CN115912603A - Power switching circuit and electrical equipment - Google Patents

Abstract

The utility model relates to a power supply switching circuit and consumer, be provided with switch circuit and drive circuit, drive circuit connects external power supply, and be connected to power supply circuit and energy storage power supply circuit through switch circuit, can distinguish the external power supply of multiple different voltage through drive circuit, and when the voltage of the external power supply who inserts reduced to corresponding preset voltage threshold, export switching control signal to switch circuit, so that in time switch on energy storage power supply circuit under switch circuit's control, and cut off power supply circuit, direct switch over is supplied power for the load with energy storage device. Through the scheme, when the voltage of the external power supply is reduced to the corresponding preset voltage threshold value, the power supply can be switched to the energy storage device to supply power for the load in time, the external power supply is not required to be excessively waited for power failure, the influence of the large electrolytic capacitor output by the external power supply on power supply switching is avoided, and the timeliness of power supply switching is ensured when the power utilization equipment is disconnected and charged.

Description

Power switching circuit and electrical equipment

technical field

The present application relates to the field of power supply technology, in particular to a power switching circuit and electrical equipment.

Background technique

With the development of science and technology and the continuous improvement of people's living standards, portable electrical equipment equipped with power modules is more and more widely used in people's daily life, which brings great convenience to people's daily life. This type of electrical equipment can supply power to the load of the electrical equipment through the power module when there is no external power supply connected, and when the external power supply is connected, it can supply power to the load through the external power supply and charge the power module at the same time.

However, the adapter used for external power supply has a large electrolytic capacitor, and cannot be powered off in time when charging is disconnected, resulting in the power module not being able to switch to supply power to the load in time.

Contents of the invention

Based on this, it is necessary to provide a power switching circuit and an electric device to solve the problem that the power module cannot switch to supply power to the load in time when the electric device is disconnected from charging.

A power switching circuit, comprising: an energy storage power supply circuit, a power supply circuit, a switch circuit and a drive circuit, the energy storage power supply circuit is connected to the load of the electrical equipment and the energy storage device, the power supply circuit is connected to an external power supply, the The load and the energy storage power supply circuit, the switch circuit is connected to the external power supply, the power supply circuit and the energy storage power supply circuit, and the drive circuit is connected to the external power supply and the switch circuit; The driving circuit is used to distinguish external power supplies of different voltages, and when the voltage of the external power supply drops to a corresponding preset voltage threshold, output a switching control signal to the switching circuit; signal to control the conduction of the energy storage power supply circuit to communicate with the load and the energy storage device, and to control the shutdown of the power supply circuit to disconnect the connection between the external power supply and the load.

The above-mentioned power switching circuit is provided with a switching circuit and a driving circuit. The driving circuit is connected to an external power supply, and is connected to the power supply circuit and the energy storage power supply circuit through the switching circuit. The driving circuit can distinguish a variety of external power supplies with different voltages. When the voltage of the connected external power supply drops to the corresponding preset voltage threshold, a switching control signal is output to the switching circuit, so that under the control of the switching circuit, the energy storage power supply circuit is turned on in time, and the power supply circuit is cut off, directly switching to The energy storage device is used as the load for power supply. Through this solution, only when the voltage of the external power supply drops to the corresponding preset voltage threshold, it can switch to the energy storage device as the power supply for the load in time, without waiting too much for the external power supply to be powered off, and avoiding the impact of the large electrolytic capacitor output by the external power supply The impact of power switching ensures the timeliness of power switching when the electrical equipment is disconnected for charging.

In one of the embodiments, the driving circuit includes a first voltage driving circuit and a second voltage driving circuit, the first voltage driving circuit is connected to the external power supply and the switching circuit, and the second voltage driving circuit is connected to The external power supply, the first voltage drive circuit and the switch circuit.

In one of the embodiments, the first voltage driving circuit includes a switching device U1, a resistor R1, a resistor R2 and a resistor R3, the first end of the resistor R1 is connected to the external power supply and the first end of the resistor R2 , the second terminal of the resistor R1 is connected to the control terminal of the switching device U1 and the first terminal of the resistor R3, the second terminal of the resistor R3 is grounded, and the first terminal of the switching device U1 is connected to the The second end of the resistor R2, the switch circuit and the second voltage drive circuit, the second end of the switch device U1 is connected to the second end of the resistor R3.

In one of the embodiments, the second voltage drive circuit includes a first switch delay circuit and a first drive control circuit, and the first voltage drive circuit and the first drive control circuit are respectively connected to the first switch A delay circuit, the first drive control circuit is connected to the external power supply and the switch circuit.

In one of the embodiments, the first switching delay circuit includes a switch tube Q1, a switch tube Q2, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, and a capacitor C1, and the first end of the resistor R4 connected to the first voltage drive circuit, the second end of the resistor R4 is connected to the first end of the resistor R5 and the control end of the switch tube Q1, and the second end of the resistor R5 is connected to the switch tube Q1 The first end of the resistor R6 is connected to the first end of the switch tube Q1 and the first drive control circuit, and the second end of the switch tube Q1 is connected to the first end of the resistor R7 and the first end of the resistor R8, the second end of the resistor R7 is connected to the control end of the switch tube Q2, the first end of the switch tube Q2 is connected to the second end of the resistor R6 and the capacitor The first end of C1, the second end of the switch tube Q2 is connected to the second end of the resistor R8 and the second end of the capacitor C1, and the first end of the capacitor C1 is connected to the first drive control circuit , the second end of the capacitor C1 is grounded;

And/or, in one of the embodiments, the first drive control circuit includes a resistor R9, a resistor R10, a resistor R11, a resistor R12, a switch device U2 and a switch tube Q3, and the first end of the resistor R9 is connected to the The first switch delay circuit and the first end of the resistor R10, the first end of the resistor R10 is connected to an external power supply, and the second end of the resistor R9 is connected to the first end of the resistor R11 and the switching device the control terminal of U2, the second terminal of the resistor R11 is connected to the first switch delay circuit and the first terminal of the resistor R12, the second terminal of the resistor R12 is connected to the control terminal of the switch tube Q3, The first end of the resistor R12 is grounded, the first end of the switching device U2 is connected to the second end of the resistor R10 and the switching circuit, and the second end of the switching device U2 is connected to the switch tube Q3. The first terminal and the second terminal of the switch tube Q3 are grounded.

In one of the embodiments, the drive circuit further includes a third voltage drive circuit, the third voltage drive circuit is connected to the first voltage drive circuit and the second voltage drive circuit, and the third voltage drive circuit Connecting the external power supply and the switching circuit.

In one of the embodiments, the third voltage drive circuit includes a second switch delay circuit and the second drive control circuit, and the second switch delay circuit is connected to the first voltage drive circuit and the second drive control circuit. A two-voltage drive circuit, the second drive control circuit is connected to the second switch delay circuit, and the second drive control circuit is connected to the external power supply and the switch circuit.

