Double-path power supply circuit capable of actively cutting off auxiliary power supply

Abstract

The utility model discloses a double-path power supply circuit capable of actively cutting off an auxiliary power supply. The double-path power supply circuit comprises a switching time setting circuit, a switching control circuit, a power switch MOS circuit and a double-diode circuit which are connected in sequence, the switch time setting circuit is used for adjusting the switch time point of the switch MOS, the switch control circuit is used for processing power-on of a main power supply to logic conversion of the switch MOS, the power supply switch MOS circuit is used for opening or closing a path of an auxiliary power supply, and the double-diode circuit is used for combining two paths of power supplies into one path of power supply for output. Compared with the prior art, the active control switching circuit is added, and passive switching of a main power supply is changed into active switching of the power supply at a proper opportunity, so that overlarge voltage drop caused by passive switching of the power supply at the moment of high load and large current is avoided, the amplitude of the voltage drop is greatly reduced, and the possibility of abnormal working of devices is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of servers, in particular to a dual-path power supply circuit for actively cutting off an auxiliary power supply. Background Art

[0002] Most motherboard systems have both a main power supply and an auxiliary power supply. The main power supply is used for high-current output during startup, while the auxiliary power supply is used to keep some circuits functioning properly when the system enters shutdown or hibernation mode, ensuring ready response to startup and exit from hibernation. A common solution is to connect the two power supplies in parallel using two diodes. The disadvantage of this approach is a voltage drop when the auxiliary power supply switches to the main power supply. For devices far from the power supply, the voltage drop is more pronounced due to the voltage drop in the traces, causing device malfunction. Utility Model Content

[0003] The purpose of the utility model is to provide a dual-power supply circuit that actively cuts off the auxiliary power supply, aiming to solve the problem in the prior art that when the auxiliary power supply is switched to the main power supply, there will be a voltage drop, which will cause abnormal operation of the device.

[0004] In order to solve the above technical problems, the purpose of this utility model is achieved through the following technical solutions:

[0005] A specific embodiment of the present application provides a dual-power supply circuit that actively cuts off an auxiliary power supply, comprising: a switching time setting circuit, a switch control circuit, a power switch MOS circuit, and a dual diode circuit connected in sequence; the switching time setting circuit is used to adjust the switching time point of the switch MOS, the switch control circuit is used to process the logic conversion from powering on the main power supply to the switch MOS, the power switch MOS circuit is used to open or close the path of the auxiliary power supply, and the dual diode circuit is used to merge the two power supplies into one power output.

[0006] In one possible implementation, a first end of the power switch MOS circuit is connected to an auxiliary power supply, a first end of the switch time setting circuit is connected to a main power supply, a second end of the switch time setting circuit is connected to a first end of the switch control circuit, a second end of the switch control circuit is connected to a second end of the power switch MOS circuit, a third end of the power switch MOS circuit is connected to a first end of the dual diode circuit, a second end of the dual diode circuit is connected to the main power supply, and a third end of the dual diode circuit is connected to an output power supply.

[0007] In one possible implementation, the switching time setting circuit includes: a first resistor, a second resistor, and a first capacitor; the first end of the first resistor is connected to a main power supply, and the second end of the first resistor is respectively connected to the first end of the second resistor and the first end of the first capacitor; the first end of the first capacitor is respectively connected to the second end of the first resistor and the switching control circuit; the second end of the first capacitor is grounded; and the second end of the second resistor is grounded.

[0008] In one possible implementation, the switch control circuit includes: a second capacitor, a third resistor, a fourth resistor, and an inverting amplifier; an inverting input terminal of the inverting amplifier is connected to the switch time setting circuit; a power input terminal of the inverting amplifier is connected to a main power supply; a ground terminal of the inverting amplifier is grounded; a signal output terminal of the inverting amplifier is connected to a first terminal of the second capacitor; a second terminal of the second capacitor is respectively connected to a first terminal of the fourth resistor and the power switch MOS circuit; a second terminal of the fourth resistor is grounded; a first terminal of the third resistor is respectively connected to an auxiliary power supply and the power switch MOS circuit; and a second terminal of the third resistor is connected to a first terminal of the fourth resistor.

[0009] In one possible implementation, the switch control circuit further includes a discharge circuit, which includes: a third diode and a seventh resistor; the anode of the third diode is connected to the first end of the seventh resistor; the cathode of the third diode is connected to the first end of the second capacitor; and the second end of the second capacitor is connected to the second end of the seventh resistor.

