seventh MOS transistor, component 45 is the eighth MOS transistor, and both the seventh MOS transistor and the eighth MOS transistor are NMOS transistors.

[0223] Accordingly, see Fig. 9 , is a flow chart of an embodiment of a dual power supply circuit control method provided by the present invention, the control method includes steps 101 to 105, each step is specifically as follows:

[0224] Step 101: Utilize a main power supply circuit to receive a first voltage signal sent by a main power supply.

[0225] Step 102: Utilize the backup power supply circuit to receive a second voltage signal sent by the backup power supply.

[0226] Step 103: Utilize the control circuit to receive the software control signal.

[0227] Step 104: Determine a power supply by combining the first voltage signal, the second voltage signal and the software control signal.

[0228] Step 105: Control the power supply to supply power to the electrical equipment; wherein the power supply includes a main power supply and a backup power supply.

[0229] As an example of an embodiment of the present invention, see Figure 2 The main power supply and the electrical equipment are connected through the main power supply circuit. The signal that controls the on / off of this path is signal 1. Its working principle is:

[0230] When signal 1 is at a high level, the collector and emitter of component 5 are turned on, which is equivalent to the collector being grounded, and a path is formed between node 1 and the ground, so a voltage division is generated at node 2. The magnitude of the voltage division can be adjusted by adjusting the resistance values ​​of components 3 and 4. Because it is a voltage division, the voltage value of node 2 must be smaller than the voltage value of node 1. Then, according to the actual application situation, the resistance values ​​of components 3 and 4 are designed so that the difference between the voltage division obtained at node 2 and the voltage at node 1 is greater than the threshold voltage of components 1 and 2. Then, the drain and source of components 1 and 2 are turned on, forming a path between the main power supply and "output 1";

[0231] When signal 1 is at a low level, the collector and emitter of component 5 are not conducting, and node 1 cannot form a path with the ground, so node 2 is pulled up to the same voltage value as node 1 through component 3. At this time, the gate and source voltages of components 1 and 2 are the same, and the gate and source of components 1 and 2 are not conducting, so there is no path between the main power supply and "output 1", and the main power supply cannot power the electrical equipment.

[0232] As an example of an embodiment of the present invention, see Figure 3 The backup power supply and the power-consuming equipment are connected through the backup power supply circuit. The signal that controls the on-off of this path is signal 1. Its working principle is: The signal that controls the on-off of this path is signal 1. Its working principle is:

[0233] When signal 1 is at a high level, the collector and emitter of component 16 are turned on, which is equivalent to the C pole of component 16 being grounded, and the B pole of component 15 being pulled down to a low level. At this time, the collector and emitter of component 15 are not turned on. Since node 3 has no path to the ground, no current or voltage division can be generated, so at this time node 4 is pulled up to the same level as node 3 through component 11. The gate and source levels of components 8 and 9 are the same, so the drain and source of components 8 and 9 are not turned on.

[0234] Combined with the analysis of the main power supply circuit, when signal 1 is at a high level, the main power supply is used to power the electrical equipment. At this time, "output 1" is at the same level as the main power supply. Since components 8 and 9 are not turned on, no matter which power supply has a higher voltage, it will only stay at node 3 and will not cause current backflow.

[0235] When signal 1 is at a low level, the collector and emitter of component 16 are not conducting. At this time, the base of component 15 is connected to the backup power supply through components 13 and 10, and is at a high level. The collector and emitter of component 15 are conducting, which is equivalent to the collector grounding signal. There is a path between node 3 and the ground, and current and voltage division are generated in this path. By setting the resistance values ​​of components 11 and 12, the voltage division size of node 4 can be controlled, so that at this time, the voltage difference between the gate and source of components 8 and 9 is greater than the threshold voltage, the drain and the source are conducting, and the backup power supply forms a path with "output 1", and the backup power supply supplies power to the electrical equipment.

[0236] Combined with the analysis of the main power supply circuit, when signal 1 is at a low level, the path between the main power supply and "output 1" is disconnected, and the electrical equipment cannot be powered. Therefore, a backup power supply is needed to power the electrical equipment at this time.