In one of the embodiments, the second switch delay circuit includes a switch tube Q4, a switch tube Q5, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, and a capacitor C2, and the first end of the resistor R13 Connect the first voltage drive circuit and the second voltage drive circuit, the second end of the resistor R13 is connected to the first end of the resistor R14 and the control end of the switch tube Q4, the second end of the resistor R14 The two ends are connected to the first end of the switch tube Q4, the first end of the resistor R15 is connected to the first end of the switch tube Q4 and the second drive control circuit, and the second end of the switch tube Q4 is connected to The first end of the resistor R16 and the first end of the resistor R17, the second end of the resistor R16 is connected to the control end of the switch tube Q5, and the first end of the switch tube Q5 is connected to the resistor R15 The second end of the second end of the capacitor C2 and the first end of the capacitor C2, the second end of the switch tube Q5 is connected to the second end of the resistor R17 and the second end of the capacitor C2, the first end of the capacitor C2 Connecting the second drive control circuit, the second end of the capacitor C2 is grounded;

And/or, in one of the embodiments, the second drive control circuit includes a resistor R18, a resistor R19, a resistor R20, a resistor R21, a switch device U3 and a switch tube Q6, and the first end of the resistor R18 is connected to the The second switch delay circuit and the first end of the resistor R19, the first end of the resistor R19 is connected to an external power supply, and the second end of the resistor R18 is connected to the first end of the resistor R20 and the switching device the control terminal of U3, the second terminal of the resistor R20 is connected to the first terminal of the resistor R21 and the control terminal of the switch tube Q6, the second terminal of the resistor R21 is connected to the second switch delay circuit, The first end of the resistor R21 is grounded, the first end of the switching device U3 is connected to the second end of the resistor R19 and the switching circuit, and the second end of the switching device U3 is connected to the switch tube Q6. The first terminal and the second terminal of the switching tube Q6 are grounded.

In one of the embodiments, the third voltage driving circuit further includes a first isolation circuit, and the second switch delay circuit is connected to the first voltage driving circuit and the second voltage through the first isolation circuit. Drive circuit.

In one embodiment, the switch circuit includes a resistor R22, a resistor R23 and a switch tube Q7, the first end of the resistor R22 is connected to the drive circuit, and the second end of the resistor R22 is connected to the resistor R23. The first end and the control end of the switch tube Q7, the second end of the resistor R23 is connected to the external power supply, the first end of the switch tube Q7 is connected to the second end of the resistor R23 and the power supply circuit, the second end of the switching tube Q7 is connected to the power supply circuit and the energy storage power supply circuit.

In one embodiment, the power supply circuit includes a resistor R24, a resistor R25, a resistor R26, a switch tube Q8, a switch device U4, and a switch device U5, and the first end of the switch device U4 is connected to the switch circuit and the The external power supply, the second end of the switching device U4 is connected to the first end of the resistor R24 and the first end of the switching device U5, and the second end of the switching device U5 is connected to the load and the storage A power supply circuit, the second terminal of the resistor R24 is connected to the control terminal of the switching device U4, the control terminal of the switching device U5 and the first terminal of the resistor R25, and the control terminal of the switching tube Q8 passes through the The resistor R26 is connected to the switch circuit and the energy storage power supply circuit, the first end of the switch tube Q8 is connected to the second end of the resistor R25, and the second end of the switch tube Q8 is grounded.

In one of the embodiments, the energy storage power supply circuit includes a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31, a switch tube Q9, a switch tube Q10, a switch device U6 and a switch device U7, and the switch device U6 The first end of the switch device U6 is connected to the load and the power supply circuit, the second end of the switch device U6 is connected to the first end of the resistor R27 and the first end of the switch device U7, and the switch device U7 The second terminal is connected to the energy storage device and the first terminal of the resistor R28, and the second terminal of the resistor R27 is connected to the control terminal of the switching device U6, the control terminal of the switching device U7 and the resistor R29 the first end of the resistor R29, the second end of the resistor R29 is connected to the first end of the switch Q9, the second end of the switch Q9 is grounded, and the control end of the switch Q9 is connected to the first end of the resistor R30 One end, the second end of the resistor R30 is connected to the second end of the resistor R28 and the first end of the switch tube Q10, and the control terminal of the switch tube Q10 is connected to the switch circuit and the switch circuit through the resistor R31 In the power supply circuit, the second end of the switching transistor Q10 is grounded.

In one of the embodiments, the power switch circuit further includes a second isolation circuit, and the switch circuit is connected to the drive circuit through the second isolation circuit.

An electric device includes an energy storage device, a load and the above-mentioned power switching circuit.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the traditional technology. Obviously, the accompanying drawings in the following description are only the present invention For some embodiments of the application, those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic structural diagram of a power switching circuit in an embodiment of the present application;

FIG. 2 is a schematic structural diagram of a power switching circuit in another embodiment of the present application;

FIG. 3 is a schematic structural diagram of a first voltage driving circuit in an embodiment of the present application;

FIG. 4 is a schematic structural diagram of a second voltage driving circuit in an embodiment of the present application;

FIG. 5 is a schematic structural diagram of a power switching circuit in another embodiment of the present application;

6 is a schematic structural diagram of a third voltage driving circuit in an embodiment of the present application;

FIG. 7 is a schematic structural diagram of a power switching circuit in another embodiment of the present application.

Detailed ways

In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Preferred embodiments of the application are shown in the accompanying drawings. However, the present application can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the application more thorough and comprehensive.

Please refer to Fig. 1, a kind of power switching circuit, comprises: energy storage power supply circuit 20, power supply circuit 10, switch circuit 30 and drive circuit 40, energy storage power supply circuit 20 is connected with the load of electrical equipment and energy storage device, power supply The circuit 10 is connected to the external power supply VIN, the load and the energy storage power supply circuit 20, the switch circuit 30 is connected to the external power supply VIN, the power supply circuit 10 and the energy storage power supply circuit 20, and the drive circuit 40 is connected to the external power supply VIN and the switch circuit 30; the drive circuit 40 is used It is used to distinguish the external power supply VIN of different voltages, and when the voltage of the external power supply VIN drops to a corresponding preset voltage threshold, output a switch control signal to the switch circuit 30; the switch circuit 30 is used to control the energy storage power supply circuit according to the switch control signal 20 is turned on to connect the load and the energy storage device, and the control power supply circuit 10 is turned off to disconnect the connection between the external power supply VIN and the load.

Specifically, the energy storage power supply circuit 20 is a circuit that uses the energy storage device to store electric energy to supply power to the load. When the energy storage power supply circuit 20 is in the on state, the load is connected to the energy storage device, and the load is powered by the energy storage device. . The specific type of energy storage device is not unique, it can be a battery, etc., the specific is not limited; the specific type of load is not unique, combined with the different application scenarios of the power switching circuit, the load will also be different, for example, it can be a fan , motor, etc., are also not specifically limited.

The power supply circuit 10 is a circuit that uses the external power supply VIN to supply power to the load; when the power supply circuit 10 is turned on, the external power supply VIN is directly transmitted to the load to provide the load with the required power. The switch circuit 30 is a circuit that outputs a switch control signal to control the energy storage power supply circuit 20 and the power supply circuit 10 to be turned on and off. The drive circuit 40 is the circuit that drives the switch circuit 30 to operate. Under the action of the drive signal of the drive circuit 40, the switch circuit 30 can output a corresponding signal to control the energy storage power supply circuit 20 and the power supply circuit 10, one of which is in a conduction state, and the other One is in the off state to realize the switching operation of the load power supply.