[0010] In one possible implementation, the power switch MOS circuit includes: a fifth resistor, a sixth resistor, an NMOS transistor, and a PMOS transistor; the gate of the NMOS transistor is connected to the switch control circuit; the source of the NMOS transistor is grounded; the drain of the NMOS transistor is connected to the second end of the sixth resistor; the first end of the sixth resistor is respectively connected to the second end of the fifth resistor and the gate of the PMOS transistor; the first end of the fifth resistor is respectively connected to the auxiliary power supply and the source of the PMOS transistor; and the drain of the PMOS transistor is connected to the dual-diode circuit.

[0011] In a possible implementation, the dual-diode circuit includes an auxiliary power supply circuit, a main power supply circuit, and an output circuit, wherein the auxiliary power supply circuit is connected to the main power supply circuit and coupled to the output circuit.

[0012] In one possible implementation, the auxiliary power supply circuit includes: a third capacitor, a fourth capacitor and a first diode; the first end of the third capacitor is respectively connected to the power switch MOS circuit and the anode of the first diode; the second end of the third capacitor is grounded; the first end of the fourth capacitor is respectively connected to the first end of the third capacitor and the first end of the first diode; the second end of the fourth capacitor is grounded; and the cathode of the first diode is connected to the main power supply circuit.

[0013] In one possible implementation, the main power supply circuit includes: a fifth capacitor, a sixth capacitor and a second diode; the first end of the fifth capacitor is respectively connected to the main power supply and the anode of the second diode; the second end of the fifth capacitor is grounded; the first end of the sixth capacitor is respectively connected to the first end of the fifth capacitor and the anode of the second diode; the second end of the sixth capacitor is grounded; and the cathode of the second diode is connected to the auxiliary power supply circuit.

[0014] In one possible implementation, the output circuit includes: a seventh capacitor and an eighth capacitor; the first end of the seventh capacitor is respectively connected to the auxiliary power supply circuit, the main power supply circuit, and the output power supply; the second end of the seventh capacitor is grounded; the first end of the eighth capacitor is respectively connected to the first end of the seventh capacitor and the output power supply; and the second end of the eighth capacitor is grounded.

[0015] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a dual-power supply circuit that actively cuts off the auxiliary power supply for an existing dual-power supply system. The dual-power supply circuit is composed of a switch time setting circuit, a switch control circuit, a power switch MOS circuit, and a dual diode circuit. The switch time setting circuit is used to adjust the switch time point of the switch MOS, the switch control circuit is used to process the logic conversion from the main power supply power-on to the switch MOS, the power switch MOS circuit is used to open or close the auxiliary power path, and the dual diode circuit is used to merge the two power supplies into one power output. Compared with the prior art, the present invention adds an active control switching circuit, changing the passive switching of the main power supply to the active selection of the appropriate time to switch the power supply, avoiding excessive voltage drops caused by passive power switching at high load and high current moments, greatly reducing the amplitude of the voltage drop, and reducing the possibility of abnormal device operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a circuit schematic diagram of a dual power supply system in the prior art in standby mode;

[0018] Figure 2 This is a circuit schematic diagram of a dual power supply system in the prior art in the power-on state (early stage);

[0019] Figure 3 This is a circuit schematic diagram of a dual power supply system in the prior art in the power-on state (load increases instantaneously);

[0020] Figure 4 A schematic diagram of the circuit structure of a dual-power supply circuit that actively cuts off the auxiliary power supply provided by an embodiment of the utility model;

[0021] Figure 5 This is a circuit schematic diagram of a dual-power supply circuit that actively cuts off the auxiliary power supply provided by an embodiment of the utility model.

[0022] Reference numerals:

[0023] 10. Switching time setting circuit; 20. Switching control circuit; 30. Power switch MOS circuit; 40. Dual diode circuit; 401. Auxiliary power supply circuit; 402. Main power supply circuit; 403. Output circuit. DETAILED DESCRIPTION

[0024] 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 embodiments described are 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 making creative efforts are within the scope of protection of the present invention.