[0237] As an example of an embodiment of the present invention, see Figure 5 The switching circuit is used to switch the main power supply and the backup power supply, and the switching principle is: when both the main power supply and the backup power supply are powered, the main power supply is used to power the power-consuming equipment by default, that is, the default setting signal 1 is high level; when both the main power supply and the backup power supply are powered, the switching of the main power supply and the backup power supply can be controlled by the high and low level changes of signal 1 through software control; when the main power supply is powered and the backup power supply is not powered, the main power supply is used for power supply and the software control cannot cause the high and low level changes of signal 1 at this time, that is, the software cannot switch the power supply equipment at this time; when the backup power supply is powered and the main power supply is not powered, the backup power supply is used for power supply and the software cannot switch the power supply equipment at this time.

[0238] The following is a detailed description of the principle of the switching circuit for the case where both the main power supply and the backup power supply are powered:

[0239] The main power supply is connected to the ground through components 19 and 21, and a voltage division is generated at node 6. The voltage division size can be adjusted by setting the resistance values ​​of components 19 and 21, and the voltage division is applied to the source of component 25. The backup power supply is connected to the ground through components 28 and 29, and a voltage division is generated at node 7. The voltage division size can be adjusted by setting the resistance values ​​of components 28 and 29, and the voltage division is applied to the gates of components 25 and 26.

[0240] The corresponding resistance value is set so that the gate voltage of component 25 is less than the source voltage and the voltage difference is greater than or equal to the threshold voltage, the source and drain of component 25 are turned on, and the main power supply is connected to signal 1 through components 19, 25, and 27, providing a high level; the corresponding resistance value is set so that the gate and source voltage difference of component 26 does not meet the conduction condition at this time, and component 26 only has an equivalent diode that conducts unidirectionally from source to drain. At the same time, the backup power supply provides a high level to the base of component 22 through component 23, and the collector and emitter of component 22 are turned on, which is equivalent to the collector being grounded. The main power supply is grounded through components 18, 20, and 22, and a voltage division is generated at node 5, that is, signal 3.

[0241] When signal 3 is at a high level, the software control circuit is turned on, and the software control signal is connected to signal 4 through the software control circuit.

[0242] When the software control signal is at a high level, signal 4 is at a high level, which has no effect on the high level of signal 1 at this time; when the software control signal is at a low level, signal 4 is at a low level. Due to the existence of the equivalent diode of component 26, signal 1 is pulled down to a low level at this time, and the power supply equipment is switched to a backup power supply.

[0243] As an example of an embodiment of the present invention, Figure 6 The software control circuit of the control circuit is described in detail:

[0244] 1. For the situation where both the main power supply and the backup power supply are powered:

[0245] When the main power supply is powered, signal 3 is high level, signal 3 passes through component 32 to the base high level signal of component 33, the collector and emitter of component 33 are turned on, and the control signal is transmitted to node 9 through components 30 and 33. The signal at node 9 is signal 4, combined with Figure 5 Signal 4 is also connected to the collector of component 22 through component 24, so the level of signal 4 is affected by the collector voltage of component 22 and the level of the control signal.

[0246] When the backup power supply is powered, component 22 is turned on, and the collector is connected to the ground signal, that is, signal 4 is connected to the ground through two paths, one is connected to the ground through components 24 and 22, and the other is connected to the ground through component 35. At this time, the high and low level changes of the control signal will not be directly pulled to a high level by other paths when it reaches signal 4 through components 30 and 33, but can change with the change of the control signal.

[0247] Therefore, when the main power supply and the backup power supply are powered, the high and low level changes of the control signal can affect the high and low level changes of signal 4. Figure 5 , when signal 4 is high, it does not affect the high level of signal 1, but due to the existence of the equivalent diode of the MOS tube, when signal 4 is low, it will pull down signal 1 to a low level. Therefore, at this time, the high and low levels of the control signal can affect the high and low levels of signal 1, thereby determining whether the main power supply or the backup power supply is used to power the electrical equipment.

[0248] 2. For the situation where the main power supply is powered but the backup power supply is not powered:

[0249] Combination Figure 5 When the backup power supply is out of power, component 22 is not conducting, signal 3 is pulled up to a high level through component 18, and signal 4 is pulled up to a high level through components 18, 20 and 24.