In the scheme of this embodiment, the driving circuit 40 can distinguish external power supply VIN of different voltages, that is, under the voltage of the external power supply VIN of different voltages, the driving circuit 40 can analyze the voltage of the external power supply VIN to drop to the corresponding level according to the actual situation. When the preset voltage threshold is set, a switch control signal is output to the switch circuit 30 to switch the load power supply from the external power supply VIN power supply mode to the energy storage device power supply in time.

For example, when the voltage of the external power supply VIN is 12V (volts), the driving circuit 40 will output a switching control signal to the switching circuit 30 when the voltage of the driving circuit 40 drops to a corresponding preset voltage threshold (for example, 11V), and then Under the control of the switch circuit 30, the energy storage power supply circuit 20 is turned on, while the power supply circuit 10 is turned off, and the energy storage device is used to supply power to the load. And when the voltage of the external power supply VIN is 9V, the driving ionization can also output a switching control signal to the switch circuit 30 when the voltage drops to the corresponding preset voltage threshold (for example, 8V), and then under the control of the switch circuit 30, the energy storage power supply The circuit 20 is turned on, while the power supply circuit 10 is turned off, and the energy storage device is used to supply power to the load. Through this setting, the power switching circuit is suitable for a variety of different external power supply VIN scenarios. Under different external power supply VIN, when the external power supply VIN stops supplying power, it can switch to the energy storage device to supply power to the load in time, so that the power switching circuit has Wider application scenarios.

It can be understood that, in one embodiment, if the external power supply VIN is in the connected state, the voltage of the external power supply VIN will be greater than the corresponding preset voltage threshold at this time, and the drive circuit 40 will not have a switching control signal at this time, and the power supply will switch The circuit will maintain the state that the load is powered by the external power supply VIN, and at the same time, the energy storage device is charged by the external power supply VIN (the charging method is not unique, it can be realized by setting an additional charging circuit, etc., the specifics are not limited).

In another embodiment, if the power supply mode of the load is switched from the energy storage device power supply to the external load power supply, the moment the external power supply VIN is connected, the voltage of the external power supply VIN detected at the drive circuit 40 will be greater than Corresponding preset voltage threshold. At this time, the drive circuit 40 will output a control signal opposite to the switching control signal to the switch circuit 30, and finally under the action of the control signal, the energy storage power supply circuit 20 will be disconnected, the power supply circuit 10 will be turned on, and the external power supply VIN will be used as the load. Power supply, while charging the energy storage device.

The above-mentioned power supply switching circuit is provided with a switch circuit 30 and a drive circuit 40. The drive circuit 40 is connected to the external power supply VIN, and is connected to the power supply circuit 10 and the energy storage power supply circuit 20 through the switch circuit 30. Through the drive circuit 40, it is possible to distinguish a variety of different Voltage of the external power supply VIN, and when the voltage of the connected external power supply VIN drops to the corresponding preset voltage threshold, a switching control signal is output to the switch circuit 30, so that the energy storage is turned on in time under the control of the switch circuit 30 power supply circuit 20, and cut off the power supply circuit 10, directly switch to the energy storage device as the load for power supply. Through this solution, only when the voltage of the external power supply VIN drops to the corresponding preset voltage threshold, it can switch to the energy storage device as the load power supply in time, without waiting too much for the external power supply VIN to be powered down, and avoiding the large output of the external power supply VIN The influence of electrolytic capacitors on power switching ensures the timeliness of power switching when electrical equipment is disconnected for charging.

Please refer to FIG. 2, in one of the embodiments, the drive circuit 40 includes a first voltage drive circuit 41 and a second voltage drive circuit 42, the first voltage drive circuit 41 is connected to the external power supply VIN and the switch circuit 30, and the second voltage drive circuit 42 is connected to the external power supply VIN, the first voltage driving circuit 41 and the switch circuit 30 .

Specifically, the first voltage driving circuit 41 is to output to the switch circuit 30 when the voltage of the external power supply VIN is the first voltage, and if the voltage of the external power supply VIN drops below the preset voltage threshold corresponding to the first voltage. A circuit that switches control signals. The second voltage driving circuit 42 is to output a switching control signal to the switch circuit 30 when the voltage of the external power supply VIN is the second voltage, and if the voltage of the external power supply VIN drops below the preset voltage threshold corresponding to the second voltage. circuit.

The driving circuit 40 distinguishes two external power supplies VIN with different voltages, and the first voltage is greater than the second voltage as an example for explanation. When the external power supply VIN is powered by the first voltage type, if the voltage of the external power supply VIN is greater than the preset voltage threshold corresponding to the first voltage, the first voltage driving circuit 41 can output a voltage to the switch circuit 30 and the second voltage driving circuit 42. The same control signal, the second voltage driving circuit 42 generates another control signal according to the control signal, and both control signals are transmitted to the switch circuit 30, and then under the control of the switch circuit 30, the energy storage power supply circuit 20 is disconnected and the power supply circuit 20 is turned on. The power supply circuit 10 is finally powered by an external power supply VIN. If the voltage of the external power supply VIN is less than or equal to the preset voltage threshold corresponding to the first voltage, the first voltage drive circuit 41 can output another control signal to the second voltage drive circuit 42 and the switch circuit 30, and the second voltage drive circuit 42 will also generate another control signal according to the control signal, and both control signals are transmitted to the switch circuit 30, and then under the control of the switch circuit 30, the energy storage power supply circuit 20 is turned on and the power supply circuit 10 is turned off, finally through The energy storage device supplies power.

When the external power supply VIN is the second voltage type power supply, the first voltage driving circuit 41 will maintain to output a type of control signal to the second voltage driving circuit 42 and the switch circuit 30, if the voltage of the external power supply VIN is greater than the second voltage corresponding to the preset voltage threshold, then the second voltage drive circuit 42 will output the first type of control signal to the switch circuit 30. At this time, the switch circuit 30 outputs the control signal in the first voltage drive circuit 41, and the first type of control signal Under the action of the signal, the energy storage power supply circuit 20 is turned off and the power supply circuit 10 is turned on, and finally the external power supply VIN is used for power supply. If the voltage of the external power supply VIN is less than or equal to the preset voltage threshold corresponding to the second voltage, then the second voltage drive circuit 42 will output a second type of control signal to the switch circuit 30, and the switch circuit 30 is driven at the first voltage. Under the action of the output control signal of the circuit 41 and the second type of control signal, the energy storage power supply circuit 20 is turned on and the power supply circuit 10 is turned off, and finally the power is supplied by the energy storage device.

It can be understood that the magnitudes of the first voltage and the second voltage are not unique. In a more detailed embodiment, the first voltage is 12V and the second voltage is 9V. Correspondingly, in one embodiment, the preset voltage threshold corresponding to the first voltage may be set to 11V, and the preset voltage threshold corresponding to the second voltage may be set to 8V.

The above scheme, through the design of the first voltage driving circuit 41 and the second voltage driving circuit 42, enables the power switching circuit to meet the power supply switching under two different voltage external voltage sources, thus suitable for the application scenario of two external power supply VIN power supply.

Please refer to FIG. 3. In one embodiment, the first voltage driving circuit 41 includes a switching device U1, a resistor R1, a resistor R2, and a resistor R3. The first end of the resistor R1 is connected to the external power supply VIN and the first end of the resistor R2. The second terminal of the resistor R1 is connected to the control terminal of the switching device U1 and the first terminal of the resistor R3, the second terminal of the resistor R3 is grounded, and the first terminal of the switching device U1 is connected to the second terminal of the resistor R2, the switch circuit 30 and the second terminal of the resistor R3. In the voltage driving circuit 42, the second terminal of the switching device U1 is connected to the second terminal of the resistor R3.