[0025] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0026] It should also be understood that the terms used in this utility model specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model. As used in this utility model specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0027] It should be further understood that the term “and / or” used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0028] See also Figures 1 to 3 The prior art provides a main power supply and auxiliary power supply coexistence circuit system composed of two diodes, D1 inputs a small current Vstby and D2 inputs a large current Vmain dual power supply, and synthesizes a Vout power supply. Figure 1 As shown, when the system is in standby mode, the Vstby power supply works normally and the Vmain power supply is at 0V output, that is, Vstby has power but Vmain has no power, and the system is only powered by D1. When the system is in the power-on state (early stage), as shown Figure 2 As shown in the figure, both Vstby and Vmain have power, but due to the difference in the parameters of D1 and D2, the on-state voltage of D2 is greater than that of D1. When D1 is on, under the premise of Vstby=Vmain, the voltage difference of D2 is insufficient to turn on, and only D1 can turn on the power supply. When the system is in the power-on state (the load increases instantly), as shown in the figure, Figure 3 As shown in the figure, because D2 is not turned on early, the power supply capacity of D1 is limited. When the device is turned on and working normally, a large current arrives instantly, causing the Vout voltage to drop. That is, when Vout suddenly has a large current demand, Vstby cannot meet the large current, resulting in a voltage drop. The remote device will have the risk of abnormal operation due to excessive voltage drop.

[0029] See also Figures 4 and 5 , please refer to Figure 4 An embodiment of the present invention provides a dual-power supply circuit for actively cutting off an auxiliary power supply, comprising: a switching time setting circuit 10, a switch control circuit 20, a power switch MOS circuit 30, and a dual diode circuit 40 connected in sequence; the switching time setting circuit 10 is used to adjust the switching time point of the switch MOS, the switch control circuit 20 is used to process the logic conversion from the main power supply being powered on to the switch MOS, the power switch MOS circuit 30 is used to open or close the auxiliary power path, and the dual diode circuit 40 is used to merge the two power supplies into one power output.

[0030] Specifically, the switching time setting circuit 10 primarily functions to adjust the switching timing of the metal oxide semiconductor field effect transistor (MOS) switch. By precisely setting the switching timing, the circuit can ensure smoother and more reliable switching between the main power supply and the auxiliary power supply. The switch control circuit 20 is primarily responsible for processing the process from the main power supply powering on to the logic conversion of the MOS switch. When the main power supply is powered on, the switch control circuit 20 receives a corresponding signal and controls the MOS switch according to preset logic rules to achieve the switching function of the circuit. The power switch MOS circuit 30 is the core component of the circuit, used to open or close the auxiliary power path. By controlling the on and off of the power switch MOS, it can achieve flexible control of the auxiliary power supply, thereby ensuring more efficient and stable switching between the main power supply and the auxiliary power supply. The dual diode circuit 40 primarily functions to combine the two power supplies into a single power output. Through the rectification and combining action of the dual diodes, the output voltages of the main power supply and the auxiliary power supply can be combined into a stable output voltage to meet the power requirements of the circuit.

[0031] like Figure 4-5 As shown, a first end of the power switch MOS circuit 30 is connected to the auxiliary power supply, a first end of the switch time setting circuit 10 is connected to the main power supply, a second end of the switch time setting circuit 10 is connected to a first end of the switch control circuit 20, a second end of the switch control circuit 20 is connected to a second end of the power switch MOS circuit 30, a third end of the power switch MOS circuit 30 is connected to a first end of the dual diode circuit 40, a second end of the dual diode circuit 40 is connected to the main power supply, and a third end of the dual diode circuit 40 is connected to the output power supply.

[0032] like Figure 5 As shown, the switching time setting circuit 10 includes: a first resistor R1, a second resistor R2 and a first capacitor C1; the first end of the first resistor R1 is connected to the main power supply, and the second end of the first resistor R1 is connected to the first end of the second resistor R2 and the first end of the first capacitor C1 respectively; the first end of the first capacitor C1 is connected to the second end of the first resistor R1 and the switch control circuit 20 respectively; the second end of the first capacitor C1 is grounded; and the second end of the second resistor R2 is grounded.

[0033] Specifically, the switching time setting circuit 10 is mainly composed of an RC delay circuit determined by the first capacitor C1. When the auxiliary power supply is powered and the main power supply is turned on, when the Vout current demand is small, the first resistor R1 and the second resistor R2 are used to divide the output voltage to enable the CTRL signal, and the capacitance of the first capacitor C1 is adjusted to change the delay generated by the CTRL signal, thereby setting the time point for active power switching (after the main power supply is turned on and before the high current moment). This delay time can be changed by adjusting the resistance and capacitance values in the circuit to adapt to different application scenarios and the current demand of the output power supply Vout.