[0250] When signal 3 is at a high level, the collector and emitter of component 33 are turned on, and the high and low level changes of the control signal are transmitted to signal 4 through components 30 and 33. However, at this time, one path of signal 4 is pulled up to the main power supply through components 18, 20 and 24, and one path is connected to the ground through component 34. A voltage division will be generated at node 9, and the voltage division size is related to the resistance value of components 18, 20, 24 and 34. The high and low level changes of the control signal will be carried out based on this voltage division. By properly adjusting the parameters of each component, the level change of signal 4 can always be greater than Figure 2 Component 5 and Figure 3 The base conduction voltage of component 16 is turned on. When signal 4 pulls the voltage of signal 1 down to the same level as signal 4 through component 26, the voltage of signal 1 is also sufficient to turn on components 5 and 16. Although the control signal will output high and low levels at this time, it cannot control the switching of the power supply, and the power is always supplied by the main power supply.

[0251] 3. For the situation where the main power supply is out of power but the backup power supply is available:

[0252] Combination Figure 5It can be seen that when the backup power supply is powered, component 22 is turned on and the collector of component 22 is grounded. At this time, the main power supply is powered off, so signal 3 is grounded through components 20 and 22 and is at a low level. One path of signal 4 is grounded through component 34, and the other path is also connected to the ground through components 24 and 22.

[0253] Since the signal 3 is at a low level, the component 33 is not conducting, and the control signal cannot be transmitted to the node 9 through the component 33 , that is, the signal 4 cannot be affected.

[0254] Therefore, when the main power supply is off and the backup power supply is on, signal 4 is always at a low level, and signal 4 always pulls signal 1 down to a low level through component 26, and the backup power supply is used for power supply.

[0255] As an example of an embodiment of the present invention, see Figure 8 , the working principle of the short-circuit protection circuit is:

[0256] When the electrical equipment does not fail, since the resistance of component 35 is very small, the voltage difference between the two ends of component 35 is also very small. This voltage difference is input to the input end of component 37 through component 36, which is not enough to make the diode emit infrared light, so the collector and the output emitter of component 37 are not conducting. The anode of the input end of component 38 is connected to the ground through component 40, and the cathode of the input end is connected to the ground through component 41, so the collector and the emitter of the output end of component 38 are not conducting. The anode of the input end of component 39 is connected to the ground through component 41, and the cathode of the input end is connected to the ground through components 42 and 43, so the collector and the emitter of the output end of component 38 are not conducting. At the same time, the gates of components 44 and 45 are connected to the ground through component 43, which is a low level and does not meet the conduction condition of the NMOS transistor, so components 44 and 45 are not conducting. And because the NMOS transistor has an equivalent diode, the level of signal 1 and signal 2 will not be affected by signal 5.

[0257] When a short circuit occurs in an electrical device, the current in the circuit suddenly increases, which causes the voltage difference at both ends of component 35 to increase. The resistance value of component 35 is appropriately selected so that the voltage difference at this time is sufficient to open the diode at the input end of component 37. Then, the output collector and the output emitter of component 37 are turned on, and the high level of signal 6 enters the input end of component 38 through component 37, causing the output collector and the output emitter of component 38 to be turned on.

[0258] The output collector of component 38 is connected to signal 6. When the output of component 38 is turned on, the output emitter obtains a high level. At the same time, the output emitter is connected to the input anode to ensure that the self-locking circuit is continuously activated after the component is turned on.

[0259] Signal 6 passes through the output collector and output emitter of component 37 and the diode of component 38, and is input to the input of component 39. The output collector and output emitter of component 39 are turned on, and signal 5 is at a low level. At the same time, a voltage division is obtained at node 10, and its voltage division value can be adjusted by the resistance value of components 42 and 43.

[0260] Adjust the hardware parameters so that the gate and source voltage difference of components 44 and 45 is greater than the threshold voltage, components 44 and 45 are turned on, and signal 1 and signal 2 are pulled down to the ground signal by signal 5, and the main power supply and the backup power supply cannot supply power.

[0261] In summary, the embodiment of the present invention provides a dual power supply circuit and a control method thereof, the power supply circuit includes a main power supply, a main power supply circuit, a backup power supply, a backup power supply circuit, a control circuit and an electric device. Regardless of the magnitude relationship between the voltages of the main power supply and the backup power supply, the main power supply circuit is used for power supply by default without software control. If the main power supply loses power to a certain extent, the backup power supply is switched by the switching circuit; when the main power supply and the backup power supply are both in a power supplyable state, the power supply is switched by receiving a control signal sent by the electric device and combining with the software control circuit; when a short circuit fault occurs in the electric device, the power supply is cut off by the short circuit protection circuit and the power supply is kept cut off. The present invention uses triodes and MOS tubes to complete the dual power supply function, and the low on-resistance characteristic of the MOS tube when it is turned on greatly reduces the power consumption; regardless of the magnitude of the voltages of the main power supply and the backup power supply, the main power supply is used for power supply by default, reducing the limitation of voltage selection; the power supply can be freely selected by software, which improves the comprehensiveness of the applicability of the power supply circuit; the power supply circuit is protected by the short circuit protection circuit, which improves the safety of the circuit.