Specifically, the resistor R1 and the resistor R3 form a voltage dividing circuit, which divides the voltage of the external power supply VIN and transmits it to the control terminal of the switching device U1, and the switching device U1 can be turned on or off under the action of the divided voltage, For ease of understanding, when the divided voltage of the switching device U1 is greater than a preset value, the switching device U1 is turned on for explanation. When the voltage of the external power supply VIN does not drop, the divided voltage obtained by dividing the first voltage can turn on the switching device U1 , and then the first voltage driving circuit 41 outputs a low-level signal to the switching circuit 30 . Under the action of the low-level signal, the switch circuit 30 controls the energy storage power supply circuit 20 to turn off, controls the power supply circuit 10 to turn on, and maintains the power supply of the external power supply VIN.

When the voltage of the external power supply VIN drops to the preset voltage threshold, the divided voltage after division is not enough to drive the switching device U1, so that the switching device U1 is turned off, and the first voltage is driven by the pull-up effect of the external power supply VIN. The circuit 41 outputs a high-level signal to the switch circuit 30 . Under the action of the high-level signal, the switch circuit 30 controls the energy storage power supply circuit 20 to turn on, controls the power supply circuit 10 to turn off, and switches to the energy storage device for power supply.

It should be noted that the specific type of the switching device U1 is not unique, as long as it is a device capable of determining the on and off states according to the magnitude of the input voltage at the control terminal. For example, in a more detailed embodiment, the switching device U1 is a controllable precision voltage regulator chip. Further, the switching device U1 can use a controllable precision voltage regulator chip with a model number of TL431.

Please refer to FIG. 4 , in one embodiment, the second voltage drive circuit 42 includes a first switch delay circuit 421 and a first drive control circuit 422, and the first voltage drive circuit 41 and the first drive control circuit 422 are respectively connected to the second A switch delay circuit 421 and a first drive control circuit 422 are connected to the external power supply VIN and the switch circuit 30 .

Specifically, in the solution of this embodiment, the second voltage drive circuit 42 specifically includes two parts: the first switch delay circuit 421 and the first drive control circuit 422, and the first switch delay circuit 421 is a drive circuit based on the first voltage. The output signal of 41 is a circuit for realizing the switch delay function. The first drive control circuit 422 is a circuit that outputs a drive control signal for the switch circuit 30 under the action of the first switch delay circuit 421 and the external power supply VIN.

In order to prevent the output of the second voltage driving circuit 42 from affecting the switch circuit 30 when the voltage of the external power supply VIN drops below the preset voltage threshold corresponding to the first voltage, the reliability of power supply mode switching is ensured. The first voltage drive circuit 41 can simultaneously output a switch control signal to the first switch delay circuit 421, and under the action of the switch control signal, the second voltage drive circuit 42 outputs a signal consistent with the first voltage drive circuit 41, Furthermore, the operation of supplying power from the external power supply VIN is maintained by the switch circuit 30 .

In the above embodiment, the first voltage drive circuit 41 outputs a high-level signal as an example for explanation. The first voltage drive circuit 41 transmits the high-level signal to the first switch delay circuit 421 at the same time. A switch delay circuit 421 delays the conduction time of the first drive control circuit 422 to ensure that the second drive control circuit also outputs a high-level signal to the switch power circuit under the pull-up effect of the first voltage.

Please refer to FIG. 4 in combination. In one embodiment, the first switch delay circuit 421 includes a switch tube Q1, a switch tube Q2, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8 and a capacitor C1, and the resistor R4 The first end is connected to the first voltage drive circuit 41, the second end of the resistor R4 is connected to the first end of the resistor R5 and the control end of the switch tube Q1, the second end of the resistor R5 is connected to the first end of the switch tube Q1, and the resistor R6 is connected to the first end of the switch tube Q1. The first end is connected to the first end of the switch tube Q1 and the first drive control circuit 422, the second end of the switch tube Q1 is connected to the first end of the resistor R7 and the first end of the resistor R8, and the second end of the resistor R7 is connected to the switch tube The control terminal of Q2, the first end of the switch tube Q2 is connected to the second end of the resistor R6 and the first end of the capacitor C1, the second end of the switch tube Q2 is connected to the second end of the resistor R8 and the second end of the capacitor C1, and the capacitor The first end of C1 is connected to the first drive control circuit 422, and the second end of the capacitor C1 is grounded;

And/or, in one of the embodiments, please refer to FIG. 4, the first drive control circuit 422 includes a resistor R9, a resistor R10, a resistor R11, a resistor R12, a switching device U2 and a switch tube Q3, the first end of the resistor R9 Connect the first switch delay circuit 421 and the first end of the resistor R10, the first end of the resistor R10 is connected to the external power supply VIN, the second end of the resistor R9 is connected to the first end of the resistor R11 and the control end of the switching device U2, the resistor R11 The second terminal of the resistor R12 is connected to the first switch delay circuit 421 and the first terminal of the resistor R12, the second terminal of the resistor R12 is connected to the control terminal of the switch tube Q3, the first terminal of the resistor R12 is grounded, and the first terminal of the switching device U2 is connected to The second end of the resistor R10 is connected to the switch circuit 30 , the second end of the switching device U2 is connected to the first end of the switching transistor Q3 , and the second end of the switching transistor Q3 is grounded.

Specifically, taking the first voltage drive circuit 41 outputting a high-level signal as a switching control signal in the above embodiment as an example, the resistor R6 and capacitor C1 form an RC circuit, and the high-level signal is transmitted through the resistor R4 and enters the first switching delay circuit 421. Specifically, by controlling the charging time of the capacitor C1, the turn-on time of the switch tube Q3 is delayed. The delay time can be set by changing the resistance value of the resistor R6 and the capacitance value of the capacitor C1, so as to ensure that the switch tube Q3 remains off within the required time. While the switch tube Q3 is in the cut-off state, the switch device U2 is in the off state, so under the pull-up effect of the external power supply VIN, the first drive control circuit 422 can output a high-level signal to the switch circuit 30 .

It can be understood that if the voltage of the external power supply VIN is the second voltage, then under the action of the second voltage, the first voltage drive circuit 41 will inevitably output a high voltage under the pull-up effect of the external power supply VIN due to the too small divided voltage. At this time, the second voltage is divided by the resistor R9 and the resistor R11, so that the second switching device U2 is turned on, and the signal output from the first driving control circuit 422 to the switching circuit 30 is pulled down to a low level. Under the action of the high-level signal output by the first voltage drive circuit 41 and the low-level signal output by the second voltage drive circuit 42, the switch circuit 30 controls the energy storage power supply circuit 20 to turn off, controls the power supply circuit 10 to turn on, The load can be powered by an external power supply VIN. However, when the voltage of the external power supply VIN drops to the preset voltage threshold corresponding to the second voltage, the divided voltage is not enough to control the conduction of the second switching device U2, and at the same time, due to the delay effect of the first switching delay circuit 421, the first The signal output from the drive control circuit 422 to the switch circuit 30 is pulled up to a high level. Finally, under the action of the high-level signal output by the first voltage drive circuit 41 and the high-level signal output by the second voltage drive circuit 42, the switch circuit 30 controls the energy storage power supply circuit 20 to turn on, and at the same time turns off the power supply circuit 10.