[0034] like Figure 5 As shown, the switch control circuit 20 includes: a second capacitor C2, a third resistor R3, a fourth resistor R4 and an inverting amplifier; the inverting input terminal of the inverting amplifier is connected to the switching time setting circuit 10; the power input terminal of the inverting amplifier is connected to the main power supply; the ground terminal of the inverting amplifier is grounded; the signal output terminal of the inverting amplifier is connected to the first terminal of the second capacitor C2; the second terminal of the second capacitor C2 is respectively connected to the first terminal of the fourth resistor R4 and the power switch MOS circuit 30; the second terminal of the fourth resistor R4 is grounded; the first terminal of the third resistor R3 is respectively connected to the auxiliary power supply and the power switch MOS circuit 30; and the second terminal of the third resistor R3 is connected to the first terminal of the fourth resistor R4.

[0035] like Figure 5 As shown, the switch control circuit 20 also includes a discharge circuit, which includes: a third diode D3 and a seventh resistor R7; the anode of the third diode D3 is connected to the first end of the seventh resistor R7; the cathode of the third diode D3 is connected to the first end of the second capacitor C2; and the second end of the second capacitor C2 is connected to the second end of the seventh resistor R7.

[0036] Specifically, when the switching time setting circuit 10 issues a CTRL signal, the CTRL signal is fed into the inverting input of the inverting amplifier. The inverting amplifier amplifies and inverts the signal, outputting a low level (point A). At this point, the voltage divided by the third resistor R3 and the seventh resistor R7 is grounded at point A, and the second capacitor C2 begins to charge from 0 to the divided voltage level. The voltage at point G is briefly lowered, thereby controlling the MOS transistor in the power MOS switch circuit to be temporarily turned off, thereby briefly cutting off the auxiliary power supply. By adjusting the second capacitor C2, the duration of the switch from the auxiliary power supply to the main power supply can be precisely controlled, ensuring relatively stable voltage and current changes during the power switching process, avoiding sudden power interruptions or voltage fluctuations, and thus protecting sensitive components and load devices in the circuit. On the other hand, if the auxiliary power supply is immediately switched on after the main power supply is turned on, the instantaneous high current of the main power supply may cause a shock, causing damage to the circuit. By adjusting the duration of the auxiliary power supply cutoff set by the second capacitor C2, the switch can be performed after the main power supply stabilizes, thereby avoiding this instantaneous high current shock.

[0037] Furthermore, in order to enable the circuit to be cycled between shutdown and startup, a seventh resistor R7 and a third diode D3 are added as a discharge circuit, which can facilitate recharging of the second capacitor C2 when the circuit is powered on next time.

[0038] like Figure 5As shown, the power MOS switch circuit includes: a fifth resistor R5, a sixth resistor R6, an NMOS transistor and a PMOS transistor; the gate of the NMOS transistor is connected to the switch control circuit 20; the source of the NMOS transistor is grounded; the drain of the NMOS transistor is connected to the second end of the sixth resistor R6; the first end of the sixth resistor R6 is respectively connected to the second end of the fifth resistor R5 and the gate of the PMOS transistor; the first end of the fifth resistor R5 is respectively connected to the auxiliary power supply and the source of the PMOS transistor; and the drain of the PMOS transistor is connected to the dual diode circuit.

[0039] Specifically, in the initial state, when the switch control circuit 20 does not issue a control signal, the gate of the NMOS transistor is at a low level, and the NMOS transistor is turned off. At this time, the auxiliary power supply provides a voltage to the gate of the PMOS transistor through the fifth resistor R5, turning on the PMOS transistor. The turned-on PMOS transistor transmits the voltage of the auxiliary power supply to the dual-diode circuit 40, providing power to the circuit. When the switch is in operation, the switch control circuit 20 issues a low-level control signal for a predetermined time. Since the gate voltage of the NMOS transistor is low, the NMOS transistor is turned off. At the same time, the gate voltage of the PMOS transistor is also low (due to the voltage divider effect of the fifth resistor R5 and the sixth resistor R6), and the PMOS transistor is also in the off state. At this time, the circuit is in the disconnected state, and no current flows, that is, the auxiliary power supply is disconnected.

[0040] like Figure 5 As shown, the dual diode circuit 40 includes an auxiliary power supply circuit 401 , a main power supply circuit 402 and an output circuit 403 . The auxiliary power supply circuit 401 is connected to the main power supply circuit 402 and coupled to the output circuit 403 .