[0262] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dual power supply circuit, characterized in that: include: Main power supply, main power supply circuit, backup power supply, backup power supply circuit, control circuit and power-consuming equipment; The first input end of the main power supply circuit is electrically connected to the output end of the main power supply; The output end of the main power supply circuit is electrically connected to the input end of the power-consuming device; The first input end of the backup power supply circuit is electrically connected to the output end of the backup power supply; The output end of the backup power supply circuit is electrically connected to the output end of the main power supply circuit; The first input terminal of the control circuit is electrically connected to the output terminal of the main power supply; The second input end of the control circuit is electrically connected to the output end of the backup power supply; The output end of the control circuit is electrically connected to the second input end of the main power supply circuit; The output end of the control circuit is electrically connected to the second input end of the backup power supply circuit.

2. The dual power supply circuit according to claim 1, characterized in that: The main power supply circuit comprises: a first MOS tube, a second MOS tube, a first resistor, a second resistor and a first triode; The current output end of the first MOS tube is electrically connected to the output end of the main power supply; The current input end of the first MOS tube is electrically connected to the current input end of the second MOS tube; The current output end of the second MOS tube is electrically connected to the input end of the electrical device; The control end of the first MOS tube is electrically connected to the control end of the second MOS tube; The first end of the first resistor is electrically connected to the current input end of the first MOS tube; The second end of the first resistor is electrically connected to the control end of the first MOS tube; The first end of the second resistor is electrically connected to the control end of the first MOS tube; The second end of the second resistor is electrically connected to the current input end of the first transistor; The control end of the first transistor is electrically connected to the output end of the control circuit; The current output terminal of the first transistor is grounded.

3. The dual power supply circuit according to claim 2, characterized in that: The backup power supply circuit comprises: a third MOS tube, a fourth MOS tube, a third resistor, a fourth resistor, a second triode and a third triode; The current output end of the third MOS tube is electrically connected to the output end of the backup power supply; The current input end of the third MOS tube is electrically connected to the current input end of the fourth MOS tube; The current output end of the fourth MOS tube is electrically connected to the output end of the main power supply circuit; The control end of the third MOS tube is electrically connected to the control end of the fourth MOS tube; The first end of the third resistor is electrically connected to the current input end of the third MOS tube; The second end of the third resistor is electrically connected to the control end of the third MOS tube; The first end of the fourth resistor is electrically connected to the control end of the third MOS tube; The second end of the fourth resistor is electrically connected to the current input end of the second transistor; The control end of the second transistor is electrically connected to the current output end of the third MOS tube; The current output terminal of the second triode is grounded; The current input end of the third triode is electrically connected to the current output end of the third MOS tube; The control end of the third transistor is electrically connected to the output end of the control circuit; The current output terminal of the third transistor is grounded.

4. The dual power supply circuit according to claim 3, characterized in that: The control circuit includes: a switching circuit and a software control circuit; The first input end of the switching circuit is electrically connected to the output end of the main power supply; The second input end of the switching circuit is electrically connected to the output end of the backup power supply; The first output terminal of the switching circuit is electrically connected to the second input terminal of the main power supply circuit; The first output terminal of the switching circuit is electrically connected to the second input terminal of the backup power supply circuit; The second output terminal of the switching circuit is electrically connected to the input terminal of the software control circuit; The output terminal of the software control circuit is electrically connected to the third input terminal of the switching circuit.