Please refer to FIG. 5, in one embodiment, the driving circuit 40 further includes a third voltage driving circuit 43, the third voltage driving circuit 43 is connected to the first voltage driving circuit 41 and the second voltage driving circuit 42, the third voltage driving The circuit 43 is connected to the external power supply VIN and the switch circuit 30 .

Specifically, the third voltage driving circuit 43 is to output to the switch circuit 30 when the voltage of the external power supply VIN is the third voltage, and if the voltage of the external power supply VIN drops below the preset voltage threshold corresponding to the third voltage. A circuit that switches control signals. In the solution of this embodiment, the voltage of the external power supply VIN can be set to three different sizes, so as to realize the switching operation of the voltage supply of the external power supply VIN with three different voltages.

When the external power supply VIN is powered by the first voltage type, if the voltage of the external power supply VIN is greater than the preset voltage threshold corresponding to the first voltage, the first voltage drive circuit 41 can provide the switch circuit 30, the second voltage drive circuit 42 and the second The three-voltage driving circuit 43 outputs the same control signal, and the second voltage driving circuit 42 and the third voltage driving circuit 43 generate two other control signals according to the control signal, and finally the three control signals are all transmitted to the switch circuit 30, and then Under the control of the switch circuit 30, the energy storage power supply circuit 20 is turned off and the power supply circuit 10 is turned on, and the external power supply VIN is used for power supply.

If the voltage of the external power supply VIN is less than or equal to the preset voltage threshold corresponding to the first voltage, the first voltage drive circuit 41 can output another control to the second voltage drive circuit 42, the third voltage drive circuit 43 and the switch circuit 30. signal, the second voltage drive circuit 42 and the third voltage drive circuit 43 will also generate another control signal according to the control signal, and the three control signals are all transmitted to the switch circuit 30, and then under the control of the switch circuit 30, the conduction The energy storage power supply circuit 20 disconnects the power supply circuit 10 and supplies power through the energy storage device.

When the external power supply VIN is powered by the second voltage type and the third voltage type, under the action of each control signal output to the switch circuit 30, the switch circuit 30 turns on the energy storage power supply circuit 20 and the power supply circuit 10 respectively, In this way, switching between different power supply modes can be realized, and the specific mode is similar to that of the above-mentioned embodiment, and will not be repeated here.

It can be understood that in the solutions of other embodiments, the drive circuit 40 may also include a fourth voltage drive circuit 40, a fifth voltage drive circuit 40, etc., so as to realize the switching of four, five or even more external power supplies VIN with different voltages. The implementation of the control is similar to that of the above-mentioned three external power supplies VIN with different voltages, and will not be repeated here.

It should be noted that the magnitude of the third voltage is not unique, and in a more detailed embodiment, the third voltage is 5V. Correspondingly, in one embodiment, the preset voltage threshold corresponding to the third voltage is 4V.

Please refer to FIG. 6 , in one embodiment, the third voltage drive circuit 43 includes a second switch delay circuit 431 and a second drive control circuit 432, and the second switch delay circuit 431 is connected to the first voltage drive circuit 41 and the second drive control circuit 432. The two-voltage drive circuit 42 , the second drive control circuit 432 is connected to the second switch delay circuit 431 , and the second drive control circuit 432 is connected to the external power supply VIN and the switch circuit 30 .

Specifically, the third voltage drive circuit 43 is similar to the above-mentioned second voltage drive circuit 42, and both include a switch delay circuit and a drive control circuit. The second switch delay circuit 431 is based on the first voltage drive circuit 41 and the second drive control circuit. The output signal of the two-voltage driving circuit 42 is a circuit for realizing the switch delay function. The second drive control circuit 432 is a circuit that outputs a drive control signal for the switch circuit 30 under the action of the second switch delay circuit 431 and the external power supply VIN.

Similarly, through the solution of this embodiment, it can be avoided that when the voltage of the external power supply VIN drops below the preset voltage threshold corresponding to the first voltage, or below the preset voltage threshold corresponding to the second voltage, the third voltage drive circuit 43 The output of the switch circuit 30 will affect the reliability of switching the power supply mode.

Please refer to FIG. 6. In one embodiment, the second switch delay circuit 431 includes a switch tube Q4, a switch tube Q5, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, and a capacitor C2. The first switch of the resistor R13 One end is connected to the first voltage drive circuit 41 and the second voltage drive circuit 42, the second end of the resistor R13 is connected to the first end of the resistor R14 and the control end of the switch tube Q4, and the second end of the resistor R14 is connected to the second end of the switch tube Q4 One end, the first end of the resistor R15 is connected to the first end of the switch tube Q4 and the second drive control circuit 432, the second end of the switch tube Q4 is connected to the first end of the resistor R16 and the first end of the resistor R17, the resistor R16 The second end is connected to the control end of the switch tube Q5, the first end of the switch tube Q5 is connected to the second end of the resistor R15 and the first end of the capacitor C2, and the second end of the switch tube Q5 is connected to the second end of the resistor R17 and the capacitor C2 the second end of the capacitor C2, the first end of the capacitor C2 is connected to the second drive control circuit 432, and the second end of the capacitor C2 is grounded;

And/or, in one of the embodiments, the second drive control circuit 432 includes a resistor R18, a resistor R19, a resistor R20, a resistor R21, a switch device U3 and a switch tube Q6, and the first end of the resistor R18 is connected to the second switch delay The circuit 431 and the first terminal of the resistor R19, the first terminal of the resistor R19 is connected to the external power supply VIN, the second terminal of the resistor R18 is connected to the first terminal of the resistor R20 and the control terminal of the switching device U3, and the second terminal of the resistor R20 is connected to the resistor The first end of R21 and the control end of the switch tube Q6, the second end of the resistor R21 is connected to the second switch delay circuit 431, the first end of the resistor R21 is grounded, and the first end of the switching device U3 is connected to the second end of the resistor R19 And the switch circuit 30, the second terminal of the switching device U3 is connected to the first terminal of the switching transistor Q6, and the second terminal of the switching transistor Q6 is grounded.

Specifically, the specific structure of the third voltage driving circuit 43 is similar to that of the second voltage driving circuit 42. Taking the external power supply VIN as an example of a power supply of the third voltage type, in the actual operation process, if the voltage of the external power supply VIN greater than the preset voltage threshold corresponding to the third voltage, both the first voltage drive circuit 41 and the second voltage drive circuit 42 will be pulled up to output a high level, and the second drive control circuit 432 will be driven by the resistor R18 and the resistor R20 The divided voltage is greater than the set value, and the switch device U3 is in the conduction state. At this time, the signal output from the second drive control circuit 432 to the switch circuit 30 is a low-level signal. That is to say, at this time, the switch circuit 30 receives the high-level signal output by the first voltage driving circuit 41, the high-level signal output by the second voltage driving circuit 42, and the low-level signal output by the third voltage driving circuit 43, and finally expresses Because the switch circuit 30 receives the low-level signal, the switch circuit 30 will control the power supply circuit 10 to be turned on, the energy storage power supply circuit 20 is turned off, and the external power supply VIN is used to supply power to the load.