[0041] Specifically, the auxiliary power supply circuit 401 provides a stable auxiliary power supply for the entire circuit system, ensuring that the circuit can obtain the required electrical energy in various stages such as startup, operation and protection; the main power supply circuit 402 provides the main power for the main circuit, ensuring that the circuit can operate stably under normal working conditions; the output circuit 403 converts the electrical energy provided by the main power supply circuit 402 and the auxiliary power supply circuit 401 into a form suitable for use by the load, such as DC voltage, AC voltage or pulse voltage of a specific frequency.

[0042] like Figure 5 As shown, the auxiliary power supply circuit 401 includes: a third capacitor C3, a fourth capacitor C4 and a first diode D1; the first end of the third capacitor C3 is respectively connected to the power switch MOS circuit 30 and the anode of the first diode D1; the second end of the third capacitor C3 is grounded; the first end of the fourth capacitor C4 is respectively connected to the first end of the third capacitor C3 and the first end of the first diode D1; the second end of the fourth capacitor C4 is grounded; and the cathode of the first diode D1 is connected to the main power supply circuit 402.

[0043] Specifically, the third capacitor C3 and the fourth capacitor C4 are used in parallel to more effectively smooth and filter the output voltage of the auxiliary power supply, reduce voltage fluctuations and ripples, and the first diode D1 ensures that current can only flow from the auxiliary power supply to the output circuit 403, preventing circuit damage that may be caused by reverse current; the auxiliary power supply is used to keep some circuits working normally when the system enters the shutdown or sleep state, so as to respond to the power-on and exit sleep actions at any time.

[0044] like Figure 5 As shown, the main power supply circuit 402 includes: a fifth capacitor C5, a sixth capacitor C6 and a second diode D2; the first end of the fifth capacitor C5 is respectively connected to the main power supply and the anode of the second diode D2; the second end of the fifth capacitor C5 is grounded; the first end of the sixth capacitor C6 is respectively connected to the first end of the fifth capacitor C5 and the anode of the second diode D2; the second end of the sixth capacitor C6 is grounded; and the cathode of the second diode D2 is connected to the auxiliary power supply circuit 401.

[0045] Specifically, the fifth capacitor C5 and the sixth capacitor C6 are connected in parallel to the main power line to filter and stabilize the voltage. They can smooth out ripple and noise in the main power supply and provide a more stable DC voltage to the subsequent circuit. The second diode D2 is used as a protection diode or isolation diode. If there is a voltage difference between the main power supply and the auxiliary power supply, the second diode D2 can prevent current from flowing back from the auxiliary power supply to the main power supply, thereby protecting the circuit from damage. At the same time, when the main power supply is unavailable, the second diode D2 can prevent the residual voltage on the main power supply line from affecting the normal operation of the auxiliary power supply.

[0046] like Figure 5 As shown, the output circuit 403 includes: a seventh capacitor C7 and an eighth capacitor C8; the first end of the seventh capacitor C7 is respectively connected to the auxiliary power supply circuit 401, the main power supply circuit 402, and the output power supply; the second end of the seventh capacitor C7 is grounded; the first end of the eighth capacitor C8 is respectively connected to the first end of the seventh capacitor C7 and the output power supply; and the second end of the eighth capacitor C8 is grounded.

[0047] Specifically, the seventh capacitor C7 and the eighth capacitor C8 are connected in parallel to the output power line, mainly playing the role of filtering and stabilizing the output voltage. They can smooth out the ripple and noise in the output power supply and provide a more stable DC voltage to the load circuit. At the same time, since the seventh capacitor C7 is connected to the outputs of multiple power supplies or circuits, it also plays a role in voltage merging and balancing, ensuring that the output voltages of different power supplies or circuits can be stably merged together and output to the load.

[0048] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and such modifications or substitutions should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A dual-power supply circuit that actively cuts off the auxiliary power supply, characterized in that: include: A switching time setting circuit, a switch control circuit, a power switch MOS circuit, and a dual diode circuit are connected in sequence; the switching time setting circuit is used to adjust the switching time point of the switch MOS, the switch control circuit is used to process the logic conversion from the main power supply being powered on to the switch MOS, the power switch MOS circuit is used to open or close the path of the auxiliary power supply, and the dual diode circuit is used to merge two power supplies into one power output.