5. The dual power supply circuit according to claim 4, characterized in that: The switching circuit comprises: a fifth MOS tube, a sixth MOS tube and a fourth triode; The current input end of the fifth MOS tube is electrically connected to the output end of the main power supply; The current output end of the fifth MOS tube is electrically connected to the second input end of the main power supply circuit; The current output end of the fifth MOS tube is electrically connected to the second input end of the backup power supply circuit; The control end of the fifth MOS tube is electrically connected to the control end of the sixth MOS tube; The current output end of the sixth MOS tube is electrically connected to the current output end of the fifth MOS tube; The current input end of the sixth MOS tube is electrically connected to the current input end of the fourth triode; The control end of the fourth transistor is electrically connected to the output end of the backup power supply; The current output terminal of the fourth triode is grounded; The current input end of the fourth transistor is electrically connected to the input end of the software control circuit; The current input end of the fourth transistor is electrically connected to the output end of the main power supply; The current input end of the sixth MOS tube is electrically connected to the output end of the software control circuit.

6. The dual power supply circuit according to claim 5, characterized in that: The software control circuit comprises: a fifth triode and a software control output terminal; The current input terminal of the fifth triode is electrically connected to the software control output terminal; The control end of the fifth transistor is electrically connected to the second output end of the switching circuit; The current output terminal of the fifth transistor is electrically connected to the third input terminal of the switching circuit; The current output terminal of the fifth transistor is grounded.

7. The dual power supply circuit according to claim 6, characterized in that: Also includes: Short circuit protection circuit; The first input end of the short-circuit protection circuit is electrically connected to the output end of the main power supply circuit; The second input end of the short circuit protection circuit is electrically connected to the output end of the main power supply; The second input end of the short circuit protection circuit is electrically connected to the output end of the backup power supply; The first output terminal of the short-circuit protection circuit is electrically connected to the input terminal of the electrical device; The second output terminal of the short-circuit protection circuit is electrically connected to the second input terminal of the main power supply circuit; The third output terminal of the short circuit protection circuit is electrically connected to the third input terminal of the backup power supply circuit.

8. The dual power supply circuit according to claim 7, characterized in that: The short-circuit protection circuit comprises: a current sampling resistor, a first transistor output optocoupler, a second transistor output optocoupler, a third transistor output optocoupler, a seventh MOS tube and an eighth MOS tube; The first end of the current sampling resistor is electrically connected to the output end of the main power supply circuit; The second end of the current sampling resistor is electrically connected to the input end of the electrical device; The input anode of the first transistor output optocoupler is electrically connected to the first end of the current sampling resistor; The cathode of the input end of the first transistor output optocoupler is electrically connected to the second end of the current sampling resistor; The output collector of the first transistor output optocoupler is electrically connected to the output collector of the second transistor output optocoupler; The emitter of the output terminal of the first transistor output optocoupler is electrically connected to the anode of the input terminal of the second transistor output optocoupler; The cathode of the input terminal of the second transistor output optocoupler is electrically connected to the anode of the input terminal of the third transistor output optocoupler; The output end emitter of the second transistor output optocoupler is electrically connected to the output end emitter of the first transistor output optocoupler; The cathode of the input end of the third transistor output optical coupler is electrically connected to the control end of the seventh MOS transistor; The collector of the output end of the third transistor output optocoupler is electrically connected to the current input end of the seventh MOS tube; The output end emitter of the third transistor output optocoupler is grounded; The current input end of the seventh MOS tube is electrically connected to the current input end of the eighth MOS tube; The control end of the seventh MOS tube is electrically connected to the control end of the eighth MOS tube; The current output end of the seventh MOS tube is electrically connected to the second input end of the main power supply circuit; The current output end of the eighth MOS tube is electrically connected to the third input end of the backup power supply circuit; The collector of the output end of the first transistor output optocoupler is electrically connected to the output end of the main power supply; The collector of the output end of the first transistor output optocoupler is electrically connected to the output end of the backup power supply.

9. The dual power supply circuit according to claim 8, characterized in that: The current output end of the eighth MOS tube is electrically connected to the third input end of the backup power supply circuit, specifically: The current output end of the eighth MOS tube is electrically connected to the control end of the second transistor.

10. A dual power supply circuit control method, characterized in that: A dual power supply circuit for controlling any one of claims 1 to 9, comprising: Utilizing a main power supply circuit to receive a first voltage signal emitted by a main power supply; Utilizing the backup power supply circuit to receive a second voltage signal sent by the backup power supply; receiving a software control signal using a control circuit; determining a power supply by combining the first voltage signal, the second voltage signal and the software control signal; Controlling the power supply to supply power to the electrical equipment; Wherein, the power supply includes a main power supply and a backup power supply.

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