If the voltage of the external power supply VIN is less than or equal to the preset voltage threshold corresponding to the third voltage, both the first voltage driving circuit 41 and the second voltage driving circuit 42 will be pulled up to output a high level, and the second driving control circuit 432 Then, because the divided voltage of the resistor R18 and the resistor R20 is less than or equal to the set value, the switch device U3 is in the off state, and the signal output from the second drive control circuit 432 to the switch circuit 30 is a high level signal. That is, at this time, the switch circuit 30 receives the high-level signal output by the first voltage driving circuit 41, the high-level signal output by the second voltage driving circuit 42, and the high-level signal output by the third voltage driving circuit 43, and finally expresses Because the switch circuit 30 receives the high-level signal, the switch circuit 30 will control the power supply circuit 10 to turn off, and the energy storage power supply circuit 20 to turn on, so that the energy storage device supplies power to the load.

Please refer to FIG. 6. In one embodiment, the third voltage drive circuit 43 further includes a first isolation circuit 433, and the second switch delay circuit 431 is connected to the first voltage drive circuit 41 and the second voltage through the first isolation circuit 433. drive circuit 42 .

Specifically, in the solution of this embodiment, an isolation circuit is also provided between the second switch delay circuit 431 and the first voltage drive circuit 41 and the second voltage drive circuit 42, and the isolation circuit is electrically isolated to avoid the third voltage The driving circuit 43 interferes with the first voltage driving circuit 41 and the second voltage driving circuit 42 .

It should be noted that the specific type of the first isolation circuit 433 is not exclusive. In a comparative embodiment, please refer to FIG. 6, the first isolation circuit 433 includes a diode D1 and a diode D2, the anode of the diode D1 and The anodes are respectively connected to the second switching delay circuit 431 , the cathode of the diode D1 is connected to the first voltage driving circuit 41 , and the cathode of the diode D2 is connected to the second voltage driving circuit 42 .

Please refer to FIG. 7. In one embodiment, the switch circuit 30 includes a resistor R22, a resistor R23 and a switch tube Q7. The first end of the resistor R22 is connected to the drive circuit 40, and the second end of the resistor R22 is connected to the first end of the resistor R23. and the control terminal of the switch tube Q7, the second end of the resistor R23 is connected to the external power supply VIN, the first end of the switch tube Q7 is connected to the second end of the resistor R23 and the power supply circuit 10, and the second end of the switch tube Q7 is connected to the power supply circuit 10 and energy storage power supply circuit 20.

Specifically, in the solution of this embodiment, the switch circuit 30 includes a switch tube Q7, a resistor R22, and a resistor R23. Under the action of the switching control signal output by the drive circuit 40, the switch tube Q7 is turned off, thereby controlling the power supply circuit 10 to turn off, Control the conduction of the energy storage power supply circuit 20 to realize the switching of the power supply mode from the external power supply VIN to the energy storage device. When the switching control signal is not received, the switching device Q7 is turned on, and then the power supply circuit 10 is controlled to be turned on, and the energy storage power supply circuit 20 is controlled to be turned off, so as to realize power supply by the external power supply VIN.

In a more detailed embodiment, the switching control signal is a high-level signal. When each voltage drive circuit 40 outputs a high-level signal, the switch circuit 30 will control the energy storage power supply circuit 20 to conduct to connect The load, the energy storage device, and the control power supply circuit 10 are turned off to disconnect the external power supply VIN from the load. Conversely, when any one of the voltage drive circuits 40 outputs a low-level signal, it will cause the switch circuit 30 to receive a low-level signal. At this time, the energy storage power supply circuit 20 will be controlled to turn off, and the power supply circuit 10 will be controlled to turn on. Pass.

It can be understood that the specific structure of the power supply circuit 10 is not unique. Please refer to FIG. Device U5, the first end of the switching device U4 is connected to the switching circuit 30 and the external power supply VIN, the second end of the switching device U4 is connected to the first end of the resistor R24 and the first end of the switching device U5, and the second end of the switching device U5 is connected to The load and energy storage power supply circuit 20, the second end of the resistor R24 is connected to the control end of the switching device U4, the control end of the switching device U5 and the first end of the resistor R25, and the control end of the switching tube Q8 is connected to the switching circuit 30 and the In the energy storage and power supply circuit 20, the first end of the switch tube Q8 is connected to the second end of the resistor R25, and the second end of the switch tube Q8 is grounded.

Specifically, under the action of the switching control signal output by the drive circuit 40, when the switching tube Q7 is turned off, the switching tube Q8 in the power supply circuit 10 is in the off state, and the switching device U4 and the switching device U5 are in the off state. Disconnect the connection between the external power supply VIN and the load, and stop the external power supply VIN from supplying power.

Referring to Fig. 7, in one of the embodiments, the energy storage power supply circuit 20 includes a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31, a switch tube Q9, a switch tube Q10, a switch device U6 and a switch device U7, the switch The first end of the device U6 is connected to the load and the power supply circuit 10, the second end of the switching device U6 is connected to the first end of the resistor R27 and the first end of the switching device U7, and the second end of the switching device U7 is connected to the energy storage device and the resistor The first terminal of R28, the second terminal of resistor R27 are connected to the control terminal of switching device U6, the control terminal of switching device U7 and the first terminal of resistor R29, the second terminal of resistor R29 is connected to the first terminal of switching tube Q9, the switch The second end of the tube Q9 is grounded, the control end of the switch tube Q9 is connected to the first end of the resistor R30, the second end of the resistor R30 is connected to the second end of the resistor R28 and the first end of the switch tube Q10, and the control end of the switch tube Q10 The switch circuit 30 is connected to the power supply circuit 10 through a resistor R31, and the second end of the switch tube Q10 is grounded.

Specifically, under the action of the switching control signal output by the drive circuit 40, when the switch tube Q7 is turned off, the switch tube Q10 in the energy storage power supply circuit 20 is in the off state, and the switch tube Q9 is in the on state, so that the switch device U6 and the switch The device U7 is turned on, correspondingly turning on the connection between the energy storage device and the load at this time, and entering the power supply state of the energy storage device.

Please refer to FIG. 7 , in one embodiment, the power switch circuit further includes a second isolation circuit 50 , and the switch circuit 30 is connected to the drive circuit 40 through the second isolation circuit 50 .

Specifically, in the solution of this embodiment, an isolation circuit is further provided between the switch circuit 30 and the drive circuit 40 , and the isolation circuit is used for electrical isolation to avoid mutual interference between the drive circuit 40 and the switch circuit 30 . It should be noted that the specific type of the second isolation circuit 50 is not exclusive. In a comparative embodiment, please refer to FIG. The anode of the diode D4 and the anode of the diode D5 are respectively connected to the switch circuit 30, the cathode of the diode D3 is connected to the first voltage driving circuit 41, the cathode of the diode D4 is connected to the second voltage driving circuit 42, and the cathode of the diode D5 is connected to the third voltage driving circuit 43 .

In order to facilitate the understanding of the technical solutions of the present application, the present application will be explained below in conjunction with the detailed circuit structure.