2. The dual-power supply circuit for actively cutting off the auxiliary power supply according to claim 1, characterized in that: A first end of the power switch MOS circuit is connected to the auxiliary power supply, a first end of the switch time setting circuit is connected to the main power supply, a second end of the switch time setting circuit is connected to the first end of the switch control circuit, a second end of the switch control circuit is connected to the second end of the power switch MOS circuit, a third end of the power switch MOS circuit is connected to the first end of the dual diode circuit, a second end of the dual diode circuit is connected to the main power supply, and a third end of the dual diode circuit is connected to the output power supply.

3. The dual-power supply circuit for actively cutting off the auxiliary power supply according to claim 1, characterized in that: The switch time setting circuit includes: a first resistor, a second resistor and a first capacitor; The first end of the first resistor is connected to the main power supply, and the second end of the first resistor is connected to the first end of the second resistor and the first end of the first capacitor respectively; The first end of the first capacitor is connected to the second end of the first resistor and the switch control circuit respectively; The second end of the first capacitor is grounded; A second end of the second resistor is grounded.

4. The dual-power supply circuit for actively cutting off the auxiliary power supply according to claim 1, characterized in that: The switch control circuit includes: a second capacitor, a third resistor, a fourth resistor and an inverting amplifier; The inverting input terminal of the inverting amplifier is connected to the switching time setting circuit; The power input terminal of the inverting amplifier is connected to the main power supply; The ground terminal of the inverting amplifier is grounded; The signal output terminal of the inverting amplifier is connected to the first terminal of the second capacitor; The second end of the second capacitor is connected to the first end of the fourth resistor and the power switch MOS circuit respectively; The second end of the fourth resistor is grounded; The first end of the third resistor is connected to the auxiliary power supply and the power switch MOS circuit respectively; The second end of the third resistor is connected to the first end of the fourth resistor.

5. The dual-power supply circuit for actively cutting off the auxiliary power supply according to claim 4, characterized in that: The switch control circuit further includes a discharge circuit, and the discharge circuit includes: a third diode and a seventh resistor; The anode of the third diode is connected to the first end of the seventh resistor; The cathode of the third diode is connected to the first end of the second capacitor; The second end of the second capacitor is connected to the second end of the seventh resistor.

6. The dual-power supply circuit for actively cutting off the auxiliary power supply according to claim 1, characterized in that: The power switch MOS circuit includes: a fifth resistor, a sixth resistor, an NMOS transistor and a PMOS transistor; The gate of the NMOS tube is connected to the switch control circuit; The source of the NMOS tube is grounded; The drain of the NMOS tube is connected to the second end of the sixth resistor; The first end of the sixth resistor is connected to the second end of the fifth resistor and the gate of the PMOS transistor respectively; The first end of the fifth resistor is connected to the auxiliary power supply and the source of the PMOS transistor respectively; The drain of the PMOS tube is connected to the dual diode circuit.

7. The dual-power supply circuit for actively cutting off the auxiliary power supply according to claim 1, characterized in that: The dual-diode circuit includes an auxiliary power supply circuit, a main power supply circuit, and an output circuit. The auxiliary power supply circuit is connected to the main power supply circuit and coupled to the output circuit.

8. The dual-power supply circuit for actively cutting off the auxiliary power supply according to claim 7, characterized in that: The auxiliary power supply circuit includes: a third capacitor, a fourth capacitor and a first diode; The first end of the third capacitor is connected to the power switch MOS circuit and the anode of the first diode respectively; The second end of the third capacitor is grounded; The first end of the fourth capacitor is connected to the first end of the third capacitor and the first end of the first diode respectively; The second end of the fourth capacitor is grounded; The cathode of the first diode is connected to the main power supply circuit.

9. The dual-power supply circuit for actively cutting off the auxiliary power supply according to claim 7, characterized in that: The main power supply circuit includes: a fifth capacitor, a sixth capacitor and a second diode; The first end of the fifth capacitor is connected to the main power supply and the anode of the second diode respectively; The second end of the fifth capacitor is grounded; The first end of the sixth capacitor is connected to the first end of the fifth capacitor and the anode of the second diode respectively; The second end of the sixth capacitor is grounded; The cathode of the second diode is connected to the auxiliary power supply circuit.

10. The dual-power supply circuit for actively cutting off the auxiliary power supply according to claim 7, characterized in that: The output circuit includes: a seventh capacitor and an eighth capacitor; The first end of the seventh capacitor is connected to the auxiliary power supply circuit, the main power supply circuit, and the output power supply respectively; The second end of the seventh capacitor is grounded; The first end of the eighth capacitor is connected to the first end of the seventh capacitor and the output power supply respectively; the second end of the eighth capacitor is grounded.

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