Take the external power supply VIN as an example of a 12V voltage type power supply. When the external power supply VIN is not powered off, that is, when the power adapter is not unplugged, the voltage of the external power supply VIN is greater than the corresponding preset voltage threshold (11V). At this time, at point a After the resistor R1 and the resistor R3 divide the voltage, the obtained voltage value is greater than the conduction voltage (2.5V) of the switch device U1, and the switch device U1 is in the conduction state at this time, and the ON1 terminal of the first voltage driving circuit 41 outputs to the second The signals of the voltage driving circuit 42 , the third voltage driving circuit 43 and the switch circuit 30 are low level signals. At this time, the divided voltages at points b and c are greater than the corresponding preset voltage thresholds, the switching device U2 and the switching device U3 are turned on, and the second voltage driving circuit 42 is activated by the low-level signal received by the switching tube Q1. is turned on, and the switch tube Q3 is turned off, at this moment, the second voltage drive circuit 42 is pulled up to output a high level to the third drive circuit 40 and the switch circuit 30 . Under the influence of the third drive circuit 40 receiving the high and low levels, the switch tube Q4 is turned on, and the switch tube Q6 is turned off. At this time, the third voltage drive circuit 43 is pulled up to output a high level to the switch circuit 30 . Finally, under the action of the high and low levels received by the switching circuit 30, the switching tube Q7 is turned on, the switching tube Q8 in the power supply circuit 10 is in the conducting state, the switching device U4 and the switching device U5 are in the conducting state, and the corresponding At this moment, the connection between the external power supply VIN and the load is realized to realize power supply from the external power supply VIN. In the energy storage power supply circuit 20, the switching tube Q10 is in the on state, and the switching tube Q9 is in the off state, so that the switching device U6 and the switching device U7 are disconnected, and correspondingly the connection between the energy storage device and the load is disconnected at this time.

When the external power supply VIN is powered off, that is, when the power adapter is unplugged, the voltage of the external power supply VIN gradually decreases until it is less than the corresponding preset voltage threshold (11V). At this time, after the resistor R1 and the resistor R3 divide the voltage at point a, the obtained voltage value is less than the conduction voltage (2.5V) of the switching device U1. The signals output from the terminal to the second voltage driving circuit 42 , the third voltage driving circuit 43 and the switch circuit 30 are high level signals. Under the action of the received high-level signal, the second voltage drive circuit 42 makes the switch tube Q3 in the cut-off state through the switch delay function, and the switch device U2 is in the off state. Therefore, under the pull-up effect of the external power supply VIN, the second The ON2 terminal of a drive control circuit 422 can output a high level signal to the switch circuit 30 and the third voltage drive circuit 43 . Under the action of the received high-level signal, the third voltage drive circuit 43 makes the switch tube Q6 in the cut-off state through the switch delay function, and the switch device U3 is in the off state, so under the pull-up effect of the external power supply VIN, the third voltage drive circuit 43 The ON3 terminal of the second drive control circuit 432 can output a high level signal to the switch circuit 30 . Finally, under the action of the high level received by the switching circuit 30, the switching tube Q7 is turned off, the switching tube Q8 in the power supply circuit 10 is in the off state, and the switching device U4 and the switching device U5 are in the off state. Correspondingly, the external The connection between the supply VIN and the load is broken. In the energy storage power supply circuit 20, the switch tube Q10 is in the off state, and the switch tube Q9 is in the on state, so that the switch device U6 and the switch device U7 are turned on, and correspondingly the connection between the energy storage device and the load is turned on at this time, realizing The energy storage device powers the operation.

When the external power supply VIN is 9V or 5V, the working principle of the power supply switching circuit is similar to that of the above 12V. Under the action of each drive circuit 40, if the external power supply VIN does not lose power, that is, the voltage of the external power supply VIN is greater than the corresponding When the voltage threshold is preset, the signals output from the three drive circuits 40 to the switch circuit 30 always have one low-level signal and two high-level signals, so as to maintain the power supply of the external power supply VIN. And when the external power supply VIN does not lose power, that is, when the voltage of the external power supply VIN is less than or equal to the corresponding preset voltage threshold, the signals output from the three drive circuits 40 to the switch circuit 30 will all be high-level signals, thereby switching The power supply for the energy storage device will not be described in detail.

An electric device includes an energy storage device, a load and the above-mentioned power switching circuit.

Specifically, the electrical equipment is specifically as shown in the foregoing embodiments and drawings, and will not be repeated here. The specific type of electrical equipment is not unique, and it may be a fan, a humidifier, etc., and is not specifically limited. The above electrical equipment is provided with a switch circuit 30 and a drive circuit 40. The drive circuit 40 is connected to the external power supply VIN, and is connected to the power supply circuit 10 and the energy storage power supply circuit 20 through the switch circuit 30. Through the drive circuit 40, it is possible to distinguish between various Voltage of the external power supply VIN, and when the voltage of the connected external power supply VIN drops to the corresponding preset voltage threshold, a switching control signal is output to the switch circuit 30, so that the energy storage is turned on in time under the control of the switch circuit 30 power supply circuit 20, and cut off the power supply circuit 10, directly switch to the energy storage device as the load for power supply. Through this solution, only when the voltage of the external power supply VIN drops to the corresponding preset voltage threshold, it can switch to the energy storage device as the load power supply in time, without waiting too much for the external power supply VIN to be powered down, and avoiding the large output of the external power supply VIN The influence of electrolytic capacitors on power switching ensures the timeliness of power switching when electrical equipment is disconnected for charging.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present application, and the description thereof is relatively specific and detailed, but should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of protection of the patent application should be based on the appended claims.

Claims (14)

1. A power switching circuit, characterized in that, comprising: Energy storage power supply circuit, connecting the load of electrical equipment and energy storage device; A power supply circuit, connected to an external power supply, the load and the energy storage power supply circuit; a switch circuit, connected to the external power supply, the power supply circuit and the energy storage power supply circuit; a drive circuit, connected to the external power supply and the switch circuit; The drive circuit is used to distinguish external power supplies of different voltages, and when the voltage of the external power supply drops to a corresponding preset voltage threshold, output a switching control signal to the switch circuit; the switch circuit is used to Switching control signals, controlling the energy storage power supply circuit to be turned on to connect the load and the energy storage device, and controlling the power supply circuit to be turned off to disconnect the external power supply from the load. 2. The power switching circuit according to claim 1, wherein the driving circuit comprises a first voltage driving circuit and a second voltage driving circuit, and the first voltage driving circuit is connected to the external power supply and the switch A circuit, the second voltage drive circuit is connected to the external power supply, the first voltage drive circuit and the switch circuit. 3. The power switching circuit according to claim 2, wherein the first voltage driving circuit comprises a switching device U1, a resistor R1, a resistor R2 and a resistor R3, and the first end of the resistor R1 is connected to the external the power supply and the first terminal of the resistor R2, the second terminal of the resistor R1 is connected to the control terminal of the switching device U1 and the first terminal of the resistor R3, the second terminal of the resistor R3 is grounded, and the A first end of the switch device U1 is connected to the second end of the resistor R2, the switch circuit and the second voltage driving circuit, and a second end of the switch device U1 is connected to the second end of the resistor R3. 4. The power switching circuit according to claim 2, wherein the second voltage drive circuit comprises a first switch delay circuit and a first drive control circuit, the first voltage drive circuit and the first The drive control circuit is respectively connected to the first switch delay circuit, and the first drive control circuit is connected to the external power supply and the switch circuit. 5. The power switching circuit according to claim 4, wherein the first switch delay circuit comprises a switch tube Q1, a switch tube Q2, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8 and a capacitor C1, the first end of the resistor R4 is connected to the first voltage drive circuit, the second end of the resistor R4 is connected to the first end of the resistor R5 and the control end of the switch tube Q1, and the resistor R5 The second end of the resistor R6 is connected to the first end of the switch tube Q1, the first end of the resistor R6 is connected to the first end of the switch tube Q1 and the first drive control circuit, and the second end of the switch tube Q1 terminal connected to the first terminal of the resistor R7 and the first terminal of the resistor R8, the second terminal of the resistor R7 is connected to the control terminal of the switching tube Q2, and the first terminal of the switching tube Q2 is connected to the The second end of the resistor R6 is connected to the first end of the capacitor C1, the second end of the switch tube Q2 is connected to the second end of the resistor R8 and the second end of the capacitor C1, and the second end of the capacitor C1 One end is connected to the first drive control circuit, and the second end of the capacitor C1 is grounded; And/or, the first drive control circuit includes a resistor R9, a resistor R10, a resistor R11, a resistor R12, a switch device U2 and a switch tube Q3, and the first end of the resistor R9 is connected to the first switch delay circuit and The first end of the resistor R10, the first end of the resistor R10 is connected to an external power supply, the second end of the resistor R9 is connected to the first end of the resistor R11 and the control end of the switching device U2, the The second end of the resistor R11 is connected to the first switch delay circuit and the first end of the resistor R12, the second end of the resistor R12 is connected to the control end of the switch tube Q3, and the first end of the resistor R12 end grounded, the first end of the switch device U2 is connected to the second end of the resistor R10 and the switch circuit, the second end of the switch device U2 is connected to the first end of the switch tube Q3, and the switch The second end of the tube Q3 is grounded. 6. The power switching circuit according to any one of claims 2-5, wherein the driving circuit further comprises a third voltage driving circuit, and the third voltage driving circuit is connected to the first voltage driving circuit and The second voltage driving circuit and the third voltage driving circuit are connected to the external power supply and the switching circuit. 7. The power switching circuit according to claim 6, wherein the third voltage drive circuit comprises a second switch delay circuit and the second drive control circuit, and the second switch delay circuit is connected to the The first voltage drive circuit and the second voltage drive circuit, the second drive control circuit is connected to the second switch delay circuit, and the second drive control circuit is connected to the external power supply and the switch circuit. 8. The power switching circuit according to claim 7, wherein the second switch delay circuit comprises a switch tube Q4, a switch tube Q5, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17 and a capacitor C2, the first end of the resistor R13 is connected to the first voltage drive circuit and the second voltage drive circuit, and the second end of the resistor R13 is connected to the first end of the resistor R14 and the switch tube Q4 the control end of the resistor R14, the second end of the resistor R14 is connected to the first end of the switch tube Q4, the first end of the resistor R15 is connected to the first end of the switch tube Q4 and the second drive control circuit, The second terminal of the switch tube Q4 is connected to the first terminal of the resistor R16 and the first terminal of the resistor R17, the second terminal of the resistor R16 is connected to the control terminal of the switch tube Q5, and the switch tube The first end of Q5 is connected to the second end of the resistor R15 and the first end of the capacitor C2, and the second end of the switching tube Q5 is connected to the second end of the resistor R17 and the second end of the capacitor C2. end, the first end of the capacitor C2 is connected to the second drive control circuit, and the second end of the capacitor C2 is grounded; And/or, the second drive control circuit includes a resistor R18, a resistor R19, a resistor R20, a resistor R21, a switch device U3 and a switch tube Q6, and the first end of the resistor R18 is connected to the second switch delay circuit and The first end of the resistor R19, the first end of the resistor R19 is connected to an external power supply, the second end of the resistor R18 is connected to the first end of the resistor R20 and the control end of the switching device U3, the The second end of the resistor R20 is connected to the first end of the resistor R21 and the control end of the switch tube Q6, the second end of the resistor R21 is connected to the second switch delay circuit, and the first end of the resistor R21 end grounded, the first end of the switch device U3 is connected to the second end of the resistor R19 and the switch circuit, the second end of the switch device U3 is connected to the first end of the switch tube Q6, and the switch The second end of the tube Q6 is grounded. 9. The power switching circuit according to claim 7, wherein the third voltage drive circuit further comprises a first isolation circuit, and the second switch delay circuit is connected to the first isolation circuit through the first isolation circuit. A voltage driving circuit and the second voltage driving circuit. 10. The power switching circuit according to any one of claims 1-5, wherein the switching circuit includes a resistor R22, a resistor R23 and a switch tube Q7, and the first end of the resistor R22 is connected to the drive circuit , the second end of the resistor R22 is connected to the first end of the resistor R23 and the control end of the switch tube Q7, the second end of the resistor R23 is connected to the external power supply, and the first end of the switch tube Q7 The end of the resistor R23 is connected to the second end of the resistor R23 and the power supply circuit, and the second end of the switch tube Q7 is connected to the power supply circuit and the energy storage power supply circuit. 11. The power switching circuit according to any one of claims 1-5, wherein the power supply circuit comprises a resistor R24, a resistor R25, a resistor R26, a switching tube Q8, a switching device U4 and a switching device U5, the The first end of the switching device U4 is connected to the switching circuit and the external power supply, the second end of the switching device U4 is connected to the first end of the resistor R24 and the first end of the switching device U5, the The second terminal of the switching device U5 is connected to the load and the energy storage power supply circuit, and the second terminal of the resistor R24 is connected to the control terminal of the switching device U4, the control terminal of the switching device U5 and the resistor R25 the first end of the switch tube Q8, the control end of the switch tube Q8 is connected to the switch circuit and the energy storage power supply circuit through the resistor R26, the first end of the switch tube Q8 is connected to the second end of the resistor R25, The second terminal of the switch tube Q8 is grounded. 12. The power switching circuit according to any one of claims 1-5, wherein the energy storage power supply circuit includes a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31, a switch tube Q9, and a switch tube Q10, a switching device U6 and a switching device U7, the first end of the switching device U6 is connected to the load and the power supply circuit, the second end of the switching device U6 is connected to the first end of the resistor R27 and the The first end of the switching device U7, the second end of the switching device U7 is connected to the energy storage device and the first end of the resistor R28, and the second end of the resistor R27 is connected to the control of the switching device U6 end, the control end of the switch device U7 and the first end of the resistor R29, the second end of the resistor R29 is connected to the first end of the switch tube Q9, the second end of the switch tube Q9 is grounded, The control end of the switch tube Q9 is connected to the first end of the resistor R30, the second end of the resistor R30 is connected to the second end of the resistor R28 and the first end of the switch tube Q10, and the switch tube The control terminal of Q10 is connected to the switch circuit and the power supply circuit through the resistor R31, and the second terminal of the switch tube Q10 is grounded. 13. The power switching circuit according to any one of claims 1-5, wherein the power switching circuit further comprises a second isolation circuit, and the switching circuit is connected to the drive circuit through the second isolation circuit . 14. An electrical device, characterized by comprising an energy storage device, a load, and the power switching circuit according to any one of claims 1-13.

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